diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 59f881f367793..ad67b848d04ee 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4355,6 +4355,12 @@ fully seed the kernel's CRNG. Default is controlled by CONFIG_RANDOM_TRUST_CPU. + random.trust_bootloader={on,off} + [KNL] Enable or disable trusting the use of a + seed passed by the bootloader (if available) to + fully seed the kernel's CRNG. Default is controlled + by CONFIG_RANDOM_TRUST_BOOTLOADER. + randomize_kstack_offset= [KNL] Enable or disable kernel stack offset randomization, which provides roughly 5 bits of diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 0f86e9f931293..264735c5d0bda 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -1025,28 +1025,22 @@ This is a directory, with the following entries: * ``boot_id``: a UUID generated the first time this is retrieved, and unvarying after that; +* ``uuid``: a UUID generated every time this is retrieved (this can + thus be used to generate UUIDs at will); + * ``entropy_avail``: the pool's entropy count, in bits; * ``poolsize``: the entropy pool size, in bits; * ``urandom_min_reseed_secs``: obsolete (used to determine the minimum - number of seconds between urandom pool reseeding). - -* ``uuid``: a UUID generated every time this is retrieved (this can - thus be used to generate UUIDs at will); + number of seconds between urandom pool reseeding). This file is + writable for compatibility purposes, but writing to it has no effect + on any RNG behavior; * ``write_wakeup_threshold``: when the entropy count drops below this (as a number of bits), processes waiting to write to ``/dev/random`` - are woken up. - -If ``drivers/char/random.c`` is built with ``ADD_INTERRUPT_BENCH`` -defined, these additional entries are present: - -* ``add_interrupt_avg_cycles``: the average number of cycles between - interrupts used to feed the pool; - -* ``add_interrupt_avg_deviation``: the standard deviation seen on the - number of cycles between interrupts used to feed the pool. + are woken up. This file is writable for compatibility purposes, but + writing to it has no effect on any RNG behavior. randomize_va_space diff --git a/Makefile b/Makefile index b821f270a4ca6..25c44dda0ef37 100644 --- a/Makefile +++ b/Makefile @@ -1,7 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 VERSION = 5 PATCHLEVEL = 17 -SUBLEVEL = 11 +SUBLEVEL = 12 EXTRAVERSION = NAME = Superb Owl diff --git a/arch/alpha/include/asm/timex.h b/arch/alpha/include/asm/timex.h index b565cc6f408e9..f89798da8a147 100644 --- a/arch/alpha/include/asm/timex.h +++ b/arch/alpha/include/asm/timex.h @@ -28,5 +28,6 @@ static inline cycles_t get_cycles (void) __asm__ __volatile__ ("rpcc %0" : "=r"(ret)); return ret; } +#define get_cycles get_cycles #endif diff --git a/arch/arm/include/asm/timex.h b/arch/arm/include/asm/timex.h index 7c3b3671d6c25..6d1337c169cd3 100644 --- a/arch/arm/include/asm/timex.h +++ b/arch/arm/include/asm/timex.h @@ -11,5 +11,6 @@ typedef unsigned long cycles_t; #define get_cycles() ({ cycles_t c; read_current_timer(&c) ? 0 : c; }) +#define random_get_entropy() (((unsigned long)get_cycles()) ?: random_get_entropy_fallback()) #endif diff --git a/arch/ia64/include/asm/timex.h b/arch/ia64/include/asm/timex.h index 869a3ac6bf23a..7ccc077a60bed 100644 --- a/arch/ia64/include/asm/timex.h +++ b/arch/ia64/include/asm/timex.h @@ -39,6 +39,7 @@ get_cycles (void) ret = ia64_getreg(_IA64_REG_AR_ITC); return ret; } +#define get_cycles get_cycles extern void ia64_cpu_local_tick (void); extern unsigned long long ia64_native_sched_clock (void); diff --git a/arch/m68k/include/asm/timex.h b/arch/m68k/include/asm/timex.h index 6a21d93582805..f4a7a340f4cae 100644 --- a/arch/m68k/include/asm/timex.h +++ b/arch/m68k/include/asm/timex.h @@ -35,7 +35,7 @@ static inline unsigned long random_get_entropy(void) { if (mach_random_get_entropy) return mach_random_get_entropy(); - return 0; + return random_get_entropy_fallback(); } #define random_get_entropy random_get_entropy diff --git a/arch/mips/include/asm/timex.h b/arch/mips/include/asm/timex.h index 8026baf46e729..2e107886f97ac 100644 --- a/arch/mips/include/asm/timex.h +++ b/arch/mips/include/asm/timex.h @@ -76,25 +76,24 @@ static inline cycles_t get_cycles(void) else return 0; /* no usable counter */ } +#define get_cycles get_cycles /* * Like get_cycles - but where c0_count is not available we desperately * use c0_random in an attempt to get at least a little bit of entropy. - * - * R6000 and R6000A neither have a count register nor a random register. - * That leaves no entropy source in the CPU itself. */ static inline unsigned long random_get_entropy(void) { - unsigned int prid = read_c0_prid(); - unsigned int imp = prid & PRID_IMP_MASK; + unsigned int c0_random; - if (can_use_mips_counter(prid)) + if (can_use_mips_counter(read_c0_prid())) return read_c0_count(); - else if (likely(imp != PRID_IMP_R6000 && imp != PRID_IMP_R6000A)) - return read_c0_random(); + + if (cpu_has_3kex) + c0_random = (read_c0_random() >> 8) & 0x3f; else - return 0; /* no usable register */ + c0_random = read_c0_random() & 0x3f; + return (random_get_entropy_fallback() << 6) | (0x3f - c0_random); } #define random_get_entropy random_get_entropy diff --git a/arch/nios2/include/asm/timex.h b/arch/nios2/include/asm/timex.h index a769f871b28d9..40a1adc9bd03e 100644 --- a/arch/nios2/include/asm/timex.h +++ b/arch/nios2/include/asm/timex.h @@ -8,5 +8,8 @@ typedef unsigned long cycles_t; extern cycles_t get_cycles(void); +#define get_cycles get_cycles + +#define random_get_entropy() (((unsigned long)get_cycles()) ?: random_get_entropy_fallback()) #endif diff --git a/arch/parisc/include/asm/timex.h b/arch/parisc/include/asm/timex.h index 06b510f8172e3..b4622cb06a75e 100644 --- a/arch/parisc/include/asm/timex.h +++ b/arch/parisc/include/asm/timex.h @@ -13,9 +13,10 @@ typedef unsigned long cycles_t; -static inline cycles_t get_cycles (void) +static inline cycles_t get_cycles(void) { return mfctl(16); } +#define get_cycles get_cycles #endif diff --git a/arch/powerpc/include/asm/timex.h b/arch/powerpc/include/asm/timex.h index fa2e76e4093a3..14b4489de52c5 100644 --- a/arch/powerpc/include/asm/timex.h +++ b/arch/powerpc/include/asm/timex.h @@ -19,6 +19,7 @@ static inline cycles_t get_cycles(void) { return mftb(); } +#define get_cycles get_cycles #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_TIMEX_H */ diff --git a/arch/riscv/include/asm/timex.h b/arch/riscv/include/asm/timex.h index 507cae273bc62..d6a7428f6248d 100644 --- a/arch/riscv/include/asm/timex.h +++ b/arch/riscv/include/asm/timex.h @@ -41,7 +41,7 @@ static inline u32 get_cycles_hi(void) static inline unsigned long random_get_entropy(void) { if (unlikely(clint_time_val == NULL)) - return 0; + return random_get_entropy_fallback(); return get_cycles(); } #define random_get_entropy() random_get_entropy() diff --git a/arch/s390/include/asm/timex.h b/arch/s390/include/asm/timex.h index 50d9b04ecbd14..bc50ee0e91ff1 100644 --- a/arch/s390/include/asm/timex.h +++ b/arch/s390/include/asm/timex.h @@ -201,6 +201,7 @@ static inline cycles_t get_cycles(void) { return (cycles_t) get_tod_clock() >> 2; } +#define get_cycles get_cycles int get_phys_clock(unsigned long *clock); void init_cpu_timer(void); diff --git a/arch/sparc/include/asm/timex_32.h b/arch/sparc/include/asm/timex_32.h index 542915b462097..f86326a6f89e0 100644 --- a/arch/sparc/include/asm/timex_32.h +++ b/arch/sparc/include/asm/timex_32.h @@ -9,8 +9,6 @@ #define CLOCK_TICK_RATE 1193180 /* Underlying HZ */ -/* XXX Maybe do something better at some point... -DaveM */ -typedef unsigned long cycles_t; -#define get_cycles() (0) +#include #endif diff --git a/arch/um/include/asm/timex.h b/arch/um/include/asm/timex.h index e392a9a5bc9bd..9f27176adb26d 100644 --- a/arch/um/include/asm/timex.h +++ b/arch/um/include/asm/timex.h @@ -2,13 +2,8 @@ #ifndef __UM_TIMEX_H #define __UM_TIMEX_H -typedef unsigned long cycles_t; - -static inline cycles_t get_cycles (void) -{ - return 0; -} - #define CLOCK_TICK_RATE (HZ) +#include + #endif diff --git a/arch/x86/include/asm/timex.h b/arch/x86/include/asm/timex.h index a4a8b1b16c0c1..956e4145311b1 100644 --- a/arch/x86/include/asm/timex.h +++ b/arch/x86/include/asm/timex.h @@ -5,6 +5,15 @@ #include #include +static inline unsigned long random_get_entropy(void) +{ + if (!IS_ENABLED(CONFIG_X86_TSC) && + !cpu_feature_enabled(X86_FEATURE_TSC)) + return random_get_entropy_fallback(); + return rdtsc(); +} +#define random_get_entropy random_get_entropy + /* Assume we use the PIT time source for the clock tick */ #define CLOCK_TICK_RATE PIT_TICK_RATE diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h index 01a300a9700b9..fbdc3d9514943 100644 --- a/arch/x86/include/asm/tsc.h +++ b/arch/x86/include/asm/tsc.h @@ -20,13 +20,12 @@ extern void disable_TSC(void); static inline cycles_t get_cycles(void) { -#ifndef CONFIG_X86_TSC - if (!boot_cpu_has(X86_FEATURE_TSC)) + if (!IS_ENABLED(CONFIG_X86_TSC) && + !cpu_feature_enabled(X86_FEATURE_TSC)) return 0; -#endif - return rdtsc(); } +#define get_cycles get_cycles extern struct system_counterval_t convert_art_to_tsc(u64 art); extern struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns); diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 32333dfc85b6a..495329ae6b1b2 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5416,14 +5416,16 @@ void kvm_mmu_invpcid_gva(struct kvm_vcpu *vcpu, gva_t gva, unsigned long pcid) uint i; if (pcid == kvm_get_active_pcid(vcpu)) { - mmu->invlpg(vcpu, gva, mmu->root_hpa); + if (mmu->invlpg) + mmu->invlpg(vcpu, gva, mmu->root_hpa); tlb_flush = true; } for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) { if (VALID_PAGE(mmu->prev_roots[i].hpa) && pcid == kvm_get_pcid(vcpu, mmu->prev_roots[i].pgd)) { - mmu->invlpg(vcpu, gva, mmu->prev_roots[i].hpa); + if (mmu->invlpg) + mmu->invlpg(vcpu, gva, mmu->prev_roots[i].hpa); tlb_flush = true; } } diff --git a/arch/xtensa/include/asm/timex.h b/arch/xtensa/include/asm/timex.h index 233ec75e60c69..3f2462f2d0270 100644 --- a/arch/xtensa/include/asm/timex.h +++ b/arch/xtensa/include/asm/timex.h @@ -29,10 +29,6 @@ extern unsigned long ccount_freq; -typedef unsigned long long cycles_t; - -#define get_cycles() (0) - void local_timer_setup(unsigned cpu); /* @@ -59,4 +55,6 @@ static inline void set_linux_timer (unsigned long ccompare) xtensa_set_sr(ccompare, SREG_CCOMPARE + LINUX_TIMER); } +#include + #endif /* _XTENSA_TIMEX_H */ diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c index a4b638bea6f16..cc2fe0618178e 100644 --- a/drivers/acpi/sysfs.c +++ b/drivers/acpi/sysfs.c @@ -415,19 +415,30 @@ static ssize_t acpi_data_show(struct file *filp, struct kobject *kobj, loff_t offset, size_t count) { struct acpi_data_attr *data_attr; - void *base; - ssize_t rc; + void __iomem *base; + ssize_t size; data_attr = container_of(bin_attr, struct acpi_data_attr, attr); + size = data_attr->attr.size; + + if (offset < 0) + return -EINVAL; + + if (offset >= size) + return 0; - base = acpi_os_map_memory(data_attr->addr, data_attr->attr.size); + if (count > size - offset) + count = size - offset; + + base = acpi_os_map_iomem(data_attr->addr, size); if (!base) return -ENOMEM; - rc = memory_read_from_buffer(buf, count, &offset, base, - data_attr->attr.size); - acpi_os_unmap_memory(base, data_attr->attr.size); - return rc; + memcpy_fromio(buf, base + offset, count); + + acpi_os_unmap_iomem(base, size); + + return count; } static int acpi_bert_data_init(void *th, struct acpi_data_attr *data_attr) diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index 740811893c570..55f48375e3fe5 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -449,6 +449,7 @@ config RANDOM_TRUST_BOOTLOADER device randomness. Say Y here to assume the entropy provided by the booloader is trustworthy so it will be added to the kernel's entropy pool. Otherwise, say N here so it will be regarded as device input that - only mixes the entropy pool. + only mixes the entropy pool. This can also be configured at boot with + "random.trust_bootloader=on/off". endmenu diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index a3db27916256d..cfb085de876b7 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include diff --git a/drivers/char/random.c b/drivers/char/random.c index 3404a91edf292..92428bfdc1431 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1,320 +1,26 @@ +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) /* - * random.c -- A strong random number generator - * * Copyright (C) 2017-2022 Jason A. Donenfeld . All Rights Reserved. - * * Copyright Matt Mackall , 2003, 2004, 2005 - * - * Copyright Theodore Ts'o, 1994, 1995, 1996, 1997, 1998, 1999. All - * rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, and the entire permission notice in its entirety, - * including the disclaimer of warranties. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. The name of the author may not be used to endorse or promote - * products derived from this software without specific prior - * written permission. - * - * ALTERNATIVELY, this product may be distributed under the terms of - * the GNU General Public License, in which case the provisions of the GPL are - * required INSTEAD OF the above restrictions. (This clause is - * necessary due to a potential bad interaction between the GPL and - * the restrictions contained in a BSD-style copyright.) - * - * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED - * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES - * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF - * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE - * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR - * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT - * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR - * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF - * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT - * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE - * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH - * DAMAGE. - */ - -/* - * (now, with legal B.S. out of the way.....) - * - * This routine gathers environmental noise from device drivers, etc., - * and returns good random numbers, suitable for cryptographic use. - * Besides the obvious cryptographic uses, these numbers are also good - * for seeding TCP sequence numbers, and other places where it is - * desirable to have numbers which are not only random, but hard to - * predict by an attacker. - * - * Theory of operation - * =================== - * - * Computers are very predictable devices. Hence it is extremely hard - * to produce truly random numbers on a computer --- as opposed to - * pseudo-random numbers, which can easily generated by using a - * algorithm. Unfortunately, it is very easy for attackers to guess - * the sequence of pseudo-random number generators, and for some - * applications this is not acceptable. So instead, we must try to - * gather "environmental noise" from the computer's environment, which - * must be hard for outside attackers to observe, and use that to - * generate random numbers. In a Unix environment, this is best done - * from inside the kernel. - * - * Sources of randomness from the environment include inter-keyboard - * timings, inter-interrupt timings from some interrupts, and other - * events which are both (a) non-deterministic and (b) hard for an - * outside observer to measure. Randomness from these sources are - * added to an "entropy pool", which is mixed using a CRC-like function. - * This is not cryptographically strong, but it is adequate assuming - * the randomness is not chosen maliciously, and it is fast enough that - * the overhead of doing it on every interrupt is very reasonable. - * As random bytes are mixed into the entropy pool, the routines keep - * an *estimate* of how many bits of randomness have been stored into - * the random number generator's internal state. - * - * When random bytes are desired, they are obtained by taking the BLAKE2s - * hash of the contents of the "entropy pool". The BLAKE2s hash avoids - * exposing the internal state of the entropy pool. It is believed to - * be computationally infeasible to derive any useful information - * about the input of BLAKE2s from its output. Even if it is possible to - * analyze BLAKE2s in some clever way, as long as the amount of data - * returned from the generator is less than the inherent entropy in - * the pool, the output data is totally unpredictable. For this - * reason, the routine decreases its internal estimate of how many - * bits of "true randomness" are contained in the entropy pool as it - * outputs random numbers. - * - * If this estimate goes to zero, the routine can still generate - * random numbers; however, an attacker may (at least in theory) be - * able to infer the future output of the generator from prior - * outputs. This requires successful cryptanalysis of BLAKE2s, which is - * not believed to be feasible, but there is a remote possibility. - * Nonetheless, these numbers should be useful for the vast majority - * of purposes. - * - * Exported interfaces ---- output - * =============================== - * - * There are four exported interfaces; two for use within the kernel, - * and two for use from userspace. - * - * Exported interfaces ---- userspace output - * ----------------------------------------- - * - * The userspace interfaces are two character devices /dev/random and - * /dev/urandom. /dev/random is suitable for use when very high - * quality randomness is desired (for example, for key generation or - * one-time pads), as it will only return a maximum of the number of - * bits of randomness (as estimated by the random number generator) - * contained in the entropy pool. - * - * The /dev/urandom device does not have this limit, and will return - * as many bytes as are requested. As more and more random bytes are - * requested without giving time for the entropy pool to recharge, - * this will result in random numbers that are merely cryptographically - * strong. For many applications, however, this is acceptable. - * - * Exported interfaces ---- kernel output - * -------------------------------------- - * - * The primary kernel interface is - * - * void get_random_bytes(void *buf, int nbytes); - * - * This interface will return the requested number of random bytes, - * and place it in the requested buffer. This is equivalent to a - * read from /dev/urandom. - * - * For less critical applications, there are the functions: - * - * u32 get_random_u32() - * u64 get_random_u64() - * unsigned int get_random_int() - * unsigned long get_random_long() - * - * These are produced by a cryptographic RNG seeded from get_random_bytes, - * and so do not deplete the entropy pool as much. These are recommended - * for most in-kernel operations *if the result is going to be stored in - * the kernel*. - * - * Specifically, the get_random_int() family do not attempt to do - * "anti-backtracking". If you capture the state of the kernel (e.g. - * by snapshotting the VM), you can figure out previous get_random_int() - * return values. But if the value is stored in the kernel anyway, - * this is not a problem. - * - * It *is* safe to expose get_random_int() output to attackers (e.g. as - * network cookies); given outputs 1..n, it's not feasible to predict - * outputs 0 or n+1. The only concern is an attacker who breaks into - * the kernel later; the get_random_int() engine is not reseeded as - * often as the get_random_bytes() one. - * - * get_random_bytes() is needed for keys that need to stay secret after - * they are erased from the kernel. For example, any key that will - * be wrapped and stored encrypted. And session encryption keys: we'd - * like to know that after the session is closed and the keys erased, - * the plaintext is unrecoverable to someone who recorded the ciphertext. - * - * But for network ports/cookies, stack canaries, PRNG seeds, address - * space layout randomization, session *authentication* keys, or other - * applications where the sensitive data is stored in the kernel in - * plaintext for as long as it's sensitive, the get_random_int() family - * is just fine. - * - * Consider ASLR. We want to keep the address space secret from an - * outside attacker while the process is running, but once the address - * space is torn down, it's of no use to an attacker any more. And it's - * stored in kernel data structures as long as it's alive, so worrying - * about an attacker's ability to extrapolate it from the get_random_int() - * CRNG is silly. - * - * Even some cryptographic keys are safe to generate with get_random_int(). - * In particular, keys for SipHash are generally fine. Here, knowledge - * of the key authorizes you to do something to a kernel object (inject - * packets to a network connection, or flood a hash table), and the - * key is stored with the object being protected. Once it goes away, - * we no longer care if anyone knows the key. - * - * prandom_u32() - * ------------- - * - * For even weaker applications, see the pseudorandom generator - * prandom_u32(), prandom_max(), and prandom_bytes(). If the random - * numbers aren't security-critical at all, these are *far* cheaper. - * Useful for self-tests, random error simulation, randomized backoffs, - * and any other application where you trust that nobody is trying to - * maliciously mess with you by guessing the "random" numbers. - * - * Exported interfaces ---- input - * ============================== - * - * The current exported interfaces for gathering environmental noise - * from the devices are: - * - * void add_device_randomness(const void *buf, unsigned int size); - * void add_input_randomness(unsigned int type, unsigned int code, - * unsigned int value); - * void add_interrupt_randomness(int irq); - * void add_disk_randomness(struct gendisk *disk); - * void add_hwgenerator_randomness(const char *buffer, size_t count, - * size_t entropy); - * void add_bootloader_randomness(const void *buf, unsigned int size); - * - * add_device_randomness() is for adding data to the random pool that - * is likely to differ between two devices (or possibly even per boot). - * This would be things like MAC addresses or serial numbers, or the - * read-out of the RTC. This does *not* add any actual entropy to the - * pool, but it initializes the pool to different values for devices - * that might otherwise be identical and have very little entropy - * available to them (particularly common in the embedded world). - * - * add_input_randomness() uses the input layer interrupt timing, as well as - * the event type information from the hardware. - * - * add_interrupt_randomness() uses the interrupt timing as random - * inputs to the entropy pool. Using the cycle counters and the irq source - * as inputs, it feeds the randomness roughly once a second. - * - * add_disk_randomness() uses what amounts to the seek time of block - * layer request events, on a per-disk_devt basis, as input to the - * entropy pool. Note that high-speed solid state drives with very low - * seek times do not make for good sources of entropy, as their seek - * times are usually fairly consistent. - * - * All of these routines try to estimate how many bits of randomness a - * particular randomness source. They do this by keeping track of the - * first and second order deltas of the event timings. - * - * add_hwgenerator_randomness() is for true hardware RNGs, and will credit - * entropy as specified by the caller. If the entropy pool is full it will - * block until more entropy is needed. - * - * add_bootloader_randomness() is the same as add_hwgenerator_randomness() or - * add_device_randomness(), depending on whether or not the configuration - * option CONFIG_RANDOM_TRUST_BOOTLOADER is set. - * - * Ensuring unpredictability at system startup - * ============================================ - * - * When any operating system starts up, it will go through a sequence - * of actions that are fairly predictable by an adversary, especially - * if the start-up does not involve interaction with a human operator. - * This reduces the actual number of bits of unpredictability in the - * entropy pool below the value in entropy_count. In order to - * counteract this effect, it helps to carry information in the - * entropy pool across shut-downs and start-ups. To do this, put the - * following lines an appropriate script which is run during the boot - * sequence: - * - * echo "Initializing random number generator..." - * random_seed=/var/run/random-seed - * # Carry a random seed from start-up to start-up - * # Load and then save the whole entropy pool - * if [ -f $random_seed ]; then - * cat $random_seed >/dev/urandom - * else - * touch $random_seed - * fi - * chmod 600 $random_seed - * dd if=/dev/urandom of=$random_seed count=1 bs=512 - * - * and the following lines in an appropriate script which is run as - * the system is shutdown: - * - * # Carry a random seed from shut-down to start-up - * # Save the whole entropy pool - * echo "Saving random seed..." - * random_seed=/var/run/random-seed - * touch $random_seed - * chmod 600 $random_seed - * dd if=/dev/urandom of=$random_seed count=1 bs=512 - * - * For example, on most modern systems using the System V init - * scripts, such code fragments would be found in - * /etc/rc.d/init.d/random. On older Linux systems, the correct script - * location might be in /etc/rcb.d/rc.local or /etc/rc.d/rc.0. - * - * Effectively, these commands cause the contents of the entropy pool - * to be saved at shut-down time and reloaded into the entropy pool at - * start-up. (The 'dd' in the addition to the bootup script is to - * make sure that /etc/random-seed is different for every start-up, - * even if the system crashes without executing rc.0.) Even with - * complete knowledge of the start-up activities, predicting the state - * of the entropy pool requires knowledge of the previous history of - * the system. - * - * Configuring the /dev/random driver under Linux - * ============================================== - * - * The /dev/random driver under Linux uses minor numbers 8 and 9 of - * the /dev/mem major number (#1). So if your system does not have - * /dev/random and /dev/urandom created already, they can be created - * by using the commands: - * - * mknod /dev/random c 1 8 - * mknod /dev/urandom c 1 9 - * - * Acknowledgements: - * ================= - * - * Ideas for constructing this random number generator were derived - * from Pretty Good Privacy's random number generator, and from private - * discussions with Phil Karn. Colin Plumb provided a faster random - * number generator, which speed up the mixing function of the entropy - * pool, taken from PGPfone. Dale Worley has also contributed many - * useful ideas and suggestions to improve this driver. - * - * Any flaws in the design are solely my responsibility, and should - * not be attributed to the Phil, Colin, or any of authors of PGP. - * - * Further background information on this topic may be obtained from - * RFC 1750, "Randomness Recommendations for Security", by Donald - * Eastlake, Steve Crocker, and Jeff Schiller. + * Copyright Theodore Ts'o, 1994, 1995, 1996, 1997, 1998, 1999. All rights reserved. + * + * This driver produces cryptographically secure pseudorandom data. It is divided + * into roughly six sections, each with a section header: + * + * - Initialization and readiness waiting. + * - Fast key erasure RNG, the "crng". + * - Entropy accumulation and extraction routines. + * - Entropy collection routines. + * - Userspace reader/writer interfaces. + * - Sysctl interface. + * + * The high level overview is that there is one input pool, into which + * various pieces of data are hashed. Prior to initialization, some of that + * data is then "credited" as having a certain number of bits of entropy. + * When enough bits of entropy are available, the hash is finalized and + * handed as a key to a stream cipher that expands it indefinitely for + * various consumers. This key is periodically refreshed as the various + * entropy collectors, described below, add data to the input pool. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt @@ -344,1371 +50,1080 @@ #include #include #include +#include +#include +#include #include #include - #include -#include #include #include #include -#define CREATE_TRACE_POINTS -#include - -/* #define ADD_INTERRUPT_BENCH */ - -/* - * If the entropy count falls under this number of bits, then we - * should wake up processes which are selecting or polling on write - * access to /dev/random. - */ -static int random_write_wakeup_bits = 28 * (1 << 5); - -/* - * Originally, we used a primitive polynomial of degree .poolwords - * over GF(2). The taps for various sizes are defined below. They - * were chosen to be evenly spaced except for the last tap, which is 1 - * to get the twisting happening as fast as possible. - * - * For the purposes of better mixing, we use the CRC-32 polynomial as - * well to make a (modified) twisted Generalized Feedback Shift - * Register. (See M. Matsumoto & Y. Kurita, 1992. Twisted GFSR - * generators. ACM Transactions on Modeling and Computer Simulation - * 2(3):179-194. Also see M. Matsumoto & Y. Kurita, 1994. Twisted - * GFSR generators II. ACM Transactions on Modeling and Computer - * Simulation 4:254-266) +/********************************************************************* * - * Thanks to Colin Plumb for suggesting this. + * Initialization and readiness waiting. * - * The mixing operation is much less sensitive than the output hash, - * where we use BLAKE2s. All that we want of mixing operation is that - * it be a good non-cryptographic hash; i.e. it not produce collisions - * when fed "random" data of the sort we expect to see. As long as - * the pool state differs for different inputs, we have preserved the - * input entropy and done a good job. The fact that an intelligent - * attacker can construct inputs that will produce controlled - * alterations to the pool's state is not important because we don't - * consider such inputs to contribute any randomness. The only - * property we need with respect to them is that the attacker can't - * increase his/her knowledge of the pool's state. Since all - * additions are reversible (knowing the final state and the input, - * you can reconstruct the initial state), if an attacker has any - * uncertainty about the initial state, he/she can only shuffle that - * uncertainty about, but never cause any collisions (which would - * decrease the uncertainty). + * Much of the RNG infrastructure is devoted to various dependencies + * being able to wait until the RNG has collected enough entropy and + * is ready for safe consumption. * - * Our mixing functions were analyzed by Lacharme, Roeck, Strubel, and - * Videau in their paper, "The Linux Pseudorandom Number Generator - * Revisited" (see: http://eprint.iacr.org/2012/251.pdf). In their - * paper, they point out that we are not using a true Twisted GFSR, - * since Matsumoto & Kurita used a trinomial feedback polynomial (that - * is, with only three taps, instead of the six that we are using). - * As a result, the resulting polynomial is neither primitive nor - * irreducible, and hence does not have a maximal period over - * GF(2**32). They suggest a slight change to the generator - * polynomial which improves the resulting TGFSR polynomial to be - * irreducible, which we have made here. - */ -enum poolinfo { - POOL_WORDS = 128, - POOL_WORDMASK = POOL_WORDS - 1, - POOL_BYTES = POOL_WORDS * sizeof(u32), - POOL_BITS = POOL_BYTES * 8, - POOL_BITSHIFT = ilog2(POOL_BITS), - - /* To allow fractional bits to be tracked, the entropy_count field is - * denominated in units of 1/8th bits. */ - POOL_ENTROPY_SHIFT = 3, -#define POOL_ENTROPY_BITS() (input_pool.entropy_count >> POOL_ENTROPY_SHIFT) - POOL_FRACBITS = POOL_BITS << POOL_ENTROPY_SHIFT, - - /* x^128 + x^104 + x^76 + x^51 +x^25 + x + 1 */ - POOL_TAP1 = 104, - POOL_TAP2 = 76, - POOL_TAP3 = 51, - POOL_TAP4 = 25, - POOL_TAP5 = 1, - - EXTRACT_SIZE = BLAKE2S_HASH_SIZE / 2 -}; + *********************************************************************/ /* - * Static global variables + * crng_init is protected by base_crng->lock, and only increases + * its value (from empty->early->ready). */ -static DECLARE_WAIT_QUEUE_HEAD(random_write_wait); +static enum { + CRNG_EMPTY = 0, /* Little to no entropy collected */ + CRNG_EARLY = 1, /* At least POOL_EARLY_BITS collected */ + CRNG_READY = 2 /* Fully initialized with POOL_READY_BITS collected */ +} crng_init __read_mostly = CRNG_EMPTY; +static DEFINE_STATIC_KEY_FALSE(crng_is_ready); +#define crng_ready() (static_branch_likely(&crng_is_ready) || crng_init >= CRNG_READY) +/* Various types of waiters for crng_init->CRNG_READY transition. */ +static DECLARE_WAIT_QUEUE_HEAD(crng_init_wait); static struct fasync_struct *fasync; +static DEFINE_SPINLOCK(random_ready_chain_lock); +static RAW_NOTIFIER_HEAD(random_ready_chain); -static DEFINE_SPINLOCK(random_ready_list_lock); -static LIST_HEAD(random_ready_list); - -struct crng_state { - u32 state[16]; - unsigned long init_time; - spinlock_t lock; -}; - -static struct crng_state primary_crng = { - .lock = __SPIN_LOCK_UNLOCKED(primary_crng.lock), - .state[0] = CHACHA_CONSTANT_EXPA, - .state[1] = CHACHA_CONSTANT_ND_3, - .state[2] = CHACHA_CONSTANT_2_BY, - .state[3] = CHACHA_CONSTANT_TE_K, -}; - -/* - * crng_init = 0 --> Uninitialized - * 1 --> Initialized - * 2 --> Initialized from input_pool - * - * crng_init is protected by primary_crng->lock, and only increases - * its value (from 0->1->2). - */ -static int crng_init = 0; -static bool crng_need_final_init = false; -#define crng_ready() (likely(crng_init > 1)) -static int crng_init_cnt = 0; -static unsigned long crng_global_init_time = 0; -#define CRNG_INIT_CNT_THRESH (2 * CHACHA_KEY_SIZE) -static void _extract_crng(struct crng_state *crng, u8 out[CHACHA_BLOCK_SIZE]); -static void _crng_backtrack_protect(struct crng_state *crng, - u8 tmp[CHACHA_BLOCK_SIZE], int used); -static void process_random_ready_list(void); -static void _get_random_bytes(void *buf, int nbytes); - -static struct ratelimit_state unseeded_warning = - RATELIMIT_STATE_INIT("warn_unseeded_randomness", HZ, 3); +/* Control how we warn userspace. */ static struct ratelimit_state urandom_warning = RATELIMIT_STATE_INIT("warn_urandom_randomness", HZ, 3); - -static int ratelimit_disable __read_mostly; - +static int ratelimit_disable __read_mostly = + IS_ENABLED(CONFIG_WARN_ALL_UNSEEDED_RANDOM); module_param_named(ratelimit_disable, ratelimit_disable, int, 0644); MODULE_PARM_DESC(ratelimit_disable, "Disable random ratelimit suppression"); -/********************************************************************** - * - * OS independent entropy store. Here are the functions which handle - * storing entropy in an entropy pool. - * - **********************************************************************/ - -static u32 input_pool_data[POOL_WORDS] __latent_entropy; - -static struct { - spinlock_t lock; - u16 add_ptr; - u16 input_rotate; - int entropy_count; -} input_pool = { - .lock = __SPIN_LOCK_UNLOCKED(input_pool.lock), -}; - -static ssize_t extract_entropy(void *buf, size_t nbytes, int min); -static ssize_t _extract_entropy(void *buf, size_t nbytes); - -static void crng_reseed(struct crng_state *crng, bool use_input_pool); - -static const u32 twist_table[8] = { - 0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158, - 0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 }; - /* - * This function adds bytes into the entropy "pool". It does not - * update the entropy estimate. The caller should call - * credit_entropy_bits if this is appropriate. + * Returns whether or not the input pool has been seeded and thus guaranteed + * to supply cryptographically secure random numbers. This applies to: the + * /dev/urandom device, the get_random_bytes function, and the get_random_{u32, + * ,u64,int,long} family of functions. * - * The pool is stirred with a primitive polynomial of the appropriate - * degree, and then twisted. We twist by three bits at a time because - * it's cheap to do so and helps slightly in the expected case where - * the entropy is concentrated in the low-order bits. + * Returns: true if the input pool has been seeded. + * false if the input pool has not been seeded. */ -static void _mix_pool_bytes(const void *in, int nbytes) -{ - unsigned long i; - int input_rotate; - const u8 *bytes = in; - u32 w; - - input_rotate = input_pool.input_rotate; - i = input_pool.add_ptr; - - /* mix one byte at a time to simplify size handling and churn faster */ - while (nbytes--) { - w = rol32(*bytes++, input_rotate); - i = (i - 1) & POOL_WORDMASK; - - /* XOR in the various taps */ - w ^= input_pool_data[i]; - w ^= input_pool_data[(i + POOL_TAP1) & POOL_WORDMASK]; - w ^= input_pool_data[(i + POOL_TAP2) & POOL_WORDMASK]; - w ^= input_pool_data[(i + POOL_TAP3) & POOL_WORDMASK]; - w ^= input_pool_data[(i + POOL_TAP4) & POOL_WORDMASK]; - w ^= input_pool_data[(i + POOL_TAP5) & POOL_WORDMASK]; - - /* Mix the result back in with a twist */ - input_pool_data[i] = (w >> 3) ^ twist_table[w & 7]; - - /* - * Normally, we add 7 bits of rotation to the pool. - * At the beginning of the pool, add an extra 7 bits - * rotation, so that successive passes spread the - * input bits across the pool evenly. - */ - input_rotate = (input_rotate + (i ? 7 : 14)) & 31; - } - - input_pool.input_rotate = input_rotate; - input_pool.add_ptr = i; -} - -static void __mix_pool_bytes(const void *in, int nbytes) +bool rng_is_initialized(void) { - trace_mix_pool_bytes_nolock(nbytes, _RET_IP_); - _mix_pool_bytes(in, nbytes); + return crng_ready(); } +EXPORT_SYMBOL(rng_is_initialized); -static void mix_pool_bytes(const void *in, int nbytes) +static void __cold crng_set_ready(struct work_struct *work) { - unsigned long flags; - - trace_mix_pool_bytes(nbytes, _RET_IP_); - spin_lock_irqsave(&input_pool.lock, flags); - _mix_pool_bytes(in, nbytes); - spin_unlock_irqrestore(&input_pool.lock, flags); + static_branch_enable(&crng_is_ready); } -struct fast_pool { - u32 pool[4]; - unsigned long last; - u16 reg_idx; - u8 count; -}; +/* Used by wait_for_random_bytes(), and considered an entropy collector, below. */ +static void try_to_generate_entropy(void); /* - * This is a fast mixing routine used by the interrupt randomness - * collector. It's hardcoded for an 128 bit pool and assumes that any - * locks that might be needed are taken by the caller. + * Wait for the input pool to be seeded and thus guaranteed to supply + * cryptographically secure random numbers. This applies to: the /dev/urandom + * device, the get_random_bytes function, and the get_random_{u32,u64,int,long} + * family of functions. Using any of these functions without first calling + * this function forfeits the guarantee of security. + * + * Returns: 0 if the input pool has been seeded. + * -ERESTARTSYS if the function was interrupted by a signal. */ -static void fast_mix(struct fast_pool *f) +int wait_for_random_bytes(void) { - u32 a = f->pool[0], b = f->pool[1]; - u32 c = f->pool[2], d = f->pool[3]; - - a += b; c += d; - b = rol32(b, 6); d = rol32(d, 27); - d ^= a; b ^= c; - - a += b; c += d; - b = rol32(b, 16); d = rol32(d, 14); - d ^= a; b ^= c; - - a += b; c += d; - b = rol32(b, 6); d = rol32(d, 27); - d ^= a; b ^= c; - - a += b; c += d; - b = rol32(b, 16); d = rol32(d, 14); - d ^= a; b ^= c; + while (!crng_ready()) { + int ret; - f->pool[0] = a; f->pool[1] = b; - f->pool[2] = c; f->pool[3] = d; - f->count++; + try_to_generate_entropy(); + ret = wait_event_interruptible_timeout(crng_init_wait, crng_ready(), HZ); + if (ret) + return ret > 0 ? 0 : ret; + } + return 0; } +EXPORT_SYMBOL(wait_for_random_bytes); -static void process_random_ready_list(void) +/* + * Add a callback function that will be invoked when the input + * pool is initialised. + * + * returns: 0 if callback is successfully added + * -EALREADY if pool is already initialised (callback not called) + */ +int __cold register_random_ready_notifier(struct notifier_block *nb) { unsigned long flags; - struct random_ready_callback *rdy, *tmp; + int ret = -EALREADY; - spin_lock_irqsave(&random_ready_list_lock, flags); - list_for_each_entry_safe(rdy, tmp, &random_ready_list, list) { - struct module *owner = rdy->owner; + if (crng_ready()) + return ret; - list_del_init(&rdy->list); - rdy->func(rdy); - module_put(owner); - } - spin_unlock_irqrestore(&random_ready_list_lock, flags); + spin_lock_irqsave(&random_ready_chain_lock, flags); + if (!crng_ready()) + ret = raw_notifier_chain_register(&random_ready_chain, nb); + spin_unlock_irqrestore(&random_ready_chain_lock, flags); + return ret; } /* - * Credit (or debit) the entropy store with n bits of entropy. - * Use credit_entropy_bits_safe() if the value comes from userspace - * or otherwise should be checked for extreme values. + * Delete a previously registered readiness callback function. */ -static void credit_entropy_bits(int nbits) +int __cold unregister_random_ready_notifier(struct notifier_block *nb) { - int entropy_count, entropy_bits, orig; - int nfrac = nbits << POOL_ENTROPY_SHIFT; - - /* Ensure that the multiplication can avoid being 64 bits wide. */ - BUILD_BUG_ON(2 * (POOL_ENTROPY_SHIFT + POOL_BITSHIFT) > 31); - - if (!nbits) - return; - -retry: - entropy_count = orig = READ_ONCE(input_pool.entropy_count); - if (nfrac < 0) { - /* Debit */ - entropy_count += nfrac; - } else { - /* - * Credit: we have to account for the possibility of - * overwriting already present entropy. Even in the - * ideal case of pure Shannon entropy, new contributions - * approach the full value asymptotically: - * - * entropy <- entropy + (pool_size - entropy) * - * (1 - exp(-add_entropy/pool_size)) - * - * For add_entropy <= pool_size/2 then - * (1 - exp(-add_entropy/pool_size)) >= - * (add_entropy/pool_size)*0.7869... - * so we can approximate the exponential with - * 3/4*add_entropy/pool_size and still be on the - * safe side by adding at most pool_size/2 at a time. - * - * The use of pool_size-2 in the while statement is to - * prevent rounding artifacts from making the loop - * arbitrarily long; this limits the loop to log2(pool_size)*2 - * turns no matter how large nbits is. - */ - int pnfrac = nfrac; - const int s = POOL_BITSHIFT + POOL_ENTROPY_SHIFT + 2; - /* The +2 corresponds to the /4 in the denominator */ - - do { - unsigned int anfrac = min(pnfrac, POOL_FRACBITS / 2); - unsigned int add = - ((POOL_FRACBITS - entropy_count) * anfrac * 3) >> s; - - entropy_count += add; - pnfrac -= anfrac; - } while (unlikely(entropy_count < POOL_FRACBITS - 2 && pnfrac)); - } - - if (WARN_ON(entropy_count < 0)) { - pr_warn("negative entropy/overflow: count %d\n", entropy_count); - entropy_count = 0; - } else if (entropy_count > POOL_FRACBITS) - entropy_count = POOL_FRACBITS; - if (cmpxchg(&input_pool.entropy_count, orig, entropy_count) != orig) - goto retry; - - trace_credit_entropy_bits(nbits, entropy_count >> POOL_ENTROPY_SHIFT, _RET_IP_); + unsigned long flags; + int ret; - entropy_bits = entropy_count >> POOL_ENTROPY_SHIFT; - if (crng_init < 2 && entropy_bits >= 128) - crng_reseed(&primary_crng, true); + spin_lock_irqsave(&random_ready_chain_lock, flags); + ret = raw_notifier_chain_unregister(&random_ready_chain, nb); + spin_unlock_irqrestore(&random_ready_chain_lock, flags); + return ret; } -static int credit_entropy_bits_safe(int nbits) +static void __cold process_random_ready_list(void) { - if (nbits < 0) - return -EINVAL; - - /* Cap the value to avoid overflows */ - nbits = min(nbits, POOL_BITS); + unsigned long flags; - credit_entropy_bits(nbits); - return 0; + spin_lock_irqsave(&random_ready_chain_lock, flags); + raw_notifier_call_chain(&random_ready_chain, 0, NULL); + spin_unlock_irqrestore(&random_ready_chain_lock, flags); } +#define warn_unseeded_randomness() \ + if (IS_ENABLED(CONFIG_WARN_ALL_UNSEEDED_RANDOM) && !crng_ready()) \ + printk_deferred(KERN_NOTICE "random: %s called from %pS with crng_init=%d\n", \ + __func__, (void *)_RET_IP_, crng_init) + + /********************************************************************* * - * CRNG using CHACHA20 + * Fast key erasure RNG, the "crng". + * + * These functions expand entropy from the entropy extractor into + * long streams for external consumption using the "fast key erasure" + * RNG described at . + * + * There are a few exported interfaces for use by other drivers: + * + * void get_random_bytes(void *buf, size_t len) + * u32 get_random_u32() + * u64 get_random_u64() + * unsigned int get_random_int() + * unsigned long get_random_long() + * + * These interfaces will return the requested number of random bytes + * into the given buffer or as a return value. This is equivalent to + * a read from /dev/urandom. The u32, u64, int, and long family of + * functions may be higher performance for one-off random integers, + * because they do a bit of buffering and do not invoke reseeding + * until the buffer is emptied. * *********************************************************************/ -#define CRNG_RESEED_INTERVAL (300 * HZ) +enum { + CRNG_RESEED_START_INTERVAL = HZ, + CRNG_RESEED_INTERVAL = 60 * HZ +}; -static DECLARE_WAIT_QUEUE_HEAD(crng_init_wait); +static struct { + u8 key[CHACHA_KEY_SIZE] __aligned(__alignof__(long)); + unsigned long birth; + unsigned long generation; + spinlock_t lock; +} base_crng = { + .lock = __SPIN_LOCK_UNLOCKED(base_crng.lock) +}; -/* - * Hack to deal with crazy userspace progams when they are all trying - * to access /dev/urandom in parallel. The programs are almost - * certainly doing something terribly wrong, but we'll work around - * their brain damage. - */ -static struct crng_state **crng_node_pool __read_mostly; +struct crng { + u8 key[CHACHA_KEY_SIZE]; + unsigned long generation; + local_lock_t lock; +}; -static void invalidate_batched_entropy(void); -static void numa_crng_init(void); +static DEFINE_PER_CPU(struct crng, crngs) = { + .generation = ULONG_MAX, + .lock = INIT_LOCAL_LOCK(crngs.lock), +}; -static bool trust_cpu __ro_after_init = IS_ENABLED(CONFIG_RANDOM_TRUST_CPU); -static int __init parse_trust_cpu(char *arg) -{ - return kstrtobool(arg, &trust_cpu); -} -early_param("random.trust_cpu", parse_trust_cpu); +/* Used by crng_reseed() and crng_make_state() to extract a new seed from the input pool. */ +static void extract_entropy(void *buf, size_t len); -static bool crng_init_try_arch(struct crng_state *crng) +/* This extracts a new crng key from the input pool. */ +static void crng_reseed(void) { - int i; - bool arch_init = true; - unsigned long rv; - - for (i = 4; i < 16; i++) { - if (!arch_get_random_seed_long(&rv) && - !arch_get_random_long(&rv)) { - rv = random_get_entropy(); - arch_init = false; - } - crng->state[i] ^= rv; - } + unsigned long flags; + unsigned long next_gen; + u8 key[CHACHA_KEY_SIZE]; - return arch_init; + extract_entropy(key, sizeof(key)); + + /* + * We copy the new key into the base_crng, overwriting the old one, + * and update the generation counter. We avoid hitting ULONG_MAX, + * because the per-cpu crngs are initialized to ULONG_MAX, so this + * forces new CPUs that come online to always initialize. + */ + spin_lock_irqsave(&base_crng.lock, flags); + memcpy(base_crng.key, key, sizeof(base_crng.key)); + next_gen = base_crng.generation + 1; + if (next_gen == ULONG_MAX) + ++next_gen; + WRITE_ONCE(base_crng.generation, next_gen); + WRITE_ONCE(base_crng.birth, jiffies); + if (!static_branch_likely(&crng_is_ready)) + crng_init = CRNG_READY; + spin_unlock_irqrestore(&base_crng.lock, flags); + memzero_explicit(key, sizeof(key)); } -static bool __init crng_init_try_arch_early(void) +/* + * This generates a ChaCha block using the provided key, and then + * immediately overwites that key with half the block. It returns + * the resultant ChaCha state to the user, along with the second + * half of the block containing 32 bytes of random data that may + * be used; random_data_len may not be greater than 32. + * + * The returned ChaCha state contains within it a copy of the old + * key value, at index 4, so the state should always be zeroed out + * immediately after using in order to maintain forward secrecy. + * If the state cannot be erased in a timely manner, then it is + * safer to set the random_data parameter to &chacha_state[4] so + * that this function overwrites it before returning. + */ +static void crng_fast_key_erasure(u8 key[CHACHA_KEY_SIZE], + u32 chacha_state[CHACHA_STATE_WORDS], + u8 *random_data, size_t random_data_len) { - int i; - bool arch_init = true; - unsigned long rv; - - for (i = 4; i < 16; i++) { - if (!arch_get_random_seed_long_early(&rv) && - !arch_get_random_long_early(&rv)) { - rv = random_get_entropy(); - arch_init = false; - } - primary_crng.state[i] ^= rv; - } + u8 first_block[CHACHA_BLOCK_SIZE]; - return arch_init; -} + BUG_ON(random_data_len > 32); -static void crng_initialize_secondary(struct crng_state *crng) -{ - chacha_init_consts(crng->state); - _get_random_bytes(&crng->state[4], sizeof(u32) * 12); - crng_init_try_arch(crng); - crng->init_time = jiffies - CRNG_RESEED_INTERVAL - 1; + chacha_init_consts(chacha_state); + memcpy(&chacha_state[4], key, CHACHA_KEY_SIZE); + memset(&chacha_state[12], 0, sizeof(u32) * 4); + chacha20_block(chacha_state, first_block); + + memcpy(key, first_block, CHACHA_KEY_SIZE); + memcpy(random_data, first_block + CHACHA_KEY_SIZE, random_data_len); + memzero_explicit(first_block, sizeof(first_block)); } -static void __init crng_initialize_primary(void) -{ - _extract_entropy(&primary_crng.state[4], sizeof(u32) * 12); - if (crng_init_try_arch_early() && trust_cpu && crng_init < 2) { - invalidate_batched_entropy(); - numa_crng_init(); - crng_init = 2; - pr_notice("crng init done (trusting CPU's manufacturer)\n"); +/* + * Return whether the crng seed is considered to be sufficiently old + * that a reseeding is needed. This happens if the last reseeding + * was CRNG_RESEED_INTERVAL ago, or during early boot, at an interval + * proportional to the uptime. + */ +static bool crng_has_old_seed(void) +{ + static bool early_boot = true; + unsigned long interval = CRNG_RESEED_INTERVAL; + + if (unlikely(READ_ONCE(early_boot))) { + time64_t uptime = ktime_get_seconds(); + if (uptime >= CRNG_RESEED_INTERVAL / HZ * 2) + WRITE_ONCE(early_boot, false); + else + interval = max_t(unsigned int, CRNG_RESEED_START_INTERVAL, + (unsigned int)uptime / 2 * HZ); } - primary_crng.init_time = jiffies - CRNG_RESEED_INTERVAL - 1; + return time_is_before_jiffies(READ_ONCE(base_crng.birth) + interval); } -static void crng_finalize_init(void) +/* + * This function returns a ChaCha state that you may use for generating + * random data. It also returns up to 32 bytes on its own of random data + * that may be used; random_data_len may not be greater than 32. + */ +static void crng_make_state(u32 chacha_state[CHACHA_STATE_WORDS], + u8 *random_data, size_t random_data_len) { - if (!system_wq) { - /* We can't call numa_crng_init until we have workqueues, - * so mark this for processing later. */ - crng_need_final_init = true; - return; - } + unsigned long flags; + struct crng *crng; - invalidate_batched_entropy(); - numa_crng_init(); - crng_init = 2; - crng_need_final_init = false; - process_random_ready_list(); - wake_up_interruptible(&crng_init_wait); - kill_fasync(&fasync, SIGIO, POLL_IN); - pr_notice("crng init done\n"); - if (unseeded_warning.missed) { - pr_notice("%d get_random_xx warning(s) missed due to ratelimiting\n", - unseeded_warning.missed); - unseeded_warning.missed = 0; + BUG_ON(random_data_len > 32); + + /* + * For the fast path, we check whether we're ready, unlocked first, and + * then re-check once locked later. In the case where we're really not + * ready, we do fast key erasure with the base_crng directly, extracting + * when crng_init is CRNG_EMPTY. + */ + if (!crng_ready()) { + bool ready; + + spin_lock_irqsave(&base_crng.lock, flags); + ready = crng_ready(); + if (!ready) { + if (crng_init == CRNG_EMPTY) + extract_entropy(base_crng.key, sizeof(base_crng.key)); + crng_fast_key_erasure(base_crng.key, chacha_state, + random_data, random_data_len); + } + spin_unlock_irqrestore(&base_crng.lock, flags); + if (!ready) + return; } - if (urandom_warning.missed) { - pr_notice("%d urandom warning(s) missed due to ratelimiting\n", - urandom_warning.missed); - urandom_warning.missed = 0; + + /* + * If the base_crng is old enough, we reseed, which in turn bumps the + * generation counter that we check below. + */ + if (unlikely(crng_has_old_seed())) + crng_reseed(); + + local_lock_irqsave(&crngs.lock, flags); + crng = raw_cpu_ptr(&crngs); + + /* + * If our per-cpu crng is older than the base_crng, then it means + * somebody reseeded the base_crng. In that case, we do fast key + * erasure on the base_crng, and use its output as the new key + * for our per-cpu crng. This brings us up to date with base_crng. + */ + if (unlikely(crng->generation != READ_ONCE(base_crng.generation))) { + spin_lock(&base_crng.lock); + crng_fast_key_erasure(base_crng.key, chacha_state, + crng->key, sizeof(crng->key)); + crng->generation = base_crng.generation; + spin_unlock(&base_crng.lock); } + + /* + * Finally, when we've made it this far, our per-cpu crng has an up + * to date key, and we can do fast key erasure with it to produce + * some random data and a ChaCha state for the caller. All other + * branches of this function are "unlikely", so most of the time we + * should wind up here immediately. + */ + crng_fast_key_erasure(crng->key, chacha_state, random_data, random_data_len); + local_unlock_irqrestore(&crngs.lock, flags); } -static void do_numa_crng_init(struct work_struct *work) +static void _get_random_bytes(void *buf, size_t len) { - int i; - struct crng_state *crng; - struct crng_state **pool; - - pool = kcalloc(nr_node_ids, sizeof(*pool), GFP_KERNEL | __GFP_NOFAIL); - for_each_online_node(i) { - crng = kmalloc_node(sizeof(struct crng_state), - GFP_KERNEL | __GFP_NOFAIL, i); - spin_lock_init(&crng->lock); - crng_initialize_secondary(crng); - pool[i] = crng; - } - /* pairs with READ_ONCE() in select_crng() */ - if (cmpxchg_release(&crng_node_pool, NULL, pool) != NULL) { - for_each_node(i) - kfree(pool[i]); - kfree(pool); - } -} + u32 chacha_state[CHACHA_STATE_WORDS]; + u8 tmp[CHACHA_BLOCK_SIZE]; + size_t first_block_len; -static DECLARE_WORK(numa_crng_init_work, do_numa_crng_init); + if (!len) + return; -static void numa_crng_init(void) -{ - if (IS_ENABLED(CONFIG_NUMA)) - schedule_work(&numa_crng_init_work); -} + first_block_len = min_t(size_t, 32, len); + crng_make_state(chacha_state, buf, first_block_len); + len -= first_block_len; + buf += first_block_len; -static struct crng_state *select_crng(void) -{ - if (IS_ENABLED(CONFIG_NUMA)) { - struct crng_state **pool; - int nid = numa_node_id(); - - /* pairs with cmpxchg_release() in do_numa_crng_init() */ - pool = READ_ONCE(crng_node_pool); - if (pool && pool[nid]) - return pool[nid]; + while (len) { + if (len < CHACHA_BLOCK_SIZE) { + chacha20_block(chacha_state, tmp); + memcpy(buf, tmp, len); + memzero_explicit(tmp, sizeof(tmp)); + break; + } + + chacha20_block(chacha_state, buf); + if (unlikely(chacha_state[12] == 0)) + ++chacha_state[13]; + len -= CHACHA_BLOCK_SIZE; + buf += CHACHA_BLOCK_SIZE; } - return &primary_crng; + memzero_explicit(chacha_state, sizeof(chacha_state)); } /* - * crng_fast_load() can be called by code in the interrupt service - * path. So we can't afford to dilly-dally. Returns the number of - * bytes processed from cp. + * This function is the exported kernel interface. It returns some + * number of good random numbers, suitable for key generation, seeding + * TCP sequence numbers, etc. It does not rely on the hardware random + * number generator. For random bytes direct from the hardware RNG + * (when available), use get_random_bytes_arch(). In order to ensure + * that the randomness provided by this function is okay, the function + * wait_for_random_bytes() should be called and return 0 at least once + * at any point prior. */ -static size_t crng_fast_load(const u8 *cp, size_t len) +void get_random_bytes(void *buf, size_t len) { - unsigned long flags; - u8 *p; - size_t ret = 0; - - if (!spin_trylock_irqsave(&primary_crng.lock, flags)) - return 0; - if (crng_init != 0) { - spin_unlock_irqrestore(&primary_crng.lock, flags); - return 0; - } - p = (u8 *)&primary_crng.state[4]; - while (len > 0 && crng_init_cnt < CRNG_INIT_CNT_THRESH) { - p[crng_init_cnt % CHACHA_KEY_SIZE] ^= *cp; - cp++; crng_init_cnt++; len--; ret++; - } - spin_unlock_irqrestore(&primary_crng.lock, flags); - if (crng_init_cnt >= CRNG_INIT_CNT_THRESH) { - invalidate_batched_entropy(); - crng_init = 1; - pr_notice("fast init done\n"); - } - return ret; + warn_unseeded_randomness(); + _get_random_bytes(buf, len); } +EXPORT_SYMBOL(get_random_bytes); -/* - * crng_slow_load() is called by add_device_randomness, which has two - * attributes. (1) We can't trust the buffer passed to it is - * guaranteed to be unpredictable (so it might not have any entropy at - * all), and (2) it doesn't have the performance constraints of - * crng_fast_load(). - * - * So we do something more comprehensive which is guaranteed to touch - * all of the primary_crng's state, and which uses a LFSR with a - * period of 255 as part of the mixing algorithm. Finally, we do - * *not* advance crng_init_cnt since buffer we may get may be something - * like a fixed DMI table (for example), which might very well be - * unique to the machine, but is otherwise unvarying. - */ -static int crng_slow_load(const u8 *cp, size_t len) +static ssize_t get_random_bytes_user(struct iov_iter *iter) { - unsigned long flags; - static u8 lfsr = 1; - u8 tmp; - unsigned int i, max = CHACHA_KEY_SIZE; - const u8 *src_buf = cp; - u8 *dest_buf = (u8 *)&primary_crng.state[4]; + u32 chacha_state[CHACHA_STATE_WORDS]; + u8 block[CHACHA_BLOCK_SIZE]; + size_t ret = 0, copied; - if (!spin_trylock_irqsave(&primary_crng.lock, flags)) - return 0; - if (crng_init != 0) { - spin_unlock_irqrestore(&primary_crng.lock, flags); + if (unlikely(!iov_iter_count(iter))) return 0; - } - if (len > max) - max = len; - - for (i = 0; i < max; i++) { - tmp = lfsr; - lfsr >>= 1; - if (tmp & 1) - lfsr ^= 0xE1; - tmp = dest_buf[i % CHACHA_KEY_SIZE]; - dest_buf[i % CHACHA_KEY_SIZE] ^= src_buf[i % len] ^ lfsr; - lfsr += (tmp << 3) | (tmp >> 5); - } - spin_unlock_irqrestore(&primary_crng.lock, flags); - return 1; -} -static void crng_reseed(struct crng_state *crng, bool use_input_pool) -{ - unsigned long flags; - int i, num; - union { - u8 block[CHACHA_BLOCK_SIZE]; - u32 key[8]; - } buf; - - if (use_input_pool) { - num = extract_entropy(&buf, 32, 16); - if (num == 0) - return; - } else { - _extract_crng(&primary_crng, buf.block); - _crng_backtrack_protect(&primary_crng, buf.block, - CHACHA_KEY_SIZE); - } - spin_lock_irqsave(&crng->lock, flags); - for (i = 0; i < 8; i++) { - unsigned long rv; - if (!arch_get_random_seed_long(&rv) && - !arch_get_random_long(&rv)) - rv = random_get_entropy(); - crng->state[i + 4] ^= buf.key[i] ^ rv; + /* + * Immediately overwrite the ChaCha key at index 4 with random + * bytes, in case userspace causes copy_to_user() below to sleep + * forever, so that we still retain forward secrecy in that case. + */ + crng_make_state(chacha_state, (u8 *)&chacha_state[4], CHACHA_KEY_SIZE); + /* + * However, if we're doing a read of len <= 32, we don't need to + * use chacha_state after, so we can simply return those bytes to + * the user directly. + */ + if (iov_iter_count(iter) <= CHACHA_KEY_SIZE) { + ret = copy_to_iter(&chacha_state[4], CHACHA_KEY_SIZE, iter); + goto out_zero_chacha; } - memzero_explicit(&buf, sizeof(buf)); - WRITE_ONCE(crng->init_time, jiffies); - spin_unlock_irqrestore(&crng->lock, flags); - if (crng == &primary_crng && crng_init < 2) - crng_finalize_init(); -} -static void _extract_crng(struct crng_state *crng, u8 out[CHACHA_BLOCK_SIZE]) -{ - unsigned long flags, init_time; + for (;;) { + chacha20_block(chacha_state, block); + if (unlikely(chacha_state[12] == 0)) + ++chacha_state[13]; + + copied = copy_to_iter(block, sizeof(block), iter); + ret += copied; + if (!iov_iter_count(iter) || copied != sizeof(block)) + break; - if (crng_ready()) { - init_time = READ_ONCE(crng->init_time); - if (time_after(READ_ONCE(crng_global_init_time), init_time) || - time_after(jiffies, init_time + CRNG_RESEED_INTERVAL)) - crng_reseed(crng, crng == &primary_crng); + BUILD_BUG_ON(PAGE_SIZE % sizeof(block) != 0); + if (ret % PAGE_SIZE == 0) { + if (signal_pending(current)) + break; + cond_resched(); + } } - spin_lock_irqsave(&crng->lock, flags); - chacha20_block(&crng->state[0], out); - if (crng->state[12] == 0) - crng->state[13]++; - spin_unlock_irqrestore(&crng->lock, flags); -} -static void extract_crng(u8 out[CHACHA_BLOCK_SIZE]) -{ - _extract_crng(select_crng(), out); + memzero_explicit(block, sizeof(block)); +out_zero_chacha: + memzero_explicit(chacha_state, sizeof(chacha_state)); + return ret ? ret : -EFAULT; } /* - * Use the leftover bytes from the CRNG block output (if there is - * enough) to mutate the CRNG key to provide backtracking protection. + * Batched entropy returns random integers. The quality of the random + * number is good as /dev/urandom. In order to ensure that the randomness + * provided by this function is okay, the function wait_for_random_bytes() + * should be called and return 0 at least once at any point prior. */ -static void _crng_backtrack_protect(struct crng_state *crng, - u8 tmp[CHACHA_BLOCK_SIZE], int used) -{ - unsigned long flags; - u32 *s, *d; - int i; - used = round_up(used, sizeof(u32)); - if (used + CHACHA_KEY_SIZE > CHACHA_BLOCK_SIZE) { - extract_crng(tmp); - used = 0; - } - spin_lock_irqsave(&crng->lock, flags); - s = (u32 *)&tmp[used]; - d = &crng->state[4]; - for (i = 0; i < 8; i++) - *d++ ^= *s++; - spin_unlock_irqrestore(&crng->lock, flags); -} - -static void crng_backtrack_protect(u8 tmp[CHACHA_BLOCK_SIZE], int used) +#define DEFINE_BATCHED_ENTROPY(type) \ +struct batch_ ##type { \ + /* \ + * We make this 1.5x a ChaCha block, so that we get the \ + * remaining 32 bytes from fast key erasure, plus one full \ + * block from the detached ChaCha state. We can increase \ + * the size of this later if needed so long as we keep the \ + * formula of (integer_blocks + 0.5) * CHACHA_BLOCK_SIZE. \ + */ \ + type entropy[CHACHA_BLOCK_SIZE * 3 / (2 * sizeof(type))]; \ + local_lock_t lock; \ + unsigned long generation; \ + unsigned int position; \ +}; \ + \ +static DEFINE_PER_CPU(struct batch_ ##type, batched_entropy_ ##type) = { \ + .lock = INIT_LOCAL_LOCK(batched_entropy_ ##type.lock), \ + .position = UINT_MAX \ +}; \ + \ +type get_random_ ##type(void) \ +{ \ + type ret; \ + unsigned long flags; \ + struct batch_ ##type *batch; \ + unsigned long next_gen; \ + \ + warn_unseeded_randomness(); \ + \ + if (!crng_ready()) { \ + _get_random_bytes(&ret, sizeof(ret)); \ + return ret; \ + } \ + \ + local_lock_irqsave(&batched_entropy_ ##type.lock, flags); \ + batch = raw_cpu_ptr(&batched_entropy_##type); \ + \ + next_gen = READ_ONCE(base_crng.generation); \ + if (batch->position >= ARRAY_SIZE(batch->entropy) || \ + next_gen != batch->generation) { \ + _get_random_bytes(batch->entropy, sizeof(batch->entropy)); \ + batch->position = 0; \ + batch->generation = next_gen; \ + } \ + \ + ret = batch->entropy[batch->position]; \ + batch->entropy[batch->position] = 0; \ + ++batch->position; \ + local_unlock_irqrestore(&batched_entropy_ ##type.lock, flags); \ + return ret; \ +} \ +EXPORT_SYMBOL(get_random_ ##type); + +DEFINE_BATCHED_ENTROPY(u64) +DEFINE_BATCHED_ENTROPY(u32) + +#ifdef CONFIG_SMP +/* + * This function is called when the CPU is coming up, with entry + * CPUHP_RANDOM_PREPARE, which comes before CPUHP_WORKQUEUE_PREP. + */ +int __cold random_prepare_cpu(unsigned int cpu) { - _crng_backtrack_protect(select_crng(), tmp, used); + /* + * When the cpu comes back online, immediately invalidate both + * the per-cpu crng and all batches, so that we serve fresh + * randomness. + */ + per_cpu_ptr(&crngs, cpu)->generation = ULONG_MAX; + per_cpu_ptr(&batched_entropy_u32, cpu)->position = UINT_MAX; + per_cpu_ptr(&batched_entropy_u64, cpu)->position = UINT_MAX; + return 0; } +#endif -static ssize_t extract_crng_user(void __user *buf, size_t nbytes) +/* + * This function will use the architecture-specific hardware random + * number generator if it is available. It is not recommended for + * use. Use get_random_bytes() instead. It returns the number of + * bytes filled in. + */ +size_t __must_check get_random_bytes_arch(void *buf, size_t len) { - ssize_t ret = 0, i = CHACHA_BLOCK_SIZE; - u8 tmp[CHACHA_BLOCK_SIZE] __aligned(4); - int large_request = (nbytes > 256); - - while (nbytes) { - if (large_request && need_resched()) { - if (signal_pending(current)) { - if (ret == 0) - ret = -ERESTARTSYS; - break; - } - schedule(); - } + size_t left = len; + u8 *p = buf; + + while (left) { + unsigned long v; + size_t block_len = min_t(size_t, left, sizeof(unsigned long)); - extract_crng(tmp); - i = min_t(int, nbytes, CHACHA_BLOCK_SIZE); - if (copy_to_user(buf, tmp, i)) { - ret = -EFAULT; + if (!arch_get_random_long(&v)) break; - } - nbytes -= i; - buf += i; - ret += i; + memcpy(p, &v, block_len); + p += block_len; + left -= block_len; } - crng_backtrack_protect(tmp, i); - - /* Wipe data just written to memory */ - memzero_explicit(tmp, sizeof(tmp)); - return ret; + return len - left; } +EXPORT_SYMBOL(get_random_bytes_arch); -/********************************************************************* + +/********************************************************************** * - * Entropy input management + * Entropy accumulation and extraction routines. * - *********************************************************************/ + * Callers may add entropy via: + * + * static void mix_pool_bytes(const void *buf, size_t len) + * + * After which, if added entropy should be credited: + * + * static void credit_init_bits(size_t bits) + * + * Finally, extract entropy via: + * + * static void extract_entropy(void *buf, size_t len) + * + **********************************************************************/ -/* There is one of these per entropy source */ -struct timer_rand_state { - cycles_t last_time; - long last_delta, last_delta2; +enum { + POOL_BITS = BLAKE2S_HASH_SIZE * 8, + POOL_READY_BITS = POOL_BITS, /* When crng_init->CRNG_READY */ + POOL_EARLY_BITS = POOL_READY_BITS / 2 /* When crng_init->CRNG_EARLY */ }; -#define INIT_TIMER_RAND_STATE { INITIAL_JIFFIES, }; +static struct { + struct blake2s_state hash; + spinlock_t lock; + unsigned int init_bits; +} input_pool = { + .hash.h = { BLAKE2S_IV0 ^ (0x01010000 | BLAKE2S_HASH_SIZE), + BLAKE2S_IV1, BLAKE2S_IV2, BLAKE2S_IV3, BLAKE2S_IV4, + BLAKE2S_IV5, BLAKE2S_IV6, BLAKE2S_IV7 }, + .hash.outlen = BLAKE2S_HASH_SIZE, + .lock = __SPIN_LOCK_UNLOCKED(input_pool.lock), +}; + +static void _mix_pool_bytes(const void *buf, size_t len) +{ + blake2s_update(&input_pool.hash, buf, len); +} /* - * Add device- or boot-specific data to the input pool to help - * initialize it. - * - * None of this adds any entropy; it is meant to avoid the problem of - * the entropy pool having similar initial state across largely - * identical devices. + * This function adds bytes into the input pool. It does not + * update the initialization bit counter; the caller should call + * credit_init_bits if this is appropriate. */ -void add_device_randomness(const void *buf, unsigned int size) +static void mix_pool_bytes(const void *buf, size_t len) { - unsigned long time = random_get_entropy() ^ jiffies; unsigned long flags; - if (!crng_ready() && size) - crng_slow_load(buf, size); - - trace_add_device_randomness(size, _RET_IP_); spin_lock_irqsave(&input_pool.lock, flags); - _mix_pool_bytes(buf, size); - _mix_pool_bytes(&time, sizeof(time)); + _mix_pool_bytes(buf, len); spin_unlock_irqrestore(&input_pool.lock, flags); } -EXPORT_SYMBOL(add_device_randomness); - -static struct timer_rand_state input_timer_state = INIT_TIMER_RAND_STATE; /* - * This function adds entropy to the entropy "pool" by using timing - * delays. It uses the timer_rand_state structure to make an estimate - * of how many bits of entropy this call has added to the pool. - * - * The number "num" is also added to the pool - it should somehow describe - * the type of event which just happened. This is currently 0-255 for - * keyboard scan codes, and 256 upwards for interrupts. - * + * This is an HKDF-like construction for using the hashed collected entropy + * as a PRF key, that's then expanded block-by-block. */ -static void add_timer_randomness(struct timer_rand_state *state, unsigned num) +static void extract_entropy(void *buf, size_t len) { + unsigned long flags; + u8 seed[BLAKE2S_HASH_SIZE], next_key[BLAKE2S_HASH_SIZE]; struct { - long jiffies; - unsigned int cycles; - unsigned int num; - } sample; - long delta, delta2, delta3; - - sample.jiffies = jiffies; - sample.cycles = random_get_entropy(); - sample.num = num; - mix_pool_bytes(&sample, sizeof(sample)); - - /* - * Calculate number of bits of randomness we probably added. - * We take into account the first, second and third-order deltas - * in order to make our estimate. - */ - delta = sample.jiffies - READ_ONCE(state->last_time); - WRITE_ONCE(state->last_time, sample.jiffies); - - delta2 = delta - READ_ONCE(state->last_delta); - WRITE_ONCE(state->last_delta, delta); - - delta3 = delta2 - READ_ONCE(state->last_delta2); - WRITE_ONCE(state->last_delta2, delta2); + unsigned long rdseed[32 / sizeof(long)]; + size_t counter; + } block; + size_t i; + + for (i = 0; i < ARRAY_SIZE(block.rdseed); ++i) { + if (!arch_get_random_seed_long(&block.rdseed[i]) && + !arch_get_random_long(&block.rdseed[i])) + block.rdseed[i] = random_get_entropy(); + } - if (delta < 0) - delta = -delta; - if (delta2 < 0) - delta2 = -delta2; - if (delta3 < 0) - delta3 = -delta3; - if (delta > delta2) - delta = delta2; - if (delta > delta3) - delta = delta3; + spin_lock_irqsave(&input_pool.lock, flags); - /* - * delta is now minimum absolute delta. - * Round down by 1 bit on general principles, - * and limit entropy estimate to 12 bits. - */ - credit_entropy_bits(min_t(int, fls(delta >> 1), 11)); -} + /* seed = HASHPRF(last_key, entropy_input) */ + blake2s_final(&input_pool.hash, seed); -void add_input_randomness(unsigned int type, unsigned int code, - unsigned int value) -{ - static unsigned char last_value; + /* next_key = HASHPRF(seed, RDSEED || 0) */ + block.counter = 0; + blake2s(next_key, (u8 *)&block, seed, sizeof(next_key), sizeof(block), sizeof(seed)); + blake2s_init_key(&input_pool.hash, BLAKE2S_HASH_SIZE, next_key, sizeof(next_key)); - /* ignore autorepeat and the like */ - if (value == last_value) - return; + spin_unlock_irqrestore(&input_pool.lock, flags); + memzero_explicit(next_key, sizeof(next_key)); + + while (len) { + i = min_t(size_t, len, BLAKE2S_HASH_SIZE); + /* output = HASHPRF(seed, RDSEED || ++counter) */ + ++block.counter; + blake2s(buf, (u8 *)&block, seed, i, sizeof(block), sizeof(seed)); + len -= i; + buf += i; + } - last_value = value; - add_timer_randomness(&input_timer_state, - (type << 4) ^ code ^ (code >> 4) ^ value); - trace_add_input_randomness(POOL_ENTROPY_BITS()); + memzero_explicit(seed, sizeof(seed)); + memzero_explicit(&block, sizeof(block)); } -EXPORT_SYMBOL_GPL(add_input_randomness); - -static DEFINE_PER_CPU(struct fast_pool, irq_randomness); -#ifdef ADD_INTERRUPT_BENCH -static unsigned long avg_cycles, avg_deviation; +#define credit_init_bits(bits) if (!crng_ready()) _credit_init_bits(bits) -#define AVG_SHIFT 8 /* Exponential average factor k=1/256 */ -#define FIXED_1_2 (1 << (AVG_SHIFT - 1)) - -static void add_interrupt_bench(cycles_t start) +static void __cold _credit_init_bits(size_t bits) { - long delta = random_get_entropy() - start; - - /* Use a weighted moving average */ - delta = delta - ((avg_cycles + FIXED_1_2) >> AVG_SHIFT); - avg_cycles += delta; - /* And average deviation */ - delta = abs(delta) - ((avg_deviation + FIXED_1_2) >> AVG_SHIFT); - avg_deviation += delta; -} -#else -#define add_interrupt_bench(x) -#endif + static struct execute_work set_ready; + unsigned int new, orig, add; + unsigned long flags; -static u32 get_reg(struct fast_pool *f, struct pt_regs *regs) -{ - u32 *ptr = (u32 *)regs; - unsigned int idx; + if (!bits) + return; - if (regs == NULL) - return 0; - idx = READ_ONCE(f->reg_idx); - if (idx >= sizeof(struct pt_regs) / sizeof(u32)) - idx = 0; - ptr += idx++; - WRITE_ONCE(f->reg_idx, idx); - return *ptr; -} + add = min_t(size_t, bits, POOL_BITS); -void add_interrupt_randomness(int irq) -{ - struct fast_pool *fast_pool = this_cpu_ptr(&irq_randomness); - struct pt_regs *regs = get_irq_regs(); - unsigned long now = jiffies; - cycles_t cycles = random_get_entropy(); - u32 c_high, j_high; - u64 ip; - - if (cycles == 0) - cycles = get_reg(fast_pool, regs); - c_high = (sizeof(cycles) > 4) ? cycles >> 32 : 0; - j_high = (sizeof(now) > 4) ? now >> 32 : 0; - fast_pool->pool[0] ^= cycles ^ j_high ^ irq; - fast_pool->pool[1] ^= now ^ c_high; - ip = regs ? instruction_pointer(regs) : _RET_IP_; - fast_pool->pool[2] ^= ip; - fast_pool->pool[3] ^= - (sizeof(ip) > 4) ? ip >> 32 : get_reg(fast_pool, regs); - - fast_mix(fast_pool); - add_interrupt_bench(cycles); - - if (unlikely(crng_init == 0)) { - if ((fast_pool->count >= 64) && - crng_fast_load((u8 *)fast_pool->pool, sizeof(fast_pool->pool)) > 0) { - fast_pool->count = 0; - fast_pool->last = now; + do { + orig = READ_ONCE(input_pool.init_bits); + new = min_t(unsigned int, POOL_BITS, orig + add); + } while (cmpxchg(&input_pool.init_bits, orig, new) != orig); + + if (orig < POOL_READY_BITS && new >= POOL_READY_BITS) { + crng_reseed(); /* Sets crng_init to CRNG_READY under base_crng.lock. */ + execute_in_process_context(crng_set_ready, &set_ready); + process_random_ready_list(); + wake_up_interruptible(&crng_init_wait); + kill_fasync(&fasync, SIGIO, POLL_IN); + pr_notice("crng init done\n"); + if (urandom_warning.missed) + pr_notice("%d urandom warning(s) missed due to ratelimiting\n", + urandom_warning.missed); + } else if (orig < POOL_EARLY_BITS && new >= POOL_EARLY_BITS) { + spin_lock_irqsave(&base_crng.lock, flags); + /* Check if crng_init is CRNG_EMPTY, to avoid race with crng_reseed(). */ + if (crng_init == CRNG_EMPTY) { + extract_entropy(base_crng.key, sizeof(base_crng.key)); + crng_init = CRNG_EARLY; } - return; + spin_unlock_irqrestore(&base_crng.lock, flags); } +} - if ((fast_pool->count < 64) && !time_after(now, fast_pool->last + HZ)) - return; - - if (!spin_trylock(&input_pool.lock)) - return; - - fast_pool->last = now; - __mix_pool_bytes(&fast_pool->pool, sizeof(fast_pool->pool)); - spin_unlock(&input_pool.lock); - fast_pool->count = 0; +/********************************************************************** + * + * Entropy collection routines. + * + * The following exported functions are used for pushing entropy into + * the above entropy accumulation routines: + * + * void add_device_randomness(const void *buf, size_t len); + * void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy); + * void add_bootloader_randomness(const void *buf, size_t len); + * void add_interrupt_randomness(int irq); + * void add_input_randomness(unsigned int type, unsigned int code, unsigned int value); + * void add_disk_randomness(struct gendisk *disk); + * + * add_device_randomness() adds data to the input pool that + * is likely to differ between two devices (or possibly even per boot). + * This would be things like MAC addresses or serial numbers, or the + * read-out of the RTC. This does *not* credit any actual entropy to + * the pool, but it initializes the pool to different values for devices + * that might otherwise be identical and have very little entropy + * available to them (particularly common in the embedded world). + * + * add_hwgenerator_randomness() is for true hardware RNGs, and will credit + * entropy as specified by the caller. If the entropy pool is full it will + * block until more entropy is needed. + * + * add_bootloader_randomness() is called by bootloader drivers, such as EFI + * and device tree, and credits its input depending on whether or not the + * configuration option CONFIG_RANDOM_TRUST_BOOTLOADER is set. + * + * add_interrupt_randomness() uses the interrupt timing as random + * inputs to the entropy pool. Using the cycle counters and the irq source + * as inputs, it feeds the input pool roughly once a second or after 64 + * interrupts, crediting 1 bit of entropy for whichever comes first. + * + * add_input_randomness() uses the input layer interrupt timing, as well + * as the event type information from the hardware. + * + * add_disk_randomness() uses what amounts to the seek time of block + * layer request events, on a per-disk_devt basis, as input to the + * entropy pool. Note that high-speed solid state drives with very low + * seek times do not make for good sources of entropy, as their seek + * times are usually fairly consistent. + * + * The last two routines try to estimate how many bits of entropy + * to credit. They do this by keeping track of the first and second + * order deltas of the event timings. + * + **********************************************************************/ - /* award one bit for the contents of the fast pool */ - credit_entropy_bits(1); +static bool trust_cpu __ro_after_init = IS_ENABLED(CONFIG_RANDOM_TRUST_CPU); +static bool trust_bootloader __ro_after_init = IS_ENABLED(CONFIG_RANDOM_TRUST_BOOTLOADER); +static int __init parse_trust_cpu(char *arg) +{ + return kstrtobool(arg, &trust_cpu); } -EXPORT_SYMBOL_GPL(add_interrupt_randomness); - -#ifdef CONFIG_BLOCK -void add_disk_randomness(struct gendisk *disk) +static int __init parse_trust_bootloader(char *arg) { - if (!disk || !disk->random) - return; - /* first major is 1, so we get >= 0x200 here */ - add_timer_randomness(disk->random, 0x100 + disk_devt(disk)); - trace_add_disk_randomness(disk_devt(disk), POOL_ENTROPY_BITS()); + return kstrtobool(arg, &trust_bootloader); } -EXPORT_SYMBOL_GPL(add_disk_randomness); -#endif - -/********************************************************************* - * - * Entropy extraction routines - * - *********************************************************************/ +early_param("random.trust_cpu", parse_trust_cpu); +early_param("random.trust_bootloader", parse_trust_bootloader); /* - * This function decides how many bytes to actually take from the - * given pool, and also debits the entropy count accordingly. + * The first collection of entropy occurs at system boot while interrupts + * are still turned off. Here we push in latent entropy, RDSEED, a timestamp, + * utsname(), and the command line. Depending on the above configuration knob, + * RDSEED may be considered sufficient for initialization. Note that much + * earlier setup may already have pushed entropy into the input pool by the + * time we get here. */ -static size_t account(size_t nbytes, int min) +int __init random_init(const char *command_line) { - int entropy_count, orig; - size_t ibytes, nfrac; + ktime_t now = ktime_get_real(); + unsigned int i, arch_bytes; + unsigned long entropy; - BUG_ON(input_pool.entropy_count > POOL_FRACBITS); +#if defined(LATENT_ENTROPY_PLUGIN) + static const u8 compiletime_seed[BLAKE2S_BLOCK_SIZE] __initconst __latent_entropy; + _mix_pool_bytes(compiletime_seed, sizeof(compiletime_seed)); +#endif - /* Can we pull enough? */ -retry: - entropy_count = orig = READ_ONCE(input_pool.entropy_count); - if (WARN_ON(entropy_count < 0)) { - pr_warn("negative entropy count: count %d\n", entropy_count); - entropy_count = 0; + for (i = 0, arch_bytes = BLAKE2S_BLOCK_SIZE; + i < BLAKE2S_BLOCK_SIZE; i += sizeof(entropy)) { + if (!arch_get_random_seed_long_early(&entropy) && + !arch_get_random_long_early(&entropy)) { + entropy = random_get_entropy(); + arch_bytes -= sizeof(entropy); + } + _mix_pool_bytes(&entropy, sizeof(entropy)); } + _mix_pool_bytes(&now, sizeof(now)); + _mix_pool_bytes(utsname(), sizeof(*(utsname()))); + _mix_pool_bytes(command_line, strlen(command_line)); + add_latent_entropy(); - /* never pull more than available */ - ibytes = min_t(size_t, nbytes, entropy_count >> (POOL_ENTROPY_SHIFT + 3)); - if (ibytes < min) - ibytes = 0; - nfrac = ibytes << (POOL_ENTROPY_SHIFT + 3); - if ((size_t)entropy_count > nfrac) - entropy_count -= nfrac; - else - entropy_count = 0; - - if (cmpxchg(&input_pool.entropy_count, orig, entropy_count) != orig) - goto retry; - - trace_debit_entropy(8 * ibytes); - if (ibytes && POOL_ENTROPY_BITS() < random_write_wakeup_bits) { - wake_up_interruptible(&random_write_wait); - kill_fasync(&fasync, SIGIO, POLL_OUT); - } + if (crng_ready()) + crng_reseed(); + else if (trust_cpu) + credit_init_bits(arch_bytes * 8); - return ibytes; + return 0; } /* - * This function does the actual extraction for extract_entropy. + * Add device- or boot-specific data to the input pool to help + * initialize it. * - * Note: we assume that .poolwords is a multiple of 16 words. + * None of this adds any entropy; it is meant to avoid the problem of + * the entropy pool having similar initial state across largely + * identical devices. */ -static void extract_buf(u8 *out) +void add_device_randomness(const void *buf, size_t len) { - struct blake2s_state state __aligned(__alignof__(unsigned long)); - u8 hash[BLAKE2S_HASH_SIZE]; - unsigned long *salt; + unsigned long entropy = random_get_entropy(); unsigned long flags; - blake2s_init(&state, sizeof(hash)); - - /* - * If we have an architectural hardware random number - * generator, use it for BLAKE2's salt & personal fields. - */ - for (salt = (unsigned long *)&state.h[4]; - salt < (unsigned long *)&state.h[8]; ++salt) { - unsigned long v; - if (!arch_get_random_long(&v)) - break; - *salt ^= v; - } - - /* Generate a hash across the pool */ spin_lock_irqsave(&input_pool.lock, flags); - blake2s_update(&state, (const u8 *)input_pool_data, POOL_BYTES); - blake2s_final(&state, hash); /* final zeros out state */ - - /* - * We mix the hash back into the pool to prevent backtracking - * attacks (where the attacker knows the state of the pool - * plus the current outputs, and attempts to find previous - * outputs), unless the hash function can be inverted. By - * mixing at least a hash worth of hash data back, we make - * brute-forcing the feedback as hard as brute-forcing the - * hash. - */ - __mix_pool_bytes(hash, sizeof(hash)); + _mix_pool_bytes(&entropy, sizeof(entropy)); + _mix_pool_bytes(buf, len); spin_unlock_irqrestore(&input_pool.lock, flags); - - /* Note that EXTRACT_SIZE is half of hash size here, because above - * we've dumped the full length back into mixer. By reducing the - * amount that we emit, we retain a level of forward secrecy. - */ - memcpy(out, hash, EXTRACT_SIZE); - memzero_explicit(hash, sizeof(hash)); } +EXPORT_SYMBOL(add_device_randomness); -static ssize_t _extract_entropy(void *buf, size_t nbytes) +/* + * Interface for in-kernel drivers of true hardware RNGs. + * Those devices may produce endless random bits and will be throttled + * when our pool is full. + */ +void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy) { - ssize_t ret = 0, i; - u8 tmp[EXTRACT_SIZE]; - - while (nbytes) { - extract_buf(tmp); - i = min_t(int, nbytes, EXTRACT_SIZE); - memcpy(buf, tmp, i); - nbytes -= i; - buf += i; - ret += i; - } + mix_pool_bytes(buf, len); + credit_init_bits(entropy); - /* Wipe data just returned from memory */ - memzero_explicit(tmp, sizeof(tmp)); - - return ret; + /* + * Throttle writing to once every CRNG_RESEED_INTERVAL, unless + * we're not yet initialized. + */ + if (!kthread_should_stop() && crng_ready()) + schedule_timeout_interruptible(CRNG_RESEED_INTERVAL); } +EXPORT_SYMBOL_GPL(add_hwgenerator_randomness); /* - * This function extracts randomness from the "entropy pool", and - * returns it in a buffer. - * - * The min parameter specifies the minimum amount we can pull before - * failing to avoid races that defeat catastrophic reseeding. + * Handle random seed passed by bootloader, and credit it if + * CONFIG_RANDOM_TRUST_BOOTLOADER is set. */ -static ssize_t extract_entropy(void *buf, size_t nbytes, int min) +void __cold add_bootloader_randomness(const void *buf, size_t len) { - trace_extract_entropy(nbytes, POOL_ENTROPY_BITS(), _RET_IP_); - nbytes = account(nbytes, min); - return _extract_entropy(buf, nbytes); + mix_pool_bytes(buf, len); + if (trust_bootloader) + credit_init_bits(len * 8); } +EXPORT_SYMBOL_GPL(add_bootloader_randomness); -#define warn_unseeded_randomness(previous) \ - _warn_unseeded_randomness(__func__, (void *)_RET_IP_, (previous)) +struct fast_pool { + struct work_struct mix; + unsigned long pool[4]; + unsigned long last; + unsigned int count; +}; -static void _warn_unseeded_randomness(const char *func_name, void *caller, void **previous) -{ -#ifdef CONFIG_WARN_ALL_UNSEEDED_RANDOM - const bool print_once = false; +static DEFINE_PER_CPU(struct fast_pool, irq_randomness) = { +#ifdef CONFIG_64BIT +#define FASTMIX_PERM SIPHASH_PERMUTATION + .pool = { SIPHASH_CONST_0, SIPHASH_CONST_1, SIPHASH_CONST_2, SIPHASH_CONST_3 } #else - static bool print_once __read_mostly; -#endif - - if (print_once || crng_ready() || - (previous && (caller == READ_ONCE(*previous)))) - return; - WRITE_ONCE(*previous, caller); -#ifndef CONFIG_WARN_ALL_UNSEEDED_RANDOM - print_once = true; +#define FASTMIX_PERM HSIPHASH_PERMUTATION + .pool = { HSIPHASH_CONST_0, HSIPHASH_CONST_1, HSIPHASH_CONST_2, HSIPHASH_CONST_3 } #endif - if (__ratelimit(&unseeded_warning)) - printk_deferred(KERN_NOTICE "random: %s called from %pS with crng_init=%d\n", - func_name, caller, crng_init); -} +}; /* - * This function is the exported kernel interface. It returns some - * number of good random numbers, suitable for key generation, seeding - * TCP sequence numbers, etc. It does not rely on the hardware random - * number generator. For random bytes direct from the hardware RNG - * (when available), use get_random_bytes_arch(). In order to ensure - * that the randomness provided by this function is okay, the function - * wait_for_random_bytes() should be called and return 0 at least once - * at any point prior. + * This is [Half]SipHash-1-x, starting from an empty key. Because + * the key is fixed, it assumes that its inputs are non-malicious, + * and therefore this has no security on its own. s represents the + * four-word SipHash state, while v represents a two-word input. */ -static void _get_random_bytes(void *buf, int nbytes) -{ - u8 tmp[CHACHA_BLOCK_SIZE] __aligned(4); - - trace_get_random_bytes(nbytes, _RET_IP_); - - while (nbytes >= CHACHA_BLOCK_SIZE) { - extract_crng(buf); - buf += CHACHA_BLOCK_SIZE; - nbytes -= CHACHA_BLOCK_SIZE; - } - - if (nbytes > 0) { - extract_crng(tmp); - memcpy(buf, tmp, nbytes); - crng_backtrack_protect(tmp, nbytes); - } else - crng_backtrack_protect(tmp, CHACHA_BLOCK_SIZE); - memzero_explicit(tmp, sizeof(tmp)); -} - -void get_random_bytes(void *buf, int nbytes) +static void fast_mix(unsigned long s[4], unsigned long v1, unsigned long v2) { - static void *previous; - - warn_unseeded_randomness(&previous); - _get_random_bytes(buf, nbytes); + s[3] ^= v1; + FASTMIX_PERM(s[0], s[1], s[2], s[3]); + s[0] ^= v1; + s[3] ^= v2; + FASTMIX_PERM(s[0], s[1], s[2], s[3]); + s[0] ^= v2; } -EXPORT_SYMBOL(get_random_bytes); +#ifdef CONFIG_SMP /* - * Each time the timer fires, we expect that we got an unpredictable - * jump in the cycle counter. Even if the timer is running on another - * CPU, the timer activity will be touching the stack of the CPU that is - * generating entropy.. - * - * Note that we don't re-arm the timer in the timer itself - we are - * happy to be scheduled away, since that just makes the load more - * complex, but we do not want the timer to keep ticking unless the - * entropy loop is running. - * - * So the re-arming always happens in the entropy loop itself. + * This function is called when the CPU has just come online, with + * entry CPUHP_AP_RANDOM_ONLINE, just after CPUHP_AP_WORKQUEUE_ONLINE. */ -static void entropy_timer(struct timer_list *t) +int __cold random_online_cpu(unsigned int cpu) { - credit_entropy_bits(1); + /* + * During CPU shutdown and before CPU onlining, add_interrupt_ + * randomness() may schedule mix_interrupt_randomness(), and + * set the MIX_INFLIGHT flag. However, because the worker can + * be scheduled on a different CPU during this period, that + * flag will never be cleared. For that reason, we zero out + * the flag here, which runs just after workqueues are onlined + * for the CPU again. This also has the effect of setting the + * irq randomness count to zero so that new accumulated irqs + * are fresh. + */ + per_cpu_ptr(&irq_randomness, cpu)->count = 0; + return 0; } +#endif -/* - * If we have an actual cycle counter, see if we can - * generate enough entropy with timing noise - */ -static void try_to_generate_entropy(void) +static void mix_interrupt_randomness(struct work_struct *work) { - struct { - unsigned long now; - struct timer_list timer; - } stack; - - stack.now = random_get_entropy(); + struct fast_pool *fast_pool = container_of(work, struct fast_pool, mix); + /* + * The size of the copied stack pool is explicitly 2 longs so that we + * only ever ingest half of the siphash output each time, retaining + * the other half as the next "key" that carries over. The entropy is + * supposed to be sufficiently dispersed between bits so on average + * we don't wind up "losing" some. + */ + unsigned long pool[2]; + unsigned int count; - /* Slow counter - or none. Don't even bother */ - if (stack.now == random_get_entropy()) + /* Check to see if we're running on the wrong CPU due to hotplug. */ + local_irq_disable(); + if (fast_pool != this_cpu_ptr(&irq_randomness)) { + local_irq_enable(); return; - - timer_setup_on_stack(&stack.timer, entropy_timer, 0); - while (!crng_ready()) { - if (!timer_pending(&stack.timer)) - mod_timer(&stack.timer, jiffies + 1); - mix_pool_bytes(&stack.now, sizeof(stack.now)); - schedule(); - stack.now = random_get_entropy(); } - del_timer_sync(&stack.timer); - destroy_timer_on_stack(&stack.timer); - mix_pool_bytes(&stack.now, sizeof(stack.now)); -} - -/* - * Wait for the urandom pool to be seeded and thus guaranteed to supply - * cryptographically secure random numbers. This applies to: the /dev/urandom - * device, the get_random_bytes function, and the get_random_{u32,u64,int,long} - * family of functions. Using any of these functions without first calling - * this function forfeits the guarantee of security. - * - * Returns: 0 if the urandom pool has been seeded. - * -ERESTARTSYS if the function was interrupted by a signal. - */ -int wait_for_random_bytes(void) -{ - if (likely(crng_ready())) - return 0; - - do { - int ret; - ret = wait_event_interruptible_timeout(crng_init_wait, crng_ready(), HZ); - if (ret) - return ret > 0 ? 0 : ret; + /* + * Copy the pool to the stack so that the mixer always has a + * consistent view, before we reenable irqs again. + */ + memcpy(pool, fast_pool->pool, sizeof(pool)); + count = fast_pool->count; + fast_pool->count = 0; + fast_pool->last = jiffies; + local_irq_enable(); - try_to_generate_entropy(); - } while (!crng_ready()); + mix_pool_bytes(pool, sizeof(pool)); + credit_init_bits(max(1u, (count & U16_MAX) / 64)); - return 0; + memzero_explicit(pool, sizeof(pool)); } -EXPORT_SYMBOL(wait_for_random_bytes); -/* - * Returns whether or not the urandom pool has been seeded and thus guaranteed - * to supply cryptographically secure random numbers. This applies to: the - * /dev/urandom device, the get_random_bytes function, and the get_random_{u32, - * ,u64,int,long} family of functions. - * - * Returns: true if the urandom pool has been seeded. - * false if the urandom pool has not been seeded. - */ -bool rng_is_initialized(void) -{ - return crng_ready(); -} -EXPORT_SYMBOL(rng_is_initialized); - -/* - * Add a callback function that will be invoked when the nonblocking - * pool is initialised. - * - * returns: 0 if callback is successfully added - * -EALREADY if pool is already initialised (callback not called) - * -ENOENT if module for callback is not alive - */ -int add_random_ready_callback(struct random_ready_callback *rdy) +void add_interrupt_randomness(int irq) { - struct module *owner; - unsigned long flags; - int err = -EALREADY; - - if (crng_ready()) - return err; - - owner = rdy->owner; - if (!try_module_get(owner)) - return -ENOENT; - - spin_lock_irqsave(&random_ready_list_lock, flags); - if (crng_ready()) - goto out; - - owner = NULL; + enum { MIX_INFLIGHT = 1U << 31 }; + unsigned long entropy = random_get_entropy(); + struct fast_pool *fast_pool = this_cpu_ptr(&irq_randomness); + struct pt_regs *regs = get_irq_regs(); + unsigned int new_count; - list_add(&rdy->list, &random_ready_list); - err = 0; + fast_mix(fast_pool->pool, entropy, + (regs ? instruction_pointer(regs) : _RET_IP_) ^ swab(irq)); + new_count = ++fast_pool->count; -out: - spin_unlock_irqrestore(&random_ready_list_lock, flags); + if (new_count & MIX_INFLIGHT) + return; - module_put(owner); + if (new_count < 64 && !time_is_before_jiffies(fast_pool->last + HZ)) + return; - return err; + if (unlikely(!fast_pool->mix.func)) + INIT_WORK(&fast_pool->mix, mix_interrupt_randomness); + fast_pool->count |= MIX_INFLIGHT; + queue_work_on(raw_smp_processor_id(), system_highpri_wq, &fast_pool->mix); } -EXPORT_SYMBOL(add_random_ready_callback); +EXPORT_SYMBOL_GPL(add_interrupt_randomness); + +/* There is one of these per entropy source */ +struct timer_rand_state { + unsigned long last_time; + long last_delta, last_delta2; +}; /* - * Delete a previously registered readiness callback function. + * This function adds entropy to the entropy "pool" by using timing + * delays. It uses the timer_rand_state structure to make an estimate + * of how many bits of entropy this call has added to the pool. The + * value "num" is also added to the pool; it should somehow describe + * the type of event that just happened. */ -void del_random_ready_callback(struct random_ready_callback *rdy) +static void add_timer_randomness(struct timer_rand_state *state, unsigned int num) { - unsigned long flags; - struct module *owner = NULL; + unsigned long entropy = random_get_entropy(), now = jiffies, flags; + long delta, delta2, delta3; + unsigned int bits; - spin_lock_irqsave(&random_ready_list_lock, flags); - if (!list_empty(&rdy->list)) { - list_del_init(&rdy->list); - owner = rdy->owner; + /* + * If we're in a hard IRQ, add_interrupt_randomness() will be called + * sometime after, so mix into the fast pool. + */ + if (in_hardirq()) { + fast_mix(this_cpu_ptr(&irq_randomness)->pool, entropy, num); + } else { + spin_lock_irqsave(&input_pool.lock, flags); + _mix_pool_bytes(&entropy, sizeof(entropy)); + _mix_pool_bytes(&num, sizeof(num)); + spin_unlock_irqrestore(&input_pool.lock, flags); } - spin_unlock_irqrestore(&random_ready_list_lock, flags); - module_put(owner); -} -EXPORT_SYMBOL(del_random_ready_callback); + if (crng_ready()) + return; -/* - * This function will use the architecture-specific hardware random - * number generator if it is available. The arch-specific hw RNG will - * almost certainly be faster than what we can do in software, but it - * is impossible to verify that it is implemented securely (as - * opposed, to, say, the AES encryption of a sequence number using a - * key known by the NSA). So it's useful if we need the speed, but - * only if we're willing to trust the hardware manufacturer not to - * have put in a back door. - * - * Return number of bytes filled in. - */ -int __must_check get_random_bytes_arch(void *buf, int nbytes) -{ - int left = nbytes; - u8 *p = buf; + /* + * Calculate number of bits of randomness we probably added. + * We take into account the first, second and third-order deltas + * in order to make our estimate. + */ + delta = now - READ_ONCE(state->last_time); + WRITE_ONCE(state->last_time, now); + + delta2 = delta - READ_ONCE(state->last_delta); + WRITE_ONCE(state->last_delta, delta); - trace_get_random_bytes_arch(left, _RET_IP_); - while (left) { - unsigned long v; - int chunk = min_t(int, left, sizeof(unsigned long)); + delta3 = delta2 - READ_ONCE(state->last_delta2); + WRITE_ONCE(state->last_delta2, delta2); - if (!arch_get_random_long(&v)) - break; + if (delta < 0) + delta = -delta; + if (delta2 < 0) + delta2 = -delta2; + if (delta3 < 0) + delta3 = -delta3; + if (delta > delta2) + delta = delta2; + if (delta > delta3) + delta = delta3; - memcpy(p, &v, chunk); - p += chunk; - left -= chunk; - } + /* + * delta is now minimum absolute delta. Round down by 1 bit + * on general principles, and limit entropy estimate to 11 bits. + */ + bits = min(fls(delta >> 1), 11); - return nbytes - left; + /* + * As mentioned above, if we're in a hard IRQ, add_interrupt_randomness() + * will run after this, which uses a different crediting scheme of 1 bit + * per every 64 interrupts. In order to let that function do accounting + * close to the one in this function, we credit a full 64/64 bit per bit, + * and then subtract one to account for the extra one added. + */ + if (in_hardirq()) + this_cpu_ptr(&irq_randomness)->count += max(1u, bits * 64) - 1; + else + _credit_init_bits(bits); } -EXPORT_SYMBOL(get_random_bytes_arch); -/* - * init_std_data - initialize pool with system data - * - * This function clears the pool's entropy count and mixes some system - * data into the pool to prepare it for use. The pool is not cleared - * as that can only decrease the entropy in the pool. - */ -static void __init init_std_data(void) +void add_input_randomness(unsigned int type, unsigned int code, unsigned int value) { - int i; - ktime_t now = ktime_get_real(); - unsigned long rv; - - mix_pool_bytes(&now, sizeof(now)); - for (i = POOL_BYTES; i > 0; i -= sizeof(rv)) { - if (!arch_get_random_seed_long(&rv) && - !arch_get_random_long(&rv)) - rv = random_get_entropy(); - mix_pool_bytes(&rv, sizeof(rv)); - } - mix_pool_bytes(utsname(), sizeof(*(utsname()))); + static unsigned char last_value; + static struct timer_rand_state input_timer_state = { INITIAL_JIFFIES }; + + /* Ignore autorepeat and the like. */ + if (value == last_value) + return; + + last_value = value; + add_timer_randomness(&input_timer_state, + (type << 4) ^ code ^ (code >> 4) ^ value); } +EXPORT_SYMBOL_GPL(add_input_randomness); -/* - * Note that setup_arch() may call add_device_randomness() - * long before we get here. This allows seeding of the pools - * with some platform dependent data very early in the boot - * process. But it limits our options here. We must use - * statically allocated structures that already have all - * initializations complete at compile time. We should also - * take care not to overwrite the precious per platform data - * we were given. - */ -int __init rand_initialize(void) +#ifdef CONFIG_BLOCK +void add_disk_randomness(struct gendisk *disk) { - init_std_data(); - if (crng_need_final_init) - crng_finalize_init(); - crng_initialize_primary(); - crng_global_init_time = jiffies; - if (ratelimit_disable) { - urandom_warning.interval = 0; - unseeded_warning.interval = 0; - } - return 0; + if (!disk || !disk->random) + return; + /* First major is 1, so we get >= 0x200 here. */ + add_timer_randomness(disk->random, 0x100 + disk_devt(disk)); } +EXPORT_SYMBOL_GPL(add_disk_randomness); -#ifdef CONFIG_BLOCK -void rand_initialize_disk(struct gendisk *disk) +void __cold rand_initialize_disk(struct gendisk *disk) { struct timer_rand_state *state; @@ -1724,109 +1139,189 @@ void rand_initialize_disk(struct gendisk *disk) } #endif -static ssize_t urandom_read_nowarn(struct file *file, char __user *buf, - size_t nbytes, loff_t *ppos) +/* + * Each time the timer fires, we expect that we got an unpredictable + * jump in the cycle counter. Even if the timer is running on another + * CPU, the timer activity will be touching the stack of the CPU that is + * generating entropy.. + * + * Note that we don't re-arm the timer in the timer itself - we are + * happy to be scheduled away, since that just makes the load more + * complex, but we do not want the timer to keep ticking unless the + * entropy loop is running. + * + * So the re-arming always happens in the entropy loop itself. + */ +static void __cold entropy_timer(struct timer_list *t) { - int ret; - - nbytes = min_t(size_t, nbytes, INT_MAX >> (POOL_ENTROPY_SHIFT + 3)); - ret = extract_crng_user(buf, nbytes); - trace_urandom_read(8 * nbytes, 0, POOL_ENTROPY_BITS()); - return ret; + credit_init_bits(1); } -static ssize_t urandom_read(struct file *file, char __user *buf, size_t nbytes, - loff_t *ppos) +/* + * If we have an actual cycle counter, see if we can + * generate enough entropy with timing noise + */ +static void __cold try_to_generate_entropy(void) { - static int maxwarn = 10; + struct { + unsigned long entropy; + struct timer_list timer; + } stack; + + stack.entropy = random_get_entropy(); + + /* Slow counter - or none. Don't even bother */ + if (stack.entropy == random_get_entropy()) + return; - if (!crng_ready() && maxwarn > 0) { - maxwarn--; - if (__ratelimit(&urandom_warning)) - pr_notice("%s: uninitialized urandom read (%zd bytes read)\n", - current->comm, nbytes); + timer_setup_on_stack(&stack.timer, entropy_timer, 0); + while (!crng_ready() && !signal_pending(current)) { + if (!timer_pending(&stack.timer)) + mod_timer(&stack.timer, jiffies + 1); + mix_pool_bytes(&stack.entropy, sizeof(stack.entropy)); + schedule(); + stack.entropy = random_get_entropy(); } - return urandom_read_nowarn(file, buf, nbytes, ppos); + del_timer_sync(&stack.timer); + destroy_timer_on_stack(&stack.timer); + mix_pool_bytes(&stack.entropy, sizeof(stack.entropy)); } -static ssize_t random_read(struct file *file, char __user *buf, size_t nbytes, - loff_t *ppos) + +/********************************************************************** + * + * Userspace reader/writer interfaces. + * + * getrandom(2) is the primary modern interface into the RNG and should + * be used in preference to anything else. + * + * Reading from /dev/random has the same functionality as calling + * getrandom(2) with flags=0. In earlier versions, however, it had + * vastly different semantics and should therefore be avoided, to + * prevent backwards compatibility issues. + * + * Reading from /dev/urandom has the same functionality as calling + * getrandom(2) with flags=GRND_INSECURE. Because it does not block + * waiting for the RNG to be ready, it should not be used. + * + * Writing to either /dev/random or /dev/urandom adds entropy to + * the input pool but does not credit it. + * + * Polling on /dev/random indicates when the RNG is initialized, on + * the read side, and when it wants new entropy, on the write side. + * + * Both /dev/random and /dev/urandom have the same set of ioctls for + * adding entropy, getting the entropy count, zeroing the count, and + * reseeding the crng. + * + **********************************************************************/ + +SYSCALL_DEFINE3(getrandom, char __user *, ubuf, size_t, len, unsigned int, flags) { + struct iov_iter iter; + struct iovec iov; int ret; - ret = wait_for_random_bytes(); - if (ret != 0) + if (flags & ~(GRND_NONBLOCK | GRND_RANDOM | GRND_INSECURE)) + return -EINVAL; + + /* + * Requesting insecure and blocking randomness at the same time makes + * no sense. + */ + if ((flags & (GRND_INSECURE | GRND_RANDOM)) == (GRND_INSECURE | GRND_RANDOM)) + return -EINVAL; + + if (!crng_ready() && !(flags & GRND_INSECURE)) { + if (flags & GRND_NONBLOCK) + return -EAGAIN; + ret = wait_for_random_bytes(); + if (unlikely(ret)) + return ret; + } + + ret = import_single_range(READ, ubuf, len, &iov, &iter); + if (unlikely(ret)) return ret; - return urandom_read_nowarn(file, buf, nbytes, ppos); + return get_random_bytes_user(&iter); } static __poll_t random_poll(struct file *file, poll_table *wait) { - __poll_t mask; - poll_wait(file, &crng_init_wait, wait); - poll_wait(file, &random_write_wait, wait); - mask = 0; - if (crng_ready()) - mask |= EPOLLIN | EPOLLRDNORM; - if (POOL_ENTROPY_BITS() < random_write_wakeup_bits) - mask |= EPOLLOUT | EPOLLWRNORM; - return mask; + return crng_ready() ? EPOLLIN | EPOLLRDNORM : EPOLLOUT | EPOLLWRNORM; } -static int write_pool(const char __user *buffer, size_t count) +static ssize_t write_pool_user(struct iov_iter *iter) { - size_t bytes; - u32 t, buf[16]; - const char __user *p = buffer; + u8 block[BLAKE2S_BLOCK_SIZE]; + ssize_t ret = 0; + size_t copied; - while (count > 0) { - int b, i = 0; + if (unlikely(!iov_iter_count(iter))) + return 0; - bytes = min(count, sizeof(buf)); - if (copy_from_user(&buf, p, bytes)) - return -EFAULT; + for (;;) { + copied = copy_from_iter(block, sizeof(block), iter); + ret += copied; + mix_pool_bytes(block, copied); + if (!iov_iter_count(iter) || copied != sizeof(block)) + break; - for (b = bytes; b > 0; b -= sizeof(u32), i++) { - if (!arch_get_random_int(&t)) + BUILD_BUG_ON(PAGE_SIZE % sizeof(block) != 0); + if (ret % PAGE_SIZE == 0) { + if (signal_pending(current)) break; - buf[i] ^= t; + cond_resched(); } + } - count -= bytes; - p += bytes; + memzero_explicit(block, sizeof(block)); + return ret ? ret : -EFAULT; +} + +static ssize_t random_write_iter(struct kiocb *kiocb, struct iov_iter *iter) +{ + return write_pool_user(iter); +} - mix_pool_bytes(buf, bytes); - cond_resched(); +static ssize_t urandom_read_iter(struct kiocb *kiocb, struct iov_iter *iter) +{ + static int maxwarn = 10; + + if (!crng_ready()) { + if (!ratelimit_disable && maxwarn <= 0) + ++urandom_warning.missed; + else if (ratelimit_disable || __ratelimit(&urandom_warning)) { + --maxwarn; + pr_notice("%s: uninitialized urandom read (%zu bytes read)\n", + current->comm, iov_iter_count(iter)); + } } - return 0; + return get_random_bytes_user(iter); } -static ssize_t random_write(struct file *file, const char __user *buffer, - size_t count, loff_t *ppos) +static ssize_t random_read_iter(struct kiocb *kiocb, struct iov_iter *iter) { - size_t ret; + int ret; - ret = write_pool(buffer, count); - if (ret) + ret = wait_for_random_bytes(); + if (ret != 0) return ret; - - return (ssize_t)count; + return get_random_bytes_user(iter); } static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) { - int size, ent_count; int __user *p = (int __user *)arg; - int retval; + int ent_count; switch (cmd) { case RNDGETENTCNT: - /* inherently racy, no point locking */ - ent_count = POOL_ENTROPY_BITS(); - if (put_user(ent_count, p)) + /* Inherently racy, no point locking. */ + if (put_user(input_pool.init_bits, p)) return -EFAULT; return 0; case RNDADDTOENTCNT: @@ -1834,40 +1329,48 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) return -EPERM; if (get_user(ent_count, p)) return -EFAULT; - return credit_entropy_bits_safe(ent_count); - case RNDADDENTROPY: + if (ent_count < 0) + return -EINVAL; + credit_init_bits(ent_count); + return 0; + case RNDADDENTROPY: { + struct iov_iter iter; + struct iovec iov; + ssize_t ret; + int len; + if (!capable(CAP_SYS_ADMIN)) return -EPERM; if (get_user(ent_count, p++)) return -EFAULT; if (ent_count < 0) return -EINVAL; - if (get_user(size, p++)) + if (get_user(len, p++)) + return -EFAULT; + ret = import_single_range(WRITE, p, len, &iov, &iter); + if (unlikely(ret)) + return ret; + ret = write_pool_user(&iter); + if (unlikely(ret < 0)) + return ret; + /* Since we're crediting, enforce that it was all written into the pool. */ + if (unlikely(ret != len)) return -EFAULT; - retval = write_pool((const char __user *)p, size); - if (retval < 0) - return retval; - return credit_entropy_bits_safe(ent_count); + credit_init_bits(ent_count); + return 0; + } case RNDZAPENTCNT: case RNDCLEARPOOL: - /* - * Clear the entropy pool counters. We no longer clear - * the entropy pool, as that's silly. - */ + /* No longer has any effect. */ if (!capable(CAP_SYS_ADMIN)) return -EPERM; - if (xchg(&input_pool.entropy_count, 0) && random_write_wakeup_bits) { - wake_up_interruptible(&random_write_wait); - kill_fasync(&fasync, SIGIO, POLL_OUT); - } return 0; case RNDRESEEDCRNG: if (!capable(CAP_SYS_ADMIN)) return -EPERM; - if (crng_init < 2) + if (!crng_ready()) return -ENODATA; - crng_reseed(&primary_crng, true); - WRITE_ONCE(crng_global_init_time, jiffies - 1); + crng_reseed(); return 0; default: return -EINVAL; @@ -1880,55 +1383,56 @@ static int random_fasync(int fd, struct file *filp, int on) } const struct file_operations random_fops = { - .read = random_read, - .write = random_write, + .read_iter = random_read_iter, + .write_iter = random_write_iter, .poll = random_poll, .unlocked_ioctl = random_ioctl, .compat_ioctl = compat_ptr_ioctl, .fasync = random_fasync, .llseek = noop_llseek, + .splice_read = generic_file_splice_read, + .splice_write = iter_file_splice_write, }; const struct file_operations urandom_fops = { - .read = urandom_read, - .write = random_write, + .read_iter = urandom_read_iter, + .write_iter = random_write_iter, .unlocked_ioctl = random_ioctl, .compat_ioctl = compat_ptr_ioctl, .fasync = random_fasync, .llseek = noop_llseek, + .splice_read = generic_file_splice_read, + .splice_write = iter_file_splice_write, }; -SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count, unsigned int, - flags) -{ - int ret; - - if (flags & ~(GRND_NONBLOCK | GRND_RANDOM | GRND_INSECURE)) - return -EINVAL; - - /* - * Requesting insecure and blocking randomness at the same time makes - * no sense. - */ - if ((flags & (GRND_INSECURE | GRND_RANDOM)) == (GRND_INSECURE | GRND_RANDOM)) - return -EINVAL; - - if (count > INT_MAX) - count = INT_MAX; - - if (!(flags & GRND_INSECURE) && !crng_ready()) { - if (flags & GRND_NONBLOCK) - return -EAGAIN; - ret = wait_for_random_bytes(); - if (unlikely(ret)) - return ret; - } - return urandom_read_nowarn(NULL, buf, count, NULL); -} /******************************************************************** * - * Sysctl interface + * Sysctl interface. + * + * These are partly unused legacy knobs with dummy values to not break + * userspace and partly still useful things. They are usually accessible + * in /proc/sys/kernel/random/ and are as follows: + * + * - boot_id - a UUID representing the current boot. + * + * - uuid - a random UUID, different each time the file is read. + * + * - poolsize - the number of bits of entropy that the input pool can + * hold, tied to the POOL_BITS constant. + * + * - entropy_avail - the number of bits of entropy currently in the + * input pool. Always <= poolsize. + * + * - write_wakeup_threshold - the amount of entropy in the input pool + * below which write polls to /dev/random will unblock, requesting + * more entropy, tied to the POOL_READY_BITS constant. It is writable + * to avoid breaking old userspaces, but writing to it does not + * change any behavior of the RNG. + * + * - urandom_min_reseed_secs - fixed to the value CRNG_RESEED_INTERVAL. + * It is writable to avoid breaking old userspaces, but writing + * to it does not change any behavior of the RNG. * ********************************************************************/ @@ -1936,25 +1440,28 @@ SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count, unsigned int, #include -static int min_write_thresh; -static int max_write_thresh = POOL_BITS; -static int random_min_urandom_seed = 60; -static char sysctl_bootid[16]; +static int sysctl_random_min_urandom_seed = CRNG_RESEED_INTERVAL / HZ; +static int sysctl_random_write_wakeup_bits = POOL_READY_BITS; +static int sysctl_poolsize = POOL_BITS; +static u8 sysctl_bootid[UUID_SIZE]; /* * This function is used to return both the bootid UUID, and random - * UUID. The difference is in whether table->data is NULL; if it is, + * UUID. The difference is in whether table->data is NULL; if it is, * then a new UUID is generated and returned to the user. - * - * If the user accesses this via the proc interface, the UUID will be - * returned as an ASCII string in the standard UUID format; if via the - * sysctl system call, as 16 bytes of binary data. */ -static int proc_do_uuid(struct ctl_table *table, int write, void *buffer, +static int proc_do_uuid(struct ctl_table *table, int write, void *buf, size_t *lenp, loff_t *ppos) { - struct ctl_table fake_table; - unsigned char buf[64], tmp_uuid[16], *uuid; + u8 tmp_uuid[UUID_SIZE], *uuid; + char uuid_string[UUID_STRING_LEN + 1]; + struct ctl_table fake_table = { + .data = uuid_string, + .maxlen = UUID_STRING_LEN + }; + + if (write) + return -EPERM; uuid = table->data; if (!uuid) { @@ -1969,32 +1476,17 @@ static int proc_do_uuid(struct ctl_table *table, int write, void *buffer, spin_unlock(&bootid_spinlock); } - sprintf(buf, "%pU", uuid); - - fake_table.data = buf; - fake_table.maxlen = sizeof(buf); - - return proc_dostring(&fake_table, write, buffer, lenp, ppos); + snprintf(uuid_string, sizeof(uuid_string), "%pU", uuid); + return proc_dostring(&fake_table, 0, buf, lenp, ppos); } -/* - * Return entropy available scaled to integral bits - */ -static int proc_do_entropy(struct ctl_table *table, int write, void *buffer, - size_t *lenp, loff_t *ppos) +/* The same as proc_dointvec, but writes don't change anything. */ +static int proc_do_rointvec(struct ctl_table *table, int write, void *buf, + size_t *lenp, loff_t *ppos) { - struct ctl_table fake_table; - int entropy_count; - - entropy_count = *(int *)table->data >> POOL_ENTROPY_SHIFT; - - fake_table.data = &entropy_count; - fake_table.maxlen = sizeof(entropy_count); - - return proc_dointvec(&fake_table, write, buffer, lenp, ppos); + return write ? 0 : proc_dointvec(table, 0, buf, lenp, ppos); } -static int sysctl_poolsize = POOL_BITS; static struct ctl_table random_table[] = { { .procname = "poolsize", @@ -2005,62 +1497,42 @@ static struct ctl_table random_table[] = { }, { .procname = "entropy_avail", + .data = &input_pool.init_bits, .maxlen = sizeof(int), .mode = 0444, - .proc_handler = proc_do_entropy, - .data = &input_pool.entropy_count, + .proc_handler = proc_dointvec, }, { .procname = "write_wakeup_threshold", - .data = &random_write_wakeup_bits, + .data = &sysctl_random_write_wakeup_bits, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec_minmax, - .extra1 = &min_write_thresh, - .extra2 = &max_write_thresh, + .proc_handler = proc_do_rointvec, }, { .procname = "urandom_min_reseed_secs", - .data = &random_min_urandom_seed, + .data = &sysctl_random_min_urandom_seed, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_do_rointvec, }, { .procname = "boot_id", .data = &sysctl_bootid, - .maxlen = 16, .mode = 0444, .proc_handler = proc_do_uuid, }, { .procname = "uuid", - .maxlen = 16, .mode = 0444, .proc_handler = proc_do_uuid, }, -#ifdef ADD_INTERRUPT_BENCH - { - .procname = "add_interrupt_avg_cycles", - .data = &avg_cycles, - .maxlen = sizeof(avg_cycles), - .mode = 0444, - .proc_handler = proc_doulongvec_minmax, - }, - { - .procname = "add_interrupt_avg_deviation", - .data = &avg_deviation, - .maxlen = sizeof(avg_deviation), - .mode = 0444, - .proc_handler = proc_doulongvec_minmax, - }, -#endif { } }; /* - * rand_initialize() is called before sysctl_init(), - * so we cannot call register_sysctl_init() in rand_initialize() + * random_init() is called before sysctl_init(), + * so we cannot call register_sysctl_init() in random_init() */ static int __init random_sysctls_init(void) { @@ -2068,170 +1540,4 @@ static int __init random_sysctls_init(void) return 0; } device_initcall(random_sysctls_init); -#endif /* CONFIG_SYSCTL */ - -struct batched_entropy { - union { - u64 entropy_u64[CHACHA_BLOCK_SIZE / sizeof(u64)]; - u32 entropy_u32[CHACHA_BLOCK_SIZE / sizeof(u32)]; - }; - unsigned int position; - spinlock_t batch_lock; -}; - -/* - * Get a random word for internal kernel use only. The quality of the random - * number is good as /dev/urandom, but there is no backtrack protection, with - * the goal of being quite fast and not depleting entropy. In order to ensure - * that the randomness provided by this function is okay, the function - * wait_for_random_bytes() should be called and return 0 at least once at any - * point prior. - */ -static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u64) = { - .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u64.lock), -}; - -u64 get_random_u64(void) -{ - u64 ret; - unsigned long flags; - struct batched_entropy *batch; - static void *previous; - - warn_unseeded_randomness(&previous); - - batch = raw_cpu_ptr(&batched_entropy_u64); - spin_lock_irqsave(&batch->batch_lock, flags); - if (batch->position % ARRAY_SIZE(batch->entropy_u64) == 0) { - extract_crng((u8 *)batch->entropy_u64); - batch->position = 0; - } - ret = batch->entropy_u64[batch->position++]; - spin_unlock_irqrestore(&batch->batch_lock, flags); - return ret; -} -EXPORT_SYMBOL(get_random_u64); - -static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u32) = { - .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u32.lock), -}; -u32 get_random_u32(void) -{ - u32 ret; - unsigned long flags; - struct batched_entropy *batch; - static void *previous; - - warn_unseeded_randomness(&previous); - - batch = raw_cpu_ptr(&batched_entropy_u32); - spin_lock_irqsave(&batch->batch_lock, flags); - if (batch->position % ARRAY_SIZE(batch->entropy_u32) == 0) { - extract_crng((u8 *)batch->entropy_u32); - batch->position = 0; - } - ret = batch->entropy_u32[batch->position++]; - spin_unlock_irqrestore(&batch->batch_lock, flags); - return ret; -} -EXPORT_SYMBOL(get_random_u32); - -/* It's important to invalidate all potential batched entropy that might - * be stored before the crng is initialized, which we can do lazily by - * simply resetting the counter to zero so that it's re-extracted on the - * next usage. */ -static void invalidate_batched_entropy(void) -{ - int cpu; - unsigned long flags; - - for_each_possible_cpu(cpu) { - struct batched_entropy *batched_entropy; - - batched_entropy = per_cpu_ptr(&batched_entropy_u32, cpu); - spin_lock_irqsave(&batched_entropy->batch_lock, flags); - batched_entropy->position = 0; - spin_unlock(&batched_entropy->batch_lock); - - batched_entropy = per_cpu_ptr(&batched_entropy_u64, cpu); - spin_lock(&batched_entropy->batch_lock); - batched_entropy->position = 0; - spin_unlock_irqrestore(&batched_entropy->batch_lock, flags); - } -} - -/** - * randomize_page - Generate a random, page aligned address - * @start: The smallest acceptable address the caller will take. - * @range: The size of the area, starting at @start, within which the - * random address must fall. - * - * If @start + @range would overflow, @range is capped. - * - * NOTE: Historical use of randomize_range, which this replaces, presumed that - * @start was already page aligned. We now align it regardless. - * - * Return: A page aligned address within [start, start + range). On error, - * @start is returned. - */ -unsigned long randomize_page(unsigned long start, unsigned long range) -{ - if (!PAGE_ALIGNED(start)) { - range -= PAGE_ALIGN(start) - start; - start = PAGE_ALIGN(start); - } - - if (start > ULONG_MAX - range) - range = ULONG_MAX - start; - - range >>= PAGE_SHIFT; - - if (range == 0) - return start; - - return start + (get_random_long() % range << PAGE_SHIFT); -} - -/* Interface for in-kernel drivers of true hardware RNGs. - * Those devices may produce endless random bits and will be throttled - * when our pool is full. - */ -void add_hwgenerator_randomness(const char *buffer, size_t count, - size_t entropy) -{ - if (unlikely(crng_init == 0)) { - size_t ret = crng_fast_load(buffer, count); - mix_pool_bytes(buffer, ret); - count -= ret; - buffer += ret; - if (!count || crng_init == 0) - return; - } - - /* Throttle writing if we're above the trickle threshold. - * We'll be woken up again once below random_write_wakeup_thresh, - * when the calling thread is about to terminate, or once - * CRNG_RESEED_INTERVAL has lapsed. - */ - wait_event_interruptible_timeout(random_write_wait, - !system_wq || kthread_should_stop() || - POOL_ENTROPY_BITS() <= random_write_wakeup_bits, - CRNG_RESEED_INTERVAL); - mix_pool_bytes(buffer, count); - credit_entropy_bits(entropy); -} -EXPORT_SYMBOL_GPL(add_hwgenerator_randomness); - -/* Handle random seed passed by bootloader. - * If the seed is trustworthy, it would be regarded as hardware RNGs. Otherwise - * it would be regarded as device data. - * The decision is controlled by CONFIG_RANDOM_TRUST_BOOTLOADER. - */ -void add_bootloader_randomness(const void *buf, unsigned int size) -{ - if (IS_ENABLED(CONFIG_RANDOM_TRUST_BOOTLOADER)) - add_hwgenerator_randomness(buf, size, size * 8); - else - add_device_randomness(buf, size); -} -EXPORT_SYMBOL_GPL(add_bootloader_randomness); +#endif diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_client.c b/drivers/hid/amd-sfh-hid/amd_sfh_client.c index c5de0ec4f9d03..444acd9e2cd6a 100644 --- a/drivers/hid/amd-sfh-hid/amd_sfh_client.c +++ b/drivers/hid/amd-sfh-hid/amd_sfh_client.c @@ -227,6 +227,17 @@ int amd_sfh_hid_client_init(struct amd_mp2_dev *privdata) dev_dbg(dev, "sid 0x%x status 0x%x\n", cl_data->sensor_idx[i], cl_data->sensor_sts[i]); } + if (privdata->mp2_ops->discovery_status && + privdata->mp2_ops->discovery_status(privdata) == 0) { + amd_sfh_hid_client_deinit(privdata); + for (i = 0; i < cl_data->num_hid_devices; i++) { + devm_kfree(dev, cl_data->feature_report[i]); + devm_kfree(dev, in_data->input_report[i]); + devm_kfree(dev, cl_data->report_descr[i]); + } + dev_warn(dev, "Failed to discover, sensors not enabled\n"); + return -EOPNOTSUPP; + } schedule_delayed_work(&cl_data->work_buffer, msecs_to_jiffies(AMD_SFH_IDLE_LOOP)); return 0; diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c index 19fa734a9a793..abd7f65860958 100644 --- a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c +++ b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c @@ -130,6 +130,12 @@ static int amd_sfh_irq_init_v2(struct amd_mp2_dev *privdata) return 0; } +static int amd_sfh_dis_sts_v2(struct amd_mp2_dev *privdata) +{ + return (readl(privdata->mmio + AMD_P2C_MSG(1)) & + SENSOR_DISCOVERY_STATUS_MASK) >> SENSOR_DISCOVERY_STATUS_SHIFT; +} + void amd_start_sensor(struct amd_mp2_dev *privdata, struct amd_mp2_sensor_info info) { union sfh_cmd_param cmd_param; @@ -245,6 +251,7 @@ static const struct amd_mp2_ops amd_sfh_ops_v2 = { .response = amd_sfh_wait_response_v2, .clear_intr = amd_sfh_clear_intr_v2, .init_intr = amd_sfh_irq_init_v2, + .discovery_status = amd_sfh_dis_sts_v2, }; static const struct amd_mp2_ops amd_sfh_ops = { diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.h b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.h index 97b99861fae25..9aa88a91ac8d1 100644 --- a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.h +++ b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.h @@ -39,6 +39,9 @@ #define AMD_SFH_IDLE_LOOP 200 +#define SENSOR_DISCOVERY_STATUS_MASK GENMASK(5, 3) +#define SENSOR_DISCOVERY_STATUS_SHIFT 3 + /* SFH Command register */ union sfh_cmd_base { u32 ul; @@ -143,5 +146,6 @@ struct amd_mp2_ops { int (*response)(struct amd_mp2_dev *mp2, u8 sid, u32 sensor_sts); void (*clear_intr)(struct amd_mp2_dev *privdata); int (*init_intr)(struct amd_mp2_dev *privdata); + int (*discovery_status)(struct amd_mp2_dev *privdata); }; #endif diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index 411a428ace4d4..481e565cc5c42 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -100,6 +100,7 @@ enum cpuhp_state { CPUHP_AP_ARM_CACHE_B15_RAC_DEAD, CPUHP_PADATA_DEAD, CPUHP_AP_DTPM_CPU_DEAD, + CPUHP_RANDOM_PREPARE, CPUHP_WORKQUEUE_PREP, CPUHP_POWER_NUMA_PREPARE, CPUHP_HRTIMERS_PREPARE, @@ -240,6 +241,7 @@ enum cpuhp_state { CPUHP_AP_PERF_CSKY_ONLINE, CPUHP_AP_WATCHDOG_ONLINE, CPUHP_AP_WORKQUEUE_ONLINE, + CPUHP_AP_RANDOM_ONLINE, CPUHP_AP_RCUTREE_ONLINE, CPUHP_AP_BASE_CACHEINFO_ONLINE, CPUHP_AP_ONLINE_DYN, diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h index 8e6dd908da216..aa1d4da03538b 100644 --- a/include/linux/hw_random.h +++ b/include/linux/hw_random.h @@ -60,7 +60,5 @@ extern int devm_hwrng_register(struct device *dev, struct hwrng *rng); /** Unregister a Hardware Random Number Generator driver. */ extern void hwrng_unregister(struct hwrng *rng); extern void devm_hwrng_unregister(struct device *dve, struct hwrng *rng); -/** Feed random bits into the pool. */ -extern void add_hwgenerator_randomness(const char *buffer, size_t count, size_t entropy); #endif /* LINUX_HWRANDOM_H_ */ diff --git a/include/linux/mm.h b/include/linux/mm.h index 5744a3fc47169..9cb0ff065e8b1 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2678,6 +2678,7 @@ extern int install_special_mapping(struct mm_struct *mm, unsigned long flags, struct page **pages); unsigned long randomize_stack_top(unsigned long stack_top); +unsigned long randomize_page(unsigned long start, unsigned long range); extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); diff --git a/include/linux/prandom.h b/include/linux/prandom.h index 056d31317e499..a4aadd2dc153e 100644 --- a/include/linux/prandom.h +++ b/include/linux/prandom.h @@ -10,6 +10,7 @@ #include #include +#include u32 prandom_u32(void); void prandom_bytes(void *buf, size_t nbytes); @@ -27,15 +28,10 @@ DECLARE_PER_CPU(unsigned long, net_rand_noise); * The core SipHash round function. Each line can be executed in * parallel given enough CPU resources. */ -#define PRND_SIPROUND(v0, v1, v2, v3) ( \ - v0 += v1, v1 = rol64(v1, 13), v2 += v3, v3 = rol64(v3, 16), \ - v1 ^= v0, v0 = rol64(v0, 32), v3 ^= v2, \ - v0 += v3, v3 = rol64(v3, 21), v2 += v1, v1 = rol64(v1, 17), \ - v3 ^= v0, v1 ^= v2, v2 = rol64(v2, 32) \ -) +#define PRND_SIPROUND(v0, v1, v2, v3) SIPHASH_PERMUTATION(v0, v1, v2, v3) -#define PRND_K0 (0x736f6d6570736575 ^ 0x6c7967656e657261) -#define PRND_K1 (0x646f72616e646f6d ^ 0x7465646279746573) +#define PRND_K0 (SIPHASH_CONST_0 ^ SIPHASH_CONST_2) +#define PRND_K1 (SIPHASH_CONST_1 ^ SIPHASH_CONST_3) #elif BITS_PER_LONG == 32 /* @@ -43,14 +39,9 @@ DECLARE_PER_CPU(unsigned long, net_rand_noise); * This is weaker, but 32-bit machines are not used for high-traffic * applications, so there is less output for an attacker to analyze. */ -#define PRND_SIPROUND(v0, v1, v2, v3) ( \ - v0 += v1, v1 = rol32(v1, 5), v2 += v3, v3 = rol32(v3, 8), \ - v1 ^= v0, v0 = rol32(v0, 16), v3 ^= v2, \ - v0 += v3, v3 = rol32(v3, 7), v2 += v1, v1 = rol32(v1, 13), \ - v3 ^= v0, v1 ^= v2, v2 = rol32(v2, 16) \ -) -#define PRND_K0 0x6c796765 -#define PRND_K1 0x74656462 +#define PRND_SIPROUND(v0, v1, v2, v3) HSIPHASH_PERMUTATION(v0, v1, v2, v3) +#define PRND_K0 (HSIPHASH_CONST_0 ^ HSIPHASH_CONST_2) +#define PRND_K1 (HSIPHASH_CONST_1 ^ HSIPHASH_CONST_3) #else #error Unsupported BITS_PER_LONG diff --git a/include/linux/random.h b/include/linux/random.h index c45b2693e51fb..917470c4490ac 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -1,9 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0 */ -/* - * include/linux/random.h - * - * Include file for the random number generator. - */ + #ifndef _LINUX_RANDOM_H #define _LINUX_RANDOM_H @@ -14,41 +10,26 @@ #include -struct random_ready_callback { - struct list_head list; - void (*func)(struct random_ready_callback *rdy); - struct module *owner; -}; +struct notifier_block; -extern void add_device_randomness(const void *, unsigned int); -extern void add_bootloader_randomness(const void *, unsigned int); +void add_device_randomness(const void *buf, size_t len); +void add_bootloader_randomness(const void *buf, size_t len); +void add_input_randomness(unsigned int type, unsigned int code, + unsigned int value) __latent_entropy; +void add_interrupt_randomness(int irq) __latent_entropy; +void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy); #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__) static inline void add_latent_entropy(void) { - add_device_randomness((const void *)&latent_entropy, - sizeof(latent_entropy)); + add_device_randomness((const void *)&latent_entropy, sizeof(latent_entropy)); } #else -static inline void add_latent_entropy(void) {} -#endif - -extern void add_input_randomness(unsigned int type, unsigned int code, - unsigned int value) __latent_entropy; -extern void add_interrupt_randomness(int irq) __latent_entropy; - -extern void get_random_bytes(void *buf, int nbytes); -extern int wait_for_random_bytes(void); -extern int __init rand_initialize(void); -extern bool rng_is_initialized(void); -extern int add_random_ready_callback(struct random_ready_callback *rdy); -extern void del_random_ready_callback(struct random_ready_callback *rdy); -extern int __must_check get_random_bytes_arch(void *buf, int nbytes); - -#ifndef MODULE -extern const struct file_operations random_fops, urandom_fops; +static inline void add_latent_entropy(void) { } #endif +void get_random_bytes(void *buf, size_t len); +size_t __must_check get_random_bytes_arch(void *buf, size_t len); u32 get_random_u32(void); u64 get_random_u64(void); static inline unsigned int get_random_int(void) @@ -80,36 +61,38 @@ static inline unsigned long get_random_long(void) static inline unsigned long get_random_canary(void) { - unsigned long val = get_random_long(); - - return val & CANARY_MASK; + return get_random_long() & CANARY_MASK; } +int __init random_init(const char *command_line); +bool rng_is_initialized(void); +int wait_for_random_bytes(void); +int register_random_ready_notifier(struct notifier_block *nb); +int unregister_random_ready_notifier(struct notifier_block *nb); + /* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes). * Returns the result of the call to wait_for_random_bytes. */ -static inline int get_random_bytes_wait(void *buf, int nbytes) +static inline int get_random_bytes_wait(void *buf, size_t nbytes) { int ret = wait_for_random_bytes(); get_random_bytes(buf, nbytes); return ret; } -#define declare_get_random_var_wait(var) \ - static inline int get_random_ ## var ## _wait(var *out) { \ +#define declare_get_random_var_wait(name, ret_type) \ + static inline int get_random_ ## name ## _wait(ret_type *out) { \ int ret = wait_for_random_bytes(); \ if (unlikely(ret)) \ return ret; \ - *out = get_random_ ## var(); \ + *out = get_random_ ## name(); \ return 0; \ } -declare_get_random_var_wait(u32) -declare_get_random_var_wait(u64) -declare_get_random_var_wait(int) -declare_get_random_var_wait(long) +declare_get_random_var_wait(u32, u32) +declare_get_random_var_wait(u64, u32) +declare_get_random_var_wait(int, unsigned int) +declare_get_random_var_wait(long, unsigned long) #undef declare_get_random_var -unsigned long randomize_page(unsigned long start, unsigned long range); - /* * This is designed to be standalone for just prandom * users, but for now we include it from @@ -120,22 +103,10 @@ unsigned long randomize_page(unsigned long start, unsigned long range); #ifdef CONFIG_ARCH_RANDOM # include #else -static inline bool __must_check arch_get_random_long(unsigned long *v) -{ - return false; -} -static inline bool __must_check arch_get_random_int(unsigned int *v) -{ - return false; -} -static inline bool __must_check arch_get_random_seed_long(unsigned long *v) -{ - return false; -} -static inline bool __must_check arch_get_random_seed_int(unsigned int *v) -{ - return false; -} +static inline bool __must_check arch_get_random_long(unsigned long *v) { return false; } +static inline bool __must_check arch_get_random_int(unsigned int *v) { return false; } +static inline bool __must_check arch_get_random_seed_long(unsigned long *v) { return false; } +static inline bool __must_check arch_get_random_seed_int(unsigned int *v) { return false; } #endif /* @@ -158,4 +129,13 @@ static inline bool __init arch_get_random_long_early(unsigned long *v) } #endif +#ifdef CONFIG_SMP +int random_prepare_cpu(unsigned int cpu); +int random_online_cpu(unsigned int cpu); +#endif + +#ifndef MODULE +extern const struct file_operations random_fops, urandom_fops; +#endif + #endif /* _LINUX_RANDOM_H */ diff --git a/include/linux/siphash.h b/include/linux/siphash.h index cce8a9acc76cb..3af1428da5597 100644 --- a/include/linux/siphash.h +++ b/include/linux/siphash.h @@ -138,4 +138,32 @@ static inline u32 hsiphash(const void *data, size_t len, return ___hsiphash_aligned(data, len, key); } +/* + * These macros expose the raw SipHash and HalfSipHash permutations. + * Do not use them directly! If you think you have a use for them, + * be sure to CC the maintainer of this file explaining why. + */ + +#define SIPHASH_PERMUTATION(a, b, c, d) ( \ + (a) += (b), (b) = rol64((b), 13), (b) ^= (a), (a) = rol64((a), 32), \ + (c) += (d), (d) = rol64((d), 16), (d) ^= (c), \ + (a) += (d), (d) = rol64((d), 21), (d) ^= (a), \ + (c) += (b), (b) = rol64((b), 17), (b) ^= (c), (c) = rol64((c), 32)) + +#define SIPHASH_CONST_0 0x736f6d6570736575ULL +#define SIPHASH_CONST_1 0x646f72616e646f6dULL +#define SIPHASH_CONST_2 0x6c7967656e657261ULL +#define SIPHASH_CONST_3 0x7465646279746573ULL + +#define HSIPHASH_PERMUTATION(a, b, c, d) ( \ + (a) += (b), (b) = rol32((b), 5), (b) ^= (a), (a) = rol32((a), 16), \ + (c) += (d), (d) = rol32((d), 8), (d) ^= (c), \ + (a) += (d), (d) = rol32((d), 7), (d) ^= (a), \ + (c) += (b), (b) = rol32((b), 13), (b) ^= (c), (c) = rol32((c), 16)) + +#define HSIPHASH_CONST_0 0U +#define HSIPHASH_CONST_1 0U +#define HSIPHASH_CONST_2 0x6c796765U +#define HSIPHASH_CONST_3 0x74656462U + #endif /* _LINUX_SIPHASH_H */ diff --git a/include/linux/timex.h b/include/linux/timex.h index 059b18eb1f1fa..3871b06bd302c 100644 --- a/include/linux/timex.h +++ b/include/linux/timex.h @@ -62,6 +62,8 @@ #include #include +unsigned long random_get_entropy_fallback(void); + #include #ifndef random_get_entropy @@ -74,8 +76,14 @@ * * By default we use get_cycles() for this purpose, but individual * architectures may override this in their asm/timex.h header file. + * If a given arch does not have get_cycles(), then we fallback to + * using random_get_entropy_fallback(). */ -#define random_get_entropy() get_cycles() +#ifdef get_cycles +#define random_get_entropy() ((unsigned long)get_cycles()) +#else +#define random_get_entropy() random_get_entropy_fallback() +#endif #endif /* diff --git a/include/trace/events/random.h b/include/trace/events/random.h deleted file mode 100644 index a2d9aa16a5d7a..0000000000000 --- a/include/trace/events/random.h +++ /dev/null @@ -1,233 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#undef TRACE_SYSTEM -#define TRACE_SYSTEM random - -#if !defined(_TRACE_RANDOM_H) || defined(TRACE_HEADER_MULTI_READ) -#define _TRACE_RANDOM_H - -#include -#include - -TRACE_EVENT(add_device_randomness, - TP_PROTO(int bytes, unsigned long IP), - - TP_ARGS(bytes, IP), - - TP_STRUCT__entry( - __field( int, bytes ) - __field(unsigned long, IP ) - ), - - TP_fast_assign( - __entry->bytes = bytes; - __entry->IP = IP; - ), - - TP_printk("bytes %d caller %pS", - __entry->bytes, (void *)__entry->IP) -); - -DECLARE_EVENT_CLASS(random__mix_pool_bytes, - TP_PROTO(int bytes, unsigned long IP), - - TP_ARGS(bytes, IP), - - TP_STRUCT__entry( - __field( int, bytes ) - __field(unsigned long, IP ) - ), - - TP_fast_assign( - __entry->bytes = bytes; - __entry->IP = IP; - ), - - TP_printk("input pool: bytes %d caller %pS", - __entry->bytes, (void *)__entry->IP) -); - -DEFINE_EVENT(random__mix_pool_bytes, mix_pool_bytes, - TP_PROTO(int bytes, unsigned long IP), - - TP_ARGS(bytes, IP) -); - -DEFINE_EVENT(random__mix_pool_bytes, mix_pool_bytes_nolock, - TP_PROTO(int bytes, unsigned long IP), - - TP_ARGS(bytes, IP) -); - -TRACE_EVENT(credit_entropy_bits, - TP_PROTO(int bits, int entropy_count, unsigned long IP), - - TP_ARGS(bits, entropy_count, IP), - - TP_STRUCT__entry( - __field( int, bits ) - __field( int, entropy_count ) - __field(unsigned long, IP ) - ), - - TP_fast_assign( - __entry->bits = bits; - __entry->entropy_count = entropy_count; - __entry->IP = IP; - ), - - TP_printk("input pool: bits %d entropy_count %d caller %pS", - __entry->bits, __entry->entropy_count, (void *)__entry->IP) -); - -TRACE_EVENT(debit_entropy, - TP_PROTO(int debit_bits), - - TP_ARGS( debit_bits), - - TP_STRUCT__entry( - __field( int, debit_bits ) - ), - - TP_fast_assign( - __entry->debit_bits = debit_bits; - ), - - TP_printk("input pool: debit_bits %d", __entry->debit_bits) -); - -TRACE_EVENT(add_input_randomness, - TP_PROTO(int input_bits), - - TP_ARGS(input_bits), - - TP_STRUCT__entry( - __field( int, input_bits ) - ), - - TP_fast_assign( - __entry->input_bits = input_bits; - ), - - TP_printk("input_pool_bits %d", __entry->input_bits) -); - -TRACE_EVENT(add_disk_randomness, - TP_PROTO(dev_t dev, int input_bits), - - TP_ARGS(dev, input_bits), - - TP_STRUCT__entry( - __field( dev_t, dev ) - __field( int, input_bits ) - ), - - TP_fast_assign( - __entry->dev = dev; - __entry->input_bits = input_bits; - ), - - TP_printk("dev %d,%d input_pool_bits %d", MAJOR(__entry->dev), - MINOR(__entry->dev), __entry->input_bits) -); - -DECLARE_EVENT_CLASS(random__get_random_bytes, - TP_PROTO(int nbytes, unsigned long IP), - - TP_ARGS(nbytes, IP), - - TP_STRUCT__entry( - __field( int, nbytes ) - __field(unsigned long, IP ) - ), - - TP_fast_assign( - __entry->nbytes = nbytes; - __entry->IP = IP; - ), - - TP_printk("nbytes %d caller %pS", __entry->nbytes, (void *)__entry->IP) -); - -DEFINE_EVENT(random__get_random_bytes, get_random_bytes, - TP_PROTO(int nbytes, unsigned long IP), - - TP_ARGS(nbytes, IP) -); - -DEFINE_EVENT(random__get_random_bytes, get_random_bytes_arch, - TP_PROTO(int nbytes, unsigned long IP), - - TP_ARGS(nbytes, IP) -); - -DECLARE_EVENT_CLASS(random__extract_entropy, - TP_PROTO(int nbytes, int entropy_count, unsigned long IP), - - TP_ARGS(nbytes, entropy_count, IP), - - TP_STRUCT__entry( - __field( int, nbytes ) - __field( int, entropy_count ) - __field(unsigned long, IP ) - ), - - TP_fast_assign( - __entry->nbytes = nbytes; - __entry->entropy_count = entropy_count; - __entry->IP = IP; - ), - - TP_printk("input pool: nbytes %d entropy_count %d caller %pS", - __entry->nbytes, __entry->entropy_count, (void *)__entry->IP) -); - - -DEFINE_EVENT(random__extract_entropy, extract_entropy, - TP_PROTO(int nbytes, int entropy_count, unsigned long IP), - - TP_ARGS(nbytes, entropy_count, IP) -); - -TRACE_EVENT(urandom_read, - TP_PROTO(int got_bits, int pool_left, int input_left), - - TP_ARGS(got_bits, pool_left, input_left), - - TP_STRUCT__entry( - __field( int, got_bits ) - __field( int, pool_left ) - __field( int, input_left ) - ), - - TP_fast_assign( - __entry->got_bits = got_bits; - __entry->pool_left = pool_left; - __entry->input_left = input_left; - ), - - TP_printk("got_bits %d nonblocking_pool_entropy_left %d " - "input_entropy_left %d", __entry->got_bits, - __entry->pool_left, __entry->input_left) -); - -TRACE_EVENT(prandom_u32, - - TP_PROTO(unsigned int ret), - - TP_ARGS(ret), - - TP_STRUCT__entry( - __field( unsigned int, ret) - ), - - TP_fast_assign( - __entry->ret = ret; - ), - - TP_printk("ret=%u" , __entry->ret) -); - -#endif /* _TRACE_RANDOM_H */ - -/* This part must be outside protection */ -#include diff --git a/init/main.c b/init/main.c index 9a5097b2251a5..0aa2e1c17b1c3 100644 --- a/init/main.c +++ b/init/main.c @@ -1035,21 +1035,18 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void) softirq_init(); timekeeping_init(); kfence_init(); + time_init(); /* * For best initial stack canary entropy, prepare it after: * - setup_arch() for any UEFI RNG entropy and boot cmdline access - * - timekeeping_init() for ktime entropy used in rand_initialize() - * - rand_initialize() to get any arch-specific entropy like RDRAND - * - add_latent_entropy() to get any latent entropy - * - adding command line entropy + * - timekeeping_init() for ktime entropy used in random_init() + * - time_init() for making random_get_entropy() work on some platforms + * - random_init() to initialize the RNG from from early entropy sources */ - rand_initialize(); - add_latent_entropy(); - add_device_randomness(command_line, strlen(command_line)); + random_init(command_line); boot_init_stack_canary(); - time_init(); perf_event_init(); profile_init(); call_function_init(); diff --git a/kernel/cpu.c b/kernel/cpu.c index 5601216eb51bd..da871eb075662 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #define CREATE_TRACE_POINTS @@ -1659,6 +1660,11 @@ static struct cpuhp_step cpuhp_hp_states[] = { .startup.single = perf_event_init_cpu, .teardown.single = perf_event_exit_cpu, }, + [CPUHP_RANDOM_PREPARE] = { + .name = "random:prepare", + .startup.single = random_prepare_cpu, + .teardown.single = NULL, + }, [CPUHP_WORKQUEUE_PREP] = { .name = "workqueue:prepare", .startup.single = workqueue_prepare_cpu, @@ -1782,6 +1788,11 @@ static struct cpuhp_step cpuhp_hp_states[] = { .startup.single = workqueue_online_cpu, .teardown.single = workqueue_offline_cpu, }, + [CPUHP_AP_RANDOM_ONLINE] = { + .name = "random:online", + .startup.single = random_online_cpu, + .teardown.single = NULL, + }, [CPUHP_AP_RCUTREE_ONLINE] = { .name = "RCU/tree:online", .startup.single = rcutree_online_cpu, diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 3b1398fbddaf8..871c912860ed5 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include #include @@ -2380,6 +2381,20 @@ static int timekeeping_validate_timex(const struct __kernel_timex *txc) return 0; } +/** + * random_get_entropy_fallback - Returns the raw clock source value, + * used by random.c for platforms with no valid random_get_entropy(). + */ +unsigned long random_get_entropy_fallback(void) +{ + struct tk_read_base *tkr = &tk_core.timekeeper.tkr_mono; + struct clocksource *clock = READ_ONCE(tkr->clock); + + if (unlikely(timekeeping_suspended || !clock)) + return 0; + return clock->read(clock); +} +EXPORT_SYMBOL_GPL(random_get_entropy_fallback); /** * do_adjtimex() - Accessor function to NTP __do_adjtimex function diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 440fd666c16d1..c7dfe1000111d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1566,8 +1566,7 @@ config WARN_ALL_UNSEEDED_RANDOM so architecture maintainers really need to do what they can to get the CRNG seeded sooner after the system is booted. However, since users cannot do anything actionable to - address this, by default the kernel will issue only a single - warning for the first use of unseeded randomness. + address this, by default this option is disabled. Say Y here if you want to receive warnings for all uses of unseeded randomness. This will be of use primarily for diff --git a/lib/random32.c b/lib/random32.c index a57a0e18819d0..976632003ec65 100644 --- a/lib/random32.c +++ b/lib/random32.c @@ -41,7 +41,6 @@ #include #include #include -#include /** * prandom_u32_state - seeded pseudo-random number generator. @@ -387,7 +386,6 @@ u32 prandom_u32(void) struct siprand_state *state = get_cpu_ptr(&net_rand_state); u32 res = siprand_u32(state); - trace_prandom_u32(res); put_cpu_ptr(&net_rand_state); return res; } @@ -553,9 +551,11 @@ static void prandom_reseed(struct timer_list *unused) * To avoid worrying about whether it's safe to delay that interrupt * long enough to seed all CPUs, just schedule an immediate timer event. */ -static void prandom_timer_start(struct random_ready_callback *unused) +static int prandom_timer_start(struct notifier_block *nb, + unsigned long action, void *data) { mod_timer(&seed_timer, jiffies); + return 0; } #ifdef CONFIG_RANDOM32_SELFTEST @@ -619,13 +619,13 @@ core_initcall(prandom32_state_selftest); */ static int __init prandom_init_late(void) { - static struct random_ready_callback random_ready = { - .func = prandom_timer_start + static struct notifier_block random_ready = { + .notifier_call = prandom_timer_start }; - int ret = add_random_ready_callback(&random_ready); + int ret = register_random_ready_notifier(&random_ready); if (ret == -EALREADY) { - prandom_timer_start(&random_ready); + prandom_timer_start(&random_ready, 0, NULL); ret = 0; } return ret; diff --git a/lib/siphash.c b/lib/siphash.c index 72b9068ab57bf..71d315a6ad623 100644 --- a/lib/siphash.c +++ b/lib/siphash.c @@ -18,19 +18,13 @@ #include #endif -#define SIPROUND \ - do { \ - v0 += v1; v1 = rol64(v1, 13); v1 ^= v0; v0 = rol64(v0, 32); \ - v2 += v3; v3 = rol64(v3, 16); v3 ^= v2; \ - v0 += v3; v3 = rol64(v3, 21); v3 ^= v0; \ - v2 += v1; v1 = rol64(v1, 17); v1 ^= v2; v2 = rol64(v2, 32); \ - } while (0) +#define SIPROUND SIPHASH_PERMUTATION(v0, v1, v2, v3) #define PREAMBLE(len) \ - u64 v0 = 0x736f6d6570736575ULL; \ - u64 v1 = 0x646f72616e646f6dULL; \ - u64 v2 = 0x6c7967656e657261ULL; \ - u64 v3 = 0x7465646279746573ULL; \ + u64 v0 = SIPHASH_CONST_0; \ + u64 v1 = SIPHASH_CONST_1; \ + u64 v2 = SIPHASH_CONST_2; \ + u64 v3 = SIPHASH_CONST_3; \ u64 b = ((u64)(len)) << 56; \ v3 ^= key->key[1]; \ v2 ^= key->key[0]; \ @@ -389,19 +383,13 @@ u32 hsiphash_4u32(const u32 first, const u32 second, const u32 third, } EXPORT_SYMBOL(hsiphash_4u32); #else -#define HSIPROUND \ - do { \ - v0 += v1; v1 = rol32(v1, 5); v1 ^= v0; v0 = rol32(v0, 16); \ - v2 += v3; v3 = rol32(v3, 8); v3 ^= v2; \ - v0 += v3; v3 = rol32(v3, 7); v3 ^= v0; \ - v2 += v1; v1 = rol32(v1, 13); v1 ^= v2; v2 = rol32(v2, 16); \ - } while (0) +#define HSIPROUND HSIPHASH_PERMUTATION(v0, v1, v2, v3) #define HPREAMBLE(len) \ - u32 v0 = 0; \ - u32 v1 = 0; \ - u32 v2 = 0x6c796765U; \ - u32 v3 = 0x74656462U; \ + u32 v0 = HSIPHASH_CONST_0; \ + u32 v1 = HSIPHASH_CONST_1; \ + u32 v2 = HSIPHASH_CONST_2; \ + u32 v3 = HSIPHASH_CONST_3; \ u32 b = ((u32)(len)) << 24; \ v3 ^= key->key[1]; \ v2 ^= key->key[0]; \ diff --git a/lib/vsprintf.c b/lib/vsprintf.c index fbf261bbea950..35cc358f8daee 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -762,14 +762,16 @@ static void enable_ptr_key_workfn(struct work_struct *work) static DECLARE_WORK(enable_ptr_key_work, enable_ptr_key_workfn); -static void fill_random_ptr_key(struct random_ready_callback *unused) +static int fill_random_ptr_key(struct notifier_block *nb, + unsigned long action, void *data) { /* This may be in an interrupt handler. */ queue_work(system_unbound_wq, &enable_ptr_key_work); + return 0; } -static struct random_ready_callback random_ready = { - .func = fill_random_ptr_key +static struct notifier_block random_ready = { + .notifier_call = fill_random_ptr_key }; static int __init initialize_ptr_random(void) @@ -783,7 +785,7 @@ static int __init initialize_ptr_random(void) return 0; } - ret = add_random_ready_callback(&random_ready); + ret = register_random_ready_notifier(&random_ready); if (!ret) { return 0; } else if (ret == -EALREADY) { diff --git a/mm/util.c b/mm/util.c index d3102081add00..5223d7e2f65ec 100644 --- a/mm/util.c +++ b/mm/util.c @@ -343,6 +343,38 @@ unsigned long randomize_stack_top(unsigned long stack_top) #endif } +/** + * randomize_page - Generate a random, page aligned address + * @start: The smallest acceptable address the caller will take. + * @range: The size of the area, starting at @start, within which the + * random address must fall. + * + * If @start + @range would overflow, @range is capped. + * + * NOTE: Historical use of randomize_range, which this replaces, presumed that + * @start was already page aligned. We now align it regardless. + * + * Return: A page aligned address within [start, start + range). On error, + * @start is returned. + */ +unsigned long randomize_page(unsigned long start, unsigned long range) +{ + if (!PAGE_ALIGNED(start)) { + range -= PAGE_ALIGN(start) - start; + start = PAGE_ALIGN(start); + } + + if (start > ULONG_MAX - range) + range = ULONG_MAX - start; + + range >>= PAGE_SHIFT; + + if (range == 0) + return start; + + return start + (get_random_long() % range << PAGE_SHIFT); +} + #ifdef CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT unsigned long arch_randomize_brk(struct mm_struct *mm) { diff --git a/sound/pci/ctxfi/ctatc.c b/sound/pci/ctxfi/ctatc.c index 78f35e88aed6b..fbdb8a3d5b8e5 100644 --- a/sound/pci/ctxfi/ctatc.c +++ b/sound/pci/ctxfi/ctatc.c @@ -36,6 +36,7 @@ | ((IEC958_AES3_CON_FS_48000) << 24)) static const struct snd_pci_quirk subsys_20k1_list[] = { + SND_PCI_QUIRK(PCI_VENDOR_ID_CREATIVE, 0x0021, "SB046x", CTSB046X), SND_PCI_QUIRK(PCI_VENDOR_ID_CREATIVE, 0x0022, "SB055x", CTSB055X), SND_PCI_QUIRK(PCI_VENDOR_ID_CREATIVE, 0x002f, "SB055x", CTSB055X), SND_PCI_QUIRK(PCI_VENDOR_ID_CREATIVE, 0x0029, "SB073x", CTSB073X), @@ -64,6 +65,7 @@ static const struct snd_pci_quirk subsys_20k2_list[] = { static const char *ct_subsys_name[NUM_CTCARDS] = { /* 20k1 models */ + [CTSB046X] = "SB046x", [CTSB055X] = "SB055x", [CTSB073X] = "SB073x", [CTUAA] = "UAA", diff --git a/sound/pci/ctxfi/cthardware.h b/sound/pci/ctxfi/cthardware.h index f406b626a28c4..2875cec83b8f2 100644 --- a/sound/pci/ctxfi/cthardware.h +++ b/sound/pci/ctxfi/cthardware.h @@ -26,8 +26,9 @@ enum CHIPTYP { enum CTCARDS { /* 20k1 models */ + CTSB046X, + CT20K1_MODEL_FIRST = CTSB046X, CTSB055X, - CT20K1_MODEL_FIRST = CTSB055X, CTSB073X, CTUAA, CT20K1_UNKNOWN,