Make slabinfo available but restricted to root only.

The existing Grsec GRKERNSEC_PROC_ADD totally removes the /proc/slabinfo file.
This is painful when debugging memory leaks, so instead of removing it
entirely, alter the permissions only.

This changes the file from 0644 to 0600.

Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>

--- a/mm/slab.c	2010-05-25 00:35:43.000000000 +0000
+++ b/mm/slab.c	2010-05-28 09:49:49.000000000 +0000
@@ -4082,7 +4082,7 @@
 	schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_CPUC));
 }
 
-#if defined(CONFIG_SLABINFO) && !defined(CONFIG_GRKERNSEC_PROC_ADD)
+#if defined(CONFIG_SLABINFO)
 
 static void print_slabinfo_header(struct seq_file *m)
 {
@@ -4471,7 +4471,13 @@
 
 static int __init slab_proc_init(void)
 {
-	proc_create("slabinfo",S_IWUSR|S_IRUGO,NULL,&proc_slabinfo_operations);
+#ifdef CONFIG_GRKERNSEC_PROC_ADD
+#define SLABINFO_PERMS S_IWUSR
+#else
+#define SLABINFO_PERMS S_IWUSR|S_IRUGO
+#endif
+	proc_create("slabinfo",SLABINFO_PERMS,NULL,&proc_slabinfo_operations);
+#undef SLABINFO_PERMS
 #ifdef CONFIG_DEBUG_SLAB_LEAK
 	proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations);
 #endif
--- a/init/Kconfig	2010-05-25 00:35:43.000000000 +0000
+++ b/init/Kconfig	2010-05-28 09:51:17.000000000 +0000
@@ -1116,7 +1116,7 @@
 
 config SLABINFO
 	bool
-	depends on PROC_FS && !GRKERNSEC_PROC_ADD
+	depends on PROC_FS
 	depends on SLAB || SLUB_DEBUG
- 	default n
+	default y