| From 5883f57ca0008ffc93e09cbb9847a1928e50c6f3 Mon Sep 17 00:00:00 2001 |
| From: Kees Cook <kees.cook@canonical.com> |
| Date: Wed, 23 Mar 2011 16:42:53 -0700 |
| Subject: proc: protect mm start_code/end_code in /proc/pid/stat |
| |
| From: Kees Cook <kees.cook@canonical.com> |
| |
| commit 5883f57ca0008ffc93e09cbb9847a1928e50c6f3 upstream. |
| |
| While mm->start_stack was protected from cross-uid viewing (commit |
| f83ce3e6b02d5 ("proc: avoid information leaks to non-privileged |
| processes")), the start_code and end_code values were not. This would |
| allow the text location of a PIE binary to leak, defeating ASLR. |
| |
| Note that the value "1" is used instead of "0" for a protected value since |
| "ps", "killall", and likely other readers of /proc/pid/stat, take |
| start_code of "0" to mean a kernel thread and will misbehave. Thanks to |
| Brad Spengler for pointing this out. |
| |
| Addresses CVE-2011-0726 |
| |
| Signed-off-by: Kees Cook <kees.cook@canonical.com> |
| Cc: Alexey Dobriyan <adobriyan@gmail.com> |
| Cc: David Howells <dhowells@redhat.com> |
| Cc: Eugene Teo <eugeneteo@kernel.sg> |
| Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> |
| Cc: Brad Spengler <spender@grsecurity.net> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| fs/proc/array.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/fs/proc/array.c |
| +++ b/fs/proc/array.c |
| @@ -488,8 +488,8 @@ static int do_task_stat(struct seq_file |
| vsize, |
| mm ? get_mm_rss(mm) : 0, |
| rsslim, |
| - mm ? mm->start_code : 0, |
| - mm ? mm->end_code : 0, |
| + mm ? (permitted ? mm->start_code : 1) : 0, |
| + mm ? (permitted ? mm->end_code : 1) : 0, |
| (permitted && mm) ? mm->start_stack : 0, |
| esp, |
| eip, |
