From 56df433ee53f5131fa58d467e68c478c06f90892 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 23 Mar 2011 16:42:53 -0700 Subject: [PATCH] proc: protect mm start_code/end_code in /proc/pid/stat 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 Cc: Alexey Dobriyan Cc: David Howells Cc: Eugene Teo Cc: Martin Schwidefsky Cc: Brad Spengler Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/proc/array.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/proc/array.c b/fs/proc/array.c index 2adedda6aab8..c5ef152b3891 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -473,8 +473,8 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, 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, -- 2.39.5