2.6.33-longterm review patch. If anyone has any objections, please let us know.
------------------
From: Kees Cook <kees.c...@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.c...@canonical.com>
Cc: Alexey Dobriyan <adobri...@gmail.com>
Cc: David Howells <dhowe...@redhat.com>
Cc: Eugene Teo <eugene...@kernel.sg>
Cc: Martin Schwidefsky <schwidef...@de.ibm.com>
Cc: Brad Spengler <spen...@grsecurity.net>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gre...@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,
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