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| author | Kees Cook <kees.cook@canonical.com> | 2011-03-23 16:42:53 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-03-27 11:36:03 -0700 |
| commit | edccdb2bd8f5cbc029820f923e4cbb737a36753c (patch) | |
| tree | 043e890db575587687ac80e98c77889441df3e38 | |
| parent | cf81eb6a73d27afd234e8072a11dad71c968953b (diff) | |
| download | lwn-edccdb2bd8f5cbc029820f923e4cbb737a36753c.tar.gz lwn-edccdb2bd8f5cbc029820f923e4cbb737a36753c.zip | |
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 <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>
| -rw-r--r-- | fs/proc/array.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c index 7c99c1cf7e5c..5e4f776b0917 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -489,8 +489,8 @@ 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, |