The patch titled
proc: protect mm start_code/end_code in /proc/pid/stat
has been added to the -mm tree. Its filename is
proc-protect-mm-start_code-end_code-in-proc-pid-stat.patch
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------------------------------------------------------
Subject: proc: protect mm start_code/end_code in /proc/pid/stat
From: Kees Cook <kees.cook@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Eugene Teo <eugeneteo@xxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Reported-by: Brad Spengler <spender@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/array.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN fs/proc/array.c~proc-protect-mm-start_code-end_code-in-proc-pid-stat fs/proc/array.c
--- a/fs/proc/array.c~proc-protect-mm-start_code-end_code-in-proc-pid-stat
+++ a/fs/proc/array.c
@@ -489,8 +489,8 @@ 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,
_
Patches currently in -mm which might be from kees.cook@xxxxxxxxxxxxx are
origin.patch
linux-next.patch
net-convert-%p-usage-to-%pk.patch
printk-use-%pk-for-proc-kallsyms-and-proc-modules.patch
proc-hide-kernel-addresses-via-%pk-in-proc-pid-stack.patch
proc-protect-mm-start_code-end_code-in-proc-pid-stat.patch
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