lkml.org 
[lkml]   [2011]   [Mar]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[29/63] proc: protect mm start_code/end_code in /proc/pid/stat
    2.6.38-stable review patch.  If anyone has any objections, please let us know.

    ------------------

    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
    @@ -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,



    \
     
     \ /
      Last update: 2011-03-26 01:23    [W:0.020 / U:30.344 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site