diff options
| author | Mathias Krause <minipli@googlemail.com> | 2014-10-04 23:06:39 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-12-14 16:23:51 +0000 |
| commit | 3cd3a349aa3519b88d29845c0bc36bcbae158e93 (patch) | |
| tree | e0197314699a1e65158a43ebfe91d7bb54259aed | |
| parent | 24dd5191befdde39387852fa03f61f17b742801c (diff) | |
posix-timers: Fix stack info leak in timer_create()
commit 6891c4509c792209c44ced55a60f13954cb50ef4 upstream.
If userland creates a timer without specifying a sigevent info, we'll
create one ourself, using a stack local variable. Particularly will we
use the timer ID as sival_int. But as sigev_value is a union containing
a pointer and an int, that assignment will only partially initialize
sigev_value on systems where the size of a pointer is bigger than the
size of an int. On such systems we'll copy the uninitialized stack bytes
from the timer_create() call to userland when the timer actually fires
and we're going to deliver the signal.
Initialize sigev_value with 0 to plug the stack info leak.
Found in the PaX patch, written by the PaX Team.
Fixes: 5a9fa7307285 ("posix-timers: kill ->it_sigev_signo and...")
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: PaX Team <pageexec@freemail.hu>
Link: http://lkml.kernel.org/r/1412456799-32339-1-git-send-email-minipli@googlemail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | kernel/posix-timers.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c index e885be1e8a11..02824a5c2693 100644 --- a/kernel/posix-timers.c +++ b/kernel/posix-timers.c @@ -589,6 +589,7 @@ SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock, goto out; } } else { + memset(&event.sigev_value, 0, sizeof(event.sigev_value)); event.sigev_notify = SIGEV_SIGNAL; event.sigev_signo = SIGALRM; event.sigev_value.sival_int = new_timer->it_id; |