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authorMathias Krause <minipli@googlemail.com>2014-10-04 23:06:39 +0200
committerBen Hutchings <ben@decadent.org.uk>2014-12-14 16:23:51 +0000
commit3cd3a349aa3519b88d29845c0bc36bcbae158e93 (patch)
treee0197314699a1e65158a43ebfe91d7bb54259aed
parent24dd5191befdde39387852fa03f61f17b742801c (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.c1
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;