This is a note to let you know that I've just added the patch titled
signalfd: fix information leak in signalfd_copyinfo
to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
signalfd-fix-information-leak-in-signalfd_copyinfo.patch
and it can be found in the queue-4.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3ead7c52bdb0ab44f4bb1feed505a8323cc12ba7 Mon Sep 17 00:00:00 2001
From: Amanieu d'Antras <amanieu@xxxxxxxxx>
Date: Thu, 6 Aug 2015 15:46:33 -0700
Subject: signalfd: fix information leak in signalfd_copyinfo
From: Amanieu d'Antras <amanieu@xxxxxxxxx>
commit 3ead7c52bdb0ab44f4bb1feed505a8323cc12ba7 upstream.
This function may copy the si_addr_lsb field to user mode when it hasn't
been initialized, which can leak kernel stack data to user mode.
Just checking the value of si_code is insufficient because the same
si_code value is shared between multiple signals. This is solved by
checking the value of si_signo in addition to si_code.
Signed-off-by: Amanieu d'Antras <amanieu@xxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/signalfd.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -121,8 +121,9 @@ static int signalfd_copyinfo(struct sign
* Other callers might not initialize the si_lsb field,
* so check explicitly for the right codes here.
*/
- if (kinfo->si_code == BUS_MCEERR_AR ||
- kinfo->si_code == BUS_MCEERR_AO)
+ if (kinfo->si_signo == SIGBUS &&
+ (kinfo->si_code == BUS_MCEERR_AR ||
+ kinfo->si_code == BUS_MCEERR_AO))
err |= __put_user((short) kinfo->si_addr_lsb,
&uinfo->ssi_addr_lsb);
#endif
Patches currently in stable-queue which might be from amanieu@xxxxxxxxx are
queue-4.1/signal-fix-information-leak-in-copy_siginfo_from_user32.patch
queue-4.1/signal-fix-information-leak-in-copy_siginfo_to_user.patch
queue-4.1/signalfd-fix-information-leak-in-signalfd_copyinfo.patch
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