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authorAmanieu d'Antras <amanieu@gmail.com>2015-08-06 15:46:29 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-08-16 20:51:42 -0700
commit16a49557bc101b804a0a74d4032556f8836b9469 (patch)
tree63d5972b3fe4fb422090c245783208e98e3bdf89 /kernel
parent5c233bffdb9ffd2c85d1f94ddd8be956ee2b353f (diff)
signal: fix information leak in copy_siginfo_to_user
commit 26135022f85105ad725cda103fa069e29e83bd16 upstream. This function may copy the si_addr_lsb, si_lower and si_upper fields to user mode when they haven'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@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> 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@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/signal.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 113411bfe8b1..fa80d104cbec 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2768,7 +2768,8 @@ int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from)
* Other callers might not initialize the si_lsb field,
* so check explicitly for the right codes here.
*/
- if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
+ if (from->si_signo == SIGBUS &&
+ (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO))
err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
#endif
break;