From: Amanieu d'Antras <amanieu@xxxxxxxxx> This patch has been added to the 3.12 stable tree. If you have any objections, please let us know. =============== 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@xxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Russell King <rmk@xxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- arch/arm64/kernel/signal32.c | 3 ++- kernel/signal.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index 3d478102b1c0..efd1dde7094b 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -193,7 +193,8 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from) * Other callers might not initialize the si_lsb field, * so check explicitely 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; diff --git a/kernel/signal.c b/kernel/signal.c index ded28b91fa53..5f558f1d3ab1 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; -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html