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| author | Amanieu d'Antras <amanieu@gmail.com> | 2015-08-06 15:46:29 -0700 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2015-08-25 16:57:03 +0200 |
| commit | ed5dbb4e2a71ab04d0d4d7be83e28ab774aefdf8 (patch) | |
| tree | 5924d9710c4ae57dff723bac325f5a7a41a7ac00 | |
| parent | ce624e9ce4ef6efa702698ba52e793a84f96d606 (diff) | |
| download | lwn-ed5dbb4e2a71ab04d0d4d7be83e28ab774aefdf8.tar.gz lwn-ed5dbb4e2a71ab04d0d4d7be83e28ab774aefdf8.zip | |
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: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | arch/arm64/kernel/signal32.c | 3 | ||||
| -rw-r--r-- | 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; |