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| author | Amanieu d'Antras <amanieu@gmail.com> | 2015-08-06 15:46:29 -0700 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-08-27 13:25:36 -0400 |
| commit | ad98e577ca49e4bc3c2d3afede2c5918dde55ba4 (patch) | |
| tree | de4ff2043664fe94c67f124c235e2d1939cef9e5 /arch | |
| parent | ab1bd6fbf4a2fa1c4321428c72029d70a2b8eb95 (diff) | |
| download | lwn-ad98e577ca49e4bc3c2d3afede2c5918dde55ba4.tar.gz lwn-ad98e577ca49e4bc3c2d3afede2c5918dde55ba4.zip | |
signal: fix information leak in copy_siginfo_to_user
[ Upstream commit c08a75d950725cdd87c19232a5a3850c51520359 ]
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>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/kernel/signal32.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index 76920d4040d4..5c961494025b 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -168,7 +168,8 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, const 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; |