Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 31/44] signal: fix information leak in copy_siginfo_to_user | Date | Fri, 14 Aug 2015 10:45:08 -0700 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: Amanieu d'Antras <amanieu@gmail.com>
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>
--- arch/arm64/kernel/signal32.c | 3 ++- kernel/signal.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-)
--- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -165,7 +165,8 @@ int copy_siginfo_to_user32(compat_siginf * 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; --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2768,7 +2768,8 @@ int copy_siginfo_to_user(siginfo_t __use * 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;
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