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| author | Amanieu d'Antras <amanieu@gmail.com> | 2015-08-06 15:46:29 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-08-16 20:52:26 -0700 |
| commit | c08a75d950725cdd87c19232a5a3850c51520359 (patch) | |
| tree | bb660703a15a30810bc0ff069d77600afb607dc2 | |
| parent | 8a97f0e58abc93f67f1f6ca571e4ff758739cedf (diff) | |
| download | linux-stable-c08a75d950725cdd87c19232a5a3850c51520359.tar.gz linux-stable-c08a75d950725cdd87c19232a5a3850c51520359.tar.bz2 linux-stable-c08a75d950725cdd87c19232a5a3850c51520359.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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arm64/kernel/signal32.c | 3 | ||||
| -rw-r--r-- | kernel/signal.c | 9 |
2 files changed, 8 insertions, 4 deletions
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index d26fcd4cd6e6..56e6ba74628d 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; diff --git a/kernel/signal.c b/kernel/signal.c index d51c5ddd855c..ac4c24ea2048 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2753,12 +2753,15 @@ int copy_siginfo_to_user(siginfo_t __user *to, const 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 #ifdef SEGV_BNDERR - err |= __put_user(from->si_lower, &to->si_lower); - err |= __put_user(from->si_upper, &to->si_upper); + if (from->si_signo == SIGSEGV && from->si_code == SEGV_BNDERR) { + err |= __put_user(from->si_lower, &to->si_lower); + err |= __put_user(from->si_upper, &to->si_upper); + } #endif break; case __SI_CHLD: |