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| author | Amanieu d'Antras <amanieu@gmail.com> | 2015-08-06 15:46:26 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-08-07 04:39:40 +0300 |
| commit | 3c00cb5e68dc719f2fc73a33b1b230aadfcb1309 (patch) | |
| tree | 68b5f2424fb18c45aa9b67a694a75160dddbbf23 /arch/powerpc | |
| parent | 209f7512d007980fd111a74a064d70a3656079cf (diff) | |
| download | linux-3c00cb5e68dc719f2fc73a33b1b230aadfcb1309.tar.bz2 | |
signal: fix information leak in copy_siginfo_from_user32
This function can leak kernel stack data when the user siginfo_t has a
positive si_code value. The top 16 bits of si_code descibe which fields
in the siginfo_t union are active, but they are treated inconsistently
between copy_siginfo_from_user32, copy_siginfo_to_user32 and
copy_siginfo_to_user.
copy_siginfo_from_user32 is called from rt_sigqueueinfo and
rt_tgsigqueueinfo in which the user has full control overthe top 16 bits
of si_code.
This fixes the following information leaks:
x86: 8 bytes leaked when sending a signal from a 32-bit process to
itself. This leak grows to 16 bytes if the process uses x32.
(si_code = __SI_CHLD)
x86: 100 bytes leaked when sending a signal from a 32-bit process to
a 64-bit process. (si_code = -1)
sparc: 4 bytes leaked when sending a signal from a 32-bit process to a
64-bit process. (si_code = any)
parsic and s390 have similar bugs, but they are not vulnerable because
rt_[tg]sigqueueinfo have checks that prevent sending a positive si_code
to a different process. These bugs are also fixed for consistency.
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>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/signal_32.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c index d3a831ac0f92..da50e0c9c57e 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c @@ -966,8 +966,6 @@ int copy_siginfo_to_user32(struct compat_siginfo __user *d, const siginfo_t *s) int copy_siginfo_from_user32(siginfo_t *to, struct compat_siginfo __user *from) { - memset(to, 0, sizeof *to); - if (copy_from_user(to, from, 3*sizeof(int)) || copy_from_user(to->_sifields._pad, from->_sifields._pad, SI_PAD_SIZE32)) |