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| author | Michael Neuling <mikey@neuling.org> | 2015-11-19 07:44:44 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2015-11-23 12:06:31 +0300 |
| commit | d2b9d2a5ad5ef04ff978c9923d19730cb05efd55 (patch) | |
| tree | 204175f5f1983ff920187640fc5263115400083e /arch/powerpc/kernel/signal_64.c | |
| parent | 1ec218373b8ebda821aec00bb156a9c94fad9cd4 (diff) | |
| download | linux-d2b9d2a5ad5ef04ff978c9923d19730cb05efd55.tar.xz | |
powerpc/tm: Block signal return setting invalid MSR state
Currently we allow both the MSR T and S bits to be set by userspace on
a signal return. Unfortunately this is a reserved configuration and
will cause a TM Bad Thing exception if attempted (via rfid).
This patch checks for this case in both the 32 and 64 bit signals
code. If both T and S are set, we mark the context as invalid.
Found using a syscall fuzzer.
Fixes: 2b0a576d15e0 ("powerpc: Add new transactional memory state to the signal context")
Cc: stable@vger.kernel.org # v3.9+
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/signal_64.c')
| -rw-r--r-- | arch/powerpc/kernel/signal_64.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c index 20756dfb9f34..c676ecec0869 100644 --- a/arch/powerpc/kernel/signal_64.c +++ b/arch/powerpc/kernel/signal_64.c @@ -438,6 +438,10 @@ static long restore_tm_sigcontexts(struct pt_regs *regs, /* get MSR separately, transfer the LE bit if doing signal return */ err |= __get_user(msr, &sc->gp_regs[PT_MSR]); + /* Don't allow reserved mode. */ + if (MSR_TM_RESV(msr)) + return -EINVAL; + /* pull in MSR TM from user context */ regs->msr = (regs->msr & ~MSR_TS_MASK) | (msr & MSR_TS_MASK); |