diff options
| author | Dave Martin <Dave.Martin@arm.com> | 2017-06-29 15:25:47 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2017-06-29 17:44:08 +0100 |
| commit | 53b1a742ed251780267a57415bc955bd50f40c3d (patch) | |
| tree | d3f864d5ac31202d46312bf85ae8bea7533b39e6 | |
| parent | 15ad6ace52039c7e39435c4d712d147126604a97 (diff) | |
arm64: ptrace: Avoid setting compat FP[SC]R to garbage if get_user fails
If get_user() fails when reading the new FPSCR value from userspace
in compat_vfp_get(), then garbage* will be written to the task's
FPSR and FPCR registers.
This patch prevents this by checking the return from get_user()
first.
[*] Actually, zero, due to the behaviour of get_user() on error, but
that's still not what userspace expects.
Fixes: 478fcb2cdb23 ("arm64: Debugging support")
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
| -rw-r--r-- | arch/arm64/kernel/ptrace.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 35846f1550db..4c068dcf1977 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -947,8 +947,10 @@ static int compat_vfp_set(struct task_struct *target, if (count && !ret) { ret = get_user(fpscr, (compat_ulong_t *)ubuf); - uregs->fpsr = fpscr & VFP_FPSCR_STAT_MASK; - uregs->fpcr = fpscr & VFP_FPSCR_CTRL_MASK; + if (!ret) { + uregs->fpsr = fpscr & VFP_FPSCR_STAT_MASK; + uregs->fpcr = fpscr & VFP_FPSCR_CTRL_MASK; + } } fpsimd_flush_task_state(target); |