mips/ptrace: Preserve previous registers for short regset write

Ensure that if userspace supplies insufficient data to PTRACE_SETREGSET
to fill all the registers, the thread's old registers are preserved.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dave Martin 2017-03-27 15:10:58 +01:00 committed by Linus Torvalds
parent 7195ee3120
commit d614fd58a2

View file

@ -485,7 +485,8 @@ static int fpr_set(struct task_struct *target,
&target->thread.fpu,
0, sizeof(elf_fpregset_t));
for (i = 0; i < NUM_FPU_REGS; i++) {
BUILD_BUG_ON(sizeof(fpr_val) != sizeof(elf_fpreg_t));
for (i = 0; i < NUM_FPU_REGS && count >= sizeof(elf_fpreg_t); i++) {
err = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&fpr_val, i * sizeof(elf_fpreg_t),
(i + 1) * sizeof(elf_fpreg_t));