4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Dave Martin <[email protected]> commit 9dd73f72f218320c6c90da5f834996e7360dc227 upstream. Ensure that if userspace supplies insufficient data to PTRACE_SETREGSET to fill all the registers, the thread's old registers are preserved. Fixes: 766a85d7bc5d ("arm64: ptrace: add NT_ARM_SYSTEM_CALL regset") Signed-off-by: Dave Martin <[email protected]> Acked-by: Will Deacon <[email protected]> Signed-off-by: Catalin Marinas <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/arm64/kernel/ptrace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -676,7 +676,8 @@ static int system_call_set(struct task_s unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { - int syscallno, ret; + int syscallno = task_pt_regs(target)->syscallno; + int ret; ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &syscallno, 0, -1); if (ret)
