From 9dd73f72f218320c6c90da5f834996e7360dc227 Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Wed, 18 Jan 2017 16:25:21 +0000 Subject: [PATCH] arm64/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. Cc: # 3.19.x- Fixes: 766a85d7bc5d ("arm64: ptrace: add NT_ARM_SYSTEM_CALL regset") Signed-off-by: Dave Martin Acked-by: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/kernel/ptrace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 8c0bc3434f55..ead36d5fad6d 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -677,7 +677,8 @@ static int system_call_set(struct task_struct *target, 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)