From 9a17b876b573441bfb3387ad55d98bf7184daf9d Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Wed, 18 Jan 2017 16:25:20 +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: # 3.7.x- Fixes: 478fcb2cdb23 ("arm64: Debugging support") Signed-off-by: Dave Martin Acked-by: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/kernel/ptrace.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index fc35e06ccaac..8c0bc3434f55 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -596,7 +596,7 @@ static int gpr_set(struct task_struct *target, const struct user_regset *regset, const void *kbuf, const void __user *ubuf) { int ret; - struct user_pt_regs newregs; + struct user_pt_regs newregs = task_pt_regs(target)->user_regs; ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newregs, 0, -1); if (ret) @@ -626,7 +626,8 @@ static int fpr_set(struct task_struct *target, const struct user_regset *regset, const void *kbuf, const void __user *ubuf) { int ret; - struct user_fpsimd_state newstate; + struct user_fpsimd_state newstate = + target->thread.fpsimd_state.user_fpsimd; ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newstate, 0, -1); if (ret) @@ -650,7 +651,7 @@ static int tls_set(struct task_struct *target, const struct user_regset *regset, const void *kbuf, const void __user *ubuf) { int ret; - unsigned long tls; + unsigned long tls = target->thread.tp_value; ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1); if (ret)