[4.9,071/130] arm64/ptrace: Preserve previous registers for short regset write - 2
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Message ID 20170124075537.849205235@linuxfoundation.org
State New, archived
Headers show
Series
  • 4.9.6-stable review
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Commit Message

Greg Kroah-Hartman Jan. 24, 2017, 7:55 a.m. UTC 
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dave Martin <Dave.Martin@arm.com>

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 <Dave.Martin@arm.com>
Acked-by: Will Deacon <Will.Deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arm64/kernel/ptrace.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Patch
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--- 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)