From: Dave Martin <Dave.Martin@arm.com>
Date: Mon, 27 Mar 2017 14:10:59 +0000 (+0100)
Subject: sparc/ptrace: Preserve previous registers for short regset write
X-Git-Tag: v3.12.73~37
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bc586353a4d9e3987e4b53d544cd76e4fdeacedb;p=thirdparty%2Fkernel%2Fstable.git

sparc/ptrace: Preserve previous registers for short regset write

commit d3805c546b275c8cc7d40f759d029ae92c7175f2 upstream.

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>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---

diff --git a/arch/sparc/kernel/ptrace_64.c b/arch/sparc/kernel/ptrace_64.c
index 773c1f2983ce3..89297b7c62611 100644
--- a/arch/sparc/kernel/ptrace_64.c
+++ b/arch/sparc/kernel/ptrace_64.c
@@ -310,7 +310,7 @@ static int genregs64_set(struct task_struct *target,
 	}
 
 	if (!ret) {
-		unsigned long y;
+		unsigned long y = regs->y;
 
 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 					 &y,