From: Dave Martin <Dave.Martin@arm.com>
Date: Mon, 27 Mar 2017 14:10:57 +0000 (+0100)
Subject: metag/ptrace: Reject partial NT_METAG_RPIPE writes
X-Git-Tag: v4.9.20~4
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=21c95eca627bf63fa56dc19f5fb5fb2a770dadc0;p=platform%2Fkernel%2Flinux-amlogic.git

metag/ptrace: Reject partial NT_METAG_RPIPE writes

commit 7195ee3120d878259e8d94a5d9f808116f34d5ea upstream.

It's not clear what behaviour is sensible when doing partial write of
NT_METAG_RPIPE, so just don't bother.

This patch assumes that userspace will never rely on a partial SETREGSET
in this case, since it's not clear what should happen anyway.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/metag/kernel/ptrace.c b/arch/metag/kernel/ptrace.c
index 2e4dfc1..5e2dc7d 100644
--- a/arch/metag/kernel/ptrace.c
+++ b/arch/metag/kernel/ptrace.c
@@ -253,6 +253,8 @@ int metag_rp_state_copyin(struct pt_regs *regs,
 	unsigned long long *ptr;
 	int ret, i;
 
+	if (count < 4*13)
+		return -EINVAL;
 	/* Read the entire pipeline before making any changes */
 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 				 &rp, 0, 4*13);