[PATCH 4.10 14/17] metag/ptrace: Reject partial NT_METAG_RPIPE writes

Greg Kroah-Hartman
2017-03-30T10:13:24Z

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

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>

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

--- a/arch/metag/kernel/ptrace.c
+++ b/arch/metag/kernel/ptrace.c
@@ -253,6 +253,8 @@ int metag_rp_state_copyin(struct pt_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);