Patch "mips/ptrace: Preserve previous registers for short regset write" has been added to the 3.18-stable tree

Patch "mips/ptrace: Preserve previous registers for short regset write" has been added to the 3.18-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    mips/ptrace: Preserve previous registers for short regset write

to the 3.18-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mips-ptrace-preserve-previous-registers-for-short-regset-write.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From d614fd58a2834cfe4efa472c33c8f3ce2338b09b Mon Sep 17 00:00:00 2001
From: Dave Martin <Dave.Martin@arm.com>
Date: Mon, 27 Mar 2017 15:10:58 +0100
Subject: mips/ptrace: Preserve previous registers for short regset write

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

commit d614fd58a2834cfe4efa472c33c8f3ce2338b09b 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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -444,7 +444,8 @@ static int fpr_set(struct task_struct *t
 					  &target->thread.fpu,
 					  0, sizeof(elf_fpregset_t));
 
-	for (i = 0; i < NUM_FPU_REGS; i++) {
+	BUILD_BUG_ON(sizeof(fpr_val) != sizeof(elf_fpreg_t));
+	for (i = 0; i < NUM_FPU_REGS && count >= sizeof(elf_fpreg_t); i++) {
 		err = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 					 &fpr_val, i * sizeof(elf_fpreg_t),
 					 (i + 1) * sizeof(elf_fpreg_t));


Patches currently in stable-queue which might be from Dave.Martin@arm.com are

queue-3.18/metag-ptrace-reject-partial-nt_metag_rpipe-writes.patch
queue-3.18/metag-ptrace-preserve-previous-registers-for-short-regset-write.patch
queue-3.18/metag-ptrace-provide-default-txstatus-for-short-nt_prstatus.patch
queue-3.18/c6x-ptrace-remove-useless-ptrace_setregset-implementation.patch
queue-3.18/mips-ptrace-preserve-previous-registers-for-short-regset-write.patch
queue-3.18/sparc-ptrace-preserve-previous-registers-for-short-regset-write.patch