From: Maciej W. Rozycki <macro@mips.com>
Date: Mon, 11 Dec 2017 22:56:54 +0000 (+0000)
Subject: MIPS: Disallow outsized PTRACE_SETREGSET NT_PRFPREG regset accesses
X-Git-Tag: v3.18.92~33
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1eaff733141a52dce42b2bcce8db7643843ba121;p=thirdparty%2Fkernel%2Fstable.git

MIPS: Disallow outsized PTRACE_SETREGSET NT_PRFPREG regset accesses

commit c8c5a3a24d395b14447a9a89d61586a913840a3b upstream.

Complement commit c23b3d1a5311 ("MIPS: ptrace: Change GP regset to use
correct core dump register layout") and also reject outsized
PTRACE_SETREGSET requests to the NT_PRFPREG regset, like with the
NT_PRSTATUS regset.

Signed-off-by: Maciej W. Rozycki <macro@mips.com>
Fixes: c23b3d1a5311 ("MIPS: ptrace: Change GP regset to use correct core dump register layout")
Cc: James Hogan <james.hogan@mips.com>
Cc: Paul Burton <Paul.Burton@mips.com>
Cc: Alex Smith <alex@alex-smith.me.uk>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17930/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index 1848877f4dc9e..ae02cd1a038e1 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -530,6 +530,9 @@ static int fpr_set(struct task_struct *target,
 
 	BUG_ON(count % sizeof(elf_fpreg_t));
 
+	if (pos + count > sizeof(elf_fpregset_t))
+		return -EIO;
+
 	if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t))
 		err = fpr_set_fpa(target, &pos, &count, &kbuf, &ubuf);
 	else