This is a note to let you know that I've just added the patch titled
um: Fix PTRACE_POKEUSER on x86_64
to the 4.4-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:
um-fix-ptrace_pokeuser-on-x86_64.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9abc74a22d85ab29cef9896a2582a530da7e79bf Mon Sep 17 00:00:00 2001
From: Richard Weinberger <richard@xxxxxx>
Date: Sat, 1 Apr 2017 00:41:57 +0200
Subject: um: Fix PTRACE_POKEUSER on x86_64
From: Richard Weinberger <richard@xxxxxx>
commit 9abc74a22d85ab29cef9896a2582a530da7e79bf upstream.
This is broken since ever but sadly nobody noticed.
Recent versions of GDB set DR_CONTROL unconditionally and
UML dies due to a heap corruption. It turns out that
the PTRACE_POKEUSER was copy&pasted from i386 and assumes
that addresses are 4 bytes long.
Fix that by using 8 as address size in the calculation.
Reported-by: jie cao <cj3054@xxxxxxxxx>
Signed-off-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/um/ptrace_64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/um/ptrace_64.c
+++ b/arch/x86/um/ptrace_64.c
@@ -121,7 +121,7 @@ int poke_user(struct task_struct *child,
else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
(addr <= offsetof(struct user, u_debugreg[7]))) {
addr -= offsetof(struct user, u_debugreg[0]);
- addr = addr >> 2;
+ addr = addr >> 3;
if ((addr == 4) || (addr == 5))
return -EIO;
child->thread.arch.debugregs[addr] = data;
Patches currently in stable-queue which might be from richard@xxxxxx are
queue-4.4/um-fix-ptrace_pokeuser-on-x86_64.patch