lkml.org 
[lkml]   [2014]   [Jul]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] x86,kprobes: Don't try to resolve kprobe faults from userspace
Date
This commit:

commit 6f6343f53d133bae516caf3d254bce37d8774625
Author: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Date: Thu Apr 17 17:17:33 2014 +0900

kprobes/x86: Call exception handlers directly from do_int3/do_debug

Trying to dereference addr when addr is user-controlled is
completely bogus.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
arch/x86/kernel/kprobes/core.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 7596df6..67e6d19 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -574,6 +574,9 @@ int kprobe_int3_handler(struct pt_regs *regs)
struct kprobe *p;
struct kprobe_ctlblk *kcb;

+ if (user_mode_vm(regs))
+ return 0;
+
addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t));
/*
* We don't want to be preempted for the entire
--
1.9.3


\
 
 \ /
  Last update: 2014-07-04 05:41    [W:0.033 / U:0.100 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site