lkml.org 
[lkml]   [2010]   [Nov]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] gpu: vga: fix ZERO_SIZE_PTR dereference
Date
count is not checked before kmalloc() call, if it is -1 then
kmalloc() returns ZERO_SIZE_PTR. This pointer is then dereferenced.
Also one may pass too big count to generate OOM condition.
To prevent this limit 'count' maximum value. PAGE_SIZE looks OK.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
---
Compile tested only.

drivers/gpu/vga/vgaarb.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
index c380c65..09e3090 100644
--- a/drivers/gpu/vga/vgaarb.c
+++ b/drivers/gpu/vga/vgaarb.c
@@ -836,6 +836,8 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf,
int ret_val;
int i;

+ if (count > PAGE_SIZE)
+ count = PAGE_SIZE;

kbuf = kmalloc(count + 1, GFP_KERNEL);
if (!kbuf)
--
1.7.0.4


\
 
 \ /
  Last update: 2010-11-21 18:43    [W:0.087 / U:1.956 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site