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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


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