2012-08-17 20:33:22

by Jesper Juhl

Subject: [PATCH] caif: Do not dereference NULL in chnl_recv_cb()

In net/caif/chnl_net.c::chnl_recv_cb() we call skb_header_pointer()
which may return NULL, but we do not check for a NULL pointer before
dereferencing it.
This patch adds such a NULL check and properly free's allocated memory
and return an error (-EINVAL) on failure - much better than crashing..

Signed-off-by: Jesper Juhl <[email protected]>
---
net/caif/chnl_net.c | 4 ++++
1 file changed, 4 insertions(+)

Note: compile tested only.

diff --git a/net/caif/chnl_net.c b/net/caif/chnl_net.c
index 69771c0..e597733 100644
--- a/net/caif/chnl_net.c
+++ b/net/caif/chnl_net.c
@@ -94,6 +94,10 @@ static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)

/* check the version of IP */
ip_version = skb_header_pointer(skb, 0, 1, &buf);
+ if (!ip_version) {
+ kfree_skb(skb);
+ return -EINVAL;
+ }

switch (*ip_version >> 4) {
case 4:
--
1.7.11.4


--
Jesper Juhl <[email protected]> http://www.chaosbits.net/
Don't top-post http://www.catb.org/jargon/html/T/top-post.html
Plain text mails only, please.

2012-08-20 06:33:25

by Sjur BRENDELAND

Subject: RE: [PATCH] caif: Do not dereference NULL in chnl_recv_cb()

> In net/caif/chnl_net.c::chnl_recv_cb() we call skb_header_pointer()
> which may return NULL, but we do not check for a NULL pointer before
> dereferencing it.
> This patch adds such a NULL check and properly free's allocated memory
> and return an error (-EINVAL) on failure - much better than crashing..
>
> Signed-off-by: Jesper Juhl <[email protected]>

Thank you for fixing this, the patch looks good to me.
Acked-by: Sjur Br?ndeland <[email protected]>

2012-08-20 09:48:10

by David Miller

Subject: Re: [PATCH] caif: Do not dereference NULL in chnl_recv_cb()

From: Sjur BRENDELAND <[email protected]>
Date: Mon, 20 Aug 2012 08:33:35 +0200

>> In net/caif/chnl_net.c::chnl_recv_cb() we call skb_header_pointer()
>> which may return NULL, but we do not check for a NULL pointer before
>> dereferencing it.
>> This patch adds such a NULL check and properly free's allocated memory
>> and return an error (-EINVAL) on failure - much better than crashing..
>>
>> Signed-off-by: Jesper Juhl <[email protected]>
>
> Thank you for fixing this, the patch looks good to me.
> Acked-by: Sjur Br?ndeland <[email protected]>

Applied, thanks.