On 7/13/2012 12:03 AM, Roland Dreier wrote:
steve, in case you didn't read this because of the generic subject:
Thanks Roland. Yes, I missed this. I'll get to this asap...
On Thu, Jul 12, 2012 at 7:16 PM, <[email protected]> wrote:
https://bugzilla.kernel.org/show_bug.cgi?id=44631
Summary: Missing NULL check of the return value of get_skb() in
function send_flowc()
Product: Drivers
Version: 2.5
Kernel Version: 2.6.39
Platform: All
OS/Version: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: Infiniband/RDMA
AssignedTo: [email protected]
ReportedBy: [email protected]
Regression: No
Function get_skb() may return a NULL pointer, and its return value shall be
checked before used. But in function send_flowc() after get_skb() is called(at
drivers/infiniband/hw/cxgb4/cm.c:362), the return value is immediately used as
a parameter of __skb_put() without NULL check. Besides, there is no check
before the parameter is dereferenced in the callee function __skb_put(). So an
invalid memory access may be triggered.
The related code snippets in send_flowc() are as following.
send_flowc() @@drivers/infiniband/hw/cxgb4/cm.c:362
362 skb = get_skb(skb, flowclen, GFP_KERNEL);
363 flowc = (struct fw_flowc_wr *)__skb_put(skb, flowclen);
And the implementation of get_skb() are as following.
get_skb() drivers/infiniband/hw/cxgb4/cm.c:301
301static struct sk_buff *get_skb(struct sk_buff *skb, int len, gfp_t gfp)
302{
303 if (skb && !skb_is_nonlinear(skb) && !skb_cloned(skb)) {
304 skb_trim(skb, 0);
305 skb_get(skb);
306 skb_reset_transport_header(skb);
307 } else {
308 skb = alloc_skb(len, gfp);
309 }
310 return skb;
311}
Following is a call instance of snd_flowc.
act_establish @@drivers/infiniband/hw/cxgb4/cm.c:695
695 /* start MPA negotiation */
696 send_flowc(ep, NULL);
So from the source code we can see that potential NULL dereference fault exists
when path act_establish()->send_flowc()->get_skb()->alloc_skb() is executed.
Thank you
RUC_Soft_Sec
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