* [bug report] RDMA/iw_cxgb4: Handle return value of c4iw_ofld_send() in abort_arp_failure()
@ 2017-02-23 15:58 Dan Carpenter
2017-04-13 10:33 ` Dan Carpenter
0 siblings, 1 reply; 3+ messages in thread
From: Dan Carpenter @ 2017-02-23 15:58 UTC (permalink / raw)
To: hariprasad-ut6Up61K2wZBDgjK7y7TUQ; +Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA
Hello Hariprasad S,
The patch 761e19a504af: "RDMA/iw_cxgb4: Handle return value of
c4iw_ofld_send() in abort_arp_failure()" from May 6, 2016, leads to
the following static checker warning:
drivers/infiniband/hw/cxgb4/cm.c:575 abort_arp_failure()
warn: passing freed memory 'skb'
drivers/infiniband/hw/cxgb4/cm.c
559 /*
560 * Handle an ARP failure for a CPL_ABORT_REQ. Change it into a no RST variant
561 * and send it along.
562 */
563 static void abort_arp_failure(void *handle, struct sk_buff *skb)
564 {
565 int ret;
566 struct c4iw_ep *ep = handle;
567 struct c4iw_rdev *rdev = &ep->com.dev->rdev;
568 struct cpl_abort_req *req = cplhdr(skb);
569
570 PDBG("%s rdev %p\n", __func__, rdev);
571 req->cmd = CPL_ABORT_NO_RST;
572 ret = c4iw_ofld_send(rdev, skb);
573 if (ret) {
If c4iw_ofld_send() fails then it frees skb.
574 __state_set(&ep->com, DEAD);
575 queue_arp_failure_cpl(ep, skb, FAKE_CPL_PUT_EP_SAFE);
^^^
Used after free here. These are ref counted data so it might actually
be that I have misread it and miscounted the references so perhaps it's
OK, but it looks might suspect at a glance.
576 }
577 }
regards,
dan carpenter
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [bug report] RDMA/iw_cxgb4: Handle return value of c4iw_ofld_send() in abort_arp_failure()
2017-02-23 15:58 [bug report] RDMA/iw_cxgb4: Handle return value of c4iw_ofld_send() in abort_arp_failure() Dan Carpenter
@ 2017-04-13 10:33 ` Dan Carpenter
2017-04-13 16:46 ` Steve Wise
0 siblings, 1 reply; 3+ messages in thread
From: Dan Carpenter @ 2017-04-13 10:33 UTC (permalink / raw)
To: hariprasad-ut6Up61K2wZBDgjK7y7TUQ; +Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA
Any update on this? It really looks buggy to me.
regards,
dan carpenter
On Thu, Feb 23, 2017 at 06:58:09PM +0300, Dan Carpenter wrote:
> Hello Hariprasad S,
>
> The patch 761e19a504af: "RDMA/iw_cxgb4: Handle return value of
> c4iw_ofld_send() in abort_arp_failure()" from May 6, 2016, leads to
> the following static checker warning:
>
> drivers/infiniband/hw/cxgb4/cm.c:575 abort_arp_failure()
> warn: passing freed memory 'skb'
>
> drivers/infiniband/hw/cxgb4/cm.c
> 559 /*
> 560 * Handle an ARP failure for a CPL_ABORT_REQ. Change it into a no RST variant
> 561 * and send it along.
> 562 */
> 563 static void abort_arp_failure(void *handle, struct sk_buff *skb)
> 564 {
> 565 int ret;
> 566 struct c4iw_ep *ep = handle;
> 567 struct c4iw_rdev *rdev = &ep->com.dev->rdev;
> 568 struct cpl_abort_req *req = cplhdr(skb);
> 569
> 570 PDBG("%s rdev %p\n", __func__, rdev);
> 571 req->cmd = CPL_ABORT_NO_RST;
> 572 ret = c4iw_ofld_send(rdev, skb);
> 573 if (ret) {
>
> If c4iw_ofld_send() fails then it frees skb.
>
> 574 __state_set(&ep->com, DEAD);
> 575 queue_arp_failure_cpl(ep, skb, FAKE_CPL_PUT_EP_SAFE);
> ^^^
> Used after free here. These are ref counted data so it might actually
> be that I have misread it and miscounted the references so perhaps it's
> OK, but it looks might suspect at a glance.
>
> 576 }
> 577 }
>
> regards,
> dan carpenter
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^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: [bug report] RDMA/iw_cxgb4: Handle return value of c4iw_ofld_send() in abort_arp_failure()
2017-04-13 10:33 ` Dan Carpenter
@ 2017-04-13 16:46 ` Steve Wise
0 siblings, 0 replies; 3+ messages in thread
From: Steve Wise @ 2017-04-13 16:46 UTC (permalink / raw)
To: 'Dan Carpenter'; +Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA
> Any update on this? It really looks buggy to me.
>
Hey Dan, I think you're correct. Seems like abort_arp_failure() needs to take a
ref before calling cxgb4_ofld_send() because cxgb4_ofld_send() will free the skb
if there is a fatal error. So abort_arp_failure() will deref the skb if
cxgb4_ofld_send() suceeds. Otherwise, the deref will happen in _put_ep_safe().
The same issue exists with FAKE_CPL_PASS_PUT_EP_SAFE too, and maybe all the arp
handlers.
Steve.
> regards,
> dan carpenter
>
> On Thu, Feb 23, 2017 at 06:58:09PM +0300, Dan Carpenter wrote:
> > Hello Hariprasad S,
> >
> > The patch 761e19a504af: "RDMA/iw_cxgb4: Handle return value of
> > c4iw_ofld_send() in abort_arp_failure()" from May 6, 2016, leads to
> > the following static checker warning:
> >
> > drivers/infiniband/hw/cxgb4/cm.c:575 abort_arp_failure()
> > warn: passing freed memory 'skb'
> >
> > drivers/infiniband/hw/cxgb4/cm.c
> > 559 /*
> > 560 * Handle an ARP failure for a CPL_ABORT_REQ. Change it into a no
RST
> variant
> > 561 * and send it along.
> > 562 */
> > 563 static void abort_arp_failure(void *handle, struct sk_buff *skb)
> > 564 {
> > 565 int ret;
> > 566 struct c4iw_ep *ep = handle;
> > 567 struct c4iw_rdev *rdev = &ep->com.dev->rdev;
> > 568 struct cpl_abort_req *req = cplhdr(skb);
> > 569
> > 570 PDBG("%s rdev %p\n", __func__, rdev);
> > 571 req->cmd = CPL_ABORT_NO_RST;
> > 572 ret = c4iw_ofld_send(rdev, skb);
> > 573 if (ret) {
> >
> > If c4iw_ofld_send() fails then it frees skb.
> >
> > 574 __state_set(&ep->com, DEAD);
> > 575 queue_arp_failure_cpl(ep, skb,
FAKE_CPL_PUT_EP_SAFE);
> > ^^^
> > Used after free here. These are ref counted data so it might actually
> > be that I have misread it and miscounted the references so perhaps it's
> > OK, but it looks might suspect at a glance.
> >
> > 576 }
> > 577 }
> >
> > regards,
> > dan carpenter
> --
> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
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2017-02-23 15:58 [bug report] RDMA/iw_cxgb4: Handle return value of c4iw_ofld_send() in abort_arp_failure() Dan Carpenter
2017-04-13 10:33 ` Dan Carpenter
2017-04-13 16:46 ` Steve Wise
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