* re: net: sctp: rework multihoming retransmission path selection to rfc4960
@ 2014-02-28 23:15 Dan Carpenter
2014-02-28 23:30 ` Daniel Borkmann
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Dan Carpenter @ 2014-02-28 23:15 UTC (permalink / raw)
To: linux-sctp
Hello Daniel Borkmann,
This is a semi-automatic email about new static checker warnings.
The patch 4c47af4d5eb2: "net: sctp: rework multihoming retransmission
path selection to rfc4960" from Feb 20, 2014, leads to the following
Smatch complaint:
net/sctp/associola.c:1322 sctp_assoc_update_retran_path()
warn: variable dereferenced before check 'trans_next' (see line 1319)
net/sctp/associola.c
1305 /* Iterate from retran_path's successor back to retran_path. */
1306 for (trans = list_next_entry(trans, transports); 1;
1307 trans = list_next_entry(trans, transports)) {
1308 /* Manually skip the head element. */
1309 if (&trans->transports = &asoc->peer.transport_addr_list)
1310 continue;
1311 if (trans->state = SCTP_UNCONFIRMED)
1312 continue;
1313 trans_next = sctp_trans_elect_best(trans, trans_next);
1314 /* Active is good enough for immediate return. */
1315 if (trans_next->state = SCTP_ACTIVE)
^^^^^^^^^^^^^^^^^
Dereference.
1316 break;
^^^^^^
1317 /* We've reached the end, time to update path. */
1318 if (trans = asoc->peer.retran_path)
1319 break;
^^^^^
These two breaks are the the only way to exit from the loop.
1320 }
1321
1322 if (trans_next != NULL)
^^^^^^^^^^^^^^^^^^
Check to late.
1323 asoc->peer.retran_path = trans_next;
1324
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: net: sctp: rework multihoming retransmission path selection to rfc4960
2014-02-28 23:15 net: sctp: rework multihoming retransmission path selection to rfc4960 Dan Carpenter
@ 2014-02-28 23:30 ` Daniel Borkmann
2014-03-01 8:44 ` Dan Carpenter
2014-03-01 10:24 ` Daniel Borkmann
2 siblings, 0 replies; 4+ messages in thread
From: Daniel Borkmann @ 2014-02-28 23:30 UTC (permalink / raw)
To: linux-sctp
On 03/01/2014 12:15 AM, Dan Carpenter wrote:
> Hello Daniel Borkmann,
>
> This is a semi-automatic email about new static checker warnings.
>
> The patch 4c47af4d5eb2: "net: sctp: rework multihoming retransmission
> path selection to rfc4960" from Feb 20, 2014, leads to the following
> Smatch complaint:
>
> net/sctp/associola.c:1322 sctp_assoc_update_retran_path()
> warn: variable dereferenced before check 'trans_next' (see line 1319)
>
> net/sctp/associola.c
> 1305 /* Iterate from retran_path's successor back to retran_path. */
> 1306 for (trans = list_next_entry(trans, transports); 1;
> 1307 trans = list_next_entry(trans, transports)) {
> 1308 /* Manually skip the head element. */
> 1309 if (&trans->transports = &asoc->peer.transport_addr_list)
> 1310 continue;
> 1311 if (trans->state = SCTP_UNCONFIRMED)
> 1312 continue;
> 1313 trans_next = sctp_trans_elect_best(trans, trans_next);
> 1314 /* Active is good enough for immediate return. */
> 1315 if (trans_next->state = SCTP_ACTIVE)
> ^^^^^^^^^^^^^^^^^
> Dereference.
That is a false-positive.
trans_next at that time is being assigned through sctp_trans_elect_best() a
guaranteed non-NULL pointer.
> 1316 break;
> ^^^^^^
> 1317 /* We've reached the end, time to update path. */
> 1318 if (trans = asoc->peer.retran_path)
> 1319 break;
> ^^^^^
> These two breaks are the the only way to exit from the loop.
>
> 1320 }
> 1321
> 1322 if (trans_next != NULL)
> ^^^^^^^^^^^^^^^^^^
> Check to late.
>
> 1323 asoc->peer.retran_path = trans_next;
> 1324
>
> regards,
> dan carpenter
> --
> To unsubscribe from this list: send the line "unsubscribe linux-sctp" in
> the body of a message to majordomo@vger.kernel.org
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>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: net: sctp: rework multihoming retransmission path selection to rfc4960
2014-02-28 23:15 net: sctp: rework multihoming retransmission path selection to rfc4960 Dan Carpenter
2014-02-28 23:30 ` Daniel Borkmann
@ 2014-03-01 8:44 ` Dan Carpenter
2014-03-01 10:24 ` Daniel Borkmann
2 siblings, 0 replies; 4+ messages in thread
From: Dan Carpenter @ 2014-03-01 8:44 UTC (permalink / raw)
To: linux-sctp
On Sat, Mar 01, 2014 at 12:30:09AM +0100, Daniel Borkmann wrote:
> On 03/01/2014 12:15 AM, Dan Carpenter wrote:
> >Hello Daniel Borkmann,
> >
> >This is a semi-automatic email about new static checker warnings.
> >
> >The patch 4c47af4d5eb2: "net: sctp: rework multihoming retransmission
> >path selection to rfc4960" from Feb 20, 2014, leads to the following
> >Smatch complaint:
> >
> >net/sctp/associola.c:1322 sctp_assoc_update_retran_path()
> > warn: variable dereferenced before check 'trans_next' (see line 1319)
> >
> >net/sctp/associola.c
> > 1305 /* Iterate from retran_path's successor back to retran_path. */
> > 1306 for (trans = list_next_entry(trans, transports); 1;
> > 1307 trans = list_next_entry(trans, transports)) {
> > 1308 /* Manually skip the head element. */
> > 1309 if (&trans->transports = &asoc->peer.transport_addr_list)
> > 1310 continue;
> > 1311 if (trans->state = SCTP_UNCONFIRMED)
> > 1312 continue;
> > 1313 trans_next = sctp_trans_elect_best(trans, trans_next);
> > 1314 /* Active is good enough for immediate return. */
> > 1315 if (trans_next->state = SCTP_ACTIVE)
> > ^^^^^^^^^^^^^^^^^
> >Dereference.
>
> That is a false-positive.
>
> trans_next at that time is being assigned through sctp_trans_elect_best() a
> guaranteed non-NULL pointer.
>
Can you remove the NULL check then?
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: net: sctp: rework multihoming retransmission path selection to rfc4960
2014-02-28 23:15 net: sctp: rework multihoming retransmission path selection to rfc4960 Dan Carpenter
2014-02-28 23:30 ` Daniel Borkmann
2014-03-01 8:44 ` Dan Carpenter
@ 2014-03-01 10:24 ` Daniel Borkmann
2 siblings, 0 replies; 4+ messages in thread
From: Daniel Borkmann @ 2014-03-01 10:24 UTC (permalink / raw)
To: linux-sctp
On 03/01/2014 09:44 AM, Dan Carpenter wrote:
> On Sat, Mar 01, 2014 at 12:30:09AM +0100, Daniel Borkmann wrote:
>> On 03/01/2014 12:15 AM, Dan Carpenter wrote:
>>> Hello Daniel Borkmann,
>>>
>>> This is a semi-automatic email about new static checker warnings.
>>>
>>> The patch 4c47af4d5eb2: "net: sctp: rework multihoming retransmission
>>> path selection to rfc4960" from Feb 20, 2014, leads to the following
>>> Smatch complaint:
>>>
>>> net/sctp/associola.c:1322 sctp_assoc_update_retran_path()
>>> warn: variable dereferenced before check 'trans_next' (see line 1319)
>>>
>>> net/sctp/associola.c
>>> 1305 /* Iterate from retran_path's successor back to retran_path. */
>>> 1306 for (trans = list_next_entry(trans, transports); 1;
>>> 1307 trans = list_next_entry(trans, transports)) {
>>> 1308 /* Manually skip the head element. */
>>> 1309 if (&trans->transports = &asoc->peer.transport_addr_list)
>>> 1310 continue;
>>> 1311 if (trans->state = SCTP_UNCONFIRMED)
>>> 1312 continue;
>>> 1313 trans_next = sctp_trans_elect_best(trans, trans_next);
>>> 1314 /* Active is good enough for immediate return. */
>>> 1315 if (trans_next->state = SCTP_ACTIVE)
>>> ^^^^^^^^^^^^^^^^^
>>> Dereference.
>>
>> That is a false-positive.
>>
>> trans_next at that time is being assigned through sctp_trans_elect_best() a
>> guaranteed non-NULL pointer.
>
> Can you remove the NULL check then?
Will do when this merges into net-next. Thanks.
> regards,
> dan carpenter
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2014-02-28 23:15 net: sctp: rework multihoming retransmission path selection to rfc4960 Dan Carpenter
2014-02-28 23:30 ` Daniel Borkmann
2014-03-01 8:44 ` Dan Carpenter
2014-03-01 10:24 ` Daniel Borkmann
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