Steffen Maier 2dfa6688aa scsi: zfcp: fix use-after-free by not tracing WKA port open/close on failed send ... Dan Carpenter kindly reported: <quote> The patch d27a7cb919: "zfcp: trace on request for open and close of WKA port" from Aug 10, 2016, leads to the following static checker warning: drivers/s390/scsi/zfcp_fsf.c:1615 zfcp_fsf_open_wka_port() warn: 'req' was already freed. drivers/s390/scsi/zfcp_fsf.c 1609 zfcp_fsf_start_timer(req, ZFCP_FSF_REQUEST_TIMEOUT); 1610 retval = zfcp_fsf_req_send(req); 1611 if (retval) 1612 zfcp_fsf_req_free(req); ^^^ Freed. 1613 out: 1614 spin_unlock_irq(&qdio->req_q_lock); 1615 if (req && !IS_ERR(req)) 1616 zfcp_dbf_rec_run_wka("fsowp_1", wka_port, req->req_id); ^^^^^^^^^^^ Use after free. 1617 return retval; 1618 } Same thing for zfcp_fsf_close_wka_port() as well. </quote> Rather than relying on req being NULL (or ERR_PTR) for all cases where we don't want to trace or should not trace, simply check retval which is unconditionally initialized with -EIO != 0 and it can only become 0 on successful retval = zfcp_fsf_req_send(req). With that we can also remove the then again unnecessary unconditional initialization of req which was introduced with that earlier commit. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Suggested-by: Benjamin Block <bblock@linux.vnet.ibm.com> Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Fixes: d27a7cb919 ("zfcp: trace on request for open and close of WKA port") Cc: <stable@vger.kernel.org> #2.6.38+ Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com> Reviewed-by: Jens Remus <jremus@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>		2017-02-09 19:28:19 -05:00
..
block	s390/dasd: channel path aware error recovery	2016-12-12 12:05:03 +01:00
char	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux	2016-12-13 16:33:33 -08:00
cio	s390: cio: make it explicitly non-modular	2016-10-31 17:55:32 +01:00
crypto	s390/zcrypt: Convert to PM ops	2016-12-02 07:36:22 +01:00
net	s390/net: use net core MTU range checking	2016-10-20 14:51:10 -04:00
scsi	scsi: zfcp: fix use-after-free by not tracing WKA port open/close on failed send	2017-02-09 19:28:19 -05:00
virtio	s390: virtio: make ccw explicitly non-modular	2016-10-31 17:55:46 +01:00
Makefile	virtio/s390: rename drivers/s390/kvm -> drivers/s390/virtio	2015-07-07 14:27:06 +03:00