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authorSteffen Maier <maier@linux.vnet.ibm.com>2017-02-08 15:34:22 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-02-14 15:22:52 -0800
commit52e02d6bf304c73d000f7b3f1448d50c08b0befc (patch)
treebcf3ccbcaedf4bea1c5326f10a1a2221db6a8183 /drivers
parentf2d256a2d49f535dcd9e1aad09f96ef0add706d2 (diff)
scsi: zfcp: fix use-after-free by not tracing WKA port open/close on failed send
commit 2dfa6688aafdc3f74efeb1cf05fb871465d67f79 upstream. Dan Carpenter kindly reported: <quote> The patch d27a7cb91960: "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: d27a7cb91960 ("zfcp: trace on request for open and close of WKA port") 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/s390/scsi/zfcp_fsf.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index 75f820ca17b7..27ff38f839fc 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -1583,7 +1583,7 @@ out:
int zfcp_fsf_open_wka_port(struct zfcp_fc_wka_port *wka_port)
{
struct zfcp_qdio *qdio = wka_port->adapter->qdio;
- struct zfcp_fsf_req *req = NULL;
+ struct zfcp_fsf_req *req;
int retval = -EIO;
spin_lock_irq(&qdio->req_q_lock);
@@ -1612,7 +1612,7 @@ int zfcp_fsf_open_wka_port(struct zfcp_fc_wka_port *wka_port)
zfcp_fsf_req_free(req);
out:
spin_unlock_irq(&qdio->req_q_lock);
- if (req && !IS_ERR(req))
+ if (!retval)
zfcp_dbf_rec_run_wka("fsowp_1", wka_port, req->req_id);
return retval;
}
@@ -1638,7 +1638,7 @@ static void zfcp_fsf_close_wka_port_handler(struct zfcp_fsf_req *req)
int zfcp_fsf_close_wka_port(struct zfcp_fc_wka_port *wka_port)
{
struct zfcp_qdio *qdio = wka_port->adapter->qdio;
- struct zfcp_fsf_req *req = NULL;
+ struct zfcp_fsf_req *req;
int retval = -EIO;
spin_lock_irq(&qdio->req_q_lock);
@@ -1667,7 +1667,7 @@ int zfcp_fsf_close_wka_port(struct zfcp_fc_wka_port *wka_port)
zfcp_fsf_req_free(req);
out:
spin_unlock_irq(&qdio->req_q_lock);
- if (req && !IS_ERR(req))
+ if (!retval)
zfcp_dbf_rec_run_wka("fscwp_1", wka_port, req->req_id);
return retval;
}