[PATCH] scsi: libfc: fix directory server rport memory leak

[Guangshuo Li <lgs201920130244@gmail.com>]

fc_rport_recv_plogi_req() creates an rport before allocating the frame
used for the PLOGI LS_ACC response.

fc_rport_create() does not add FC_FID_DIR_SERV rports to the discovery
rport list. If fc_frame_alloc() fails while handling a PLOGI from the
directory server, the function returns without starting the rport state
machine or dropping the initial rport reference.

Since the directory server rport is not present in the discovery list,
there is no later teardown path that can find the object and release
that reference. The allocated fc_rport_priv is therefore leaked.

Record when the failed frame allocation leaves an unlisted directory
server rport behind and drop its initial reference after releasing the
rport mutex. Keep the existing lifetime unchanged for ordinary rports,
which remain owned by the discovery list.

The issue was identified by a static analysis tool I developed and
confirmed by manual review.

Fixes: 3ac6f98f4113 ("[SCSI] libfc: correctly handle incoming PLOGI request.")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/scsi/libfc/fc_rport.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/libfc/fc_rport.c b/drivers/scsi/libfc/fc_rport.c
index c25979d96808..884b233c2f72 100644
--- a/drivers/scsi/libfc/fc_rport.c
+++ b/drivers/scsi/libfc/fc_rport.c
@@ -1848,6 +1848,7 @@ static void fc_rport_recv_plogi_req(struct fc_lport *lport,
 	struct fc_els_flogi *pl;
 	struct fc_seq_els_data rjt_data;
 	u32 sid;
+	bool drop_rdata = false;
 
 	lockdep_assert_held(&lport->lp_mutex);
 
@@ -1940,8 +1941,10 @@ static void fc_rport_recv_plogi_req(struct fc_lport *lport,
 	 * Send LS_ACC.	 If this fails, the originator should retry.
 	 */
 	fp = fc_frame_alloc(lport, sizeof(*pl));
-	if (!fp)
+	if (!fp) {
+		drop_rdata = sid == FC_FID_DIR_SERV;
 		goto out;
+	}
 
 	fc_plogi_fill(lport, fp, ELS_LS_ACC);
 	fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_ELS_REP, 0);
@@ -1949,6 +1952,8 @@ static void fc_rport_recv_plogi_req(struct fc_lport *lport,
 	fc_rport_enter_prli(rdata);
 out:
 	mutex_unlock(&rdata->rp_mutex);
+	if (drop_rdata)
+		kref_put(&rdata->kref, fc_rport_destroy);
 	fc_frame_free(rx_fp);
 	return;
 
-- 
2.43.0