scsi: qla2xxx: Fix mem access after free

System crash, where driver is accessing scsi layer's
memory (scsi_cmnd->device->host) to search for a well known internal
pointer (vha). The scsi_cmnd was released back to upper layer which
could be freed, but the driver is still accessing it.

7 [ffffa8e8d2c3f8d0] page_fault at ffffffff86c010fe
  [exception RIP: __qla2x00_eh_wait_for_pending_commands+240]
  RIP: ffffffffc0642350  RSP: ffffa8e8d2c3f988  RFLAGS: 00010286
  RAX: 0000000000000165  RBX: 0000000000000002  RCX: 00000000000036d8
  RDX: 0000000000000000  RSI: ffff9c5c56535188  RDI: 0000000000000286
  RBP: ffff9c5bf7aa4a58   R8: ffff9c589aecdb70   R9: 00000000000003d1
  R10: 0000000000000001  R11: 0000000000380000 R12: ffff9c5c5392bc78
  R13: ffff9c57044ff5c0 R14: ffff9c56b5a3aa00  R15: 00000000000006db
  ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
8 [ffffa8e8d2c3f9c8] qla2x00_eh_wait_for_pending_commands at ffffffffc0646dd5 [qla2xxx]
9 [ffffa8e8d2c3fa00] __qla2x00_async_tm_cmd at ffffffffc0658094 [qla2xxx]

Remove access of freed memory. Currently the driver was checking to see if
scsi_done was called by seeing if the sp->type has changed. Instead,
check to see if the command has left the  oustanding_cmds[] array as
sign of scsi_done was called.

Cc: stable@vger.kernel.org
Signed-off-by: Quinn Tran <qutran@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Link: https://lore.kernel.org/r/20230428075339.32551-6-njavali@marvell.com
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 31 insertions, 7 deletions

diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index f3107508cf12..a07c010b0843 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -1862,9 +1862,9 @@ qla2x00_process_completed_request(struct scsi_qla_host *vha,
 	}
 }
 
-srb_t *
-qla2x00_get_sp_from_handle(scsi_qla_host_t *vha, const char *func,
-    struct req_que *req, void *iocb)
+static srb_t *
+qla_get_sp_from_handle(scsi_qla_host_t *vha, const char *func,
+		       struct req_que *req, void *iocb, u16 *ret_index)
 {
 	struct qla_hw_data *ha = vha->hw;
 	sts_entry_t *pkt = iocb;
@@ -1899,12 +1899,25 @@ qla2x00_get_sp_from_handle(scsi_qla_host_t *vha, const char *func,
 		return NULL;
 	}
 
-	req->outstanding_cmds[index] = NULL;
-
+	*ret_index = index;
 	qla_put_fw_resources(sp->qpair, &sp->iores);
 	return sp;
 }
 
+srb_t *
+qla2x00_get_sp_from_handle(scsi_qla_host_t *vha, const char *func,
+			   struct req_que *req, void *iocb)
+{
+	uint16_t index;
+	srb_t *sp;
+
+	sp = qla_get_sp_from_handle(vha, func, req, iocb, &index);
+	if (sp)
+		req->outstanding_cmds[index] = NULL;
+
+	return sp;
+}
+
 static void
 qla2x00_mbx_iocb_entry(scsi_qla_host_t *vha, struct req_que *req,
     struct mbx_entry *mbx)
@@ -3237,13 +3250,13 @@ qla2x00_status_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, void *pkt)
 		return;
 	}
 
-	req->outstanding_cmds[handle] = NULL;
 	cp = GET_CMD_SP(sp);
 	if (cp == NULL) {
 		ql_dbg(ql_dbg_io, vha, 0x3018,
 		    "Command already returned (0x%x/%p).\n",
 		    sts->handle, sp);
 
+		req->outstanding_cmds[handle] = NULL;
 		return;
 	}
 
@@ -3514,6 +3527,9 @@ out:
 
 	if (rsp->status_srb == NULL)
 		sp->done(sp, res);
+
+	/* for io's, clearing of outstanding_cmds[handle] means scsi_done was called */
+	req->outstanding_cmds[handle] = NULL;
 }
 
 /**
@@ -3590,6 +3606,7 @@ qla2x00_error_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, sts_entry_t *pkt)
 	uint16_t que = MSW(pkt->handle);
 	struct req_que *req = NULL;
 	int res = DID_ERROR << 16;
+	u16 index;
 
 	ql_dbg(ql_dbg_async, vha, 0x502a,
 	    "iocb type %xh with error status %xh, handle %xh, rspq id %d\n",
@@ -3608,7 +3625,6 @@ qla2x00_error_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, sts_entry_t *pkt)
 
 	switch (pkt->entry_type) {
 	case NOTIFY_ACK_TYPE:
-	case STATUS_TYPE:
 	case STATUS_CONT_TYPE:
 	case LOGINOUT_PORT_IOCB_TYPE:
 	case CT_IOCB_TYPE:
@@ -3628,6 +3644,14 @@ qla2x00_error_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, sts_entry_t *pkt)
 	case CTIO_TYPE7:
 	case CTIO_CRC2:
 		return 1;
+	case STATUS_TYPE:
+		sp = qla_get_sp_from_handle(vha, func, req, pkt, &index);
+		if (sp) {
+			sp->done(sp, res);
+			req->outstanding_cmds[index] = NULL;
+			return 0;
+		}
+		break;
 	}
 fatal:
 	ql_log(ql_log_warn, vha, 0x5030,