[Scst-svn] [master] qla2x00t-32gbit: Fix mem access after free

[Gleb C. <lna...@ya...>]

Commit: 284f444
GitHub URL: https://github.com/SCST-project/scst/commit/284f4446e18600e59dc93aefbe948b74dd85eac4
Author: Gleb Chesnokov
Date: 2023-07-19T11:35:51+03:00
Log Message:
-----------
qla2x00t-32gbit: 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: st...@vg...
Signed-off-by: Quinn Tran <qu...@ma...>
Signed-off-by: Nilesh Javali <nj...@ma...>
Link: https://lore.kernel.org/r/202...@ma...
Reviewed-by: Himanshu Madhani <him...@or...>
Signed-off-by: Martin K. Petersen <mar...@or...>
[ commit b843adde8d49 upstream ]

Modified Paths:
--------------
 qla2x00t-32gbit/qla_isr.c |  38 ++++-
 qla2x00t-32gbit/qla_os.c  | 130 +++++++--------
 2 files changed, 95 insertions(+), 73 deletions(-)

===================================================================
diff --git a/qla2x00t-32gbit/qla_isr.c b/qla2x00t-32gbit/qla_isr.c
index 70a8edd..a238f3f 100644
--- a/qla2x00t-32gbit/qla_isr.c
+++ b/qla2x00t-32gbit/qla_isr.c
@@ -1874,9 +1874,9 @@ 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;
@@ -1911,12 +1911,25 @@ 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)
@@ -3260,13 +3273,13 @@ 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;
 	}
 
@@ -3537,6 +3550,9 @@ 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;
 }
 
 /**
@@ -3613,6 +3629,7 @@ 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",
@@ -3631,7 +3648,6 @@ 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:
@@ -3651,6 +3667,14 @@ 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,
diff --git a/qla2x00t-32gbit/qla_os.c b/qla2x00t-32gbit/qla_os.c
index 490568e..e08ddac 100644
--- a/qla2x00t-32gbit/qla_os.c
+++ b/qla2x00t-32gbit/qla_os.c
@@ -1119,43 +1119,6 @@ qc24_fail_command:
 	return 0;
 }
 
-/*
- * qla2x00_eh_wait_on_command
- *    Waits for the command to be returned by the Firmware for some
- *    max time.
- *
- * Input:
- *    cmd = Scsi Command to wait on.
- *
- * Return:
- *    Completed in time : QLA_SUCCESS
- *    Did not complete in time : QLA_FUNCTION_FAILED
- */
-static int
-qla2x00_eh_wait_on_command(struct scsi_cmnd *cmd)
-{
-#define ABORT_POLLING_PERIOD	1000
-#define ABORT_WAIT_ITER		((2 * 1000) / (ABORT_POLLING_PERIOD))
-	unsigned long wait_iter = ABORT_WAIT_ITER;
-	scsi_qla_host_t *vha = shost_priv(cmd->device->host);
-	struct qla_hw_data *ha = vha->hw;
-	srb_t *sp = scsi_cmd_priv(cmd);
-	int ret = QLA_SUCCESS;
-
-	if (unlikely(pci_channel_offline(ha->pdev)) || ha->flags.eeh_busy) {
-		ql_dbg(ql_dbg_taskm, vha, 0x8005,
-		    "Return:eh_wait.\n");
-		return ret;
-	}
-
-	while (sp->type && wait_iter--)
-		msleep(ABORT_POLLING_PERIOD);
-	if (sp->type)
-		ret = QLA_FUNCTION_FAILED;
-
-	return ret;
-}
-
 /*
  * qla2x00_wait_for_hba_online
  *    Wait till the HBA is online after going through
@@ -1406,6 +1369,9 @@ qla2xxx_eh_abort(struct scsi_cmnd *cmd)
 	return ret;
 }
 
+#define ABORT_POLLING_PERIOD	1000
+#define ABORT_WAIT_ITER		((2 * 1000) / (ABORT_POLLING_PERIOD))
+
 /*
  * Returns: QLA_SUCCESS or QLA_FUNCTION_FAILED.
  */
@@ -1419,41 +1385,73 @@ __qla2x00_eh_wait_for_pending_commands(struct qla_qpair *qpair, unsigned int t,
 	struct req_que *req = qpair->req;
 	srb_t *sp;
 	struct scsi_cmnd *cmd;
+	unsigned long wait_iter = ABORT_WAIT_ITER;
+	bool found;
+	struct qla_hw_data *ha = vha->hw;
 
 	status = QLA_SUCCESS;
 
-	spin_lock_irqsave(qpair->qp_lock_ptr, flags);
-	for (cnt = 1; status == QLA_SUCCESS &&
-		cnt < req->num_outstanding_cmds; cnt++) {
-		sp = req->outstanding_cmds[cnt];
-		if (!sp)
-			continue;
-		if (sp->type != SRB_SCSI_CMD)
-			continue;
-		if (vha->vp_idx != sp->vha->vp_idx)
-			continue;
-		match = 0;
-		cmd = GET_CMD_SP(sp);
-		switch (type) {
-		case WAIT_HOST:
-			match = 1;
-			break;
-		case WAIT_TARGET:
-			match = cmd->device->id == t;
-			break;
-		case WAIT_LUN:
-			match = (cmd->device->id == t &&
-				cmd->device->lun == l);
-			break;
-		}
-		if (!match)
-			continue;
+	while (wait_iter--) {
+		found = false;
 
-		spin_unlock_irqrestore(qpair->qp_lock_ptr, flags);
-		status = qla2x00_eh_wait_on_command(cmd);
 		spin_lock_irqsave(qpair->qp_lock_ptr, flags);
+		for (cnt = 1; cnt < req->num_outstanding_cmds; cnt++) {
+			sp = req->outstanding_cmds[cnt];
+			if (!sp)
+				continue;
+			if (sp->type != SRB_SCSI_CMD)
+				continue;
+			if (vha->vp_idx != sp->vha->vp_idx)
+				continue;
+			match = 0;
+			cmd = GET_CMD_SP(sp);
+			switch (type) {
+			case WAIT_HOST:
+				match = 1;
+				break;
+			case WAIT_TARGET:
+				if (sp->fcport)
+					match = sp->fcport->d_id.b24 == t;
+				else
+					match = 0;
+				break;
+			case WAIT_LUN:
+				if (sp->fcport)
+					match = (sp->fcport->d_id.b24 == t &&
+						cmd->device->lun == l);
+				else
+					match = 0;
+				break;
+			}
+			if (!match)
+				continue;
+
+			spin_unlock_irqrestore(qpair->qp_lock_ptr, flags);
+
+			if (unlikely(pci_channel_offline(ha->pdev)) ||
+			    ha->flags.eeh_busy) {
+				ql_dbg(ql_dbg_taskm, vha, 0x8005,
+				    "Return:eh_wait.\n");
+				return status;
+			}
+
+			/*
+			 * SRB_SCSI_CMD is still in the outstanding_cmds array.
+			 * it means scsi_done has not called. Wait for it to
+			 * clear from outstanding_cmds.
+			 */
+			msleep(ABORT_POLLING_PERIOD);
+			spin_lock_irqsave(qpair->qp_lock_ptr, flags);
+			found = true;
+		}
+		spin_unlock_irqrestore(qpair->qp_lock_ptr, flags);
+
+		if (!found)
+			break;
 	}
-	spin_unlock_irqrestore(qpair->qp_lock_ptr, flags);
+
+	if (!wait_iter && found)
+		status = QLA_FUNCTION_FAILED;
 
 	return status;
 }