diff mbox

scsi: libiscsi: fix possible NULL pointer dereference in case of TMF

Message ID 1531327192-11975-1-git-send-email-varun@chelsio.com (mailing list archive)
State Accepted
Headers show

Commit Message

Varun Prakash July 11, 2018, 4:39 p.m. UTC
In iscsi_check_tmf_restrictions() task->hdr is dereferenced
to print the opcode, it is possible that task->hdr is NULL.

There are two cases based on opcode argument -
1. ISCSI_OP_SCSI_CMD - In this case alloc_pdu() is called
after iscsi_check_tmf_restrictions()

iscsi_prep_scsi_cmd_pdu() -> iscsi_check_tmf_restrictions() ->
alloc_pdu().

Transport drivers allocate memory for iSCSI hdr in alloc_pdu()
and assign it to task->hdr. In case of TMF task->hdr will be NULL
resulting in NULL pointer dereference.

2. ISCSI_OP_SCSI_DATA_OUT - In this case transport driver
can free the memory for iSCSI hdr after transmitting the pdu
so task->hdr can be NULL or invalid.

This patch fixes this issue by removing task->hdr->opcode
from the printk statement.

Signed-off-by: Varun Prakash <varun@chelsio.com>
---
 drivers/scsi/libiscsi.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

Comments

Martin K. Petersen July 13, 2018, 3:08 a.m. UTC | #1
Varun,

> In iscsi_check_tmf_restrictions() task->hdr is dereferenced to print
> the opcode, it is possible that task->hdr is NULL.

Applied to 4.18/scsi-fixes, thanks!
diff mbox

Patch

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index d609383..c972cc2 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -284,11 +284,11 @@  static int iscsi_check_tmf_restrictions(struct iscsi_task *task, int opcode)
 		 */
 		if (opcode != ISCSI_OP_SCSI_DATA_OUT) {
 			iscsi_conn_printk(KERN_INFO, conn,
-					  "task [op %x/%x itt "
+					  "task [op %x itt "
 					  "0x%x/0x%x] "
 					  "rejected.\n",
-					  task->hdr->opcode, opcode,
-					  task->itt, task->hdr_itt);
+					  opcode, task->itt,
+					  task->hdr_itt);
 			return -EACCES;
 		}
 		/*
@@ -297,10 +297,10 @@  static int iscsi_check_tmf_restrictions(struct iscsi_task *task, int opcode)
 		 */
 		if (conn->session->fast_abort) {
 			iscsi_conn_printk(KERN_INFO, conn,
-					  "task [op %x/%x itt "
+					  "task [op %x itt "
 					  "0x%x/0x%x] fast abort.\n",
-					  task->hdr->opcode, opcode,
-					  task->itt, task->hdr_itt);
+					  opcode, task->itt,
+					  task->hdr_itt);
 			return -EACCES;
 		}
 		break;