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 <[email protected]> --- drivers/scsi/libiscsi.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) 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; -- 2.0.2
