Re: [PATCH] scsi: lpfc: don't dereference dma_buf->iocbq before null check

From: James Smart
Date: Sat Mar 04 2017 - 12:43:13 EST


Looks good. I included it in the lpfc patch set just posted.

-- james


On 2/24/2017 6:09 AM, Colin King wrote:
From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

dma_buf->iocbq is being dereferenced immediately before it is
being null checked, so we have a potential null pointer dereference
bug. Fix this by only dereferencing it only once we have passed
a null check on the pointer.

Detected by CoverityScan, CID#1411652 ("Dereference before null check")

Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
drivers/scsi/lpfc/lpfc_mem.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/lpfc/lpfc_mem.c b/drivers/scsi/lpfc/lpfc_mem.c
index c61d8d6..5986c79 100644
--- a/drivers/scsi/lpfc/lpfc_mem.c
+++ b/drivers/scsi/lpfc/lpfc_mem.c
@@ -646,7 +646,6 @@ lpfc_sli4_nvmet_alloc(struct lpfc_hba *phba)
}
dma_buf->iocbq = lpfc_sli_get_iocbq(phba);
- dma_buf->iocbq->iocb_flag = LPFC_IO_NVMET;
if (!dma_buf->iocbq) {
kfree(dma_buf->context);
pci_pool_free(phba->lpfc_drb_pool, dma_buf->dbuf.virt,
@@ -658,6 +657,7 @@ lpfc_sli4_nvmet_alloc(struct lpfc_hba *phba)
"2621 Ran out of nvmet iocb/WQEs\n");
return NULL;
}
+ dma_buf->iocbq->iocb_flag = LPFC_IO_NVMET;
nvmewqe = dma_buf->iocbq;
wqe = (union lpfc_wqe128 *)&nvmewqe->wqe;
/* Initialize WQE */