[PATCH -next] scsi: be2iscsi: fix null-ptr-deref in beiscsi_alloc_mem

From: Ye Bin
Date: Wed Jul 27 2022 - 03:09:36 EST


Coccicheck report follow issue:
./drivers/scsi/be2iscsi/be_main.c:2561:37-41: ERROR: mem_descr -> mem_array is NULL but dereferenced.
./drivers/scsi/be2iscsi/be_main.c:2563:9-24: ERROR: mem_descr -> mem_array is NULL but dereferenced.
./drivers/scsi/be2iscsi/be_main.c:2566:9-20: ERROR: mem_descr -> mem_array is NULL but dereferenced.

If goto free_mem, that's mean last "mem_descr->mem_array" is NULL. However,
to avoid resource there will set "mem_descr->num_elements" with "j" which
maybe non-zero. Then will lead to null-ptr-deref when free dma resource.

To solved above issue set "mem_descr->mem_array" with "mem_arr_orig"
when free memory.

Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx>
---
drivers/scsi/be2iscsi/be_main.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/be2iscsi/be_main.c b/drivers/scsi/be2iscsi/be_main.c
index 50a577ac3bb4..08f856447b4a 100644
--- a/drivers/scsi/be2iscsi/be_main.c
+++ b/drivers/scsi/be2iscsi/be_main.c
@@ -2540,13 +2540,13 @@ static int beiscsi_alloc_mem(struct beiscsi_hba *phba)
mem_arr++;
}
} while (alloc_size);
- mem_descr->num_elements = j;
- mem_descr->size_in_bytes = phba->mem_req[i];
mem_descr->mem_array = kmalloc_array(j, sizeof(*mem_arr),
GFP_KERNEL);
if (!mem_descr->mem_array)
goto free_mem;

+ mem_descr->num_elements = j;
+ mem_descr->size_in_bytes = phba->mem_req[i];
memcpy(mem_descr->mem_array, mem_arr_orig,
sizeof(struct mem_array) * j);
mem_descr++;
@@ -2554,7 +2554,11 @@ static int beiscsi_alloc_mem(struct beiscsi_hba *phba)
kfree(mem_arr_orig);
return 0;
free_mem:
- mem_descr->num_elements = j;
+ if (j) {
+ mem_descr->num_elements = j;
+ mem_descr->mem_array = mem_arr_orig;
+ mem_arr_orig = NULL;
+ }
while ((i) || (j)) {
for (j = mem_descr->num_elements; j > 0; j--) {
dma_free_coherent(&phba->pcidev->dev,
--
2.31.1