On 2019/7/29 19:15, Oliver Neukum wrote:
Am Montag, den 29.07.2019, 18:05 +0800 schrieb Jia-Ju Bai:
Hi,
In sddr55_transport(), there is an if statement on line 836 to check
whether info->lba_to_pba is NULL:
if (info->lba_to_pba == NULL || ...)
When info->lba_to_pba is NULL, it is used on line 948:
pba = info->lba_to_pba[lba];
Thus, a possible null-pointer dereference may occur.
Yes, in practice READ_CAPACITY will always be called and set
up the correct translation table, but you can probably exploit
this.
To fix this bug, info->lba_to_pba is checked before being used.
This bug is found by a static analysis tool STCheck written by us.
Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
---
drivers/usb/storage/sddr55.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/storage/sddr55.c b/drivers/usb/storage/sddr55.c
index b8527c55335b..50afc39aa21d 100644
--- a/drivers/usb/storage/sddr55.c
+++ b/drivers/usb/storage/sddr55.c
@@ -945,7 +945,8 @@ static int sddr55_transport(struct scsi_cmnd *srb, struct us_data *us)
return USB_STOR_TRANSPORT_FAILED;
}
- pba = info->lba_to_pba[lba];
+ if (info->lba_to_pba)
+ pba = info->lba_to_pba[lba];
If you use that fix, pba will be uninitialized when used. It should be
something like:
pba = info->lba_to_pba ? info->lba_to_pba[lba] : 0;
Thanks for the advice.
I will send a v2 patch.
Best wishes,
Jia-Ju Bai
