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; Regards Oliver
