On Fri, 1 Mar 2024 at 01:00, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > The isd200 sub-driver in usb-storage uses the HEADS and SECTORS values > in the ATA ID information to calculate cylinder and head values when > creating a CDB for READ or WRITE commands. The calculation involves > division and modulus operations, which will cause a crash if either of > these values is 0. While this never happens with a genuine device, it > could happen with a flawed or subversive emulation, as reported by the > syzbot fuzzer. > > Protect against this possibility by refusing to bind to the device if > either the ATA_ID_HEADS or ATA_ID_SECTORS value in the device's ID > information is 0. This requires isd200_Initialization() to return a > negative error code when initialization fails; currently it always > returns 0 (even when there is an error). > > Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > Reported-and-tested-by: syzbot+28748250ab47a8f04100@xxxxxxxxxxxxxxxxxxxxxxxxx > Link: https://lore.kernel.org/linux-usb/0000000000003eb868061245ba7f@xxxxxxxxxx/ > Fixes: 1da177e4c3f4 ("v2.6.12-rc2") > Cc: <stable@xxxxxxxxxxxxxxx> > > --- > > drivers/usb/storage/isd200.c | 23 ++++++++++++++++++----- > 1 file changed, 18 insertions(+), 5 deletions(-) > > Index: usb-devel/drivers/usb/storage/isd200.c > =================================================================== > --- usb-devel.orig/drivers/usb/storage/isd200.c > +++ usb-devel/drivers/usb/storage/isd200.c > @@ -1105,7 +1105,7 @@ static void isd200_dump_driveid(struct u > static int isd200_get_inquiry_data( struct us_data *us ) > { > struct isd200_info *info = (struct isd200_info *)us->extra; > - int retStatus = ISD200_GOOD; > + int retStatus; > u16 *id = info->id; > > usb_stor_dbg(us, "Entering isd200_get_inquiry_data\n"); > @@ -1137,6 +1137,13 @@ static int isd200_get_inquiry_data( stru > isd200_fix_driveid(id); > isd200_dump_driveid(us, id); > > + /* Prevent division by 0 in isd200_scsi_to_ata() */ > + if (id[ATA_ID_HEADS] == 0 || id[ATA_ID_SECTORS] == 0) { > + usb_stor_dbg(us, " Invalid ATA Identify data\n"); > + retStatus = ISD200_ERROR; > + goto Done; > + } > + > memset(&info->InquiryData, 0, sizeof(info->InquiryData)); > > /* Standard IDE interface only supports disks */ > @@ -1202,6 +1209,7 @@ static int isd200_get_inquiry_data( stru > } > } > > + Done: > usb_stor_dbg(us, "Leaving isd200_get_inquiry_data %08X\n", retStatus); > > return(retStatus); > @@ -1481,22 +1489,27 @@ static int isd200_init_info(struct us_da > > static int isd200_Initialization(struct us_data *us) > { > + int rc = 0; > + > usb_stor_dbg(us, "ISD200 Initialization...\n"); > > /* Initialize ISD200 info struct */ > > - if (isd200_init_info(us) == ISD200_ERROR) { > + if (isd200_init_info(us) < 0) { > usb_stor_dbg(us, "ERROR Initializing ISD200 Info struct\n"); > + rc = -ENOMEM; > } else { > /* Get device specific data */ > > - if (isd200_get_inquiry_data(us) != ISD200_GOOD) > + if (isd200_get_inquiry_data(us) != ISD200_GOOD) { > usb_stor_dbg(us, "ISD200 Initialization Failure\n"); > - else > + rc = -EINVAL; > + } else { > usb_stor_dbg(us, "ISD200 Initialization complete\n"); > + } > } > > - return 0; > + return rc; > } > > > Looks good to me. Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@xxxxxxxxx> Regards, PrasannaKumar
