| Message ID | b1e605ea-333f-4ac0-9511-da04f411763e@rowland.harvard.edu (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 014bcf41d946b36a8f0b8e9b5d9529efbb822f49 |
| Headers | show |
| Series | USB: usb-storage: Prevent divide-by-0 error in isd200_ata_command | expand |
Alan, > 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. Looks good to me. Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
On Fri, 1 Mar 2024 at 01:00, Alan Stern <stern@rowland.harvard.edu> 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@rowland.harvard.edu> > Reported-and-tested-by: syzbot+28748250ab47a8f04100@syzkaller.appspotmail.com > Link: https://lore.kernel.org/linux-usb/0000000000003eb868061245ba7f@google.com/ > Fixes: 1da177e4c3f4 ("v2.6.12-rc2") > Cc: <stable@vger.kernel.org> > > --- > > 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@gmail.com> Regards, PrasannaKumar
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; }
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@rowland.harvard.edu> Reported-and-tested-by: syzbot+28748250ab47a8f04100@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-usb/0000000000003eb868061245ba7f@google.com/ Fixes: 1da177e4c3f4 ("v2.6.12-rc2") Cc: <stable@vger.kernel.org> --- drivers/usb/storage/isd200.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-)