On 2021/12/14 7:15, George Kennedy wrote:
>
>
> On 12/13/2021 4:37 PM, Damien Le Moal wrote:
>> On 2021/12/14 0:33, George Kennedy wrote:
>>> Avoid data corruption by rejecting pass-through commands where
>>> T_LENGTH is zero (No data is transferred) and the dma direction
>>> is not DMA_NONE.
>>>
>>> Cc:<stable@xxxxxxxxxxxxxxx> # 5.4.y
>> 5.4 only ? What about other LTS versions ? They do not have that bug ?
> Our distros are based on 5.4.y, 5.15.y and 4.14.y, so the fix should go
> there,
> but it looks like the fix is also needed in: 5.14.y, 5.13.y, 5.10.y, and
> 4.19.y.
Then please resend with:
Cc: stable@xxxxxxxxxxxxxxx
No version specified.
>
> Thank you,
> George
>>
>>> Reported-by: syzkaller<syzkaller@xxxxxxxxxxxxxxxx>
>>> Signed-off-by: George Kennedy<george.kennedy@xxxxxxxxxx>
>>> ---
>>> drivers/ata/libata-scsi.c | 6 ++++++
>>> 1 file changed, 6 insertions(+)
>>>
>>> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
>>> index 1b84d55..d428392 100644
>>> --- a/drivers/ata/libata-scsi.c
>>> +++ b/drivers/ata/libata-scsi.c
>>> @@ -2859,6 +2859,12 @@ static unsigned int ata_scsi_pass_thru(struct ata_queued_cmd *qc)
>>> goto invalid_fld;
>>> }
>>>
>>> + /* if T_LENGTH is zero (No data is transferred), then dir should be DMA_NONE */
>>> + if ((cdb[2 + cdb_offset] & 3) == 0 && scmd->sc_data_direction != DMA_NONE) {
>>> + fp = 2 + cdb_offset;
>>> + goto invalid_fld;
>>> + }
>>> +
>>> if (ata_is_ncq(tf->protocol) && (cdb[2 + cdb_offset] & 0x3) == 0)
cdb[2 + cdb_offset] & 3) is used again for the ncq test, so you can group things:
if (!(cdb[2 + cdb_offset] & 0x3)) {
/*
* When T_LENGTH is zero (no data is transferred),
* then dir should be DMA_NONE.
*/
if (scmd->sc_data_direction != DMA_NONE) {
fp = 2 + cdb_offset;
goto invalid_fld;
}
if (ata_is_ncq(tf->protocol))
tf->protocol = ATA_PROT_NCQ_NODATA;
}
>>> tf->protocol = ATA_PROT_NCQ_NODATA;
>>>
>>> -- 1.8.3.1
>>>
>>
>
--
Damien Le Moal
Western Digital Research
