On 1/21/20 12:48 PM, Dan Carpenter wrote:
> On Tue, Jan 21, 2020 at 12:15:54PM +0100, Bartlomiej Zolnierkiewicz wrote:
>>
>> Hi,
>>
>> On 1/20/20 2:40 PM, David Miller wrote:
>>> From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>>> Date: Tue, 7 Jan 2020 16:04:41 +0300
>>>
>>>> The "drive->dn" value is a u8 and it is controlled by root only, but
>>>> it could be out of bounds here so let's check.
>>
>> drive->dn should not be root controllable, please point me where it
>> happens as this may need fixing instead of cmd64x driver.
>>
>> [ IDE core makes sure that drive->dn is never > 3 and a lot of code
>> assumes it. ]
>>
>
> It's a marked as a setable field in ide-proc.c
>
> drivers/ide/ide-proc.c
> 206 ide_devset_rw(current_speed, xfer_rate);
> 207 ide_devset_rw_field(init_speed, init_speed);
> 208 ide_devset_rw_flag(nice1, IDE_DFLAG_NICE1);
> 209 ide_devset_rw_field(number, dn);
> ^^^^^^^^^^
> Sets ->dn
It is a bug.
We should add:
#define ide_devset_ro_field(_name, _field) \
ide_devset_get(_name, _field); \
IDE_DEVSET(_name, 0, get_##_name, NULL)
in <linux/ide.h> (just after ide_devset_rw_field())
and use it instead.
Care to make a patch?
> 210
> 211 static const struct ide_proc_devset ide_generic_settings[] = {
> 212 IDE_PROC_DEVSET(current_speed, 0, 70),
> 213 IDE_PROC_DEVSET(init_speed, 0, 70),
> 214 IDE_PROC_DEVSET(io_32bit, 0, 1 + (SUPPORT_VLB_SYNC << 1)),
> 215 IDE_PROC_DEVSET(keepsettings, 0, 1),
> 216 IDE_PROC_DEVSET(nice1, 0, 1),
> 217 IDE_PROC_DEVSET(number, 0, 3),
Please note the minimum and maximum values above and look at code in
ide_write_setting():
if ((ds->flags & DS_SYNC)
&& (val < setting->min || val > setting->max))
return -EINVAL;
[ DS_SYNC flag is set by ide_devset_rw_field() macro. ]
Thus even without fixing ide-proc.c both your patches are superfluous.
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
> 218 IDE_PROC_DEVSET(pio_mode, 0, 255),
> 219 IDE_PROC_DEVSET(unmaskirq, 0, 1),
> 220 IDE_PROC_DEVSET(using_dma, 0, 1),
> 221 { NULL },
> 222 };
>
> drivers/ide/ide-devsets.c
> 159 int ide_devset_execute(ide_drive_t *drive, const struct ide_devset *setting,
> 160 int arg)
> 161 {
> 162 struct request_queue *q = drive->queue;
> 163 struct request *rq;
> 164 int ret = 0;
> 165
> 166 if (!(setting->flags & DS_SYNC))
> 167 return setting->set(drive, arg);
> ^^^^^^^^^^^^^^^^^^^^^^^^
> Called from here according to Smatch.
>
> 168
> 169 rq = blk_get_request(q, REQ_OP_DRV_IN, 0);
>
> regards,
> dan carpenter
