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* [bug report] power: supply: bq256xx: Introduce the BQ256XX charger driver
@ 2021-01-12  8:54 Dan Carpenter
  2021-01-12 23:44 ` [EXTERNAL] " Ricardo Rivera-Matos
  0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2021-01-12  8:54 UTC (permalink / raw)
  To: r-rivera-matos; +Cc: linux-pm

Hello Ricardo Rivera-Matos,

The patch 32e4978bb920: "power: supply: bq256xx: Introduce the
BQ256XX charger driver" from Jan 6, 2021, leads to the following
static checker warning:

	drivers/power/supply/bq256xx_charger.c:1512 bq256xx_hw_init()
	error: buffer overflow 'bq256xx_watchdog_time' 8 <= 8

drivers/power/supply/bq256xx_charger.c
  1503  static int bq256xx_hw_init(struct bq256xx_device *bq)
  1504  {
  1505          struct power_supply_battery_info bat_info = { };
  1506          int wd_reg_val = BQ256XX_WATCHDOG_DIS;
  1507          int ret = 0;
  1508          int i;
  1509  
  1510          for (i = 0; i < BQ256XX_NUM_WD_VAL; i++) {
  1511                  if (bq->watchdog_timer > bq256xx_watchdog_time[i] &&
  1512                      bq->watchdog_timer < bq256xx_watchdog_time[i + 1])
                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The last four members of this array are all zero.

On the last iteration through the loop this will read beyond the end of
the array possibly setting "wd_reg_val = 7" uninitentionally.

  1513                          wd_reg_val = i;
  1514          }
  1515          ret = regmap_update_bits(bq->regmap, BQ256XX_CHARGER_CONTROL_1,
  1516                                   BQ256XX_WATCHDOG_MASK, wd_reg_val <<
  1517                                                  BQ256XX_WDT_BIT_SHIFT);

regards,
dan carpenter

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [EXTERNAL] [bug report] power: supply: bq256xx: Introduce the BQ256XX charger driver
  2021-01-12  8:54 [bug report] power: supply: bq256xx: Introduce the BQ256XX charger driver Dan Carpenter
@ 2021-01-12 23:44 ` Ricardo Rivera-Matos
  2021-01-13  9:13   ` Dan Carpenter
  0 siblings, 1 reply; 4+ messages in thread
From: Ricardo Rivera-Matos @ 2021-01-12 23:44 UTC (permalink / raw)
  To: Dan Carpenter; +Cc: linux-pm

Dan,

On 1/12/21 2:54 AM, Dan Carpenter wrote:
> Hello Ricardo Rivera-Matos,
>
> The patch 32e4978bb920: "power: supply: bq256xx: Introduce the
> BQ256XX charger driver" from Jan 6, 2021, leads to the following
> static checker warning:
>
> 	drivers/power/supply/bq256xx_charger.c:1512 bq256xx_hw_init()
> 	error: buffer overflow 'bq256xx_watchdog_time' 8 <= 8
>
> drivers/power/supply/bq256xx_charger.c
>    1503  static int bq256xx_hw_init(struct bq256xx_device *bq)
>    1504  {
>    1505          struct power_supply_battery_info bat_info = { };
>    1506          int wd_reg_val = BQ256XX_WATCHDOG_DIS;
>    1507          int ret = 0;
>    1508          int i;
>    1509
>    1510          for (i = 0; i < BQ256XX_NUM_WD_VAL; i++) {
>    1511                  if (bq->watchdog_timer > bq256xx_watchdog_time[i] &&
>    1512                      bq->watchdog_timer < bq256xx_watchdog_time[i + 1])
>                                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> The last four members of this array are all zero.
ACK, BQ256XX_NUM_WD_VAL should actually be 4 instead of 8
>
> On the last iteration through the loop this will read beyond the end of
> the array possibly setting "wd_reg_val = 7" uninitentionally.
ACK, bq256xx_parse_dt() will clamp bq->watchdog_timer so then in 
bq256xx_hw_init()

     for (i = 0; i < BQ256XX_NUM_WD_VAL; i++) {
         if (bq->watchdog_timer == bq256xx_watchdog_time[i]) {
             wd_reg_val = i;
             break;
         }
         if (bq->watchdog_timer > bq256xx_watchdog_time[i] &&
             bq->watchdog_timer < bq256xx_watchdog_time[i + 1])
             wd_reg_val = i;
     }

The first if will catch the exact matches and the second if will catch 
the "in-betweens" and round down. The final iteration will always fall 
into the first if statement and break.

>
>    1513                          wd_reg_val = i;
>    1514          }
>    1515          ret = regmap_update_bits(bq->regmap, BQ256XX_CHARGER_CONTROL_1,
>    1516                                   BQ256XX_WATCHDOG_MASK, wd_reg_val <<
>    1517                                                  BQ256XX_WDT_BIT_SHIFT);
>
> regards,
> dan carpenter
Ricardo

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [EXTERNAL] [bug report] power: supply: bq256xx: Introduce the BQ256XX charger driver
  2021-01-12 23:44 ` [EXTERNAL] " Ricardo Rivera-Matos
@ 2021-01-13  9:13   ` Dan Carpenter
  2021-01-13 22:51     ` Ricardo Rivera-Matos
  0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2021-01-13  9:13 UTC (permalink / raw)
  To: Ricardo Rivera-Matos; +Cc: linux-pm

On Tue, Jan 12, 2021 at 05:44:52PM -0600, Ricardo Rivera-Matos wrote:
> Dan,
> 
> On 1/12/21 2:54 AM, Dan Carpenter wrote:
> > Hello Ricardo Rivera-Matos,
> > 
> > The patch 32e4978bb920: "power: supply: bq256xx: Introduce the
> > BQ256XX charger driver" from Jan 6, 2021, leads to the following
> > static checker warning:
> > 
> > 	drivers/power/supply/bq256xx_charger.c:1512 bq256xx_hw_init()
> > 	error: buffer overflow 'bq256xx_watchdog_time' 8 <= 8
> > 
> > drivers/power/supply/bq256xx_charger.c
> >    1503  static int bq256xx_hw_init(struct bq256xx_device *bq)
> >    1504  {
> >    1505          struct power_supply_battery_info bat_info = { };
> >    1506          int wd_reg_val = BQ256XX_WATCHDOG_DIS;
> >    1507          int ret = 0;
> >    1508          int i;
> >    1509
> >    1510          for (i = 0; i < BQ256XX_NUM_WD_VAL; i++) {
> >    1511                  if (bq->watchdog_timer > bq256xx_watchdog_time[i] &&
> >    1512                      bq->watchdog_timer < bq256xx_watchdog_time[i + 1])
> >                                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > The last four members of this array are all zero.
> ACK, BQ256XX_NUM_WD_VAL should actually be 4 instead of 8
> > 
> > On the last iteration through the loop this will read beyond the end of
> > the array possibly setting "wd_reg_val = 7" uninitentionally.
> ACK, bq256xx_parse_dt() will clamp bq->watchdog_timer so then in
> bq256xx_hw_init()
> 
>     for (i = 0; i < BQ256XX_NUM_WD_VAL; i++) {
>         if (bq->watchdog_timer == bq256xx_watchdog_time[i]) {
>             wd_reg_val = i;
>             break;
>         }
>         if (bq->watchdog_timer > bq256xx_watchdog_time[i] &&
>             bq->watchdog_timer < bq256xx_watchdog_time[i + 1])
>             wd_reg_val = i;
>     }
> 
> The first if will catch the exact matches and the second if will catch the
> "in-betweens" and round down. The final iteration will always fall into the
> first if statement and break.
> 

This looks good.  This is a patch you are proposing or it's already
merged in an upstream tree somewhere?  Either way, that sounds fine.
Thank!

regards,
dan carpenter


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [EXTERNAL] [bug report] power: supply: bq256xx: Introduce the BQ256XX charger driver
  2021-01-13  9:13   ` Dan Carpenter
@ 2021-01-13 22:51     ` Ricardo Rivera-Matos
  0 siblings, 0 replies; 4+ messages in thread
From: Ricardo Rivera-Matos @ 2021-01-13 22:51 UTC (permalink / raw)
  To: Dan Carpenter; +Cc: linux-pm

Dan,

On 1/13/21 3:13 AM, Dan Carpenter wrote:
> On Tue, Jan 12, 2021 at 05:44:52PM -0600, Ricardo Rivera-Matos wrote:
>> Dan,
>>
>> On 1/12/21 2:54 AM, Dan Carpenter wrote:
>>> Hello Ricardo Rivera-Matos,
>>>
>>> The patch 32e4978bb920: "power: supply: bq256xx: Introduce the
>>> BQ256XX charger driver" from Jan 6, 2021, leads to the following
>>> static checker warning:
>>>
>>> 	drivers/power/supply/bq256xx_charger.c:1512 bq256xx_hw_init()
>>> 	error: buffer overflow 'bq256xx_watchdog_time' 8 <= 8
>>>
>>> drivers/power/supply/bq256xx_charger.c
>>>     1503  static int bq256xx_hw_init(struct bq256xx_device *bq)
>>>     1504  {
>>>     1505          struct power_supply_battery_info bat_info = { };
>>>     1506          int wd_reg_val = BQ256XX_WATCHDOG_DIS;
>>>     1507          int ret = 0;
>>>     1508          int i;
>>>     1509
>>>     1510          for (i = 0; i < BQ256XX_NUM_WD_VAL; i++) {
>>>     1511                  if (bq->watchdog_timer > bq256xx_watchdog_time[i] &&
>>>     1512                      bq->watchdog_timer < bq256xx_watchdog_time[i + 1])
>>>                                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>> The last four members of this array are all zero.
>> ACK, BQ256XX_NUM_WD_VAL should actually be 4 instead of 8
>>> On the last iteration through the loop this will read beyond the end of
>>> the array possibly setting "wd_reg_val = 7" uninitentionally.
>> ACK, bq256xx_parse_dt() will clamp bq->watchdog_timer so then in
>> bq256xx_hw_init()
>>
>>      for (i = 0; i < BQ256XX_NUM_WD_VAL; i++) {
>>          if (bq->watchdog_timer == bq256xx_watchdog_time[i]) {
>>              wd_reg_val = i;
>>              break;
>>          }
>>          if (bq->watchdog_timer > bq256xx_watchdog_time[i] &&
>>              bq->watchdog_timer < bq256xx_watchdog_time[i + 1])
>>              wd_reg_val = i;
>>      }
>>
>> The first if will catch the exact matches and the second if will catch the
>> "in-betweens" and round down. The final iteration will always fall into the
>> first if statement and break.
>>
> This looks good.  This is a patch you are proposing or it's already
> merged in an upstream tree somewhere?  Either way, that sounds fine.
> Thank!
I am proposing it. I will CC you when I send off the patchset.
>
> regards,
> dan carpenter
>
Best Regards,
Ricardo

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-01-14  1:56 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-01-12  8:54 [bug report] power: supply: bq256xx: Introduce the BQ256XX charger driver Dan Carpenter
2021-01-12 23:44 ` [EXTERNAL] " Ricardo Rivera-Matos
2021-01-13  9:13   ` Dan Carpenter
2021-01-13 22:51     ` Ricardo Rivera-Matos

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