Re: [PATCH 1/1] Char: ipmi_bt_sm, fix infinite loop

From: Corey Minyard
Date: Mon Mar 24 2014 - 15:00:11 EST


On 03/24/2014 07:24 AM, Jiri Slaby wrote:
> On 02/25/2014 10:50 PM, Corey Minyard wrote:
>> Looks right to me. Rocky, copying you in case there's an issue with this.
> Hi,
>
> any updates here, I don't see it in the -next tree yet?
>
> Thanks.

I normally don't submit to the -next tree because there is little to
integrate with in the IPMI driver. Maybe it would be a good idea to
start, though. If you want to, I can.

Thanks,

-corey

>> On 02/25/2014 04:14 AM, Jiri Slaby wrote:
>>> In read_all_bytes, we do
>>> unsigned char i;
>>> ...
>>> bt->read_data[0] = BMC2HOST;
>>> bt->read_count = bt->read_data[0];
>>> ...
>>> for (i = 1; i <= bt->read_count; i++)
>>> bt->read_data[i] = BMC2HOST;
>>>
>>> If bt->read_data[0] == bt->read_count == 255, we loop infinitely in
>>> the 'for' loop. Make 'i' an 'int' instead of 'char' to get rid of the
>>> overflow and finish the loop after 255 iterations every time.
>>>
>>> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
>>> Reported-and-debugged-by: Rui Hui Dian <rhdian@xxxxxxxxxx>
>>> Cc: Tomas Cech <tcech@xxxxxxx>
>>> Cc: Corey Minyard <minyard@xxxxxxx>
>>> Cc: <openipmi-developer@xxxxxxxxxxxxxxxxxxxxx>
>>> ---
>>> drivers/char/ipmi/ipmi_bt_sm.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/char/ipmi/ipmi_bt_sm.c b/drivers/char/ipmi/ipmi_bt_sm.c
>>> index f5e4cd7617f6..61e71616689b 100644
>>> --- a/drivers/char/ipmi/ipmi_bt_sm.c
>>> +++ b/drivers/char/ipmi/ipmi_bt_sm.c
>>> @@ -352,7 +352,7 @@ static inline void write_all_bytes(struct si_sm_data *bt)
>>>
>>> static inline int read_all_bytes(struct si_sm_data *bt)
>>> {
>>> - unsigned char i;
>>> + unsigned int i;
>>>
>>> /*
>>> * length is "framing info", minimum = 4: NetFn, Seq, Cmd, cCode.
>

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