On Wed, Jan 30, 2013 at 3:00 PM, walter harms <wharms@xxxxxx> wrote:
>
>
> Am 30.01.2013 10:51, schrieb Benny Halevy:
>> On Wed, Jan 30, 2013 at 10:57 AM, walter harms <wharms@xxxxxx> wrote:
>>>
>>>
>>> Am 30.01.2013 09:27, schrieb Dan Carpenter:
>>>> On Wed, Jan 30, 2013 at 09:15:43AM +0100, walter harms wrote:
>>>>>
>>>>>
>>>>> Am 30.01.2013 08:06, schrieb Dan Carpenter:
>>>>>> There wasn't any error handling for this kzalloc().
>>>>>>
>>>>>> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>>>>>>
>>>>>> diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
>>>>>> index c06b8e5..d8293f2 100644
>>>>>> --- a/drivers/scsi/osd/osd_initiator.c
>>>>>> +++ b/drivers/scsi/osd/osd_initiator.c
>>>>>> @@ -144,6 +144,10 @@ static int _osd_get_print_system_info(struct osd_dev *od,
>>>>>> odi->osdname_len = get_attrs[a].len;
>>>>>> /* Avoid NULL for memcmp optimization 0-length is good enough */
>>>>>> odi->osdname = kzalloc(odi->osdname_len + 1, GFP_KERNEL);
>>>>>> + if (!odi->osdname) {
>>>>>> + ret = -ENOMEM;
>>>>>> + goto out;
>>>>>> + }
>>>>>> if (odi->osdname_len)
>>>>>> memcpy(odi->osdname, get_attrs[a].val_ptr, odi->osdname_len);
>>>>>> OSD_INFO("OSD_NAME [%s]\n", odi->osdname);
>>>>>> --
>>>>>
>>>>> this looks like strdup() ?
>>>>>
>>>>
>>>> Maybe? It's a funny thing going on with the NUL terminator and I
>>>> don't understand what the comment is about.
>>>>
>>>> It appears that normally "get_attrs[a].val_ptr" is a NUL terminated
>>>> string but "get_attrs[a].len" does not count the terminator.
>>>>
>>>> Odd.
>>>>
>>> i have no clue what the programmer was thinking. if i read this correct
>>> osdname is u8 *osdname; so a simple strdup() or strndup() would be ok
>>> the comment seems to indicate that get_attrs[a].val_ptr could be NULL
>>> but where is the check ?
>>> Perhaps they are not using ascii here ? then a memdup(get_attrs[a].len)
>>> would be better.
>>
>> There are subtle differences between kstrdup or kmemdup and this implementation.
>>
>> kmemdup is problematic as get_attrs[a].val_ptr does not contain the
>> NUL terminator
>
> ok, i understand - but can we assume that we are talking ascii here ?
>
No, it can be anything. UTF-8 is more likely but not guaranteed either.
>> In the following case:
>> if get_attrs[a].len == 0
>> then get_attrs[a].val_ptr == NULL
>>
>> The end result should be
>> odi->osdname_len = 0
>> odi->osdname = kzalloc(1, GFP_KERNEL);
>>
>> while with kstrdup, odi->osdname will end up being NULL
>> as it's input arg "s" is NULL.
>>
>
> and you want the argument to be "" ?
> May i ask why ? kfree() can handle NULL and kprintf() (-family) also.
It was Boaz' decision at the time to simplify internal tests
like _the_same_or_null in drivers/scsi/osd/osd_uld.c
that doesn't check for NULL
Nothing spectacular :)
Benny
>
> re,
> wh
>
>
>> Benny
>>
>>>
>>> re,
>>> wh
>>>
>>>
>>
>>
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