Re: [HPDD-discuss] [PATCH] staging: lustre: include: lustre_update.h: Fix for possible null pointer dereference

[Rickard Strandqvist]

2015-01-29 20:40 GMT+01:00 Frank Zago <fzago@xxxxxxxx>:
> On 01/29/2015 12:47 PM, Rickard Strandqvist wrote:
>>
>> Fix a possible null pointer dereference, there is
>> otherwise a risk of a possible null pointer dereference.
>>
>> This was found using a static code analysis program called cppcheck
>>
>> Signed-off-by: Rickard Strandqvist
>> <rickard_strandqvist@xxxxxxxxxxxxxxxxxx>
>> ---
>>   drivers/staging/lustre/lustre/include/lustre_update.h |    4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/staging/lustre/lustre/include/lustre_update.h
>> b/drivers/staging/lustre/lustre/include/lustre_update.h
>> index 84defce..00e1361 100644
>> --- a/drivers/staging/lustre/lustre/include/lustre_update.h
>> +++ b/drivers/staging/lustre/lustre/include/lustre_update.h
>> @@ -165,12 +165,14 @@ static inline int update_get_reply_buf(struct
>> update_reply *reply, void **buf,
>>         int  result;
>>
>>         ptr = update_get_buf_internal(reply, index, &size);
>> +
>> +       LASSERT((ptr != NULL && size >= sizeof(int)));
>
>
> Now size is tested before result. So it could assert if result < 0, while
> the function would have returned before.
>
>
>> +
>>         result = *(int *)ptr;
>>
>>         if (result < 0)
>>                 return result;
>>
>> -       LASSERT((ptr != NULL && size >= sizeof(int)));
>>         *buf = ptr + sizeof(int);
>>         return size - sizeof(int);
>>   }
>>
>



But if prt is null krachar on the line:
result = *(int *)ptr;

Maybe there should be two LASSERT then.

Kind regards
Rickard Strandqvist
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