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

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

[Rickard Strandqvist]

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@spectrumdigital.se>
---
 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)));
+
 	result = *(int *)ptr;
 
 	if (result < 0)
 		return result;
 
-	LASSERT((ptr != NULL && size >= sizeof(int)));
 	*buf = ptr + sizeof(int);
 	return size - sizeof(int);
 }
-- 
1.7.10.4

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

[Frank Zago]

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@spectrumdigital.se>
> ---
>   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);
>   }
>

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@cray.com>:
> 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@spectrumdigital.se>
>> ---
>>   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

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

[Frank Zago]

On 01/29/2015 01:47 PM, Rickard Strandqvist wrote:
> 2015-01-29 20:40 GMT+01:00 Frank Zago <fzago@cray.com>:
>> 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@spectrumdigital.se>
>>> ---
>>>    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.


Yes, that would be safer.

Frank.

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

[Drokin, Oleg]

Hello!

On Jan 29, 2015, at 2:49 PM, Frank Zago wrote:
>>>> @@ -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.
>> 
>> But if prt is null krachar on the line:
>> result = *(int *)ptr;
>> 
>> Maybe there should be two LASSERT then.
> 
> 
> Yes, that would be safer.


   Actually I just noticed this function does not appear to be used in the client code at all.
   As such let's just remove update_get_reply_buf()?

   In fat I bet this entire lustre_update.h contains server side updating code, and is unused anywhere in the client code,
   so we might just be able to easily remove that.
   I see the only includer is ./lustre/ptlrpc/layout.c that I don't think actually uses anything there?

   Thanks.

Bye,
    Oleg