[PATCH v3 1/2] xfsprogs: fix potential memory leak in verify_set_primary_sb()

[Eric Sandeen]

> On Sep 26, 2013, at 10:05 PM, Li Zhong <zhong at linux.vnet.ibm.com> wrote:
> 
>> On Thu, 2013-09-26 at 09:31 -0500, Eric Sandeen wrote:
>>> On 9/26/13 1:45 AM, Li Zhong wrote:
>>> If verify_set_primary_sb() completes the secondary sb scanning loop with
>>> too few valid secondaries found (num_ok < num_sbs / 2), it will immediately
>>> return without freeing any of the previously allocated memory (variables
>>> sb, checked, and any items on the geo list).  This was reported by
>>> the Coverity scanner as CID 997012, 997013 and 997014.
>>> 
>>> Fix this by using the out_free_list: goto target for this error case.
>>> 
>>> Earlier, if get_sb() fails in the secondary scan loop, it goes to
>>> the out: target which does not free any items on the geo list.   Fix
>>> this by using the out_free_list: target as well, and remove the now-unused
>>> out: target.
>>> 
>>> Signed-off-by: Li Zhong <zhong at linux.vnet.ibm.com>
>>> ---
>>> v2: as Mark pointed out, out in the for loop before also needs list to
>>> be freed. Also remove out lable as it is not referenced any more.
>>> v3: use a meaningful changlog from Eric, and hide the patch changlogs below "---".
>> 
>> Thanks for that; you can add my:
>> 
>> Reviewed-by: Eric Sandeen <sandeen at redhat.com>
>> 
>> alongside Mark's.
> 
> Ah, I missed that. Is it ok to just add it here in this mail? 
> 
> Reviewed-by: Mark Tinguely <tinguely at sgi.com>
> 
Sorry, I meant that for sgi but wasn't clear.  Sometimes I talk too much.  :)

Eric

>> 
>>> repair/sb.c | 9 +++++----
>>> 1 file changed, 5 insertions(+), 4 deletions(-)
>>> 
>>> diff --git a/repair/sb.c b/repair/sb.c
>>> index aa550e3..d34d7a2 100644
>>> --- a/repair/sb.c
>>> +++ b/repair/sb.c
>>> @@ -733,7 +733,7 @@ verify_set_primary_sb(xfs_sb_t        *rsb,
>>> 
>>>            if (get_sb(sb, off, size, agno) == XR_EOF)  {
>>>                retval = 1;
>>> -                goto out;
>>> +                goto out_free_list;
>>>            }
>>> 
>>>            if (verify_sb(sb, 0) == XR_OK)  {
>>> @@ -756,8 +756,10 @@ verify_set_primary_sb(xfs_sb_t        *rsb,
>>>    /*
>>>     * see if we have enough superblocks to bother with
>>>     */
>>> -    if (num_ok < num_sbs / 2)
>>> -        return(XR_INSUFF_SEC_SB);
>>> +    if (num_ok < num_sbs / 2) {
>>> +        retval = XR_INSUFF_SEC_SB;
>>> +        goto out_free_list;
>>> +    }
>>> 
>>>    current = get_best_geo(list);
>>> 
>>> @@ -841,7 +843,6 @@ verify_set_primary_sb(xfs_sb_t        *rsb,
>>> 
>>> out_free_list:
>>>    free_geo(list);
>>> -out:
>>>    free(sb);
>>>    free(checked);
>>>    return(retval);
> 
>