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

[Eric Sandeen <sandeen@sandeen.net>]

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@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@redhat.com>

alongside Mark's.

>  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);
> 

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