Re: [PATCH] xfs_db: release ip resource before returning from get_next_unlinked()

[Bill O'Donnell <bodonnel@redhat.com>]

On Wed, Aug 07, 2024 at 12:07:37PM -0500, Eric Sandeen wrote:
> On 8/5/24 9:42 AM, Bill O'Donnell wrote:
> > On Fri, Aug 02, 2024 at 04:23:00PM -0700, Darrick J. Wong wrote:
> >> On Fri, Aug 02, 2024 at 05:25:52PM -0500, Bill O'Donnell wrote:
> >>> Fix potential memory leak in function get_next_unlinked(). Call
> >>> libxfs_irele(ip) before exiting.
> >>>
> >>> Details:
> >>> Error: RESOURCE_LEAK (CWE-772):
> >>> xfsprogs-6.5.0/db/iunlink.c:51:2: alloc_arg: "libxfs_iget" allocates memory that is stored into "ip".
> >>> xfsprogs-6.5.0/db/iunlink.c:68:2: noescape: Resource "&ip->i_imap" is not freed or pointed-to in "libxfs_imap_to_bp".
> >>> xfsprogs-6.5.0/db/iunlink.c:76:2: leaked_storage: Variable "ip" going out of scope leaks the storage it points to.
> >>> #   74|   	libxfs_buf_relse(ino_bp);
> >>> #   75|
> >>> #   76|-> 	return ret;
> >>> #   77|   bad:
> >>> #   78|   	dbprintf(_("AG %u agino %u: %s\n"), agno, agino, strerror(error));
> >>>
> >>> Signed-off-by: Bill O'Donnell <bodonnel@redhat.com>
> >>> ---
> >>>  db/iunlink.c | 1 +
> >>>  1 file changed, 1 insertion(+)
> >>>
> >>> diff --git a/db/iunlink.c b/db/iunlink.c
> >>> index d87562e3..3b2417c5 100644
> >>> --- a/db/iunlink.c
> >>> +++ b/db/iunlink.c
> >>> @@ -72,6 +72,7 @@ get_next_unlinked(
> >>>  	dip = xfs_buf_offset(ino_bp, ip->i_imap.im_boffset);
> >>>  	ret = be32_to_cpu(dip->di_next_unlinked);
> >>>  	libxfs_buf_relse(ino_bp);
> >>> +	libxfs_irele(ip);
> >>
> >> I think this needs to cover the error return for libxfs_imap_to_bp too,
> >> doesn't it?
> > 
> > I considered that, but there are several places in the code where the
> > error return doesn't release the resource. Not that that's correct, but the
> > scans didn't flag them. For example, in bmap_inflate.c, bmapinflate_f()
> > does not release the resource and scans didn't flag it.
> 
> Upstream coverity scan does flag it, CID 1554242 (that CID actually covers
> both instances of the leak).

Ah, thanks. I'll send a v2.
-Bill


> >>>  
> >>>  	return ret;
> >>>  bad:
> >>> -- 
> >>> 2.45.2
> >>>
> >>
> > 
> > 
>