linux-kernel - Re: [ 3/7] ext4: fix memory leak in xattr

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Message-ID: <CA+5g0SLgfgAaTBTL11hG-vYKtgZ75_KOz-Y40o3m6FwNohUg9A@mail.gmail.com>
Date:	Mon, 21 Oct 2013 19:30:22 -0200
From:	Felipe Pena <felipensp@...il.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	Dave Jones <davej@...oraproject.org>,
	Theodore Tso <tytso@....edu>, Eric Sandeen <sandeen@...hat.com>
Subject: Re: [ 3/7] ext4: fix memory leak in xattr

Hi,

On Fri, Oct 18, 2013 at 4:52 PM, Greg Kroah-Hartman
<gregkh@...uxfoundation.org> wrote:
> 3.0-stable review patch.  If anyone has any objections, please let me know.
>
> ------------------
>
> From: Dave Jones <davej@...hat.com>
>
> commit 6e4ea8e33b2057b85d75175dd89b93f5e26de3bc upstream.
>
> If we take the 2nd retry path in ext4_expand_extra_isize_ea, we
> potentionally return from the function without having freed these
> allocations.  If we don't do the return, we over-write the previous
> allocation pointers, so we leak either way.
>
> Spotted with Coverity.
>
> [ Fixed by tytso to set is and bs to NULL after freeing these
>   pointers, in case in the retry loop we later end up triggering an
>   error causing a jump to cleanup, at which point we could have a double
>   free bug. -- Ted ]
>
> Signed-off-by: Dave Jones <davej@...oraproject.org>
> Signed-off-by: "Theodore Ts'o" <tytso@....edu>
> Reviewed-by: Eric Sandeen <sandeen@...hat.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
>
> ---
>  fs/ext4/xattr.c |    2 ++
>  1 file changed, 2 insertions(+)
>
> --- a/fs/ext4/xattr.c
> +++ b/fs/ext4/xattr.c
> @@ -1271,6 +1271,8 @@ retry:
>                                     s_min_extra_isize) {
>                                         tried_min_extra_isize++;
>                                         new_extra_isize = s_min_extra_isize;
> +                                       kfree(is); is = NULL;
> +                                       kfree(bs); bs = NULL;

Looks like such lines are not conforming to coding style, or?

>                                         goto retry;
>                                 }
>                                 error = -1;
>
>
> --
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-- 
Regards,
Felipe Pena
--
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