linux-kernel - Re: [PATCH] Fix mountpoint reference leakage in linkat

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20140131210334.GO10323@ZenIV.linux.org.uk>
Date:	Fri, 31 Jan 2014 21:03:34 +0000
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Oleg Drokin <green@...uxhacker.ru>
Cc:	linux-kernel@...r.kernel.org, jlayton@...hat.com,
	linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH] Fix mountpoint reference leakage in linkat

On Fri, Jan 31, 2014 at 03:41:58PM -0500, Oleg Drokin wrote:
> Recent changes to retry on ESTALE in linkat
> (commit 442e31ca5a49e398351b2954b51f578353fdf210)
> introduced a mountpoint reference leak and a small memory
> leak in case a filesystem link operation returns ESTALE
> which is pretty normal for distributed filesystems like
> lustre, nfs and so on.
> Free old_path in such a case.
> 
> Signed-off-by: Oleg Drokin: <green@...uxhacker.ru>
> ---
>  fs/namei.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/namei.c b/fs/namei.c
> index bcb838e..e620937 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -3931,6 +3931,7 @@ out_dput:
>  			goto retry;
>  	}
>  	if (retry_estale(error, how)) {
> +		path_put(&old_path);
>  		how |= LOOKUP_REVAL;
>  		goto retry;
>  	}

Umm...  That obviously can't be right - we have another goto retry
in the same situation (see in your diff context).  I agree that
we have a leak there, but you've fixed only a half of it.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/