linux-kernel - Re: [PATCH] fsnotify: don't put user context if it was never assigned

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: <540788A3.80101@oracle.com>
Date:	Wed, 03 Sep 2014 17:31:15 -0400
From:	Sasha Levin <sasha.levin@...cle.com>
To:	Sasha Levin <sasha.levin@...cle.com>, john@...nmccutchan.com,
	rlove@...ve.org, eparis@...isplace.org
CC:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] fsnotify: don't put user context if it was never assigned

Ping? This is a NULL ptr deref that userspace can trigger.

On 07/29/2014 09:25 AM, Sasha Levin wrote:
> On some failure paths we may attempt to free user context even
> if it wasn't assigned yet. This will cause a NULL ptr deref
> and a kernel BUG.
> 
> Signed-off-by: Sasha Levin <sasha.levin@...cle.com>
> ---
>  fs/notify/inotify/inotify_fsnotify.c |    6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c
> index 43ab1e1..9c8187e 100644
> --- a/fs/notify/inotify/inotify_fsnotify.c
> +++ b/fs/notify/inotify/inotify_fsnotify.c
> @@ -165,8 +165,10 @@ static void inotify_free_group_priv(struct fsnotify_group *group)
>  	/* ideally the idr is empty and we won't hit the BUG in the callback */
>  	idr_for_each(&group->inotify_data.idr, idr_callback, group);
>  	idr_destroy(&group->inotify_data.idr);
> -	atomic_dec(&group->inotify_data.user->inotify_devs);
> -	free_uid(group->inotify_data.user);
> +	if (group->inotify_data.user) {
> +		atomic_dec(&group->inotify_data.user->inotify_devs);
> +		free_uid(group->inotify_data.user);
> +	}
>  }
>  
>  static void inotify_free_event(struct fsnotify_event *fsn_event)
> 

--
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/