linux-kernel - Re: [PATCH] cgroups: fix a serious bug in cgroupstats

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] [day] [month] [year] [list]

Message-ID: <6599ad830811191431k1994017dr5a08bb4811eb7466@mail.gmail.com>
Date:	Wed, 19 Nov 2008 14:31:30 -0800
From:	Paul Menage <menage@...gle.com>
To:	Li Zefan <lizf@...fujitsu.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Balbir Singh <balbir@...ux.vnet.ibm.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux Containers <containers@...ts.linux-foundation.org>
Subject: Re: [PATCH] cgroups: fix a serious bug in cgroupstats

On Wed, Nov 19, 2008 at 12:14 AM, Li Zefan <lizf@...fujitsu.com> wrote:
> Try this, and you'll get oops immediately:
>  # cd Documentation/accounting/
>  # gcc -o getdelays getdelays.c
>  # mount -t cgroup -o debug xxx /mnt
>  # ./getdelays -C /mnt/tasks
>
> Because a normal file's dentry->d_fsdata is a pointer to struct cftype,
> not struct cgroup.
>
> After the patch, it returns EINVAL if we try to get cgroupstats
> from a normal file.
>
> CC: Balbir Singh <balbir@...ux.vnet.ibm.com>
> Signed-off-by: Li Zefan <lizf@...fujitsu.com>

Good catch, thanks.

Acked-by: Paul Menage <menage@...gle.com>



> ---
>  kernel/cgroup.c |    7 +++++--
>  1 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 358e775..f6f5219 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -2039,10 +2039,13 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
>        struct cgroup *cgrp;
>        struct cgroup_iter it;
>        struct task_struct *tsk;
> +
>        /*
> -        * Validate dentry by checking the superblock operations
> +        * Validate dentry by checking the superblock operations,
> +        * and make sure it's a directory.
>         */
> -       if (dentry->d_sb->s_op != &cgroup_ops)
> +       if (dentry->d_sb->s_op != &cgroup_ops ||
> +           !S_ISDIR(dentry->d_inode->i_mode))
>                 goto err;
>
>        ret = 0;
> --
> 1.5.4.rc3
>
--
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/