From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760710AbZC3Wr6 (ORCPT ); Mon, 30 Mar 2009 18:47:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753697AbZC3Wrk (ORCPT ); Mon, 30 Mar 2009 18:47:40 -0400 Received: from fg-out-1718.google.com ([72.14.220.158]:9406 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753546AbZC3Wrj (ORCPT ); Mon, 30 Mar 2009 18:47:39 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:mime-version:content-type :content-disposition:user-agent; b=a55RhbxFerfDoivqt9okmyPTdGMVzYd2JqyMTTitFrIgqtweRE07ZVZa1d+FngjPRp Zjckqt/bLlaJrlfIAWzZwgyG+pfhPknT/P53yihb67FhN4PdisWNKQAaBI4GEBhT+Njw sjIg3MGT0f7DioRxGUzPDQILzoncYkZp0TZ0g= Date: Tue, 31 Mar 2009 02:55:08 +0400 From: Alexey Dobriyan To: viro@ZenIV.linux.org.uk Cc: ebiederm@xmission.com, linux-kernel@vger.kernel.org Subject: [PATCH] proc 4/6: don't show the wrong /proc/net after unshare Message-ID: <20090330225508.GE19892@x200.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>From 5e13392318f9cd68a96bbc916bfca28f5effa65e Mon Sep 17 00:00:00 2001 From: Eric W. Biederman Date: Wed, 19 Nov 2008 04:57:28 +0300 Subject: [PATCH 09/11] proc 4/6: don't show the wrong /proc/net after unshare This is accomplished by dropping the /proc//net dentry when we discover an older version of /proc/net is mounted upon it. This prevents new lookups from using the mount and ultimately proc_shrink_automounts will catch up with it and remove the old mount point. Signed-off-by: Eric W. Biederman Signed-off-by: Alexey Dobriyan --- fs/proc/base.c | 11 +++++++---- fs/proc/internal.h | 9 +++++++++ fs/proc/proc_net.c | 35 +++++++++++++++++++++++++++++++++++ 3 files changed, 51 insertions(+), 4 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 71c9caa..82eea38 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1498,6 +1498,7 @@ static int pid_revalidate(struct dentry *dentry, struct nameidata *nd) struct inode *inode = dentry->d_inode; struct task_struct *task = get_proc_task(inode); const struct cred *cred; + int ret = 0; if (task) { if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) || @@ -1512,12 +1513,14 @@ static int pid_revalidate(struct dentry *dentry, struct nameidata *nd) inode->i_gid = 0; } inode->i_mode &= ~(S_ISUID | S_ISGID); - security_task_to_inode(task, inode); + ret = proc_net_revalidate(task, dentry, nd); + if (ret == 1) + security_task_to_inode(task, inode); put_task_struct(task); - return 1; } - d_drop(dentry); - return 0; + if (ret == 0) + d_drop(dentry); + return ret; } static int pid_delete_dentry(struct dentry * dentry) diff --git a/fs/proc/internal.h b/fs/proc/internal.h index ef482f5..5b890ba 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -60,6 +60,15 @@ extern const struct file_operations proc_clear_refs_operations; extern const struct file_operations proc_pagemap_operations; extern const struct inode_operations proc_net_inode_operations; +#ifdef CONFIG_NET +int proc_net_revalidate(struct task_struct *tsk, struct dentry *dentry, struct nameidata *nd); +#else +static inline int proc_net_revalidate(struct task_struct *tsk, struct dentry *dentry, struct nameidata *nd) +{ + return 1; +} +#endif + void free_proc_entry(struct proc_dir_entry *de); void proc_init_inodecache(void); diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c index 54fc2c8..e4c7a20 100644 --- a/fs/proc/proc_net.c +++ b/fs/proc/proc_net.c @@ -169,6 +169,41 @@ const struct inode_operations proc_net_inode_operations = { }; +int proc_net_revalidate(struct task_struct *task, struct dentry *dentry, + struct nameidata *nd) +{ + struct inode *inode = dentry->d_inode; + struct dentry *tdentry; + struct vfsmount *tmnt; + int ret = 1; + + /* Are we talking about a proc/net mount point? */ + if (!nd || inode->i_op != &proc_net_inode_operations) + goto out; + + /* + * If the wrong filesystem is mounted on /proc//net report the + * dentry is invalid. + */ + tmnt = mntget(nd->path.mnt); + tdentry = dget(dentry); + if (follow_down(&tmnt, &tdentry)) { + struct nsproxy *ns; + + rcu_read_lock(); + ns = task_nsproxy(task); + if ((ns == NULL) || + (tmnt->mnt_sb->s_magic != PROC_NET_SUPER_MAGIC) || + (tmnt->mnt_sb->s_fs_info != ns->net_ns)) + ret = 0; + rcu_read_unlock(); + } + dput(tdentry); + mntput(tmnt); +out: + return ret; +} + struct proc_dir_entry *proc_net_fops_create(struct net *net, const char *name, mode_t mode, const struct file_operations *fops) { -- 1.5.6.5