>From e61d04ffef58c5c088d333a67d56241fa29ab2dc Mon Sep 17 00:00:00 2001 From: Eric W. Biederman <[email protected]> Date: Wed, 19 Nov 2008 04:57:28 +0300 Subject: [PATCH 4/6] proc: don't show the wrong /proc/net after unshare
This is accomplished by dropping the /proc/<pid>/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 <[email protected]> Signed-off-by: Alexey Dobriyan <[email protected]> --- 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 e6e89d3..a4b7cac 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1518,6 +1518,7 @@ 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)) || @@ -1532,12 +1533,14 @@ 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 36e0636..5cfe798 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -62,6 +62,15 @@ 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 1054d92..b026c87 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/<pid>/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 _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
