From e9720acd728a46cb40daa52c99a979f7c4ff195c Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Fri, 7 Mar 2008 11:08:40 -0800 Subject: [NET]: Make /proc/net a symlink on /proc/self/net (v3) Current /proc/net is done with so called "shadows", but current implementation is broken and has little chances to get fixed. The problem is that dentries subtree of /proc/net directory has fancy revalidation rules to make processes living in different net namespaces see different entries in /proc/net subtree, but currently, tasks see in the /proc/net subdir the contents of any other namespace, depending on who opened the file first. The proposed fix is to turn /proc/net into a symlink, which points to /proc/self/net, which in turn shows what previously was in /proc/net - the network-related info, from the net namespace the appropriate task lives in. # ls -l /proc/net lrwxrwxrwx 1 root root 8 Mar 5 15:17 /proc/net -> self/net In other words - this behaves like /proc/mounts, but unlike "mounts", "net" is not a file, but a directory. Changes from v2: * Fixed discrepancy of /proc/net nlink count and selinux labeling screwup pointed out by Stephen. To get the correct nlink count the ->getattr callback for /proc/net is overridden to read one from the net->proc_net entry. To make selinux still work the net->proc_net entry is initialized properly, i.e. with the "net" name and the proc_net parent. Selinux fixes are Acked-by: Stephen Smalley Changes from v1: * Fixed a task_struct leak in get_proc_task_net, pointed out by Paul. Signed-off-by: Pavel Emelyanov Acked-by: "Eric W. Biederman" Signed-off-by: David S. Miller --- include/linux/proc_fs.h | 3 --- include/net/net_namespace.h | 1 - 2 files changed, 4 deletions(-) (limited to 'include') diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index d9a9e718ad1..9b6c935f69c 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -50,8 +50,6 @@ typedef int (read_proc_t)(char *page, char **start, off_t off, typedef int (write_proc_t)(struct file *file, const char __user *buffer, unsigned long count, void *data); typedef int (get_info_t)(char *, char **, off_t, int); -typedef struct proc_dir_entry *(shadow_proc_t)(struct task_struct *task, - struct proc_dir_entry *pde); struct proc_dir_entry { unsigned int low_ino; @@ -82,7 +80,6 @@ struct proc_dir_entry { int pde_users; /* number of callers into module in progress */ spinlock_t pde_unload_lock; /* proc_fops checks and pde_users bumps */ struct completion *pde_unload_completion; - shadow_proc_t *shadow_proc; }; struct kcore_list { diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 28738b7d53e..923f2b8b909 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -31,7 +31,6 @@ struct net { struct proc_dir_entry *proc_net; struct proc_dir_entry *proc_net_stat; - struct proc_dir_entry *proc_net_root; struct list_head sysctl_table_headers; -- cgit v1.2.3