1 files changed, 21 insertions, 27 deletions

diff --git a/fs/proc/root.c b/fs/proc/root.c
index 9a2d9fd7cadd..87dbcbef7fe4 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -16,6 +16,7 @@
 #include <linux/sched.h>
 #include <linux/module.h>
 #include <linux/bitops.h>
+#include <linux/user_namespace.h>
 #include <linux/mount.h>
 #include <linux/pid_namespace.h>
 #include <linux/parser.h>
@@ -61,7 +62,7 @@ static int proc_parse_options(char *options, struct pid_namespace *pid)
 		if (!*p)
 			continue;
 
-		args[0].to = args[0].from = 0;
+		args[0].to = args[0].from = NULL;
 		token = match_token(p, tokens, args);
 		switch (token) {
 		case Opt_gid:
@@ -100,15 +101,21 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
 	int err;
 	struct super_block *sb;
 	struct pid_namespace *ns;
-	struct proc_inode *ei;
 	char *options;
 
 	if (flags & MS_KERNMOUNT) {
 		ns = (struct pid_namespace *)data;
 		options = NULL;
 	} else {
-		ns = current->nsproxy->pid_ns;
+		ns = task_active_pid_ns(current);
 		options = data;
+
+		if (!capable(CAP_SYS_ADMIN) && !fs_fully_visible(fs_type))
+			return ERR_PTR(-EPERM);
+
+		/* Does the mounter have privilege over the pid namespace? */
+		if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
+			return ERR_PTR(-EPERM);
 	}
 
 	sb = sget(fs_type, proc_test_super, proc_set_super, flags, ns);
@@ -130,13 +137,6 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
 		sb->s_flags |= MS_ACTIVE;
 	}
 
-	ei = PROC_I(sb->s_root->d_inode);
-	if (!ei->pid) {
-		rcu_read_lock();
-		ei->pid = get_pid(find_pid_ns(1, ns));
-		rcu_read_unlock();
-	}
-
 	return dget(sb->s_root);
 }
 
@@ -145,6 +145,8 @@ static void proc_kill_sb(struct super_block *sb)
 	struct pid_namespace *ns;
 
 	ns = (struct pid_namespace *)sb->s_fs_info;
+	if (ns->proc_self)
+		dput(ns->proc_self);
 	kill_anon_super(sb);
 	put_pid_ns(ns);
 }
@@ -153,6 +155,7 @@ static struct file_system_type proc_fs_type = {
 	.name		= "proc",
 	.mount		= proc_mount,
 	.kill_sb	= proc_kill_sb,
+	.fs_flags	= FS_USERNS_MOUNT,
 };
 
 void __init proc_root_init(void)
@@ -163,12 +166,8 @@ void __init proc_root_init(void)
 	err = register_filesystem(&proc_fs_type);
 	if (err)
 		return;
-	err = pid_ns_prepare_proc(&init_pid_ns);
-	if (err) {
-		unregister_filesystem(&proc_fs_type);
-		return;
-	}
 
+	proc_self_init();
 	proc_symlink("mounts", NULL, "self/mounts");
 
 	proc_net_init();
@@ -207,21 +206,16 @@ static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentr
 	return proc_pid_lookup(dir, dentry, flags);
 }
 
-static int proc_root_readdir(struct file * filp,
-	void * dirent, filldir_t filldir)
+static int proc_root_readdir(struct file *file, struct dir_context *ctx)
 {
-	unsigned int nr = filp->f_pos;
-	int ret;
-
-	if (nr < FIRST_PROCESS_ENTRY) {
-		int error = proc_readdir(filp, dirent, filldir);
-		if (error <= 0)
+	if (ctx->pos < FIRST_PROCESS_ENTRY) {
+		int error = proc_readdir(file, ctx);
+		if (unlikely(error <= 0))
 			return error;
-		filp->f_pos = FIRST_PROCESS_ENTRY;
+		ctx->pos = FIRST_PROCESS_ENTRY;
 	}
 
-	ret = proc_pid_readdir(filp, dirent, filldir);
-	return ret;
+	return proc_pid_readdir(file, ctx);
 }
 
 /*
@@ -231,7 +225,7 @@ static int proc_root_readdir(struct file * filp,
  */
 static const struct file_operations proc_root_operations = {
 	.read		 = generic_read_dir,
-	.readdir	 = proc_root_readdir,
+	.iterate	 = proc_root_readdir,
 	.llseek		= default_llseek,
 };