1 files changed, 108 insertions, 66 deletions

diff --git a/fs/proc/root.c b/fs/proc/root.c
index b080b791d9e3..87dbcbef7fe4 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -16,8 +16,10 @@
 #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>
 
 #include "internal.h"
 
@@ -28,62 +30,114 @@ static int proc_test_super(struct super_block *sb, void *data)
 
 static int proc_set_super(struct super_block *sb, void *data)
 {
-	struct pid_namespace *ns;
+	int err = set_anon_super(sb, NULL);
+	if (!err) {
+		struct pid_namespace *ns = (struct pid_namespace *)data;
+		sb->s_fs_info = get_pid_ns(ns);
+	}
+	return err;
+}
+
+enum {
+	Opt_gid, Opt_hidepid, Opt_err,
+};
+
+static const match_table_t tokens = {
+	{Opt_hidepid, "hidepid=%u"},
+	{Opt_gid, "gid=%u"},
+	{Opt_err, NULL},
+};
 
-	ns = (struct pid_namespace *)data;
-	sb->s_fs_info = get_pid_ns(ns);
-	return set_anon_super(sb, NULL);
+static int proc_parse_options(char *options, struct pid_namespace *pid)
+{
+	char *p;
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+
+	if (!options)
+		return 1;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token;
+		if (!*p)
+			continue;
+
+		args[0].to = args[0].from = NULL;
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_gid:
+			if (match_int(&args[0], &option))
+				return 0;
+			pid->pid_gid = make_kgid(current_user_ns(), option);
+			break;
+		case Opt_hidepid:
+			if (match_int(&args[0], &option))
+				return 0;
+			if (option < 0 || option > 2) {
+				pr_err("proc: hidepid value must be between 0 and 2.\n");
+				return 0;
+			}
+			pid->hide_pid = option;
+			break;
+		default:
+			pr_err("proc: unrecognized mount option \"%s\" "
+			       "or missing value\n", p);
+			return 0;
+		}
+	}
+
+	return 1;
 }
 
-static int proc_get_sb(struct file_system_type *fs_type,
-	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
+int proc_remount(struct super_block *sb, int *flags, char *data)
+{
+	struct pid_namespace *pid = sb->s_fs_info;
+	return !proc_parse_options(data, pid);
+}
+
+static struct dentry *proc_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
 {
 	int err;
 	struct super_block *sb;
 	struct pid_namespace *ns;
-	struct proc_inode *ei;
-
-	if (proc_mnt) {
-		/* Seed the root directory with a pid so it doesn't need
-		 * to be special in base.c.  I would do this earlier but
-		 * the only task alive when /proc is mounted the first time
-		 * is the init_task and it doesn't have any pids.
-		 */
-		ei = PROC_I(proc_mnt->mnt_sb->s_root->d_inode);
-		if (!ei->pid)
-			ei->pid = find_get_pid(1);
-	}
+	char *options;
 
-	if (flags & MS_KERNMOUNT)
+	if (flags & MS_KERNMOUNT) {
 		ns = (struct pid_namespace *)data;
-	else
-		ns = current->nsproxy->pid_ns;
+		options = NULL;
+	} else {
+		ns = task_active_pid_ns(current);
+		options = data;
 
-	sb = sget(fs_type, proc_test_super, proc_set_super, ns);
+		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);
 	if (IS_ERR(sb))
-		return PTR_ERR(sb);
+		return ERR_CAST(sb);
+
+	if (!proc_parse_options(options, ns)) {
+		deactivate_locked_super(sb);
+		return ERR_PTR(-EINVAL);
+	}
 
 	if (!sb->s_root) {
-		sb->s_flags = flags;
 		err = proc_fill_super(sb);
 		if (err) {
 			deactivate_locked_super(sb);
-			return err;
-		}
-
-		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 ERR_PTR(err);
 		}
 
 		sb->s_flags |= MS_ACTIVE;
-		ns->proc_mnt = mnt;
 	}
 
-	simple_set_mnt(mnt, sb);
-	return 0;
+	return dget(sb->s_root);
 }
 
 static void proc_kill_sb(struct super_block *sb)
@@ -91,14 +145,17 @@ 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);
 }
 
 static struct file_system_type proc_fs_type = {
 	.name		= "proc",
-	.get_sb		= proc_get_sb,
+	.mount		= proc_mount,
 	.kill_sb	= proc_kill_sb,
+	.fs_flags	= FS_USERNS_MOUNT,
 };
 
 void __init proc_root_init(void)
@@ -109,13 +166,8 @@ void __init proc_root_init(void)
 	err = register_filesystem(&proc_fs_type);
 	if (err)
 		return;
-	proc_mnt = kern_mount_data(&proc_fs_type, &init_pid_ns);
-	err = PTR_ERR(proc_mnt);
-	if (IS_ERR(proc_mnt)) {
-		unregister_filesystem(&proc_fs_type);
-		return;
-	}
 
+	proc_self_init();
 	proc_symlink("mounts", NULL, "self/mounts");
 
 	proc_net_init();
@@ -146,30 +198,24 @@ static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct
 	return 0;
 }
 
-static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
+static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
 {
-	if (!proc_lookup(dir, dentry, nd)) {
+	if (!proc_lookup(dir, dentry, flags))
 		return NULL;
-	}
 	
-	return proc_pid_lookup(dir, dentry, nd);
+	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);
 }
 
 /*
@@ -179,7 +225,8 @@ 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,
 };
 
 /*
@@ -196,13 +243,13 @@ static const struct inode_operations proc_root_inode_operations = {
 struct proc_dir_entry proc_root = {
 	.low_ino	= PROC_ROOT_INO, 
 	.namelen	= 5, 
-	.name		= "/proc",
 	.mode		= S_IFDIR | S_IRUGO | S_IXUGO, 
 	.nlink		= 2, 
 	.count		= ATOMIC_INIT(1),
 	.proc_iops	= &proc_root_inode_operations, 
 	.proc_fops	= &proc_root_operations,
 	.parent		= &proc_root,
+	.name		= "/proc",
 };
 
 int pid_ns_prepare_proc(struct pid_namespace *ns)
@@ -213,16 +260,11 @@ int pid_ns_prepare_proc(struct pid_namespace *ns)
 	if (IS_ERR(mnt))
 		return PTR_ERR(mnt);
 
+	ns->proc_mnt = mnt;
 	return 0;
 }
 
 void pid_ns_release_proc(struct pid_namespace *ns)
 {
-	mntput(ns->proc_mnt);
+	kern_unmount(ns->proc_mnt);
 }
-
-EXPORT_SYMBOL(proc_symlink);
-EXPORT_SYMBOL(proc_mkdir);
-EXPORT_SYMBOL(create_proc_entry);
-EXPORT_SYMBOL(proc_create_data);
-EXPORT_SYMBOL(remove_proc_entry);