Commit a82ba839 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 

Pull mount propagation fix from Al Viro:
 "6.15 allowed mount propagation to destinations in detached trees;
  unfortunately, that breaks existing userland, so the old behaviour
  needs to be restored.

  It's not exactly a revert - the original behaviour had a bug, where
  existence of detached tree might disrupt propagation between locations
  not in detached trees. Thankfully, userland did not depend upon that
  bug, so we want to keep the fix"

* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  Don't propagate mounts into detached trees
parents 724b03ee 3b5260d1

fs/mount.h

+0 −5
Original line number Diff line number Diff line
@@ -7,10 +7,6 @@ 


extern struct list_head notify_list;



typedef __u32 __bitwise mntns_flags_t;



#define MNTNS_PROPAGATING	((__force mntns_flags_t)(1 << 0))



struct mnt_namespace {

	struct ns_common	ns;

	struct mount *	root;
@@ -37,7 +33,6 @@ struct mnt_namespace { 
	struct rb_node		mnt_ns_tree_node; /* node in the mnt_ns_tree */

	struct list_head	mnt_ns_list; /* entry in the sequential list of mounts namespace */

	refcount_t		passive; /* number references not pinning @mounts */

	mntns_flags_t		mntns_flags;

} __randomize_layout;



struct mnt_pcp {

fs/namespace.c

+2 −13
Original line number Diff line number Diff line
@@ -3649,7 +3649,7 @@ static int do_move_mount(struct path *old_path, 
	if (!(attached ? check_mnt(old) : is_anon_ns(ns)))

		goto out;



	if (is_anon_ns(ns)) {

	if (is_anon_ns(ns) && ns == p->mnt_ns) {

		/*

		 * Ending up with two files referring to the root of the

		 * same anonymous mount namespace would cause an error
@@ -3657,16 +3657,7 @@ static int do_move_mount(struct path *old_path, 
		 * twice into the mount tree which would be rejected

		 * later. But be explicit about it right here.

		 */

		if ((is_anon_ns(p->mnt_ns) && ns == p->mnt_ns))

		goto out;



		/*

		 * If this is an anonymous mount tree ensure that mount

		 * propagation can detect mounts that were just

		 * propagated to the target mount tree so we don't

		 * propagate onto them.

		 */

		ns->mntns_flags |= MNTNS_PROPAGATING;

	} else if (is_anon_ns(p->mnt_ns)) {

		/*

		 * Don't allow moving an attached mount tree to an
@@ -3723,8 +3714,6 @@ static int do_move_mount(struct path *old_path, 
	if (attached)

		put_mountpoint(old_mp);

out:

	if (is_anon_ns(ns))

		ns->mntns_flags &= ~MNTNS_PROPAGATING;

	unlock_mount(mp);

	if (!err) {

		if (attached) {

fs/pnode.c

+2 −2
Original line number Diff line number Diff line
@@ -231,8 +231,8 @@ static int propagate_one(struct mount *m, struct mountpoint *dest_mp) 
	/* skip if mountpoint isn't visible in m */

	if (!is_subdir(dest_mp->m_dentry, m->mnt.mnt_root))

		return 0;

	/* skip if m is in the anon_ns we are emptying */

	if (m->mnt_ns->mntns_flags & MNTNS_PROPAGATING)

	/* skip if m is in the anon_ns */

	if (is_anon_ns(m->mnt_ns))

		return 0;



	if (peers(m, last_dest)) {