diff options
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 59 |
1 files changed, 37 insertions, 22 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index a677b59efd74..9ed2f2930dfd 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1013,27 +1013,6 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root, mnt->mnt.mnt_flags = old->mnt.mnt_flags; mnt->mnt.mnt_flags &= ~(MNT_WRITE_HOLD|MNT_MARKED|MNT_INTERNAL); - /* Don't allow unprivileged users to change mount flags */ - if (flag & CL_UNPRIVILEGED) { - mnt->mnt.mnt_flags |= MNT_LOCK_ATIME; - - if (mnt->mnt.mnt_flags & MNT_READONLY) - mnt->mnt.mnt_flags |= MNT_LOCK_READONLY; - - if (mnt->mnt.mnt_flags & MNT_NODEV) - mnt->mnt.mnt_flags |= MNT_LOCK_NODEV; - - if (mnt->mnt.mnt_flags & MNT_NOSUID) - mnt->mnt.mnt_flags |= MNT_LOCK_NOSUID; - - if (mnt->mnt.mnt_flags & MNT_NOEXEC) - mnt->mnt.mnt_flags |= MNT_LOCK_NOEXEC; - } - - /* Don't allow unprivileged users to reveal what is under a mount */ - if ((flag & CL_UNPRIVILEGED) && - (!(flag & CL_EXPIRE) || list_empty(&old->mnt_expire))) - mnt->mnt.mnt_flags |= MNT_LOCKED; atomic_inc(&sb->s_active); mnt->mnt.mnt_sb = sb; @@ -1837,6 +1816,33 @@ int iterate_mounts(int (*f)(struct vfsmount *, void *), void *arg, return 0; } +static void lock_mnt_tree(struct mount *mnt) +{ + struct mount *p; + + for (p = mnt; p; p = next_mnt(p, mnt)) { + int flags = p->mnt.mnt_flags; + /* Don't allow unprivileged users to change mount flags */ + flags |= MNT_LOCK_ATIME; + + if (flags & MNT_READONLY) + flags |= MNT_LOCK_READONLY; + + if (flags & MNT_NODEV) + flags |= MNT_LOCK_NODEV; + + if (flags & MNT_NOSUID) + flags |= MNT_LOCK_NOSUID; + + if (flags & MNT_NOEXEC) + flags |= MNT_LOCK_NOEXEC; + /* Don't allow unprivileged users to reveal what is under a mount */ + if (list_empty(&p->mnt_expire)) + flags |= MNT_LOCKED; + p->mnt.mnt_flags = flags; + } +} + static void cleanup_group_ids(struct mount *mnt, struct mount *end) { struct mount *p; @@ -1954,6 +1960,7 @@ static int attach_recursive_mnt(struct mount *source_mnt, struct mountpoint *dest_mp, struct path *parent_path) { + struct user_namespace *user_ns = current->nsproxy->mnt_ns->user_ns; HLIST_HEAD(tree_list); struct mnt_namespace *ns = dest_mnt->mnt_ns; struct mountpoint *smp; @@ -2004,6 +2011,9 @@ static int attach_recursive_mnt(struct mount *source_mnt, child->mnt_mountpoint); if (q) mnt_change_mountpoint(child, smp, q); + /* Notice when we are propagating across user namespaces */ + if (child->mnt_parent->mnt_ns->user_ns != user_ns) + lock_mnt_tree(child); commit_tree(child); } put_mountpoint(smp); @@ -2941,13 +2951,18 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns, /* First pass: copy the tree topology */ copy_flags = CL_COPY_UNBINDABLE | CL_EXPIRE; if (user_ns != ns->user_ns) - copy_flags |= CL_SHARED_TO_SLAVE | CL_UNPRIVILEGED; + copy_flags |= CL_SHARED_TO_SLAVE; new = copy_tree(old, old->mnt.mnt_root, copy_flags); if (IS_ERR(new)) { namespace_unlock(); free_mnt_ns(new_ns); return ERR_CAST(new); } + if (user_ns != ns->user_ns) { + lock_mount_hash(); + lock_mnt_tree(new); + unlock_mount_hash(); + } new_ns->root = new; list_add_tail(&new_ns->list, &new->mnt_list); |