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-rw-r--r--fs/namespace.c11
-rw-r--r--fs/pnode.c198
-rw-r--r--fs/pnode.h3
-rw-r--r--include/linux/mount.h3
4 files changed, 133 insertions, 82 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 2ffc5a2905d4..65233a5f390a 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -885,7 +885,7 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
goto out_free;
}
- mnt->mnt.mnt_flags = old->mnt.mnt_flags & ~MNT_WRITE_HOLD;
+ mnt->mnt.mnt_flags = old->mnt.mnt_flags & ~(MNT_WRITE_HOLD|MNT_MARKED);
/* Don't allow unprivileged users to change mount flags */
if ((flag & CL_UNPRIVILEGED) && (mnt->mnt.mnt_flags & MNT_READONLY))
mnt->mnt.mnt_flags |= MNT_LOCK_READONLY;
@@ -1661,9 +1661,9 @@ static int attach_recursive_mnt(struct mount *source_mnt,
if (err)
goto out;
err = propagate_mnt(dest_mnt, dest_mp, source_mnt, &tree_list);
+ lock_mount_hash();
if (err)
goto out_cleanup_ids;
- lock_mount_hash();
for (p = source_mnt; p; p = next_mnt(p, source_mnt))
set_mnt_shared(p);
} else {
@@ -1690,6 +1690,11 @@ static int attach_recursive_mnt(struct mount *source_mnt,
return 0;
out_cleanup_ids:
+ while (!hlist_empty(&tree_list)) {
+ child = hlist_entry(tree_list.first, struct mount, mnt_hash);
+ umount_tree(child, 0);
+ }
+ unlock_mount_hash();
cleanup_group_ids(source_mnt, NULL);
out:
return err;
@@ -2044,7 +2049,7 @@ static int do_add_mount(struct mount *newmnt, struct path *path, int mnt_flags)
struct mount *parent;
int err;
- mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL | MNT_DOOMED | MNT_SYNC_UMOUNT);
+ mnt_flags &= ~MNT_INTERNAL_FLAGS;
mp = lock_mount(path);
if (IS_ERR(mp))
diff --git a/fs/pnode.c b/fs/pnode.c
index 88396df725b4..302bf22c4a30 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -164,46 +164,94 @@ static struct mount *propagation_next(struct mount *m,
}
}
-/*
- * return the source mount to be used for cloning
- *
- * @dest the current destination mount
- * @last_dest the last seen destination mount
- * @last_src the last seen source mount
- * @type return CL_SLAVE if the new mount has to be
- * cloned as a slave.
- */
-static struct mount *get_source(struct mount *dest,
- struct mount *last_dest,
- struct mount *last_src,
- int *type)
+static struct mount *next_group(struct mount *m, struct mount *origin)
{
- struct mount *p_last_src = NULL;
- struct mount *p_last_dest = NULL;
-
- while (last_dest != dest->mnt_master) {
- p_last_dest = last_dest;
- p_last_src = last_src;
- last_dest = last_dest->mnt_master;
- last_src = last_src->mnt_master;
+ while (1) {
+ while (1) {
+ struct mount *next;
+ if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list))
+ return first_slave(m);
+ next = next_peer(m);
+ if (m->mnt_group_id == origin->mnt_group_id) {
+ if (next == origin)
+ return NULL;
+ } else if (m->mnt_slave.next != &next->mnt_slave)
+ break;
+ m = next;
+ }
+ /* m is the last peer */
+ while (1) {
+ struct mount *master = m->mnt_master;
+ if (m->mnt_slave.next != &master->mnt_slave_list)
+ return next_slave(m);
+ m = next_peer(master);
+ if (master->mnt_group_id == origin->mnt_group_id)
+ break;
+ if (master->mnt_slave.next == &m->mnt_slave)
+ break;
+ m = master;
+ }
+ if (m == origin)
+ return NULL;
}
+}
- if (p_last_dest) {
- do {
- p_last_dest = next_peer(p_last_dest);
- } while (IS_MNT_NEW(p_last_dest));
- /* is that a peer of the earlier? */
- if (dest == p_last_dest) {
- *type = CL_MAKE_SHARED;
- return p_last_src;
+/* all accesses are serialized by namespace_sem */
+static struct user_namespace *user_ns;
+static struct mount *last_dest, *last_source, *dest_master;
+static struct mountpoint *mp;
+static struct hlist_head *list;
+
+static int propagate_one(struct mount *m)
+{
+ struct mount *child;
+ int type;
+ /* skip ones added by this propagate_mnt() */
+ if (IS_MNT_NEW(m))
+ return 0;
+ /* skip if mountpoint isn't covered by it */
+ if (!is_subdir(mp->m_dentry, m->mnt.mnt_root))
+ return 0;
+ if (m->mnt_group_id == last_dest->mnt_group_id) {
+ type = CL_MAKE_SHARED;
+ } else {
+ struct mount *n, *p;
+ for (n = m; ; n = p) {
+ p = n->mnt_master;
+ if (p == dest_master || IS_MNT_MARKED(p)) {
+ while (last_dest->mnt_master != p) {
+ last_source = last_source->mnt_master;
+ last_dest = last_source->mnt_parent;
+ }
+ if (n->mnt_group_id != last_dest->mnt_group_id) {
+ last_source = last_source->mnt_master;
+ last_dest = last_source->mnt_parent;
+ }
+ break;
+ }
}
+ type = CL_SLAVE;
+ /* beginning of peer group among the slaves? */
+ if (IS_MNT_SHARED(m))
+ type |= CL_MAKE_SHARED;
}
- /* slave of the earlier, then */
- *type = CL_SLAVE;
- /* beginning of peer group among the slaves? */
- if (IS_MNT_SHARED(dest))
- *type |= CL_MAKE_SHARED;
- return last_src;
+
+ /* Notice when we are propagating across user namespaces */
+ if (m->mnt_ns->user_ns != user_ns)
+ type |= CL_UNPRIVILEGED;
+ child = copy_tree(last_source, last_source->mnt.mnt_root, type);
+ if (IS_ERR(child))
+ return PTR_ERR(child);
+ mnt_set_mountpoint(m, mp, child);
+ last_dest = m;
+ last_source = child;
+ if (m->mnt_master != dest_master) {
+ read_seqlock_excl(&mount_lock);
+ SET_MNT_MARK(m->mnt_master);
+ read_sequnlock_excl(&mount_lock);
+ }
+ hlist_add_head(&child->mnt_hash, list);
+ return 0;
}
/*
@@ -222,56 +270,48 @@ static struct mount *get_source(struct mount *dest,
int propagate_mnt(struct mount *dest_mnt, struct mountpoint *dest_mp,
struct mount *source_mnt, struct hlist_head *tree_list)
{
- struct user_namespace *user_ns = current->nsproxy->mnt_ns->user_ns;
- struct mount *m, *child;
+ struct mount *m, *n;
int ret = 0;
- struct mount *prev_dest_mnt = dest_mnt;
- struct mount *prev_src_mnt = source_mnt;
- HLIST_HEAD(tmp_list);
-
- for (m = propagation_next(dest_mnt, dest_mnt); m;
- m = propagation_next(m, dest_mnt)) {
- int type;
- struct mount *source;
-
- if (IS_MNT_NEW(m))
- continue;
-
- source = get_source(m, prev_dest_mnt, prev_src_mnt, &type);
-
- /* Notice when we are propagating across user namespaces */
- if (m->mnt_ns->user_ns != user_ns)
- type |= CL_UNPRIVILEGED;
-
- child = copy_tree(source, source->mnt.mnt_root, type);
- if (IS_ERR(child)) {
- ret = PTR_ERR(child);
- tmp_list = *tree_list;
- tmp_list.first->pprev = &tmp_list.first;
- INIT_HLIST_HEAD(tree_list);
+
+ /*
+ * we don't want to bother passing tons of arguments to
+ * propagate_one(); everything is serialized by namespace_sem,
+ * so globals will do just fine.
+ */
+ user_ns = current->nsproxy->mnt_ns->user_ns;
+ last_dest = dest_mnt;
+ last_source = source_mnt;
+ mp = dest_mp;
+ list = tree_list;
+ dest_master = dest_mnt->mnt_master;
+
+ /* all peers of dest_mnt, except dest_mnt itself */
+ for (n = next_peer(dest_mnt); n != dest_mnt; n = next_peer(n)) {
+ ret = propagate_one(n);
+ if (ret)
goto out;
- }
+ }
- if (is_subdir(dest_mp->m_dentry, m->mnt.mnt_root)) {
- mnt_set_mountpoint(m, dest_mp, child);
- hlist_add_head(&child->mnt_hash, tree_list);
- } else {
- /*
- * This can happen if the parent mount was bind mounted
- * on some subdirectory of a shared/slave mount.
- */
- hlist_add_head(&child->mnt_hash, &tmp_list);
- }
- prev_dest_mnt = m;
- prev_src_mnt = child;
+ /* all slave groups */
+ for (m = next_group(dest_mnt, dest_mnt); m;
+ m = next_group(m, dest_mnt)) {
+ /* everything in that slave group */
+ n = m;
+ do {
+ ret = propagate_one(n);
+ if (ret)
+ goto out;
+ n = next_peer(n);
+ } while (n != m);
}
out:
- lock_mount_hash();
- while (!hlist_empty(&tmp_list)) {
- child = hlist_entry(tmp_list.first, struct mount, mnt_hash);
- umount_tree(child, 0);
+ read_seqlock_excl(&mount_lock);
+ hlist_for_each_entry(n, tree_list, mnt_hash) {
+ m = n->mnt_parent;
+ if (m->mnt_master != dest_mnt->mnt_master)
+ CLEAR_MNT_MARK(m->mnt_master);
}
- unlock_mount_hash();
+ read_sequnlock_excl(&mount_lock);
return ret;
}
diff --git a/fs/pnode.h b/fs/pnode.h
index fc28a27fa892..4a246358b031 100644
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -16,6 +16,9 @@
#define IS_MNT_NEW(m) (!(m)->mnt_ns)
#define CLEAR_MNT_SHARED(m) ((m)->mnt.mnt_flags &= ~MNT_SHARED)
#define IS_MNT_UNBINDABLE(m) ((m)->mnt.mnt_flags & MNT_UNBINDABLE)
+#define IS_MNT_MARKED(m) ((m)->mnt.mnt_flags & MNT_MARKED)
+#define SET_MNT_MARK(m) ((m)->mnt.mnt_flags |= MNT_MARKED)
+#define CLEAR_MNT_MARK(m) ((m)->mnt.mnt_flags &= ~MNT_MARKED)
#define CL_EXPIRE 0x01
#define CL_SLAVE 0x02
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 371d346fa270..839bac270904 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -44,6 +44,8 @@ struct mnt_namespace;
#define MNT_SHARED_MASK (MNT_UNBINDABLE)
#define MNT_PROPAGATION_MASK (MNT_SHARED | MNT_UNBINDABLE)
+#define MNT_INTERNAL_FLAGS (MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL | \
+ MNT_DOOMED | MNT_SYNC_UMOUNT | MNT_MARKED)
#define MNT_INTERNAL 0x4000
@@ -51,6 +53,7 @@ struct mnt_namespace;
#define MNT_LOCKED 0x800000
#define MNT_DOOMED 0x1000000
#define MNT_SYNC_UMOUNT 0x2000000
+#define MNT_MARKED 0x4000000
struct vfsmount {
struct dentry *mnt_root; /* root of the mounted tree */
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.