From: Valerie Aurora <vaurora@xxxxxxxxxx>
copy_tree() can theoretically fail in a case other than ENOMEM, but
always returns NULL which is interpreted by callers as -ENOMEM.
Convert to return an explicit error. Convert clone_mnt() for
consistency and because union mounts will add new error cases.
Thanks to Andreas Gruenbacher <agruen@xxxxxxx> for a bug fix.
Cc: Andreas Gruenbacher <agruen@xxxxxxx>
Signed-off-by: Valerie Aurora <valerie.aurora@xxxxxxxxx>
---
fs/namespace.c | 111 +++++++++++++++++++++++++++-----------------------
fs/pnode.c | 5 +-
kernel/audit_tree.c | 10 ++--
3 files changed, 68 insertions(+), 58 deletions(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index 745feaf..79be922 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -593,53 +593,57 @@ static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root,
int flag)
{
struct super_block *sb = old->mnt_sb;
- struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname);
+ struct vfsmount *mnt;
+ int err;
- if (mnt) {
- if (flag & (CL_SLAVE | CL_PRIVATE))
- mnt->mnt_group_id = 0; /* not a peer of original */
- else
- mnt->mnt_group_id = old->mnt_group_id;
-
- if ((flag & CL_MAKE_SHARED) && !mnt->mnt_group_id) {
- int err = mnt_alloc_group_id(mnt);
- if (err)
- goto out_free;
- }
+ mnt = alloc_vfsmnt(old->mnt_devname);
+ if (!mnt)
+ return ERR_PTR(-ENOMEM);
- mnt->mnt_flags = old->mnt_flags;
- atomic_inc(&sb->s_active);
- mnt->mnt_sb = sb;
- mnt->mnt_root = dget(root);
- mnt->mnt_mountpoint = mnt->mnt_root;
- mnt->mnt_parent = mnt;
-
- if (flag & CL_SLAVE) {
- list_add(&mnt->mnt_slave, &old->mnt_slave_list);
- mnt->mnt_master = old;
- CLEAR_MNT_SHARED(mnt);
- } else if (!(flag & CL_PRIVATE)) {
- if ((flag & CL_MAKE_SHARED) || IS_MNT_SHARED(old))
- list_add(&mnt->mnt_share, &old->mnt_share);
- if (IS_MNT_SLAVE(old))
- list_add(&mnt->mnt_slave, &old->mnt_slave);
- mnt->mnt_master = old->mnt_master;
- }
- if (flag & CL_MAKE_SHARED)
- set_mnt_shared(mnt);
-
- /* stick the duplicate mount on the same expiry list
- * as the original if that was on one */
- if (flag & CL_EXPIRE) {
- if (!list_empty(&old->mnt_expire))
- list_add(&mnt->mnt_expire, &old->mnt_expire);
- }
+ if (flag & (CL_SLAVE | CL_PRIVATE))
+ mnt->mnt_group_id = 0; /* not a peer of original */
+ else
+ mnt->mnt_group_id = old->mnt_group_id;
+
+ if ((flag & CL_MAKE_SHARED) && !mnt->mnt_group_id) {
+ err = mnt_alloc_group_id(mnt);
+ if (err)
+ goto out_free;
}
+
+ mnt->mnt_flags = old->mnt_flags;
+ atomic_inc(&sb->s_active);
+ mnt->mnt_sb = sb;
+ mnt->mnt_root = dget(root);
+ mnt->mnt_mountpoint = mnt->mnt_root;
+ mnt->mnt_parent = mnt;
+
+ if (flag & CL_SLAVE) {
+ list_add(&mnt->mnt_slave, &old->mnt_slave_list);
+ mnt->mnt_master = old;
+ CLEAR_MNT_SHARED(mnt);
+ } else if (!(flag & CL_PRIVATE)) {
+ if ((flag & CL_MAKE_SHARED) || IS_MNT_SHARED(old))
+ list_add(&mnt->mnt_share, &old->mnt_share);
+ if (IS_MNT_SLAVE(old))
+ list_add(&mnt->mnt_slave, &old->mnt_slave);
+ mnt->mnt_master = old->mnt_master;
+ }
+ if (flag & CL_MAKE_SHARED)
+ set_mnt_shared(mnt);
+
+ /* stick the duplicate mount on the same expiry list
+ * as the original if that was on one */
+ if (flag & CL_EXPIRE) {
+ if (!list_empty(&old->mnt_expire))
+ list_add(&mnt->mnt_expire, &old->mnt_expire);
+ }
+
return mnt;
out_free:
free_vfsmnt(mnt);
- return NULL;
+ return ERR_PTR(err);
}
static inline void __mntput(struct vfsmount *mnt)
@@ -1255,11 +1259,12 @@ struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry,
struct path path;
if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt))
- return NULL;
+ return ERR_PTR(-EINVAL);
res = q = clone_mnt(mnt, dentry, flag);
- if (!q)
- goto Enomem;
+ if (IS_ERR(q))
+ return q;
+
q->mnt_mountpoint = mnt->mnt_mountpoint;
p = mnt;
@@ -1280,8 +1285,8 @@ struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry,
path.mnt = q;
path.dentry = p->mnt_mountpoint;
q = clone_mnt(p, p->mnt_root, flag);
- if (!q)
- goto Enomem;
+ if (IS_ERR(q))
+ goto out;
br_write_lock(vfsmount_lock);
list_add_tail(&q->mnt_list, &res->mnt_list);
attach_mnt(q, &path);
@@ -1289,7 +1294,7 @@ struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry,
}
}
return res;
-Enomem:
+out:
if (res) {
LIST_HEAD(umount_list);
br_write_lock(vfsmount_lock);
@@ -1297,9 +1302,11 @@ Enomem:
br_write_unlock(vfsmount_lock);
release_mounts(&umount_list);
}
- return NULL;
+ return q;
}
+/* Caller should check returned pointer for errors */
+
struct vfsmount *collect_mounts(struct path *path)
{
struct vfsmount *tree;
@@ -1574,14 +1581,15 @@ static int do_loopback(struct path *path, char *old_name,
if (!check_mnt(path->mnt) || !check_mnt(old_path.mnt))
goto out;
- err = -ENOMEM;
if (recurse)
mnt = copy_tree(old_path.mnt, old_path.dentry, 0);
else
mnt = clone_mnt(old_path.mnt, old_path.dentry, 0);
- if (!mnt)
+ if (IS_ERR(mnt)) {
+ err = PTR_ERR(mnt);
goto out;
+ }
err = graft_tree(mnt, path);
if (err) {
@@ -2119,10 +2127,11 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
/* First pass: copy the tree topology */
new_ns->root = copy_tree(mnt_ns->root, mnt_ns->root->mnt_root,
CL_COPY_ALL | CL_EXPIRE);
- if (!new_ns->root) {
+ if (IS_ERR(new_ns->root)) {
+ int err = PTR_ERR(new_ns->root);
up_write(&namespace_sem);
kfree(new_ns);
- return ERR_PTR(-ENOMEM);
+ return ERR_PTR(err);
}
br_write_lock(vfsmount_lock);
list_add_tail(&new_ns->list, &new_ns->root->mnt_list);
diff --git a/fs/pnode.c b/fs/pnode.c
index 8066b8d..0710bb9 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -253,8 +253,9 @@ int propagate_mnt(struct vfsmount *dest_mnt, struct dentry *dest_dentry,
source = get_source(m, prev_dest_mnt, prev_src_mnt, &type);
- if (!(child = copy_tree(source, source->mnt_root, type))) {
- ret = -ENOMEM;
+ child = copy_tree(source, source->mnt_root, type);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
list_splice(tree_list, tmp_list.prev);
goto out;
}
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index 7f18d3a..d32ca7a 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -596,7 +596,7 @@ void audit_trim_trees(void)
root_mnt = collect_mounts(&path);
path_put(&path);
- if (!root_mnt)
+ if (IS_ERR(root_mnt))
goto skip_it;
spin_lock(&hash_lock);
@@ -670,8 +670,8 @@ int audit_add_tree_rule(struct audit_krule *rule)
goto Err;
mnt = collect_mounts(&path);
path_put(&path);
- if (!mnt) {
- err = -ENOMEM;
+ if (IS_ERR(mnt)) {
+ err = PTR_ERR(mnt);
goto Err;
}
@@ -720,8 +720,8 @@ int audit_tag_tree(char *old, char *new)
return err;
tagged = collect_mounts(&path2);
path_put(&path2);
- if (!tagged)
- return -ENOMEM;
+ if (IS_ERR(tagged))
+ return PTR_ERR(tagged);
err = kern_path(old, 0, &path1);
if (err) {
--
1.7.0.4
--
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