ovl: check namelen
We already calculate f_namelen in statfs as the maximum of the name lengths
provided by the filesystems taking part in the overlay.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index f4057fc..2e0b84c6 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -20,7 +20,8 @@ static struct dentry *ovl_lookup_real(struct dentry *dir,
dentry = lookup_one_len_unlocked(name->name, dir, name->len);
if (IS_ERR(dentry)) {
- if (PTR_ERR(dentry) == -ENOENT)
+ if (PTR_ERR(dentry) == -ENOENT ||
+ PTR_ERR(dentry) == -ENAMETOOLONG)
dentry = NULL;
} else if (!dentry->d_inode) {
dput(dentry);
@@ -74,6 +75,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
{
struct ovl_entry *oe;
const struct cred *old_cred;
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
struct ovl_entry *poe = dentry->d_parent->d_fsdata;
struct path *stack = NULL;
struct dentry *upperdir, *upperdentry = NULL;
@@ -86,6 +88,9 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
unsigned int i;
int err;
+ if (dentry->d_name.len > ofs->namelen)
+ return ERR_PTR(-ENAMETOOLONG);
+
old_cred = ovl_override_creds(dentry->d_sb);
upperdir = ovl_upperdentry_dereference(poe);
if (upperdir) {
@@ -127,14 +132,9 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
this = ovl_lookup_real(lowerpath.dentry, &dentry->d_name);
err = PTR_ERR(this);
- if (IS_ERR(this)) {
- /*
- * If it's positive, then treat ENAMETOOLONG as ENOENT.
- */
- if (err == -ENAMETOOLONG && (upperdentry || ctr))
- continue;
+ if (IS_ERR(this))
goto out_put;
- }
+
if (!this)
continue;
if (ovl_is_whiteout(this)) {
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 3b7ba59..b10745e 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -21,7 +21,7 @@ struct ovl_fs {
unsigned numlower;
struct vfsmount **lower_mnt;
struct dentry *workdir;
- long lower_namelen;
+ long namelen;
/* pathnames of lower and upper dirs, for show_options */
struct ovl_config config;
/* creds of process who forced instantiation of super block */
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 011482e..e19e2ed 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -174,7 +174,7 @@ static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
err = vfs_statfs(&path, buf);
if (!err) {
- buf->f_namelen = max(buf->f_namelen, ofs->lower_namelen);
+ buf->f_namelen = ofs->namelen;
buf->f_type = OVERLAYFS_SUPER_MAGIC;
}
@@ -461,22 +461,33 @@ static int ovl_mount_dir(const char *name, struct path *path)
return err;
}
-static int ovl_lower_dir(const char *name, struct path *path, long *namelen,
- int *stack_depth, bool *remote)
+static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs,
+ const char *name)
+{
+ struct kstatfs statfs;
+ int err = vfs_statfs(path, &statfs);
+
+ if (err)
+ pr_err("overlayfs: statfs failed on '%s'\n", name);
+ else
+ ofs->namelen = max(ofs->namelen, statfs.f_namelen);
+
+ return err;
+}
+
+static int ovl_lower_dir(const char *name, struct path *path,
+ struct ovl_fs *ofs, int *stack_depth, bool *remote)
{
int err;
- struct kstatfs statfs;
err = ovl_mount_dir_noesc(name, path);
if (err)
goto out;
- err = vfs_statfs(path, &statfs);
- if (err) {
- pr_err("overlayfs: statfs failed on '%s'\n", name);
+ err = ovl_check_namelen(path, ofs, name);
+ if (err)
goto out_put;
- }
- *namelen = max(*namelen, statfs.f_namelen);
+
*stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth);
if (ovl_dentry_remote(path->dentry))
@@ -708,6 +719,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
goto out_put_upperpath;
}
+ err = ovl_check_namelen(&upperpath, ufs, ufs->config.upperdir);
+ if (err)
+ goto out_put_upperpath;
+
err = ovl_mount_dir(ufs->config.workdir, &workpath);
if (err)
goto out_put_upperpath;
@@ -745,9 +760,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
lower = lowertmp;
for (numlower = 0; numlower < stacklen; numlower++) {
- err = ovl_lower_dir(lower, &stack[numlower],
- &ufs->lower_namelen, &sb->s_stack_depth,
- &remote);
+ err = ovl_lower_dir(lower, &stack[numlower], ufs,
+ &sb->s_stack_depth, &remote);
if (err)
goto out_put_lowerpath;