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Commit 6b2d5fe4 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

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: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent bbb1e54d

fs/overlayfs/namei.c

+8 −8
Original line number Diff line number Diff line
@@ -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)) {

fs/overlayfs/ovl_entry.h

+1 −1
Original line number Diff line number Diff line
@@ -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 */

fs/overlayfs/super.c

+26 −12
Original line number Diff line number Diff line
@@ -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)

{

	int err;

	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;



	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;