Commit 48bd024b authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

ovl: switch to mounter creds in readdir 



In preparation for more permission checking, override credentials for
directory operations on the underlying filesystems.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 130fdbc3

fs/overlayfs/readdir.c

+21 −6
Original line number Diff line number Diff line
@@ -743,8 +743,10 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx) 
	struct ovl_dir_file *od = file->private_data;

	struct dentry *dentry = file->f_path.dentry;

	struct ovl_cache_entry *p;

	const struct cred *old_cred;

	int err;



	old_cred = ovl_override_creds(dentry->d_sb);

	if (!ctx->pos)

		ovl_dir_reset(file);
@@ -758,17 +760,20 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx) 
		    (ovl_same_fs(dentry->d_sb) &&

		     (ovl_is_impure_dir(file) ||

		      OVL_TYPE_MERGE(ovl_path_type(dentry->d_parent))))) {

			return ovl_iterate_real(file, ctx);

			err = ovl_iterate_real(file, ctx);

		} else {

			err = iterate_dir(od->realfile, ctx);

		}

		return iterate_dir(od->realfile, ctx);

		goto out;

	}



	if (!od->cache) {

		struct ovl_dir_cache *cache;



		cache = ovl_cache_get(dentry);

		err = PTR_ERR(cache);

		if (IS_ERR(cache))

			return PTR_ERR(cache);

			goto out;



		od->cache = cache;

		ovl_seek_cursor(od, ctx->pos);
@@ -780,7 +785,7 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx) 
			if (!p->ino) {

				err = ovl_cache_update_ino(&file->f_path, p);

				if (err)

					return err;

					goto out;

			}

			if (!dir_emit(ctx, p->name, p->len, p->ino, p->type))

				break;
@@ -788,7 +793,10 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx) 
		od->cursor = p->l_node.next;

		ctx->pos++;

	}

	return 0;

	err = 0;

out:

	revert_creds(old_cred);

	return err;

}



static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin)
@@ -834,7 +842,14 @@ static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin) 
static struct file *ovl_dir_open_realfile(struct file *file,

					  struct path *realpath)

{

	return ovl_path_open(realpath, O_RDONLY | (file->f_flags & O_LARGEFILE));

	struct file *res;

	const struct cred *old_cred;



	old_cred = ovl_override_creds(file_inode(file)->i_sb);

	res = ovl_path_open(realpath, O_RDONLY | (file->f_flags & O_LARGEFILE));

	revert_creds(old_cred);



	return res;

}



static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,