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Commit 714ac6de authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Greg Kroah-Hartman
Browse files

ovl: copy_up_xattr(): use strnlen 



commit 8b326c61de08f5ca4bc454a168f19e7e43c4cc2a upstream.

Be defensive about what underlying fs provides us in the returned xattr
list buffer.  strlen() may overrun the buffer, so use strnlen() and WARN if
the contents are not properly null terminated.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 0a5600d8

fs/overlayfs/copy_up.c

+11 −1
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ int ovl_copy_xattr(struct dentry *old, struct dentry *new) 
	ssize_t list_size, size, value_size = 0;

	char *buf, *name, *value = NULL;

	int uninitialized_var(error);

	size_t slen;



	if (!old->d_inode->i_op->getxattr ||

	    !new->d_inode->i_op->getxattr)
@@ -47,7 +48,16 @@ int ovl_copy_xattr(struct dentry *old, struct dentry *new) 
		goto out;

	}



	for (name = buf; name < (buf + list_size); name += strlen(name) + 1) {

	for (name = buf; list_size; name += slen) {

		slen = strnlen(name, list_size) + 1;



		/* underlying fs providing us with an broken xattr list? */

		if (WARN_ON(slen > list_size)) {

			error = -EIO;

			break;

		}

		list_size -= slen;



		if (ovl_is_private_xattr(name))

			continue;

retry: