From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756270AbdBPAmQ (ORCPT ); Wed, 15 Feb 2017 19:42:16 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52179 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752204AbdBOWvN (ORCPT ); Wed, 15 Feb 2017 17:51:13 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Miklos Szeredi" Date: Wed, 15 Feb 2017 22:41:34 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 038/126] fuse: listxattr: verify xattr list In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.85-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Miklos Szeredi commit cb3ae6d25a5471be62bfe6ac1fccc0e91edeaba0 upstream. Make sure userspace filesystem is returning a well formed list of xattr names (zero or more nonzero length, null terminated strings). [Michael Theall: only verify in the nonzero size case] Signed-off-by: Miklos Szeredi [bwh: Backported to 3.2: adjust context, indentation] Signed-off-by: Ben Hutchings --- --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -1536,6 +1536,23 @@ static ssize_t fuse_getxattr(struct dent return ret; } +static int fuse_verify_xattr_list(char *list, size_t size) +{ + size_t origsize = size; + + while (size) { + size_t thislen = strnlen(list, size); + + if (!thislen || thislen == size) + return -EIO; + + size -= thislen + 1; + list += thislen + 1; + } + + return origsize; +} + static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size) { struct inode *inode = entry->d_inode; @@ -1574,9 +1591,11 @@ static ssize_t fuse_listxattr(struct den } fuse_request_send(fc, req); ret = req->out.h.error; - if (!ret) + if (!ret) { ret = size ? req->out.args[0].size : outarg.size; - else { + if (ret > 0 && size) + ret = fuse_verify_xattr_list(list, ret); + } else { if (ret == -ENOSYS) { fc->no_listxattr = 1; ret = -EOPNOTSUPP;