From patchwork Thu May 2 07:05:11 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 2510371 Return-Path: X-Original-To: patchwork-linux-nfs@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 8EFC2DF215 for ; Thu, 2 May 2013 07:05:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751529Ab3EBHFX (ORCPT ); Thu, 2 May 2013 03:05:23 -0400 Received: from cantor2.suse.de ([195.135.220.15]:56810 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753754Ab3EBHFV (ORCPT ); Thu, 2 May 2013 03:05:21 -0400 Received: from relay1.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id E1C5FA341E; Thu, 2 May 2013 09:05:19 +0200 (CEST) Date: Thu, 2 May 2013 17:05:11 +1000 From: NeilBrown To: Steve Dickson Cc: NFS Subject: [PATCH] mountd: Fix is_subdirectory again. Message-ID: <20130502170511.646e2717@notabene.brown> X-Mailer: Claws Mail 3.9.0 (GTK+ 2.24.14; x86_64-suse-linux-gnu) Mime-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Hi Steve, I just noticed commit ebe2826ca571a3959c3b5c8e29686c621f2775cf Author: Steve Dickson Date: Sat Mar 23 10:30:17 2013 -0400 mountd: regression in crossmounts Sorry I missed the email you presumably sent me to let me know that I had caused a regression. Here is the proper fix. Thanks, NeilBrown Subject: [PATCH] mountd: Fix is_subdirectory again. commit ebe2826ca571a (mountd: regression in crossmounts) said it was: Reverting the logic of commit 8e2fb3fc until a better solution can be found for the original problem. here is the "something better". The problem was that is_subdirectory() would also succeed if the two directories were the same. This is needed for path_matches() which needs to see if the child is same-or-descendant. So this patch rearranges path_matches() to do the "are they the same" test itself and only bother with is_subdirectory() if it they are not the same. So now is_subdirectory() can be strict, and so can be usable for subexport(), which needs a strong 'in subdirectory - not the same' test. Signed-off-by: NeilBrown diff --git a/utils/mountd/cache.c b/utils/mountd/cache.c index 737927c..517aa62 100644 --- a/utils/mountd/cache.c +++ b/utils/mountd/cache.c @@ -347,20 +347,26 @@ static char *next_mnt(void **v, char *p) static int is_subdirectory(char *child, char *parent) { + /* Check is child is strictly a subdirectory of + * parent or a more distant descendant. + */ size_t l = strlen(parent); - if (strcmp(parent, "/") == 0) + if (strcmp(parent, "/") == 0 && child[1] != 0) return 1; - return strcmp(child, parent) == 0 - || (strncmp(child, parent, l) == 0 && child[l] == '/'); + return (strncmp(child, parent, l) == 0 && child[l] == '/'); } static int path_matches(nfs_export *exp, char *path) { - if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT) - return is_subdirectory(path, exp->m_export.e_path); - return strcmp(path, exp->m_export.e_path) == 0; + /* Does the path match the export? I.e. is it an + * exact match, or does the export have CROSSMOUNT, and path + * is a descendant? + */ + return strcmp(path, exp->m_export.e_path) == 0 + || ((exp->m_export.e_flags & NFSEXP_CROSSMOUNT) + && is_subdirectory(path, exp->m_export.e_path)); } static int @@ -369,15 +375,13 @@ export_matches(nfs_export *exp, char *dom, char *path, struct addrinfo *ai) return path_matches(exp, path) && client_matches(exp, dom, ai); } -/* True iff e1 is a child of e2 and e2 has crossmnt set: */ +/* True iff e1 is a child of e2 (or descendant) and e2 has crossmnt set: */ static bool subexport(struct exportent *e1, struct exportent *e2) { char *p1 = e1->e_path, *p2 = e2->e_path; - size_t l2 = strlen(p2); return e2->e_flags & NFSEXP_CROSSMOUNT - && strncmp(p1, p2, l2) == 0 - && p1[l2] == '/'; + && is_subdirectory(p1, p2); } struct parsed_fsid {