From patchwork Thu Apr 1 08:32:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jeff King X-Patchwork-Id: 12177509 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35EC3C43460 for ; Thu, 1 Apr 2021 08:33:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E7FA361001 for ; Thu, 1 Apr 2021 08:33:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233605AbhDAIdA (ORCPT ); Thu, 1 Apr 2021 04:33:00 -0400 Received: from cloud.peff.net ([104.130.231.41]:39586 "EHLO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233509AbhDAIc0 (ORCPT ); Thu, 1 Apr 2021 04:32:26 -0400 Received: (qmail 7452 invoked by uid 109); 1 Apr 2021 08:32:25 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with ESMTP; Thu, 01 Apr 2021 08:32:24 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 12274 invoked by uid 111); 1 Apr 2021 08:32:25 -0000 Received: from coredump.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.2) by peff.net (qpsmtpd/0.94) with (TLS_AES_256_GCM_SHA384 encrypted) ESMTPS; Thu, 01 Apr 2021 04:32:25 -0400 Authentication-Results: peff.net; auth=none Date: Thu, 1 Apr 2021 04:32:24 -0400 From: Jeff King To: =?utf-8?b?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason Cc: Olga Telezhnaya , Junio C Hamano , git@vger.kernel.org, Taylor Blau , Elijah Newren , Johannes Schindelin Subject: [PATCH] ref-filter: fix NULL check for parse object failure Message-ID: References: <20210308200426.21824-1-avarab@gmail.com> <87k0pnkwej.fsf@evledraar.gmail.com> <87eefvkq5d.fsf@evledraar.gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Thu, Apr 01, 2021 at 03:54:56AM -0400, Jeff King wrote: > On Wed, Mar 31, 2021 at 10:46:22PM +0200, Ævar Arnfjörð Bjarmason wrote: > > > > Neither of those types is the correct one. And the segfault is just a > > > bonus! :) > > > > > > I'd expect similar cases with parsing commit parents and tree pointers. > > > And probably tree entries whose modes are wrong. > > > > So the segfault happens without my patches, > > Yeah, sorry if that was unclear. It is definitely a pre-existing bug. Here's a patch to fix it. This is mostly orthogonal to your patch series. It happens to use a similar recipe to reproduce, but that is not the only way to do it, and the fix and the test shouldn't conflict textually or semantically. -- >8 -- Subject: [PATCH] ref-filter: fix NULL check for parse object failure After we run parse_object_buffer() to get an object's contents, we try to check that the return value wasn't NULL. However, since our "struct object" is a pointer-to-pointer, and we assign like: *obj = parse_object_buffer(...); it's not correct to check: if (!obj) That will always be true, since our double pointer will continue to point to the single pointer (which is itself NULL). This is a regression that was introduced by aa46a0da30 (ref-filter: use oid_object_info() to get object, 2018-07-17); since that commit we'll segfault on a parse failure, as we try to look at the NULL object pointer. There are many ways a parse could fail, but most of them are hard to set up in the tests (it's easy to make a bogus object, but update-ref will refuse to point to it). The test here uses a tag which points to a wrong object type. A parse of just the broken tag object will succeed, but seeing both tag objects in the same process will lead to a parse error (since we'll see the pointed-to object as both types). Signed-off-by: Jeff King --- ref-filter.c | 2 +- t/t6300-for-each-ref.sh | 10 ++++++++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/ref-filter.c b/ref-filter.c index f0bd32f714..a0adb4551d 100644 --- a/ref-filter.c +++ b/ref-filter.c @@ -1608,7 +1608,7 @@ static int get_object(struct ref_array_item *ref, int deref, struct object **obj if (oi->info.contentp) { *obj = parse_object_buffer(the_repository, &oi->oid, oi->type, oi->size, oi->content, &eaten); - if (!obj) { + if (!*obj) { if (!eaten) free(oi->content); return strbuf_addf_ret(err, -1, _("parse_object_buffer failed on %s for %s"), diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh index cac7f443d0..2e7c32d50c 100755 --- a/t/t6300-for-each-ref.sh +++ b/t/t6300-for-each-ref.sh @@ -1134,4 +1134,14 @@ test_expect_success 'for-each-ref --ignore-case works on multiple sort keys' ' test_cmp expect actual ' +test_expect_success 'for-each-ref reports broken tags' ' + git tag -m "good tag" broken-tag-good HEAD && + git cat-file tag broken-tag-good >good && + sed s/commit/blob/ bad && + bad=$(git hash-object -w -t tag bad) && + git update-ref refs/tags/broken-tag-bad $bad && + test_must_fail git for-each-ref --format="%(*objectname)" \ + refs/tags/broken-tag-* +' + test_done