From patchwork Wed Apr 10 02:13:14 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Taylor Blau X-Patchwork-Id: 10892939 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8D4E717E1 for ; Wed, 10 Apr 2019 02:13:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 75ADD285A4 for ; Wed, 10 Apr 2019 02:13:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6A418289C4; Wed, 10 Apr 2019 02:13:19 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BE7C8285A4 for ; Wed, 10 Apr 2019 02:13:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727178AbfDJCNR (ORCPT ); Tue, 9 Apr 2019 22:13:17 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:32976 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726532AbfDJCNR (ORCPT ); Tue, 9 Apr 2019 22:13:17 -0400 Received: by mail-pl1-f195.google.com with SMTP id t16so399677plo.0 for ; Tue, 09 Apr 2019 19:13:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ttaylorr-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=184R+gIqcEZHsADEqxOOSCWhDR9lJDz8+T+aZFKddmI=; b=SjSo8ARAs9TycQU62bvePVV2D58RIN+S7i7Ajg3ozrNMLUFB0Zhrzd2V73kBr51XY8 gQIlHnaULotzUMePW4BS1QQtU9qmNSrsmm5CXq6Sqr8y311Vdb9EalOVf+iMDXLZImul p7q2zn2iwUqH9d24h4FS/pSRq9uwqUQWcK0VqcQSTpEN6uBd4Jw5vZF3o6j70+QWfBcP gXLt6TMh+5LMhov6yiiG1s1ACfm7xNd46iJaN5iX371kgEoJt2m47C1oFHNPqLh/R8cA ihJ30tD2QHHFIEqQQY1fyIh25kdbQKiO4cBFpdWgouEspENCHQ1qQMF1K7gxjn5+SUwX PAPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=184R+gIqcEZHsADEqxOOSCWhDR9lJDz8+T+aZFKddmI=; b=jA0G2yGHAd61mhtZsaELJxCZRWMkdY7XL/fm1zXRLoYzo9678X3KEhHn4kBH2gzME/ FAAl8eAteKaYZGTzx7GZfeHFqFfjHngCGIp5ngvzMGzutMe6euBCKgLvcP+huJBFIW/Z zb1gy04Q8lMDIWeaIAsJSu5Qv9uBbehysxschQvtBAJAeQvkJUoIXqQOfil/eief5z/e 2yLfFiCXDwDpkKFxtC+bkV5AkPXNmQLWE7hVfwRqRBGC3XtdP7hrxfLvCzBQdZFAHLX3 W6fNW2EdBZvwhajZ86AH9QmcvlRCOrOjxLmlzsBAGKSZW9vAXwN5u7L8vbNuNsIhavV/ eg0w== X-Gm-Message-State: APjAAAVNyb4PwmBGioN6RqGZ/QJCgD0abCTNssh7kdm7LySDoSmYa3/i wR99TEa9hPa7/7O7cTDl2Fs7X/ngXJTAjZdR X-Google-Smtp-Source: APXvYqwlUG0L6S/Bl1klis8HMrM0wjGbChnWjQLGtdASKAi1/WyzNiLHIKmyIijIGLN998SHvE9jug== X-Received: by 2002:a17:902:31c3:: with SMTP id x61mr39412727plb.143.1554862395886; Tue, 09 Apr 2019 19:13:15 -0700 (PDT) Received: from localhost ([2601:602:9200:32b0:c47d:9491:9418:887]) by smtp.gmail.com with ESMTPSA id k10sm22966695pgo.82.2019.04.09.19.13.15 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 09 Apr 2019 19:13:15 -0700 (PDT) Date: Tue, 9 Apr 2019 19:13:14 -0700 From: Taylor Blau To: git@vger.kernel.org Cc: avarab@gmail.com, gitster@pobox.com, peff@peff.net, sunshine@sunshineco.com, szeder.dev@gmail.com Subject: [PATCH v2 2/7] t: introduce tests for unexpected object types Message-ID: <137e2df24d80f796675691e57d08948b6eede6e3.1554861974.git.me@ttaylorr.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.4 (2019-03-13) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Call an object's type "unexpected" when the actual type of an object does not match Git's contextual expectation. For example, a tree entry whose mode differs from the object's actual type, or a commit's parent which is not another commit, and so on. This can manifest itself in various unfortunate ways, including Git SIGSEGV-ing under specific conditions. Consider the following example: Git traverses a blob (say, via `git rev-list`), and then tries to read out a tree-entry which lists that object as something other than a blob. In this case, `lookup_blob()` will return NULL, and the subsequent dereference will result in a SIGSEGV. Introduce tests that present objects of "unexpected" type in the above fashion to 'git rev-list'. Mark as failures the combinations that are already broken (i.e., they exhibit the segfault described above). In the cases that are not broken (i.e., they have NULL-ness checks or similar), mark these as expecting success. We might hit an unexpected type in two different ways (imagine we have a tree entry that claims to be a tree but actually points to a blob): - when we call lookup_tree(), we might find that we've already seen the object referenced as a blob, in which case we'd get NULL. We can exercise this with "git rev-list --objects $blob $tree", which guarantees that the blob will have been parsed before we look in the tree. These tests are marked as "seen" in the test script. - we call lookup_tree() successfully, but when we try to read the object, we find out it's something else. We construct our tests such that $blob is not otherwise mentioned in $tree. These tests are marked as "lone" in the script. We should check that we behave sensibly in both cases (especially because it is easy for a malicious actor to provoke one case or the other). Co-authored-by: Jeff King Signed-off-by: Taylor Blau Signed-off-by: Jeff King --- t/t6102-rev-list-unexpected-objects.sh | 123 +++++++++++++++++++++++++ 1 file changed, 123 insertions(+) create mode 100755 t/t6102-rev-list-unexpected-objects.sh diff --git a/t/t6102-rev-list-unexpected-objects.sh b/t/t6102-rev-list-unexpected-objects.sh new file mode 100755 index 0000000000..15072ecce3 --- /dev/null +++ b/t/t6102-rev-list-unexpected-objects.sh @@ -0,0 +1,123 @@ +#!/bin/sh + +test_description='git rev-list should handle unexpected object types' + +. ./test-lib.sh + +test_expect_success 'setup well-formed objects' ' + blob="$(printf "foo" | git hash-object -w --stdin)" && + tree="$(printf "100644 blob $blob\tfoo" | git mktree)" && + commit="$(git commit-tree $tree -m "first commit")" && + git cat-file commit $commit >good-commit +' + +test_expect_success 'setup unexpected non-blob entry' ' + printf "100644 foo\0$(echo $tree | hex2oct)" >broken-tree && + broken_tree="$(git hash-object -w --literally -t tree broken-tree)" +' + +test_expect_failure 'traverse unexpected non-blob entry (lone)' ' + test_must_fail git rev-list --objects $broken_tree +' + +test_expect_failure 'traverse unexpected non-blob entry (seen)' ' + test_must_fail git rev-list --objects $tree $broken_tree +' + +test_expect_success 'setup unexpected non-tree entry' ' + printf "40000 foo\0$(echo $blob | hex2oct)" >broken-tree && + broken_tree="$(git hash-object -w --literally -t tree broken-tree)" +' + +test_expect_failure 'traverse unexpected non-tree entry (lone)' ' + test_must_fail git rev-list --objects $broken_tree +' + +test_expect_failure 'traverse unexpected non-tree entry (seen)' ' + test_must_fail git rev-list --objects $blob $broken_tree +' + +test_expect_success 'setup unexpected non-commit parent' ' + sed "/^author/ { h; s/.*/parent $blob/; G; }" broken-commit && + broken_commit="$(git hash-object -w --literally -t commit \ + broken-commit)" +' + +test_expect_success 'traverse unexpected non-commit parent (lone)' ' + test_must_fail git rev-list --objects $broken_commit >output 2>&1 && + test_i18ngrep "not a commit" output +' + +test_expect_success 'traverse unexpected non-commit parent (seen)' ' + test_must_fail git rev-list --objects $commit $broken_commit \ + >output 2>&1 && + test_i18ngrep "not a commit" output +' + +test_expect_success 'setup unexpected non-tree root' ' + sed -e "s/$tree/$blob/" broken-commit && + broken_commit="$(git hash-object -w --literally -t commit \ + broken-commit)" +' + +test_expect_failure 'traverse unexpected non-tree root (lone)' ' + test_must_fail git rev-list --objects $broken_commit +' + +test_expect_failure 'traverse unexpected non-tree root (seen)' ' + test_must_fail git rev-list --objects $blob $broken_commit +' + +test_expect_success 'setup unexpected non-commit tag' ' + git tag -a -m "tagged commit" tag $commit && + git cat-file tag tag >good-tag && + test_when_finished "git tag -d tag" && + sed -e "s/$commit/$blob/" broken-tag && + tag=$(git hash-object -w --literally -t tag broken-tag) +' + +test_expect_success 'traverse unexpected non-commit tag (lone)' ' + test_must_fail git rev-list --objects $tag +' + +test_expect_success 'traverse unexpected non-commit tag (seen)' ' + test_must_fail git rev-list --objects $blob $tag >output 2>&1 && + test_i18ngrep "not a commit" output +' + +test_expect_success 'setup unexpected non-tree tag' ' + git tag -a -m "tagged tree" tag $tree && + git cat-file tag tag >good-tag && + test_when_finished "git tag -d tag" && + sed -e "s/$tree/$blob/" broken-tag && + tag=$(git hash-object -w --literally -t tag broken-tag) +' + +test_expect_success 'traverse unexpected non-tree tag (lone)' ' + test_must_fail git rev-list --objects $tag +' + +test_expect_success 'traverse unexpected non-tree tag (seen)' ' + test_must_fail git rev-list --objects $blob $tag >output 2>&1 && + test_i18ngrep "not a tree" output +' + +test_expect_success 'setup unexpected non-blob tag' ' + git tag -a -m "tagged blob" tag $blob && + git cat-file tag tag >good-tag && + test_when_finished "git tag -d tag" && + sed -e "s/$blob/$commit/" broken-tag && + tag=$(git hash-object -w --literally -t tag broken-tag) +' + +test_expect_failure 'traverse unexpected non-blob tag (lone)' ' + test_must_fail git rev-list --objects $tag +' + +test_expect_success 'traverse unexpected non-blob tag (seen)' ' + test_must_fail git rev-list --objects $commit $tag >output 2>&1 && + test_i18ngrep "not a blob" output +' + +test_done