From patchwork Thu Oct 3 11:58:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Derrick Stolee X-Patchwork-Id: 13820958 Received: from mail-ed1-f51.google.com (mail-ed1-f51.google.com [209.85.208.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 06A791B969 for ; Thu, 3 Oct 2024 11:58:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727956731; cv=none; b=PcyleYOkxF52EqPctaImeE4q4xSTZqt3Zyz8JVQc62T4APfdSb4FBBK5vhhMY7CkJ4rlNyIK9Exe7dadWd4L+7uzXsRlCeCRt5svnlqR6yF+Q1ykbiSqlSYSv5dhNYtHT/59uOmTXL+csnz+nX/OHYmuMI8ZdLgo9fm0LNb4uqI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727956731; c=relaxed/simple; bh=cSSONYwffILE9Zwm9D7dllDMUlkcRZZR4sVbgHtEVwQ=; h=Message-Id:In-Reply-To:References:From:Date:Subject:Content-Type: MIME-Version:To:Cc; b=PALlH3pEvcn7hltTTs0WXZBQsxKWMvOlqcsbTDFG9x0hX0PfkyudEceQGeCIGtwdl5Ak+z0ani6uvPKF0+hdHZgvkEls6I6/nK9dRNjdM4zhkkEuSSpB1e18D+NBeHLJW8S3qjVF+30Ldmzul6GzqxD1gcdbw7VTPFP0f6un6SM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=S9Gmq4MZ; arc=none smtp.client-ip=209.85.208.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="S9Gmq4MZ" Received: by mail-ed1-f51.google.com with SMTP id 4fb4d7f45d1cf-5c8af23a4fcso1085122a12.0 for ; Thu, 03 Oct 2024 04:58:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1727956728; x=1728561528; darn=vger.kernel.org; h=cc:to:mime-version:content-transfer-encoding:fcc:subject:date:from :references:in-reply-to:message-id:from:to:cc:subject:date :message-id:reply-to; bh=z+pJZ6fIL+kBWvYRwCGhv8uD94GYeNkvuaeGZxu4edg=; b=S9Gmq4MZjayxnmabffMzRja6J9DR03QNVVlA8UJ3rywlV9RiFHOI99IApWYV7o0xhx e0RX3ClxnJvm2JXNm9NoBKo9PGUw4rBKOM/79WB/mPaKRfKySHmwskVF2wRa4d4VuXBM KlfqwZ482qEtP6iW+BoPStGH3xMk88NwrPfK+gtU606MbRS8KauUuwsMjaavAkWf2yLA I9w+DQtR//yJnzQ2Nc7WTo+eGanilHU1p3K7r4p43z+c9yTKzBlnPmFopkTSOt8JeeQt 4IPlHYPrRmKnjHPuD2YBDzynv0TIUjoT6juRwPS7fX7ojy5AU2ReIQe4QMy8LkOl2sIa IpMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727956728; x=1728561528; h=cc:to:mime-version:content-transfer-encoding:fcc:subject:date:from :references:in-reply-to:message-id:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=z+pJZ6fIL+kBWvYRwCGhv8uD94GYeNkvuaeGZxu4edg=; b=dxamiufNuAA3K9Hp5dWQ+QGuaW3e1hIbew9JOEBjgay1JrkPDOMHA4a0MnwmdQaInI QTHQ7eLSxz/seGVXGF+w9kr70ZKUXmkKk9ruAQsM5zy/ceXXkOzMT8JHVChyXclNyeso JSqT1p4xRYOi5e60k2yQKB0I1tjS5/NuVXVBrStEd2lBz3ZmbyuxmGwULmW1NiFnnXrN 4JDVQpPvQw/s9y5ZZAYSr5PtRV8jYc+DjLaX8CQ7p3XrxwCMtGxUbJIxYs0qQg7pWYK1 bjKmXrvT6NP7hK8+dBK0sjcysc+JurrkQi/J4HtSngxh/ajpQYZGHrB/WHg/uKNFCAkk 1VUg== X-Gm-Message-State: AOJu0YyZtMlsc1HtSa9a/77+IzCJW5jF2MM5jvNQNQed+deoK40aiT0l HgGesWaYLU/wcSxRI/iBs7YwFu1xht8GH2fncEc4xxDPyYHxMtf82p5xMg== X-Google-Smtp-Source: AGHT+IGju7rO/prclquGNqzoIMjo9rMV1jcAWpCzV9mU99ckJl7Yy3ODFkbUuhPqqProgDw2lCHSvA== X-Received: by 2002:a05:6402:40d4:b0:5c8:8bde:a1d3 with SMTP id 4fb4d7f45d1cf-5c8b1b727bdmr4982317a12.22.1727956727913; Thu, 03 Oct 2024 04:58:47 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5c8ca4d6dcdsm629200a12.70.2024.10.03.04.58.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Oct 2024 04:58:46 -0700 (PDT) Message-Id: <05c21616c350b5141c17fde1aa5d3aea881c6031.1727956724.git.gitgitgadget@gmail.com> In-Reply-To: References: Date: Thu, 03 Oct 2024 11:58:42 +0000 Subject: [PATCH v2 1/3] line-log: protect inner strbuf from free Fcc: Sent Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 To: git@vger.kernel.org Cc: gitster@pobox.com, ps@pks.im, Jeff King , Derrick Stolee , Derrick Stolee From: Derrick Stolee From: Derrick Stolee The output_prefix() method in line-log.c may call a function pointer via the diff_options struct. This function pointer returns a strbuf struct and then its buffer is passed back. However, that implies that the consumer is responsible to free the string. This is especially true because the default behavior is to duplicate the empty string. The existing functions used in the output_prefix pointer include: 1. idiff_prefix_cb() in diff-lib.c. This returns the data pointer, so the value exists across multiple calls. 2. diff_output_prefix_callback() in graph.c. This uses a static strbuf struct, so it reuses buffers across calls. These should not be freed. 3. output_prefix_cb() in range-diff.c. This is similar to the diff-lib.c case. In each case, we should not be freeing this buffer. We can convert the output_prefix() function to return a const char pointer and stop freeing the result. This choice is essentially the opposite of what was done in 394affd46d (line-log: always allocate the output prefix, 2024-06-07). This was discovered via 'valgrind' while investigating a public report of a bug in 'git log --graph -L' [1]. [1] https://github.com/git-for-windows/git/issues/5185 This issue would have been caught by the new test, when Git is compiled with ASan to catch these double frees. Co-authored-by: Jeff King Signed-off-by: Jeff King Signed-off-by: Derrick Stolee --- line-log.c | 10 ++++------ t/t4211-line-log.sh | 28 ++++++++++++++++++++++++++++ 2 files changed, 32 insertions(+), 6 deletions(-) diff --git a/line-log.c b/line-log.c index 67c80b39a0d..29cf66bdd10 100644 --- a/line-log.c +++ b/line-log.c @@ -897,13 +897,13 @@ static void print_line(const char *prefix, char first, fputs("\\ No newline at end of file\n", file); } -static char *output_prefix(struct diff_options *opt) +static const char *output_prefix(struct diff_options *opt) { if (opt->output_prefix) { struct strbuf *sb = opt->output_prefix(opt, opt->output_prefix_data); return sb->buf; } else { - return xstrdup(""); + return ""; } } @@ -916,7 +916,7 @@ static void dump_diff_hacky_one(struct rev_info *rev, struct line_log_data *rang struct diff_ranges *diff = &range->diff; struct diff_options *opt = &rev->diffopt; - char *prefix = output_prefix(opt); + const char *prefix = output_prefix(opt); const char *c_reset = diff_get_color(opt->use_color, DIFF_RESET); const char *c_frag = diff_get_color(opt->use_color, DIFF_FRAGINFO); const char *c_meta = diff_get_color(opt->use_color, DIFF_METAINFO); @@ -1003,7 +1003,6 @@ static void dump_diff_hacky_one(struct rev_info *rev, struct line_log_data *rang out: free(p_ends); free(t_ends); - free(prefix); } /* @@ -1012,10 +1011,9 @@ out: */ static void dump_diff_hacky(struct rev_info *rev, struct line_log_data *range) { - char *prefix = output_prefix(&rev->diffopt); + const char *prefix = output_prefix(&rev->diffopt); fprintf(rev->diffopt.file, "%s\n", prefix); - free(prefix); while (range) { dump_diff_hacky_one(rev, range); diff --git a/t/t4211-line-log.sh b/t/t4211-line-log.sh index 02d76dca284..950451cf6a6 100755 --- a/t/t4211-line-log.sh +++ b/t/t4211-line-log.sh @@ -337,4 +337,32 @@ test_expect_success 'zero-width regex .* matches any function name' ' test_cmp expect actual ' +test_expect_success 'show line-log with graph' ' + qz_to_tab_space >expect <<-EOF && + * $head_oid Modify func2() in file.c + |Z + | diff --git a/file.c b/file.c + | --- a/file.c + | +++ b/file.c + | @@ -6,4 +6,4 @@ + | int func2() + | { + | - return F2; + | + return F2 + 2; + | } + * $root_oid Add func1() and func2() in file.c + ZZ + diff --git a/file.c b/file.c + --- /dev/null + +++ b/file.c + @@ -0,0 +6,4 @@ + +int func2() + +{ + + return F2; + +} + EOF + git log --graph --oneline -L:func2:file.c >actual && + test_cmp expect actual +' + test_done