From patchwork Sat Apr 18 20:18:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Martin_=C3=85gren?= X-Patchwork-Id: 11496953 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B35A214DD for ; Sat, 18 Apr 2020 20:19:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9A717221F7 for ; Sat, 18 Apr 2020 20:19:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Y2OBHLmA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728283AbgDRUTQ (ORCPT ); Sat, 18 Apr 2020 16:19:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1727927AbgDRUTQ (ORCPT ); Sat, 18 Apr 2020 16:19:16 -0400 Received: from mail-lj1-x242.google.com (mail-lj1-x242.google.com [IPv6:2a00:1450:4864:20::242]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1EB8DC061A0C for ; Sat, 18 Apr 2020 13:19:16 -0700 (PDT) Received: by mail-lj1-x242.google.com with SMTP id z26so5685420ljz.11 for ; Sat, 18 Apr 2020 13:19:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=6jd9LgKzoOq+hd7wqtU/p8gY/rWBNQiwrdfRnY+o7Fk=; b=Y2OBHLmAU3tWHy8M7xlOTiYTQaYQn/OrgptlPoQApXwYPUlmtFjpqokwZah+iRCTgQ nYtkNJw7PEOScW1YggPw1yVB9KGcTrbp498k5u98PXRUCEdiKqUWXaCJljs8ZYq3nkLT eHx5KPEb3TB7AOwnPuuQJ1o6jDSnSQgi/Cnl4neWsb+qR2NfXEyUNHs9Jna6kChOeEP9 +5L3OmO3oYKWF5NMgO7NMM+eind1hdlitStMj3WdZtkiPnWzVABorPsPhaEFRVSNdkE9 F0pn+GCOE8In1kJuk9sCn3/bk+8+g5RmH455YxGgKqRlV80zycFgK2QisYCXzAa6hUnb lcFQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=6jd9LgKzoOq+hd7wqtU/p8gY/rWBNQiwrdfRnY+o7Fk=; b=T5B43l3+hoWuD4nmFZ5dK81zrwYUwenTkm09DuApX1Pc65WIpBoRLT+3ztbxiBU39O NmfobFqQjxZhTMeWiUQrNof3Eik3f+J4Goyjnu9rihNsoMhKusZJQtis5HOj/0GweG3j qHLxaDXuXXtjJzYAGPe+4jM+MhEKuaa3ecc4Tz8UdywsaQPszrebJ8cQoJBk83/fL4B5 BRjmhYx5UcTHSwwjghPe+QOd89LYeEO2MfDvi1X+3Z5rNsNUGqRcBhSZxV5iymI9jfKx y3914kBI/pF50iXxy1VAsIwDUFIlhAVpRsZbQCA2k6t1t0GtodAQdP0p8XBUbyuhj91A MEnw== X-Gm-Message-State: AGi0PuaMgGsTKlXdUaAvcCJTlcRBo0GuCUD4KByzPrYx2f9dUl51cmen f8+8iBVlivBDJv1fmX9dHGCPX2EF X-Google-Smtp-Source: APiQypLcmME2E5SJTKEKTNxgyU9jnUI99uy8BhDLulESS06LWIdOi79AJuufWeVzg0DBGLB6xjkRoQ== X-Received: by 2002:a2e:95d2:: with SMTP id y18mr1116762ljh.65.1587241154428; Sat, 18 Apr 2020 13:19:14 -0700 (PDT) Received: from localhost.localdomain (31-211-229-121.customers.ownit.se. [31.211.229.121]) by smtp.gmail.com with ESMTPSA id 73sm218713ljj.72.2020.04.18.13.19.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 18 Apr 2020 13:19:13 -0700 (PDT) From: =?utf-8?q?Martin_=C3=85gren?= To: git@vger.kernel.org Cc: =?utf-8?b?xJBvw6BuIFRy4bqnbiBDw7RuZyBEYW5o?= Subject: [PATCH 5/6] rerere: avoid awkward use of `strbuf_attach()` Date: Sat, 18 Apr 2020 22:18:28 +0200 Message-Id: X-Mailer: git-send-email 2.26.1 In-Reply-To: References: MIME-Version: 1.0 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Similar to the previous commit, avoid passing `strbuf_attach()` the same value for `len` and `alloc` by switching to `strbuf_add()`. This avoids a subtle allocate+copy+free dance in favour of a much more obvious one. Unlike in the previous commit, for this site, I know that it's not safe to pass in "len, len + 1". Trying that makes `strbuf_attach()` write a trailing '\0' at `result.ptr[len]`. Running our test suite with AddressSanitizer will spot an out-of-bounds write due to this. Signed-off-by: Martin Ågren --- rerere.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/rerere.c b/rerere.c index 9281131a9f..c3e3714824 100644 --- a/rerere.c +++ b/rerere.c @@ -1007,7 +1007,8 @@ static int handle_cache(struct index_state *istate, else io.io.output = NULL; strbuf_init(&io.input, 0); - strbuf_attach(&io.input, result.ptr, result.size, result.size); + strbuf_add(&io.input, result.ptr, result.size); + free(result.ptr); /* * Grab the conflict ID and optionally write the original