From patchwork Fri Jun 19 17:55:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "brian m. carlson" X-Patchwork-Id: 11614851 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 E29E213A0 for ; Fri, 19 Jun 2020 17:57:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C8EC720776 for ; Fri, 19 Jun 2020 17:57:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (3072-bit key) header.d=crustytoothpaste.net header.i=@crustytoothpaste.net header.b="ou+MNh76" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2436519AbgFSR5Z (ORCPT ); Fri, 19 Jun 2020 13:57:25 -0400 Received: from injection.crustytoothpaste.net ([192.241.140.119]:39624 "EHLO injection.crustytoothpaste.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404749AbgFSR4q (ORCPT ); Fri, 19 Jun 2020 13:56:46 -0400 Received: from camp.crustytoothpaste.net (unknown [IPv6:2001:470:b978:101:7d4e:cde:7c41:71c2]) (using TLSv1.2 with cipher ECDHE-RSA-CHACHA20-POLY1305 (256/256 bits)) (No client certificate requested) by injection.crustytoothpaste.net (Postfix) with ESMTPSA id B6F4160A5E; Fri, 19 Jun 2020 17:56:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=crustytoothpaste.net; s=default; t=1592589375; bh=VRoONdvcbARP5+3wr28J+/lkAxkxEY4gUpFmTPvhqlU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From:Reply-To: Subject:Date:To:CC:Resent-Date:Resent-From:Resent-To:Resent-Cc: In-Reply-To:References:Content-Type:Content-Disposition; b=ou+MNh767hw6VmhymtyGEFb+BR67zJBGeu+mU4sAe367aFxImUuxQgm4Hwrnyemnb PpmbcwS53G2c9jE4CoC5qSutoaJtLJh8HMVtqdP7bN0gpbhc0n14Xt3zSBapUsB+aK vGNnEx1zLWTDyIDZTe3o3sERqktXGFeiedt8SqMc/GwIXWJgK3uJV6yWFkvZ8z3PF6 zv27MM6Q9e1EczuXamTdTqRqpXGr6mBg/FFKH9X6vytRzPHXzOpPjnhG08+fCMbn+H nbIHYnx2kszV/yKeP2yBOZTxDiSyK4ChOyxWCa5qrgKWJ5Y/EOCYA2cRE+zr49pSoG caivI5+PHuaibEsxZS51JneVgsfK1kd95uGNL9bOCr/CFzMI4mLH+CpGNrV0KPigVi SnrcccuAOIwHqiaPuftqsDp/yT5zBHccg5g9NpYnL2DV4V/pGXUVz+6jbDlZWRlcSD ytG49RIDcjsdNKZSSHYUbUcVJPpKYu4UlsKxJbDhvegYzES6Q/p From: "brian m. carlson" To: Cc: Junio C Hamano , =?utf-8?q?Martin_=C3=85gren?= Subject: [PATCH v3 04/44] wrapper: add function to compare strings with different NUL termination Date: Fri, 19 Jun 2020 17:55:21 +0000 Message-Id: <20200619175601.569856-5-sandals@crustytoothpaste.net> X-Mailer: git-send-email 2.27.0.278.ge193c7cf3a9 In-Reply-To: <20200619175601.569856-1-sandals@crustytoothpaste.net> References: <20200513005424.81369-1-sandals@crustytoothpaste.net> <20200619175601.569856-1-sandals@crustytoothpaste.net> MIME-Version: 1.0 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org When parsing capabilities for the pack protocol, there are times we'll want to compare the value of a capability to a NUL-terminated string. Since the data we're reading will be space-terminated, not NUL-terminated, we need a function that compares the two strings, but also checks that they're the same length. Otherwise, if we used strncmp to compare these strings, we might accidentally accept a parameter that was a prefix of the expected value. Add a function, xstrncmpz, that takes a NUL-terminated string and a non-NUL-terminated string, plus a length, and compares them, ensuring that they are the same length. Signed-off-by: brian m. carlson --- git-compat-util.h | 6 ++++++ wrapper.c | 8 ++++++++ 2 files changed, 14 insertions(+) diff --git a/git-compat-util.h b/git-compat-util.h index a73632e8e4..5637114b8d 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -868,6 +868,12 @@ char *xgetcwd(void); FILE *fopen_for_writing(const char *path); FILE *fopen_or_warn(const char *path, const char *mode); +/* + * Like strncmp, but only return zero if s is NUL-terminated and exactly len + * characters long. If it is not, consider it greater than t. + */ +int xstrncmpz(const char *s, const char *t, size_t len); + /* * FREE_AND_NULL(ptr) is like free(ptr) followed by ptr = NULL. Note * that ptr is used twice, so don't pass e.g. ptr++. diff --git a/wrapper.c b/wrapper.c index 3a1c0e0526..4ff4a9c3db 100644 --- a/wrapper.c +++ b/wrapper.c @@ -105,6 +105,14 @@ char *xstrndup(const char *str, size_t len) return xmemdupz(str, p ? p - str : len); } +int xstrncmpz(const char *s, const char *t, size_t len) +{ + int res = strncmp(s, t, len); + if (res) + return res; + return s[len] == '\0' ? 0 : 1; +} + void *xrealloc(void *ptr, size_t size) { void *ret;