From patchwork Sat Jun 22 10:03:30 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Ren=C3=A9_Scharfe?= X-Patchwork-Id: 11011255 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 D187413AF for ; Sat, 22 Jun 2019 10:03:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C2FFA28BAF for ; Sat, 22 Jun 2019 10:03:40 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B77AB28BB3; Sat, 22 Jun 2019 10:03:40 +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=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,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 5884728BAF for ; Sat, 22 Jun 2019 10:03:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726287AbfFVKDj (ORCPT ); Sat, 22 Jun 2019 06:03:39 -0400 Received: from mout.web.de ([217.72.192.78]:53285 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726112AbfFVKDj (ORCPT ); Sat, 22 Jun 2019 06:03:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1561197811; bh=7X4HbrMkKGgcLrziqQKrS5CImUzlzOdTAfAcBIVgh80=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=UZbUuCTN0VO27YjEG2hzb++9TxUCNMm/oMQUjJGOaQ6sa313xq9a4wjovmYo2ybqL QA665C41p0VbYqMAhFrLfRavyFpKLFCtODhkf56Rcp3ngbu/DWHEeXwr1uXgo3MoGD wLPvf5LNMtfdgeWoDPrchwqClwaTJbnrAw9j6ANw= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from [192.168.178.23] ([79.203.26.169]) by smtp.web.de (mrweb101 [213.165.67.124]) with ESMTPSA (Nemesis) id 0LtFYd-1ic3Am0wvr-012rfu; Sat, 22 Jun 2019 12:03:31 +0200 Subject: [PATCH v2 1/3] config: use unsigned_mult_overflows to check for overflows To: Junio C Hamano Cc: Johannes Schindelin via GitGitGadget , git@vger.kernel.org, Johannes Schindelin References: <9613c88849e53e00e1f7ade49c6c9056309ef0b9.1560426581.git.gitgitgadget@gmail.com> <03a68560-8058-7436-6edb-38e276a37190@web.de> <90ef3797-78a6-f6d9-443b-387c0ab7cbe7@web.de> From: =?utf-8?q?Ren=C3=A9_Scharfe?= Message-ID: <7a580777-2ccc-6097-477a-e66eb28d5f9b@web.de> Date: Sat, 22 Jun 2019 12:03:30 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.1 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Provags-ID: V03:K1:Yy174peznYIIttcQKbfAFSfCbbvkew/9StB2Iy2J+GjaxoVC5wW DQYGzcg7Qv2zbO98RxrbVhATU3M/dWVxYRVSszXTz5eGTfjYJyoPcy+Dpa/Ulofrs5RqiS4 wd0qxNkPkCu2ssfFga6TmEn0f+hUIuYxe+0/Vruzdihc/TK4T4oHtpelRY9nqriYwgsCHqC 7/CCCAarR+HrcqaE6E7cw== X-UI-Out-Filterresults: notjunk:1;V03:K0:7RgEzeDvZaQ=:BdxMRriDL8rcdvlUqJbHfX iGrr3THvoOmIv6Ls80agdP4IZPHwcyAcr7PyTpYFIYMbFAJvDffAxyDRh8lcLreFINHd4Nj9H smDQmEzZmcWjn+rsS7fpYmCjDzyRm/rBuBEctIxzv6gAAd/+Vi000J1izFBDrKwSf3/zrgMec 393uG7674ruoEKkHk3runoDHMP1RgerhSVPBtRgckBrRj9FzfmS6+E+jzsibtHuO/+3ZgVpep reFh0sr6Sc3Nh58kZ82rSfLt3Jip8+kUkHnNmO9KAvZ02kIDkw4vo7tt7XbyxUoyMGxrc9Kf7 HKxs+IY3Wn12gsmcRq1sAahTP+jsB0EmdqC9ER18+9pbYZJCrVRwgkU3kpAqbN4Ov9Hmy+3py xsd21Pr/D5HICKviKJteElXqeaIxq4SIfChKxua6g9Y/NO7yNoaRbdWDLyydkNAJcEmIGtYbL pMSvhSy6a0PTe3xA8/81ffr76EOnP4lHp3KgMb/pyFhnO4C50XHp61UOKbPo8cSgyrKfcVq7M YaQw6FVKHf4vhwouUO28IKH9kh0gwOWUgEFRYKyPnlzazF192/vxBQ9NfgZylm+RAS3d0cbCI Xc8CjpR0XiksCxfcMQdSFEzPsACj95vwWuZNg0eq9We3ZUTy69nLbUxTXyjZIYWBLtPObGRz4 4hUlXYM8PztnYcE3S3HYphrtD9uu10p3lDShft1Tk4qPX1b4OcY6OXAX5y5epM9aT5B5W3df6 FECUcR/kETMQl6T4KPllWJd9paGzqTWv+GmnuVCNHDz7xOBZtuqPD6cIyY9p51AdLHcafamOg qGM1YQxTMbIRJBn0vWbAE9konOk32xX4GB8MIzETNMnRY9MOarHgv1vqU4w6Jp6UQciWstCL2 FPl+E210jhtV6RNef7GJGiF+oBxjTPvXXC9MoTnn1F+JLQIfeu2Jd6LAkVqzqHYwDJQoiaNLk InWckgYsQfvKMIIA+HfxRXcHMAu9b4rA= Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP parse_unit_factor() checks if a K, M or G is present after a number and multiplies it by 2^10, 2^20 or 2^30, respectively. One of its callers checks if the result is smaller than the number alone to detect overflows. The other one passes 1 as the number and does multiplication and overflow check itself in a similar manner. This works, but is inconsistent, and it would break if we added support for a bigger unit factor. E.g. 16777217T is 2^64 + 2^40, i.e. too big for a 64-bit number. Modulo 2^64 we get 2^40 == 1TB, which is bigger than the raw number 16777217 == 2^24 + 1, so the overflow would go undetected by that method. Let both callers pass 1 and handle overflow check and multiplication themselves. Do the check before the multiplication, using unsigned_mult_overflows, which is simpler and can deal with larger unit factors. Signed-off-by: Rene Scharfe --- Patch generated with --function-context for easier review (e.g. to see why we can stop updating uval in place). config.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) -- 2.22.0 diff --git a/config.c b/config.c index 01c6e9df23..3c00369ba8 100644 --- a/config.c +++ b/config.c @@ -856,29 +856,29 @@ static int parse_unit_factor(const char *end, uintmax_t *val) static int git_parse_signed(const char *value, intmax_t *ret, intmax_t max) { if (value && *value) { char *end; intmax_t val; uintmax_t uval; uintmax_t factor = 1; errno = 0; val = strtoimax(value, &end, 0); if (errno == ERANGE) return 0; if (!parse_unit_factor(end, &factor)) { errno = EINVAL; return 0; } uval = val < 0 ? -val : val; - uval *= factor; - if (uval > max || (val < 0 ? -val : val) > uval) { + if (unsigned_mult_overflows(factor, uval) || + factor * uval > max) { errno = ERANGE; return 0; } val *= factor; *ret = val; return 1; } errno = EINVAL; return 0; } @@ -886,26 +886,27 @@ static int git_parse_signed(const char *value, intmax_t *ret, intmax_t max) static int git_parse_unsigned(const char *value, uintmax_t *ret, uintmax_t max) { if (value && *value) { char *end; uintmax_t val; - uintmax_t oldval; + uintmax_t factor = 1; errno = 0; val = strtoumax(value, &end, 0); if (errno == ERANGE) return 0; - oldval = val; - if (!parse_unit_factor(end, &val)) { + if (!parse_unit_factor(end, &factor)) { errno = EINVAL; return 0; } - if (val > max || oldval > val) { + if (unsigned_mult_overflows(factor, val) || + factor * val > max) { errno = ERANGE; return 0; } + val *= factor; *ret = val; return 1; } errno = EINVAL; return 0; }