From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_NONE shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 4B1471F461 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-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable 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 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 =3D=3D 1TB, which is bigger than the raw number 16777217 =3D=3D 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 =2D-- 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(-) diff --git a/config.c b/config.c index 01c6e9df23..3c00369ba8 100644 =2D-- a/config.c +++ b/config.c @@ -856,29 +856,29 @@ static int parse_unit_factor(const char *end, uintma= x_t *val) static int git_parse_signed(const char *value, intmax_t *ret, intmax_t ma= x) { if (value && *value) { char *end; intmax_t val; uintmax_t uval; uintmax_t factor =3D 1; errno =3D 0; val =3D strtoimax(value, &end, 0); if (errno =3D=3D ERANGE) return 0; if (!parse_unit_factor(end, &factor)) { errno =3D EINVAL; return 0; } uval =3D val < 0 ? -val : val; - uval *=3D factor; - if (uval > max || (val < 0 ? -val : val) > uval) { + if (unsigned_mult_overflows(factor, uval) || + factor * uval > max) { errno =3D ERANGE; return 0; } val *=3D factor; *ret =3D val; return 1; } errno =3D EINVAL; return 0; } @@ -886,26 +886,27 @@ static int git_parse_signed(const char *value, intma= x_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 =3D 1; errno =3D 0; val =3D strtoumax(value, &end, 0); if (errno =3D=3D ERANGE) return 0; - oldval =3D val; - if (!parse_unit_factor(end, &val)) { + if (!parse_unit_factor(end, &factor)) { errno =3D EINVAL; return 0; } - if (val > max || oldval > val) { + if (unsigned_mult_overflows(factor, val) || + factor * val > max) { errno =3D ERANGE; return 0; } + val *=3D factor; *ret =3D val; return 1; } errno =3D EINVAL; return 0; } =2D- 2.22.0