From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D4C11C282C4 for ; Thu, 7 Feb 2019 12:35:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A154121917 for ; Thu, 7 Feb 2019 12:35:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=bewilderbeest.net header.i=@bewilderbeest.net header.b="opJMkZ81" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727132AbfBGMfV (ORCPT ); Thu, 7 Feb 2019 07:35:21 -0500 Received: from thorn.bewilderbeest.net ([71.19.156.171]:33673 "EHLO thorn.bewilderbeest.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726561AbfBGMfV (ORCPT ); Thu, 7 Feb 2019 07:35:21 -0500 Received: from hatter.bewilderbeest.net (hatter.bewilderbeest.net [IPv6:2001:470:c3f4:1::1:1]) (using TLSv1.2 with cipher DHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: zev) by thorn.bewilderbeest.net (Postfix) with ESMTPSA id 5FA6D8053A; Thu, 7 Feb 2019 04:35:19 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 thorn.bewilderbeest.net 5FA6D8053A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bewilderbeest.net; s=thorn; t=1549542919; bh=xVX06y1LKMu5NfBzZAvl9SlvAUxKIpLVfzCNS4mE4yw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=opJMkZ815m+5zeE2hkaDj5/sHI2JXMafvcWDMTFH4jh/E/+zN5ZRG7tEjYRWrG+k9 +OhACV0TAT+qHG16DcMdXB3yj9aea27a0Wk0TC0BN39MKeG+ix5gY363su40qjRDXa t4rs0kEFfIE/QKrVDZY3UvnnzCLONLcioSoEDwtM= From: Zev Weiss To: Luis Chamberlain , Kees Cook Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , yzaikin@google.com, brendanhiggins@google.com, Zev Weiss Subject: [PATCH v2 3/3] kernel/sysctl.c: define minmax conv functions in terms of non-minmax versions Date: Thu, 7 Feb 2019 06:34:26 -0600 Message-Id: <20190207123426.9202-4-zev@bewilderbeest.net> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190207123426.9202-1-zev@bewilderbeest.net> References: <20190206195807.GG11489@garbanzo.do-not-panic.com> <20190207123426.9202-1-zev@bewilderbeest.net> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org do_proc_do[u]intvec_minmax_conv() had included open-coded versions of do_proc_do[u]intvec_conv(); the duplication led to buggy inconsistencies (missing range checks). To reduce the likelihood of such problems in the future, we can instead refactor both to be defined in terms of their non-bounded counterparts (plus the added check). Signed-off-by: Zev Weiss --- kernel/sysctl.c | 59 ++++++++++++++++++++++--------------------------- 1 file changed, 27 insertions(+), 32 deletions(-) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index a71c4b3935bc..4b6bce36737e 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2562,32 +2562,26 @@ static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp, int *valp, int write, void *data) { + int tmp, ret; struct do_proc_dointvec_minmax_conv_param *param = data; + + /* + * If writing, first do so via a temporary local int so we can + * bounds-check it before touching *valp. + */ + int *ip = write ? &tmp : valp; + + ret = do_proc_dointvec_conv(negp, lvalp, ip, write, data); + if (ret) + return ret; + if (write) { - int val; - if (*negp) { - if (*lvalp > (unsigned long) INT_MAX + 1) - return -EINVAL; - val = -*lvalp; - } else { - if (*lvalp > (unsigned long) INT_MAX) - return -EINVAL; - val = *lvalp; - } - if ((param->min && *param->min > val) || - (param->max && *param->max < val)) + if ((param->min && *param->min > tmp) || + (param->max && *param->max < tmp)) return -EINVAL; - *valp = val; - } else { - int val = *valp; - if (val < 0) { - *negp = true; - *lvalp = -(unsigned long)val; - } else { - *negp = false; - *lvalp = (unsigned long)val; - } + *valp = tmp; } + return 0; } @@ -2636,22 +2630,23 @@ static int do_proc_douintvec_minmax_conv(unsigned long *lvalp, unsigned int *valp, int write, void *data) { + int ret; + unsigned int tmp; struct do_proc_douintvec_minmax_conv_param *param = data; - if (write) { - unsigned int val = *lvalp; + /* write via temporary local uint for bounds-checking */ + unsigned int *up = write ? &tmp : valp; - if (*lvalp > UINT_MAX) - return -EINVAL; + ret = do_proc_douintvec_conv(lvalp, up, write, data); + if (ret) + return ret; - if ((param->min && *param->min > val) || - (param->max && *param->max < val)) + if (write) { + if ((param->min && *param->min > tmp) || + (param->max && *param->max < tmp)) return -ERANGE; - *valp = val; - } else { - unsigned int val = *valp; - *lvalp = (unsigned long) val; + *valp = tmp; } return 0; -- 2.20.1