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=-8.8 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,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 C24A3C6787C for ; Sun, 14 Oct 2018 13:25:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 84BC220835 for ; Sun, 14 Oct 2018 13:25:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=brauner.io header.i=@brauner.io header.b="bC61NBjp" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 84BC220835 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=brauner.io Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726520AbeJNVGu (ORCPT ); Sun, 14 Oct 2018 17:06:50 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:44450 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726129AbeJNVGp (ORCPT ); Sun, 14 Oct 2018 17:06:45 -0400 Received: by mail-wr1-f65.google.com with SMTP id 63-v6so18147064wra.11 for ; Sun, 14 Oct 2018 06:25:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=brauner.io; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=7rk7nET3rv10X6UFsonWmDDg5xB784tUbjvoqunsV1U=; b=bC61NBjpubeR1t2BHtLf6u7vBS2c2uAKUFPOXNeJcWWGxLhyzDeNU+CKO1KFA+02vF IYgxVqBLtyYH0885nGhUPqJF8OytCihpVwWKdHyF2alj4dIVSJIw7QMeUAmBjhhxsvIC nsl+O589NrYlwBohdFQL8n9abH8fxnepmQrrolqgCd7L+YQDB5vJ4aUAZfzVWjkpyISz P2ssvY/r9odnbhDltLHe9smwSRMkRYTOCFaSIzHJZ3Yx+MypSjQU9Z78WTaN8S7H2ceu tqOAuRWFSZlAJLvJTIJhX+7bGJn3QEER8XESBik7/s+OgfjAJyze28zJBhnIJ6oiGHVa 23qw== 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; bh=7rk7nET3rv10X6UFsonWmDDg5xB784tUbjvoqunsV1U=; b=XpnvT0WEhie5633kHmXHIJM5gNxQYsqrc8BWCztftFtiv2IAVxIal8hEZszT+UfSPi l2H3hysMFh0GhwvkudPHb2/21sT4O93jrfpE/9g/QY1V7jJBEK01JKPw39IVv02pgw0V IuGweb3Q61tUUSF040eqMgHwYRLjbzdGghDji0OowuABYWm2I1qxh0hYX8bPpfO679yV 5edWoUKie/eJM4fnfYfBUDr9FMRsirXlsMJHM29LtPsfPqQ7pp31VvtCdkPQJjm5Kb9a U1PWIU0gg+y+hZOAmD8eeK1aqXFHygIbYh17nJd++iTx5hBOXSkuqejIHv2djpdtJoNv oX/A== X-Gm-Message-State: ABuFfoiqX/yy8QUlQJXBx6dllBwm0RMe3v88Mt1P6LaFtMWHpCmZTiJQ R0EXDn6yHtq8TbRAR/Hq19J+j6s9tyOMLw== X-Google-Smtp-Source: ACcGV60AokLTp3hpH5XKLDT34TuMDIzU2+cvL/Q06XQ7Odiy2UO/mtzYUcqANb44G84tffQclkXo0A== X-Received: by 2002:adf:a481:: with SMTP id g1-v6mr12117458wrb.167.1539523543894; Sun, 14 Oct 2018 06:25:43 -0700 (PDT) Received: from localhost.localdomain ([2a02:8070:8895:9700:8197:8849:535a:4f00]) by smtp.gmail.com with ESMTPSA id a11-v6sm10550050wrp.3.2018.10.14.06.25.42 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 14 Oct 2018 06:25:43 -0700 (PDT) From: Christian Brauner To: keescook@chromium.org, linux-kernel@vger.kernel.org Cc: ebiederm@xmission.com, mcgrof@kernel.org, akpm@linux-foundation.org, joe.lawrence@redhat.com, longman@redhat.com, Christian Brauner Subject: [PATCH 2/2] sysctl: handle overflow for file-max Date: Sun, 14 Oct 2018 15:25:10 +0200 Message-Id: <20181014132510.25943-3-christian@brauner.io> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181014132510.25943-1-christian@brauner.io> References: <20181014132510.25943-1-christian@brauner.io> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, when writing echo 18446744073709551616 > /proc/sys/fs/file-max /proc/sys/fs/file-max will overflow and be set to 0. That quickly crashes the system. Let's detect the overflow and set to ULONG_MAX in this case effectively capping the value. Cc: Kees Cook Signed-off-by: Christian Brauner --- kernel/sysctl.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index a9409375380c..a3e4321b8ffa 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -127,6 +127,7 @@ static int __maybe_unused one = 1; static int __maybe_unused two = 2; static int __maybe_unused four = 4; static unsigned long one_ul = 1; +static unsigned long ulong_max = ULONG_MAX; static int one_hundred = 100; static int one_thousand = 1000; #ifdef CONFIG_PRINTK @@ -1696,6 +1697,7 @@ static struct ctl_table fs_table[] = { .maxlen = sizeof(files_stat.max_files), .mode = 0644, .proc_handler = proc_doulongvec_minmax, + .extra2 = &ulong_max, }, { .procname = "nr_open", @@ -2789,17 +2791,20 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int unsigned long val; if (write) { - bool neg; + bool neg, overflow; left -= proc_skip_spaces(&p); err = proc_get_long(&p, &left, &val, &neg, proc_wspace_sep, - sizeof(proc_wspace_sep), NULL); + sizeof(proc_wspace_sep), NULL, + &overflow); if (err) break; if (neg) continue; + if (overflow && max) + val = *max; val = convmul * val / convdiv; if ((min && val < *min) || (max && val > *max)) continue; -- 2.17.1