From patchwork Wed May 12 12:52:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marcelo Henrique Cerri X-Patchwork-Id: 12253533 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 9C9C5C433B4 for ; Wed, 12 May 2021 12:54:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6434F613CA for ; Wed, 12 May 2021 12:54:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233645AbhELMz6 (ORCPT ); Wed, 12 May 2021 08:55:58 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:56942 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230385AbhELMxx (ORCPT ); Wed, 12 May 2021 08:53:53 -0400 Received: from mail-qv1-f71.google.com ([209.85.219.71]) by youngberry.canonical.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1lgoLz-0004WT-8z for linux-fsdevel@vger.kernel.org; Wed, 12 May 2021 12:52:43 +0000 Received: by mail-qv1-f71.google.com with SMTP id s15-20020a0cdc0f0000b02901e9373e40e2so7443354qvk.17 for ; Wed, 12 May 2021 05:52:43 -0700 (PDT) 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:mime-version :content-transfer-encoding; bh=JdJWPsLAfKdSrlcJXApgGOgu0SgFC1Lxu+sFe1F8Mh4=; b=WeydyXcG2OU0orhG7MijSV+JcLZPX9DU070av8xHwSJTtAIAbjLSCIKbK8HXAOkQ/+ K7F9pQaRXDvOwUJWWB6EUD+kMToxZ7O/lyKcWkEclvMKT10r1URCOin4iE7zZNo05CKU bw4/3obCEFqJfnDmdaPyMbS9gBu5hAu6xlxqB3l/rBbPxVEXzCKFDeKsbdxxkHBiwlDQ jv2nmXZmQzx2PEVe5Op2Q8h/ARG3XnohYcoCK6Dc2SdKLrhgLws5tidXtgGu9YRPA0du CZX+9C3Iowc4+Ppadq2+cmB9ryymuyvqbiAaRVfnnlaE5PqN6rnK+d0eXsj+LsL1pKDH Ji6Q== X-Gm-Message-State: AOAM533pdgjk8zGnwM5kPVOf8iEEX73Lx0x56iaw57ELzbfuNxQOvfVU H/xcK6qpmCbZaQDUZ7ESiEWQywazukp7UHagZaBT95iLiPDPaq189qio8eqbdz7JUIPd2ggAeCo 1NYec9BThom37em3jMWBeHU4b3Bndze4o1f5vMHeiTg== X-Received: by 2002:a05:622a:486:: with SMTP id p6mr33319009qtx.98.1620823962013; Wed, 12 May 2021 05:52:42 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwuqjEQEtmFz73vd/icEA1cwnnEhbXyEvzkiSraOE0deF0dDap5hbBWAE60w5hReydESlh81A== X-Received: by 2002:a05:622a:486:: with SMTP id p6mr33318983qtx.98.1620823961725; Wed, 12 May 2021 05:52:41 -0700 (PDT) Received: from valinor.lan ([177.76.120.156]) by smtp.gmail.com with ESMTPSA id f16sm2947074qtv.82.2021.05.12.05.52.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 May 2021 05:52:41 -0700 (PDT) From: Marcelo Henrique Cerri To: linux-fsdevel@vger.kernel.org Cc: Marcelo Henrique Cerri , David Disseldorp , Thadeu Lima de Souza Cascardo , Alexey Dobriyan , Andrew Morton , Christian Brauner , Michel Lespinasse , Helge Deller , Oleg Nesterov , Lorenzo Stoakes , linux-kernel@vger.kernel.org Subject: [PATCH] proc: Avoid mixing integer types in mem_rw() Date: Wed, 12 May 2021 09:52:12 -0300 Message-Id: <20210512125215.3348316-1-marcelo.cerri@canonical.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Use size_t when capping the count argument received by mem_rw(). Since count is size_t, using min_t(int, ...) can lead to a negative value that will later be passed to access_remote_vm(), which can cause unexpected behavior. Since we are capping the value to at maximum PAGE_SIZE, the conversion from size_t to int when passing it to access_remote_vm() as "len" shouldn't be a problem. Reviewed-by: David Disseldorp Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Marcelo Henrique Cerri --- fs/proc/base.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 3851bfcdba56..8dbc6a1aaadb 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -854,7 +854,7 @@ static ssize_t mem_rw(struct file *file, char __user *buf, flags = FOLL_FORCE | (write ? FOLL_WRITE : 0); while (count > 0) { - int this_len = min_t(int, count, PAGE_SIZE); + size_t this_len = min_t(size_t, count, PAGE_SIZE); if (write && copy_from_user(page, buf, this_len)) { copied = -EFAULT;