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=-8.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT 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 1D082C31E44 for ; Mon, 17 Jun 2019 06:56:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D2F6E2189F for ; Mon, 17 Jun 2019 06:56:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="riwHpDTP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726264AbfFQG4N (ORCPT ); Mon, 17 Jun 2019 02:56:13 -0400 Received: from mail-pf1-f196.google.com ([209.85.210.196]:46062 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725793AbfFQG4N (ORCPT ); Mon, 17 Jun 2019 02:56:13 -0400 Received: by mail-pf1-f196.google.com with SMTP id r1so5113246pfq.12; Sun, 16 Jun 2019 23:56:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :user-agent; bh=QNjAimqYETJrQ2TQbFTWoOubQzT+2nG9itcAL9Hoj+M=; b=riwHpDTPyrJoTf8HVQfOsZoeWP75I5emiFn9tpaJQvj4AhvoJEEFcJTvV8KXLUY7SA R/b4snMsGn1QeiMQ5sugmesIpSbbtGWa/OBfaJ45akbqu4D/Aw6GAPlCdwRS7DHUJHP8 HSyBsC3XkZEKpkHbLAn5ChxiPQtxQq1zPVFLhdMkP2PdOdC5+T32MBBQSgenTtonVDCu SmNt7kNm5hMrMgtT4ovEolctDEUFkFf38ckyIdzfQZHmDvQYA6wzwvb1B9DuWXSe5SXY ra1D8We7mcOjBrr9ZesnRqeTJ3bH3o1Ck7SpYFCMOVcKk87LiL1Z0A/d72lFsCPUyC8b LBZw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:user-agent; bh=QNjAimqYETJrQ2TQbFTWoOubQzT+2nG9itcAL9Hoj+M=; b=AemOHa2GkVJ1ZHsybc/5NotTA4Vuh/jARnHK2hOq9+ojpZwpnTCHK0Hi84iAWSQzak Tm/bUsFsaeH8g+LmU5eksVkN9QI8b4GVZPELPt6scfHXPPjOy+aUl5kuhrkFXD8dQP5F Uyv89NqBteRhwUFT/pnRLLQfbEhYmxR6AZSk8NBYSTNhrt/90IdSxkXRCY1Jiu2IzmJ8 LG1sn9lAMUPAnIvZgi7KOKir5I6TitdmVceX+ZbanWrt0ImiYjtrEb3BVyAEJa8WKYHd Oxbg6XCiPmaEI3Y8VkUvEIFO1NOkVJUAUIcqv5Vd7BOBezupQqhUthEMz8VbVBvTWRVP HXTw== X-Gm-Message-State: APjAAAV8GB7vSGtuO3i8PUh+fE3v+R7KqXl0XYiZoil0diHoNEf7SCdT MVIyKV3FIAMoSreW6UlatBO6e3qE5w4HJg== X-Google-Smtp-Source: APXvYqy+htIhb0RboG5wzl8Vm9I/9MrSYYRmIKXomipGELL46I0I48r4qD2ECvMwU5BrEM4gd0fmbQ== X-Received: by 2002:a63:e001:: with SMTP id e1mr892000pgh.306.1560754572129; Sun, 16 Jun 2019 23:56:12 -0700 (PDT) Received: from hjy-HP-Notebook ([2409:8900:2500:7501:45ca:ff9c:a1f5:5b9b]) by smtp.gmail.com with ESMTPSA id a22sm11427741pfn.173.2019.06.16.23.56.10 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Sun, 16 Jun 2019 23:56:11 -0700 (PDT) Date: Mon, 17 Jun 2019 14:56:05 +0800 From: JingYi Hou To: davem@davemloft.net Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] net: remove duplicate fetch in sock_getsockopt Message-ID: <20190617065605.GA5924@hjy-HP-Notebook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org In sock_getsockopt(), 'optlen' is fetched the first time from userspace. 'len < 0' is then checked. Then in condition 'SO_MEMINFO', 'optlen' is fetched the second time from userspace. If change it between two fetches may cause security problems or unexpected behaivor, and there is no reason to fetch it a second time. To fix this, we need to remove the second fetch. Signed-off-by: JingYi Hou --- net/core/sock.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/net/core/sock.c b/net/core/sock.c index 2b3701958486..932bcbf2d565 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1477,9 +1477,6 @@ int sock_getsockopt(struct socket *sock, int level, int optname, { u32 meminfo[SK_MEMINFO_VARS]; - if (get_user(len, optlen)) - return -EFAULT; - sk_get_meminfo(sk, meminfo); len = min_t(unsigned int, len, sizeof(meminfo)); -- 2.20.1