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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 A3F3CC4CED1 for ; Fri, 4 Oct 2019 15:56:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7AC0421D81 for ; Fri, 4 Oct 2019 15:56:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="QxJ7VeTk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390143AbfJDP4L (ORCPT ); Fri, 4 Oct 2019 11:56:11 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:38630 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389968AbfJDP4K (ORCPT ); Fri, 4 Oct 2019 11:56:10 -0400 Received: by mail-pl1-f195.google.com with SMTP id w8so3326738plq.5 for ; Fri, 04 Oct 2019 08:56:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=XuTFm7PmBnOTEXwk6HOm9tTaZO7sz0lj99hGKjmHVpY=; b=QxJ7VeTkadELxH/Iy/fJ4QBoLHE+jrTZuju/6HbUfQ+SsRCVL32NJjVA+NMrsu82/5 u6GhYGfWUJcLdaCVyEV2l4bcbg6AAiojH6HJBNTvUAcravI0qPjzYMN55IFkpTawGXyQ 9RJ/B0spq8hjtL7HcKMoa8eKFpFf5e0TdIVmo= 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:references :mime-version:content-disposition:in-reply-to; bh=XuTFm7PmBnOTEXwk6HOm9tTaZO7sz0lj99hGKjmHVpY=; b=Q1ACFhRufVZ9015h9zyZ+6Ia0jiNAdlkAiUSqAmzoODYUPC3MLq4ul1zeLmICJRm+I KS5AcVkb+AKlipEbMFmv8fcH9VBQqMZ04siSnVKTt7OOdvBPF149ThaKgAHjazpYhJ7V lG1iF3ot56rQmqo7eiHqfeOYibgdhVAdiK1MpaEid5CkAWsniauazkzUtqk+2BY/sm8t UCDpLU0rCpdxR1zWOdEA2YVC9sYDyWeGFFSI74506k6tUMWV581Jgux7VfxAOnQx9G2x gTHNK7yjfq3T6oiTqr2lDjr1/N2zVlhdVnCzr2atRTwkUNdSPJU//qUqxPjpZDLeeYtm 0Q1g== X-Gm-Message-State: APjAAAV+tyI87KC98jVwbLPZiuIwBMCK7+dlBfdcbvzPijVpV4M+OSU2 TSgdvzrrOoh4Gl7bUZLThZLjhQ== X-Google-Smtp-Source: APXvYqwXwW9gr3TP/4gIxZCVkrUW1BJFdOLdlW0Xrehgp//g/KdmNeXpOWkYjeWazMIbwhgVGrTofw== X-Received: by 2002:a17:902:a586:: with SMTP id az6mr16193131plb.12.1570204570070; Fri, 04 Oct 2019 08:56:10 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id w10sm6645699pfi.137.2019.10.04.08.56.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Oct 2019 08:56:09 -0700 (PDT) Date: Fri, 4 Oct 2019 08:56:08 -0700 From: Kees Cook To: Will Deacon Cc: linux-wireless@vger.kernel.org, nico@semmle.com, stable@vger.kernel.org, Johannes Berg Subject: Re: [PATCH 2/2] cfg80211: wext: Reject malformed SSID elements Message-ID: <201910040856.C85EDF91@keescook> References: <20191004095132.15777-1-will@kernel.org> <20191004095132.15777-2-will@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191004095132.15777-2-will@kernel.org> Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org On Fri, Oct 04, 2019 at 10:51:32AM +0100, Will Deacon wrote: > Ensure the SSID element is bounds-checked prior to invoking memcpy() > with its length field. > > Cc: > Cc: Johannes Berg > Cc: Kees Cook > Reported-by: Nicolas Waisman > Signed-off-by: Will Deacon Reviewed-by: Kees Cook -Kees > --- > net/wireless/wext-sme.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/net/wireless/wext-sme.c b/net/wireless/wext-sme.c > index c67d7a82ab13..3fd2cc7fc36a 100644 > --- a/net/wireless/wext-sme.c > +++ b/net/wireless/wext-sme.c > @@ -201,6 +201,7 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev, > struct iw_request_info *info, > struct iw_point *data, char *ssid) > { > + int ret = 0; > struct wireless_dev *wdev = dev->ieee80211_ptr; > > /* call only for station! */ > @@ -219,7 +220,10 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev, > if (ie) { > data->flags = 1; > data->length = ie[1]; > - memcpy(ssid, ie + 2, data->length); > + if (data->length > IW_ESSID_MAX_SIZE) > + ret = -EINVAL; > + else > + memcpy(ssid, ie + 2, data->length); > } > rcu_read_unlock(); > } else if (wdev->wext.connect.ssid && wdev->wext.connect.ssid_len) { > @@ -229,7 +233,7 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev, > } > wdev_unlock(wdev); > > - return 0; > + return ret; > } > > int cfg80211_mgd_wext_siwap(struct net_device *dev, > -- > 2.23.0.581.g78d2f28ef7-goog > -- Kees Cook