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 7817CC47404 for ; Fri, 4 Oct 2019 15:55:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F398222BE for ; Fri, 4 Oct 2019 15:55:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="P9uryt8X" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390031AbfJDPzy (ORCPT ); Fri, 4 Oct 2019 11:55:54 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:46685 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390124AbfJDPzy (ORCPT ); Fri, 4 Oct 2019 11:55:54 -0400 Received: by mail-pf1-f195.google.com with SMTP id q5so4117747pfg.13 for ; Fri, 04 Oct 2019 08:55:52 -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=tKT3NphsS8aC+Hm20wz5BTowxyu8Cj2InabWiB0c0GY=; b=P9uryt8X7gX4iN8K3stEiJTJcM2cNtvg5fWgSYMUEnyNUbpf0ORwDeV01gZKcjRXCO VCwvJSIUMUzDCJGqe3vTdQ1hMWFKYBkDV4e2OYCKawfibi6tstydDPA3//MRuqJbtD4R z8UKcn4TKlwv5xv6uJJi8wck3MSYJwOu971ps= 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=tKT3NphsS8aC+Hm20wz5BTowxyu8Cj2InabWiB0c0GY=; b=m5SnvcK4b4oYiQMaohn7mhNTz0LnhQS2vPiDSfF7bbLa6yLswo9DZ4Ax9eIwm2V4qB k8YqKZPy+r0OpJaPNI5E52Jjzz/mnAKLwkF4uh0Wt70HsSTTPYQYRsxFiYQyeBKmbSwI N2SOGPXQbJ8PKzm2vEmUm06aiLusRacH1XJRNkCVhLzpokaeJsvVOcFhqAA2bDqtJAXj 6LWdbf2tfI0FoLim29/6XszP1t3SBLq53bHkmyO4ebrqzCt3Rlbtl5SDbREaEcoINX8n j3/2opGLX9xUj0UgjXm44lUf5D0Db3pQ7jOROEvSJTqqF0jHuhe/BylOHI7XOgEIWjir X2GQ== X-Gm-Message-State: APjAAAVE0Ux/I4xcXR9fQ3Lia175X87TvLR+FrZylbnqZncmU6IYKPVD IfNyHKrG7ZdEd4QBBmptZEfI3wXV8Sg= X-Google-Smtp-Source: APXvYqzseQzsIEYKPy2lca6iSmI4k9mLnTVGFyHajRsnq7Qjy0ko5OuaFD/y5oKMSoGkp+PZoeYkLQ== X-Received: by 2002:a63:368a:: with SMTP id d132mr16009995pga.428.1570204552364; Fri, 04 Oct 2019 08:55:52 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id z4sm5730004pjt.17.2019.10.04.08.55.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Oct 2019 08:55:51 -0700 (PDT) Date: Fri, 4 Oct 2019 08:55:50 -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 1/2] mac80211: Reject malformed SSID elements Message-ID: <201910040855.8E8B4D7A@keescook> References: <20191004095132.15777-1-will@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191004095132.15777-1-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 10:51:31AM +0100, Will Deacon wrote: > Although this shouldn't occur in practice, it's a good idea to bounds > check the length field of the SSID element prior to using it for things > like allocations or memcpy operations. > > Cc: > Cc: Johannes Berg > Cc: Kees Cook > Reported-by: Nicolas Waisman > Signed-off-by: Will Deacon Reviewed-by: Kees Cook -Kees > --- > net/mac80211/mlme.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c > index 26a2f49208b6..54dd8849d1cc 100644 > --- a/net/mac80211/mlme.c > +++ b/net/mac80211/mlme.c > @@ -2633,7 +2633,8 @@ struct sk_buff *ieee80211_ap_probereq_get(struct ieee80211_hw *hw, > > rcu_read_lock(); > ssid = ieee80211_bss_get_ie(cbss, WLAN_EID_SSID); > - if (WARN_ON_ONCE(ssid == NULL)) > + if (WARN_ONCE(!ssid || ssid[1] > IEEE80211_MAX_SSID_LEN, > + "invalid SSID element (len=%d)", ssid ? ssid[1] : -1)) > ssid_len = 0; > else > ssid_len = ssid[1]; > @@ -5233,7 +5234,7 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata, > > rcu_read_lock(); > ssidie = ieee80211_bss_get_ie(req->bss, WLAN_EID_SSID); > - if (!ssidie) { > + if (!ssidie || ssidie[1] > sizeof(assoc_data->ssid)) { > rcu_read_unlock(); > kfree(assoc_data); > return -EINVAL; > -- > 2.23.0.581.g78d2f28ef7-goog > -- Kees Cook