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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 73A43C433E0 for ; Mon, 22 Feb 2021 15:21:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EA9364E57 for ; Mon, 22 Feb 2021 15:21:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230471AbhBVPVO (ORCPT ); Mon, 22 Feb 2021 10:21:14 -0500 Received: from mail-pj1-f50.google.com ([209.85.216.50]:39074 "EHLO mail-pj1-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230510AbhBVPOi (ORCPT ); Mon, 22 Feb 2021 10:14:38 -0500 Received: by mail-pj1-f50.google.com with SMTP id d2so9262655pjs.4 for ; Mon, 22 Feb 2021 07:14:21 -0800 (PST) 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=sg3iIrkkDsgypdsbDNoge70vzTAFrCPegzLsFOlHOJg=; b=ozpRx7B/ujwWcqQAVIvFGPN45LpPGV7yK0NsuEQ8NUW5WlroKxfZo4TxxsAMTwTpBn /aVFhYopjSdTwPSpqVXsZZgYbTYgAwy4HpSv7DHi1/lSZtvEmU/kd1FjChojwnT6sTkT JQao6z3iderYG7+5mBH0OBSO6nN715oWIqkxRb9aIZ0x0Ccfc1OMwSLwtJXyIqwLctwx vD3G/5F92VvlLGHMxOhfmEpjTvPsHaR94SXZ5yYl6/ufv3NMp76jh7dw/oxF0DiSqPwl Q1RDousDct2MusAeESL+zBrhWVCoguFdob8cz+UR+My0rWdolXTHpcOVK2Q4hEByBjk2 fSrA== X-Gm-Message-State: AOAM532vTrzrZYkzUNp/7l3YSAuRZsVFpVMf/ynBZsD5SUU7A0uXTPgk uWRYfLxtGC2HlbcgLbxVzjc= X-Google-Smtp-Source: ABdhPJzy5v7UB0lwfUGmYizhvLtXQNvKKDOnN6VOd5KsBhRU/l6ZCxbtcGYdlwbeEfpEfcKmL45Xuw== X-Received: by 2002:a17:902:744a:b029:e3:795d:b809 with SMTP id e10-20020a170902744ab02900e3795db809mr22856518plt.7.1614006835839; Mon, 22 Feb 2021 07:13:55 -0800 (PST) Received: from karthik-strix-linux.karthek.com ([192.140.155.255]) by smtp.gmail.com with ESMTPSA id v4sm5460329pjo.32.2021.02.22.07.13.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Feb 2021 07:13:55 -0800 (PST) Date: Mon, 22 Feb 2021 20:43:51 +0530 From: karthek To: Dan Carpenter Cc: linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org Subject: Re: [PATCH] staging: wlan-ng/p80211 : check userspacebuf size for sanity Message-ID: References: <20210222132132.GU2222@kadam> <20210222135937.GV2222@kadam> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210222135937.GV2222@kadam> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 22, 2021 at 04:59:37PM +0300, Dan Carpenter wrote: > I have added the Driver Devel list to the CC list. Adding linux-kernel > is sort of useless. The correct people who are interested in this patch > are all on the Driver Devel list. > > On Mon, Feb 22, 2021 at 07:12:22PM +0530, karthek wrote: > > On Mon, Feb 22, 2021 at 04:21:33PM +0300, Dan Carpenter wrote: > > > On Mon, Feb 22, 2021 at 06:16:24PM +0530, karthek wrote: > > > > currently p80211knetdev_do_ioctl() is testing user passed > > > > struct ifreq for sanity by checking for presence of a magic number, > > > > in addition to that also check size field, preventing buffer overflow > > > > before passing data to p80211req_dorequest() which casts it > > > > to *struct p80211msg > > > > > > > > Signed-off-by: karthek > > > > --- > > > > is this correct? > > > > is it necessary to check for size in addition to magicnum? > > > > did i even understand the problem correctly? > > > > > > > > drivers/staging/wlan-ng/p80211netdev.c | 5 ++++- > > > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/staging/wlan-ng/p80211netdev.c b/drivers/staging/wlan-ng/p80211netdev.c > > > > index 70570e8a5..c7b78d870 100644 > > > > --- a/drivers/staging/wlan-ng/p80211netdev.c > > > > +++ b/drivers/staging/wlan-ng/p80211netdev.c > > > > @@ -568,7 +568,10 @@ static int p80211knetdev_do_ioctl(struct net_device *dev, > > > > result = -EINVAL; > > > > goto bail; > > > > } > > > > - > > > > + if (req->len < sizeof(struct p80211msg)) { > > > > + result = -EINVAL; > > > > + goto bail; > > > > + } > > > > > > Please don't send private emails. Always CC the list. > > sorry > > > > > > That's only a partial solution. You need to check in p80211req_handlemsg() > > > as well and probably other places. > > currently p80211req_handlemsg() is only referenced in p80211req_dorequest() > > can we check that there instead? > > If I have to do all the work in finding the buffer overflows, then I > should write my own patch. :/ > > Anyway the p80211knetdev_do_ioctl() function calls p80211req_dorequest() > which calls p80211req_handlemsg(wlandev, msg); and > wlandev->mlmerequest(wlandev, msg);. > > We have already discussed the p80211req_handlemsg() function. The > wlandev->mlmerequest() function is always just prism2sta_mlmerequest(). > The prism2sta_mlmerequest() calls a bunch of functions and each of those > functions need to have a different limit check added to prevent memory > corruption. > > Homework #1: Should we get rid of the wlandev->mlmerequest() pointer > and just call prism2sta_mlmerequest() directly? yeah > > Homework #2: Another solution is to just delete all these custom IOCTLs. > I don't know what they do so I don't know if they are necessary or not. i wish i could > > regards, > dan carpenter >