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=-6.6 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 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 E960CC83004 for ; Tue, 28 Apr 2020 01:11:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF3D8206E2 for ; Tue, 28 Apr 2020 01:11:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="en/JylFl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726261AbgD1BLj (ORCPT ); Mon, 27 Apr 2020 21:11:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50174 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726233AbgD1BLj (ORCPT ); Mon, 27 Apr 2020 21:11:39 -0400 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A028EC03C1A8; Mon, 27 Apr 2020 18:11:37 -0700 (PDT) Received: by mail-pf1-x444.google.com with SMTP id d184so9882585pfd.4; Mon, 27 Apr 2020 18:11:37 -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:references:mime-version :content-disposition:in-reply-to; bh=iv9VG1ml9YtdubxTkSVKWnfhCAm26tdpMZmL56nVCYc=; b=en/JylFl8KERUCoB06g3lH9RTFt6u/pTLuDKe6cjSmoQ/jz0G8pmGFKwYMOT4X0fn3 EEwjVaRfYwGFygNhQZNxFnWQ4y4K/g7TQwr9HCUw/YaW66/Yb44ptlT8uiXlxypxao6D 3TE/MngCCXMHbpwafPDK9jg0BRrVuet52wxuH7uC/n2PUKW4AgpNT5F2nwrg2xSmVWlT ji7pfJhI8LHCfbV2mRBtMXEK0yM1yoKgwcA+S2NFJyYQgi52v88JaqEISqezul0Um9FO yrzvSZMH3W/YAyogV070gXVIo7aa3GqChkh7WZYanrXfTGbOE7BJQqdfOpq7bz6KJ8uP 2PiA== 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=iv9VG1ml9YtdubxTkSVKWnfhCAm26tdpMZmL56nVCYc=; b=paimORPPK4KqHMQf2TILNf1p1RdM36kX9TfLErX9Y862pik1aK5VDw2DF9+f7RN727 AoUanG/DFFB7yBAzPKyzwMCXDx6bZ+d4dsCGKNNIsLnysAe2wxakTra09PVymf5fjTGn sU2AyHElDWNWSwCzX5d28wVxewU16fdapfuE8QIv/dDKQWd06fFFN61ltXFaf2JDuQDG 8MTd3y43O0LL/v4QJeFuItJl+vNcW6Ovsp3f0Cg+eLpycmetF9sdDV07Y20+CU710dhC OZYcfwxUrGVhB1l1ruXmaET+/Bm/VUB9gLCS+RZBZT+khWOBMpcDgASTQ+ynSVKwOqVK io3w== X-Gm-Message-State: AGi0PuaiEg4ezBIVoy250MIulRdoUg2c2NWfJxauB2jfGcYxWKWCP4KL 1moJNay8xvtFbuez150so+A= X-Google-Smtp-Source: APiQypJB9eoHpfKd85W5XG6LcAJS6p+QLoEsa2/CGJqTZyMNhrDTGELNXXx6D+FPslZDHI2wzSjwmQ== X-Received: by 2002:a63:4c08:: with SMTP id z8mr25135272pga.175.1588036296910; Mon, 27 Apr 2020 18:11:36 -0700 (PDT) Received: from dtor-ws ([2620:15c:202:201:3c2a:73a9:c2cf:7f45]) by smtp.gmail.com with ESMTPSA id 138sm13429682pfz.31.2020.04.27.18.11.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Apr 2020 18:11:36 -0700 (PDT) Date: Mon, 27 Apr 2020 18:11:34 -0700 From: Dmitry Torokhov To: Evan Green Cc: stable@vger.kernel.org, Nick Desaulniers , Allison Randal , Andrew Duggan , Benjamin Tissoires , Enrico Weigelt , Thomas Gleixner , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Input: synaptics-rmi4 - Really fix attn_data use-after-free Message-ID: <20200428011134.GV125362@dtor-ws> References: <20200427145537.1.Ic8f898e0147beeee2c005ee7b20f1aebdef1e7eb@changeid> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200427145537.1.Ic8f898e0147beeee2c005ee7b20f1aebdef1e7eb@changeid> Sender: linux-input-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org On Mon, Apr 27, 2020 at 02:55:48PM -0700, Evan Green wrote: > Fix a use-after-free noticed by running with KASAN enabled. If > rmi_irq_fn() is run twice in a row, then rmi_f11_attention() (among > others) will end up reading from drvdata->attn_data.data, which was > freed and left dangling in rmi_irq_fn(). > > Commit 55edde9fff1a ("Input: synaptics-rmi4 - prevent UAF reported by > KASAN") correctly identified and analyzed this bug. However the attempted > fix only NULLed out a local variable, missing the fact that > drvdata->attn_data is a struct, not a pointer. > > NULL out the correct pointer in the driver data to prevent the attention > functions from copying from it. > > Fixes: 55edde9fff1a ("Input: synaptics-rmi4 - prevent UAF reported by KASAN") > Fixes: b908d3cd812a ("Input: synaptics-rmi4 - allow to add attention data") > > Signed-off-by: Evan Green > > Cc: stable@vger.kernel.org > Cc: Nick Desaulniers Ugh, this is all kind of ugly, but I guess that's what we have now. Applied, thank you. > --- > > drivers/input/rmi4/rmi_driver.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/input/rmi4/rmi_driver.c b/drivers/input/rmi4/rmi_driver.c > index 190b9974526bb..c18e1a25bca6e 100644 > --- a/drivers/input/rmi4/rmi_driver.c > +++ b/drivers/input/rmi4/rmi_driver.c > @@ -205,7 +205,7 @@ static irqreturn_t rmi_irq_fn(int irq, void *dev_id) > > if (count) { > kfree(attn_data.data); > - attn_data.data = NULL; > + drvdata->attn_data.data = NULL; > } > > if (!kfifo_is_empty(&drvdata->attn_fifo)) > -- > 2.24.1 > -- Dmitry