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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 72011CA9EC0 for ; Mon, 28 Oct 2019 16:48:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5254421721 for ; Mon, 28 Oct 2019 16:48:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403877AbfJ1QsD (ORCPT ); Mon, 28 Oct 2019 12:48:03 -0400 Received: from webclient5.webclient5.de ([136.243.32.184]:55093 "EHLO webclient5.webclient5.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403866AbfJ1QsC (ORCPT ); Mon, 28 Oct 2019 12:48:02 -0400 X-Greylist: delayed 447 seconds by postgrey-1.27 at vger.kernel.org; Mon, 28 Oct 2019 12:48:01 EDT Received: from olorin.ladisch.de (x2f7f95e.dyn.telefonica.de [2.247.249.94]) by webclient5.webclient5.de (Postfix) with ESMTPSA id 7F6BC5583F65; Mon, 28 Oct 2019 17:40:32 +0100 (CET) Subject: Re: [PATCH] ALSA: usb-audio: Fix memory leak in __snd_usbmidi_create To: Navid Emamdoost Cc: Takashi Iwai , Navid Emamdoost , Kangjie Lu , Stephen McCamant , Jaroslav Kysela , alsa-devel@alsa-project.org, LKML References: <20191027221007.14317-1-navid.emamdoost@gmail.com> From: Clemens Ladisch Message-ID: Date: Mon, 28 Oct 2019 17:38:56 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Virus-Scanned: clamav-milter 0.99.4 at webclient5 X-Virus-Status: Clean Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Navid Emamdoost wrote: > On Mon, Oct 28, 2019 at 1:27 AM Takashi Iwai wrote: >> On Sun, 27 Oct 2019 23:10:06 +0100, >> Navid Emamdoost wrote: >>> In the implementation of __snd_usbmidi_create() there is a memory leak >>> caused by incorrect goto destination. Go to free_midi if >>> snd_usbmidi_create_endpoints_midiman() or snd_usbmidi_create_endpoints() >>> fail. >> >> No, this will lead to double-free. After registering the rawmidi >> interface at snd_usbmidi_create_rawmidi(), the common destructor will >> be called via rawmidi private_free callback, and this will release the >> all resources already. > > Now I can see how rawmidi private_free is set up to release the > resources, but what concerns me is that at the moment of endpoint/port > creation umidi is not yet added to the midi_list. > In other words, what I see is that we still have just one local > pointer to umidi if any of snd_usbmidi_create_endpoint* fail. The snd_rawmidi device is automatically registered with the card, so the line "rmidi->private_free = snd_usbmidi_rawmidi_free;" is the exact point where the ownership of umidi changes. midi_list does not matter. Regards, Clemens 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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 B3E73CA9EC0 for ; Mon, 28 Oct 2019 16:41:31 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1B05D20717 for ; Mon, 28 Oct 2019 16:41:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="ZsOx3igL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B05D20717 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ladisch.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-devel-bounces@alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 49065203D; Mon, 28 Oct 2019 17:40:39 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 49065203D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1572280889; bh=iY5gjzO7g7CgZqLJYV1Y/ikyWbJt8YhPhEvTD9E41gM=; h=To:References:From:Date:In-Reply-To:Cc:Subject:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=ZsOx3igLGPwP9q5xPmNvndFxWB3IaQhB+dZE2HLkXP9OIylR753siL7YaZG0B5uTp KYWB3eiXjj0OSZNQMkOMEwXS0q5xbLMvAFZyU8R/f/5lgkajEXQ1sRyiiPKmAqThQC sIdLTQEfn5wBaaRkLcYBlJeoqfclPHvCGIzRRxGo= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id C5ADDF80145; Mon, 28 Oct 2019 17:40:38 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 34883F802BD; Mon, 28 Oct 2019 17:40:37 +0100 (CET) Received: from webclient5.webclient5.de (webclient5.webclient5.de [136.243.32.184]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 4F32FF80145 for ; Mon, 28 Oct 2019 17:40:33 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 4F32FF80145 Received: from olorin.ladisch.de (x2f7f95e.dyn.telefonica.de [2.247.249.94]) by webclient5.webclient5.de (Postfix) with ESMTPSA id 7F6BC5583F65; Mon, 28 Oct 2019 17:40:32 +0100 (CET) To: Navid Emamdoost References: <20191027221007.14317-1-navid.emamdoost@gmail.com> From: Clemens Ladisch Message-ID: Date: Mon, 28 Oct 2019 17:38:56 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Virus-Scanned: clamav-milter 0.99.4 at webclient5 X-Virus-Status: Clean Cc: alsa-devel@alsa-project.org, Takashi Iwai , Kangjie Lu , LKML , Navid Emamdoost , Stephen McCamant Subject: Re: [alsa-devel] [PATCH] ALSA: usb-audio: Fix memory leak in __snd_usbmidi_create X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" Navid Emamdoost wrote: > On Mon, Oct 28, 2019 at 1:27 AM Takashi Iwai wrote: >> On Sun, 27 Oct 2019 23:10:06 +0100, >> Navid Emamdoost wrote: >>> In the implementation of __snd_usbmidi_create() there is a memory leak >>> caused by incorrect goto destination. Go to free_midi if >>> snd_usbmidi_create_endpoints_midiman() or snd_usbmidi_create_endpoints() >>> fail. >> >> No, this will lead to double-free. After registering the rawmidi >> interface at snd_usbmidi_create_rawmidi(), the common destructor will >> be called via rawmidi private_free callback, and this will release the >> all resources already. > > Now I can see how rawmidi private_free is set up to release the > resources, but what concerns me is that at the moment of endpoint/port > creation umidi is not yet added to the midi_list. > In other words, what I see is that we still have just one local > pointer to umidi if any of snd_usbmidi_create_endpoint* fail. The snd_rawmidi device is automatically registered with the card, so the line "rmidi->private_free = snd_usbmidi_rawmidi_free;" is the exact point where the ownership of umidi changes. midi_list does not matter. Regards, Clemens _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org https://mailman.alsa-project.org/mailman/listinfo/alsa-devel