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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 ADABAC433DB for ; Tue, 12 Jan 2021 14:00:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6BB7023121 for ; Tue, 12 Jan 2021 14:00:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731162AbhALN72 (ORCPT ); Tue, 12 Jan 2021 08:59:28 -0500 Received: from mx2.suse.de ([195.135.220.15]:60202 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726389AbhALN72 (ORCPT ); Tue, 12 Jan 2021 08:59:28 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 0B353AC8F; Tue, 12 Jan 2021 13:58:47 +0000 (UTC) Date: Tue, 12 Jan 2021 14:58:47 +0100 Message-ID: From: Takashi Iwai To: Geert Uytterhoeven Cc: Clemens Ladisch , Takashi Sakamoto , Jaroslav Kysela , Takashi Iwai , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH/RFC 2/2] ALSA: firewire-tascam: Fix integer overflow in midi_port_work() In-Reply-To: <20210111130251.361335-3-geert+renesas@glider.be> References: <20210111130251.361335-1-geert+renesas@glider.be> <20210111130251.361335-3-geert+renesas@glider.be> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 11 Jan 2021 14:02:51 +0100, Geert Uytterhoeven wrote: > > As snd_fw_async_midi_port.consume_bytes is unsigned int, and > NSEC_PER_SEC is 1000000000L, the second multiplication in > > port->consume_bytes * 8 * NSEC_PER_SEC / 31250 > > always overflows on 32-bit platforms, truncating the result. Fix this > by precalculating "NSEC_PER_SEC / 31250", which is an integer constant. > > Note that this assumes port->consume_bytes <= 16777. > > Fixes: 531f471834227d03 ("ALSA: firewire-lib/firewire-tascam: localize async midi port") > Signed-off-by: Geert Uytterhoeven > --- > Compile-tested only. > > I don't know the maximum transfer length of MIDI, but given it's an old > standard, I guess it's rather small. If it is larger than 16777, the > constant "8" should be replaced by "8ULL", to force 64-bit arithmetic. Applied now. Thanks. Takashi