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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AFF88C433FE for ; Wed, 23 Nov 2022 06:56:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236144AbiKWG4B (ORCPT ); Wed, 23 Nov 2022 01:56:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236072AbiKWGz7 (ORCPT ); Wed, 23 Nov 2022 01:55:59 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 14094F41A7 for ; Tue, 22 Nov 2022 22:55:57 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 8003D220D5; Wed, 23 Nov 2022 06:55:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1669186556; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=DWIEFciCRBJZr4QjejGTJsTfwg2gOtGq8bBxtqG2n8Y=; b=wfmbIv8JpgkhaZK8IIXmc5hWdRBRECNB1gXH6/QkPtm9Wo3WSygKkxZqNqy8O8FVv9VXNg GY++2ZG1C9iM2Q/aamtiCsmgpXQAt9sjfUKXYBqEgWKddynrY6Dn7S3OlHkQcKmFiU4HT4 q5uIGt359H+869VsnU8MsYPHvDtx+rA= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1669186556; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=DWIEFciCRBJZr4QjejGTJsTfwg2gOtGq8bBxtqG2n8Y=; b=GFRPrWkEHgYQbiDNPXUQHVtuSEx0ietQjcKiXG9GwaQasQCLjXIXUYPQkDqo7wmo/Gn9T8 6pOIeDfor7etEDAQ== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 5114913A37; Wed, 23 Nov 2022 06:55:56 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id krdFEvzDfWO2RQAAMHmgww (envelope-from ); Wed, 23 Nov 2022 06:55:56 +0000 Date: Wed, 23 Nov 2022 07:55:56 +0100 Message-ID: <87mt8i5fcz.wl-tiwai@suse.de> From: Takashi Iwai To: Xiaolong Huang Cc: perex@perex.cz, tiwai@suse.com, baolin.wang@linux.alibaba.com, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org Subject: Re: [RESEND PATCH] ALSA: rawmidi: fix infoleak in snd_rawmidi_ioctl_status_compat64 In-Reply-To: <20221123050911.1045190-1-butterflyhuangxx@gmail.com> References: <20221123050911.1045190-1-butterflyhuangxx@gmail.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/27.2 Mule/6.0 MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 23 Nov 2022 06:09:11 +0100, Xiaolong Huang wrote: > > The compat_status is declared off of the stack, so it needs to > be zeroed out before copied back to userspace to prevent any > unintentional data leakage. > > Fixes: d9e5582c4bb2 ("ALSA: Avoid using timespec for struct snd_rawmidi_status") > Signed-off-by: Xiaolong Huang > > --- > > Reason for resend: > 1. add Fixes line. > --- > sound/core/rawmidi_compat.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/sound/core/rawmidi_compat.c b/sound/core/rawmidi_compat.c > index 68a93443583c..6afa68165b17 100644 > --- a/sound/core/rawmidi_compat.c > +++ b/sound/core/rawmidi_compat.c > @@ -80,6 +80,7 @@ static int snd_rawmidi_ioctl_status_compat64(struct snd_rawmidi_file *rfile, > if (err < 0) > return err; > > + memset(&compat_status, 0, sizeof(compat_status)); > compat_status = (struct compat_snd_rawmidi_status64) { > .stream = status.stream, > .tstamp_sec = status.tstamp_sec, Here at the line just after your addition, compat_status is fully initialized by substitution, so I believe the memset is superfluous. Or have you verified that it really leaks the uninitialized memory? thanks, Takashi