From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 21A3D4499AA; Tue, 11 Aug 2026 16:22:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786465372; cv=none; b=nmja9+pscInIS/mGW8IO0kiqKZ+efdhqpjZNM+aaXp+5Kh50idcGsqzOtfzb1wXQ6qgHfN3+anmvpJUTdOZIwGLRlB5AMwFsiEF5K01xpw585HS/BV2cSJiV8uV7riSyhbbiwz4nMCUArliIlm7E928m/54ptw3YlAmEwLjwuTA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786465372; c=relaxed/simple; bh=PKP7cVujzxM/QtMzrkWTiipn07OsFpzFm9E5dIpBsPQ=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=mj0APwefeoWVijPVK4BzHLoG/pDhSRDTEUlovJukE1QX/7ADm5Ni4vpHqdBf9mQCM9xbxpPDz2GaWq6bdYzaJXoZg5nIV1wQG1bmzqsmK4YtjaJYXZ8K5agDk8Q8HClHm1FQ8JyNzN6HFGQlbKClNP8Mdnn+BZUGHrSrPxwdC00= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de; spf=pass smtp.mailfrom=suse.de; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=hcQjvRsq; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=0nX4UqDo; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=0wwXqFpG; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=Xm/cUW0G; arc=none smtp.client-ip=195.135.223.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="hcQjvRsq"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="0nX4UqDo"; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="0wwXqFpG"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="Xm/cUW0G" Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id CD6B481DE5; Tue, 11 Aug 2026 16:22:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1786465365; 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=wu6ecGBl+O5NQAHf9K8a5/GdWSyuXmiBqAenu6ciyBI=; b=hcQjvRsqNlrzekrmlcUtuBqWrr0D0+VkJ10N1UGFa7A1oQJtvHX4fSy3dKgA1xmqUWCnx1 OPaLjsNh83KVDGJgXvGUHd9ansXo+WjAG46fH+yAkDJ/e1N0gJ3MY8qmeILpOJVdugRtju pvIbav0GVpzylfYX6Yk+ZYArwRTv2OE= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1786465365; 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=wu6ecGBl+O5NQAHf9K8a5/GdWSyuXmiBqAenu6ciyBI=; b=0nX4UqDoLbSMKLYwS9K0AXGsIn1UyV0wKoK5461wR+oqpLHhztbmb/oNIXh1ETaGmGMLm6 VrdwyJg5wwO1BEBw== Authentication-Results: smtp-out1.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=0wwXqFpG; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b="Xm/cUW0G" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1786465360; 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=wu6ecGBl+O5NQAHf9K8a5/GdWSyuXmiBqAenu6ciyBI=; b=0wwXqFpGIZX6m6SSNV3y1HkQQRuljxN35ukVBCrSkWzxiQwq/1lr+LiI16N6DzcH6+Xocg GCLttEGmKc/I4Xii4aFEZYozNkMKJbXSDO34jdzOFLhS3UObRnhbWBq1rZ2551GqsgE3mU Js3xoTUzGAyKCHaFzo35FB6Ya6yfuxg= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1786465360; 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=wu6ecGBl+O5NQAHf9K8a5/GdWSyuXmiBqAenu6ciyBI=; b=Xm/cUW0GoG7BOU7gZUl8d5taFdZuIbAxjlqehM9zhd3AkSZMSnTcwvBbshVyvuZ8TGgkqS Zua14sRhEliXpdDw== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id A6F02779BC; Tue, 11 Aug 2026 16:22:40 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id JzCCJ1BMe2q/EwAAD6G6ig (envelope-from ); Tue, 11 Aug 2026 16:22:40 +0000 Date: Tue, 11 Aug 2026 18:22:40 +0200 Message-ID: <87mrusaapb.wl-tiwai@suse.de> From: Takashi Iwai To: HyeongJun An Cc: Takashi Iwai , Jaroslav Kysela , linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ALSA: seq: Don't leak the extension cell pointer in the bounce payload In-Reply-To: <20260811131835.3837024-1-sammiee5311@gmail.com> References: <20260811131835.3837024-1-sammiee5311@gmail.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/30.2 Mule/6.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-Spam-Score: -4.51 X-Spam-Level: X-Rspamd-Action: no action X-Rspamd-Queue-Id: CD6B481DE5 X-Spamd-Result: default: False [-4.51 / 50.00]; BAYES_HAM(-3.00)[99.99%]; DWL_DNSWL_LOW(-1.00)[suse.de:dkim]; NEURAL_HAM_LONG(-1.00)[-1.000]; MID_CONTAINS_FROM(1.00)[]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-0.988]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FREEMAIL_TO(0.00)[gmail.com]; ARC_NA(0.00)[]; RBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from]; TO_DN_SOME(0.00)[]; MIME_TRACE(0.00)[0:+]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_TRACE(0.00)[suse.de:+]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_FIVE(0.00)[5]; RCVD_COUNT_TWO(0.00)[2]; RECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received]; DNSWL_BLOCKED(0.00)[2a07:de40:b281:104:10:150:64:97:from,2a07:de40:b281:106:10:150:64:167:received]; RCVD_VIA_SMTP_AUTH(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:mid,suse.de:dkim,imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spam-Flag: NO On Tue, 11 Aug 2026 15:18:35 +0200, HyeongJun An wrote: > > The bounce_error_event() embeds the failed event in the bounce payload > by pointing data.ext.ptr at it. When that event is a queued > variable-length event, its own data.ext.ptr holds the address of its > first extension cell, put there by snd_seq_event_dup(). The payload > goes out verbatim through snd_seq_expand_var_event(), so the address > reaches userspace. > > That is the same address commit 705dd6dcbc0e ("ALSA: seq: Clear > variable event pointer on read") removed from the event header. The > read path still clears it there, just above the call that expands the > payload. > > Embed a sanitised copy instead, treated exactly as snd_seq_read() > treats the header. A stack copy is enough because delivery is > synchronous and snd_seq_event_dup() copies before returning. > > An unprivileged client reaches this by setting SNDRV_SEQ_FILTER_BOUNCE, > queueing a variable-length event to a port that does not exist and > reading the bounce back. Eight bytes on 64-bit, from its own pool. > > Fixes: efc86691e4d8 ("ALSA: seq: Fix kernel heap address leak in bounce_error_event()") > Assisted-by: Claude:claude-opus-5 > Signed-off-by: HyeongJun An Applied now to for-next branch now. > --- > Unrelated, and not part of the change: the payload does not match struct > snd_seq_event_bounce in include/uapi/sound/asequencer.h - the err field is > not sent. Nothing regressed, since the kernel never produced the event > before efc86691e4d8. I can fix that separately if you want it. Any further fix would be appreciated. thanks, Takashi