From nobody Fri Sep 25 12:33:45 2026 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) (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 8D93647277D; Sat, 12 Sep 2026 12:52:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.131 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789217542; cv=none; b=FzLdfjZOC4tsyQR7ul8MV/BKChD1rbKGaEjRiZ3Fp4U4U7pTZyDt64VTDI3xGeSlf47vVRPM4nPei4YgfirSXME/0MlbLrvRxwML6aZJADHL1LvYoHTV7sYr7lEOT9AqREzRXl34zuI0XSqO+I9T2bjNrEbflqv2ieas2OoX9Lc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789217542; c=relaxed/simple; bh=lQacYLv3te9B/89A0+GB49kCkBCkbkX+/qHcRDvnmsI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=UjJkoyHmimmULK8Ipojv1VEvZTB+l5HcqHtaGRlhLgPkz7kvDqwngrA2vysqY1ef/IpjEhpnpJshKIODuf3V21D8y9bHMefQEiBVrTQD3kXhT4JVQWVW2zl6cu3tUPLbv0B8GPpWx1DNHsvUs9PL8LMthCzgB89N/C5oXPRUqps= 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=GiDU82CP; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=2CjfxTM7; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=tNKwQNQX; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=cvu8IijU; arc=none smtp.client-ip=195.135.223.131 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="GiDU82CP"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="2CjfxTM7"; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="tNKwQNQX"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="cvu8IijU" 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-out2.suse.de (Postfix) with ESMTPS id 5A38E1F38E; Sat, 12 Sep 2026 12:52:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1789217534; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=z0rsfkpi+MtVIAwLx93HCl/8glkcoIECYAhMbIs3M+4=; b=GiDU82CPtzfBrk8hyNiQvz/ORff6XiFAoclXW+lnf8k8ohXQJqHnZT7XO9wgrrmwPByLdV tyFTlurDcC/JFPSl2tHrUbhAc1FcNeNc/z5FZ8o1+exySJwZ/5B7yDFEGYiEmOo8XC/j0i 7PLVcsaMbit+O2Mbc+Y+txwYrbU57mQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1789217534; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=z0rsfkpi+MtVIAwLx93HCl/8glkcoIECYAhMbIs3M+4=; b=2CjfxTM7Npx1/8RhO5RApIjAf/yk1sVQ2lQVOe0LcNmILbszvhx4KFQhDB9OhADhj2TW9w yq22xQzgGQfJtXDQ== Authentication-Results: smtp-out2.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=tNKwQNQX; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=cvu8IijU DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1789217530; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=z0rsfkpi+MtVIAwLx93HCl/8glkcoIECYAhMbIs3M+4=; b=tNKwQNQXapiwwn/nFej/7U31DqxFEeVrZWav0MiRMgTol73hQzQgXD5SOsX/eCuhXpxFWK qj/jstcXXeT6kHfprs53LT7Dh+uUeOTrCz6/EWgKUnCJH279ZgrIpIBaAtelR2K5SwKl6U LqEXLOLMW84OtkKR8YBo0njKUe/8Uwc= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1789217530; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=z0rsfkpi+MtVIAwLx93HCl/8glkcoIECYAhMbIs3M+4=; b=cvu8IijUmgFFpXOoA9PkOH8xd8awnRbKz8tJj39vGoml+HKnvx0IzkJL12LwfKp5AZckrc AOmwHJ3LY+KEt9Cw== 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 1928213687; Sat, 12 Sep 2026 12:52:10 +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 06zlBPpKpWrSHQAAD6G6ig (envelope-from ); Sat, 12 Sep 2026 12:52:10 +0000 From: Takashi Iwai To: linux-sound@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Farhad Alemi Subject: [PATCH] ALSA: core: Fix potential UAF after asynchronous card release Date: Sat, 12 Sep 2026 14:52:03 +0200 Message-ID: <20260912125205.417429-1-tiwai@suse.de> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Spam-Level: X-Rspamd-Action: no action X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Rspamd-Queue-Id: 5A38E1F38E X-Spamd-Result: default: False [-3.01 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; ARC_NA(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; MIME_TRACE(0.00)[0:+]; TO_DN_SOME(0.00)[]; RBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from]; RCVD_TLS_ALL(0.00)[]; DKIM_TRACE(0.00)[suse.de:+]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; RCVD_COUNT_TWO(0.00)[2]; RCVD_VIA_SMTP_AUTH(0.00)[]; RECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received]; RCPT_COUNT_THREE(0.00)[3]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:dkim,suse.de:email,suse.de:mid,berkeley.edu:email,imap1.dmz-prg2.suse.org:rdns,imap1.dmz-prg2.suse.org:helo] X-Spam-Flag: NO X-Spam-Score: -3.01 Content-Type: text/plain; charset="utf-8" Usually a sound driver releases the resources assigned to the card via snd_card_free(), and it synchronizes with the whole release procedure. However, when the card is released asynchronously via snd_card_free_when_closed() like USB-audio driver, the situation is slightly different; although the snd_card_disconnect() call at the disconnection guarantees that any newer accesses will be gated, the in-flight tasks might be still accessing to the underlying card->dev device even after the disconnection, which would cause a use-after-free in the end, as reported by fuzzers. For addressing the bug above, this patch takes the refcount of card->dev at initialization of the card object, and releases at its destructor. This assures the availability of the card->dev in its whole lifecycle. Reported-by: Farhad Alemi Closes: https://lore.kernel.org/CA+0ovChexj4TrZL_2iG_P0WBEbZc5+73GfB3DkciQi= =3DR8pZOnA@mail.gmail.com Closes: https://lore.kernel.org/CA+0ovCgQUQNN=3DZ1tJTouiCsDaXR5M-3-SQEGk-cp= PXQkM5Xh+w@mail.gmail.com Cc: Signed-off-by: Takashi Iwai --- sound/core/init.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/sound/core/init.c b/sound/core/init.c index 2f7f83a7611b..bffa94b7b956 100644 --- a/sound/core/init.c +++ b/sound/core/init.c @@ -310,7 +310,7 @@ static int snd_card_init(struct snd_card *card, struct = device *parent, kfree(card); /* manually free here, as no destructor called */ return err; } - card->dev =3D parent; + card->dev =3D get_device(parent); card->number =3D idx; WARN_ON(IS_MODULE(CONFIG_SND) && !module); card->module =3D module; @@ -605,6 +605,7 @@ static int snd_card_do_free(struct snd_card *card) } if (card->release_completion) complete(card->release_completion); + put_device(card->dev); if (!managed) kfree(card); return 0; --=20 2.55.0