From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=109.224.244.123 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792973458; b=LsHN1ZT9aqjeMhOpk3fJ4aAwYN2bUmMgxe/hvS4R1ADVoII6u7g3fV1Rqu4I8bdDfqe/ UPnkKLoNP84BtHVi0vsS3Mhz8n1sX1JEPeA7oNyMzqp7hU+PXYQz0/cnyf5yRtBZMN1sV ltyDQN7JoPuoovPArj8jaK3Sv44rV/bLiowR0WxOrSBo1xZjJ9qBQxSXOP5bqR0cS9Qvi djmz7qylyMgZsKSf8rVhzYQz13PbhEsaqjiLEKQ4xMLz4MBzA77VfR5ZFgDMC5l/feQ/o iK/ImVHMwfBNh7hf0C0B6BCkDyxgzLrXyM+mrZhdBeZmrVGH3LefFuDoI0RjryeJYLA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792973458; h=DMARC-Filter:DKIM-Signature:Date:To:From:Cc:Subject:Message-ID: In-Reply-To:References:Feedback-ID:X-Pm-Message-ID:MIME-Version: Content-Type:Content-Transfer-Encoding; bh=ZcjPezzps46dzV2jP1tt2AUCN0jXr3QNikTRiI36eR4=; b=MhBvp1vAUNjP+qLjJuuEBYZrd55BxDWti1073pWUV9gEQuxJOzIoLHDfCp4w357p5xjW dixmRlRgrhD6pKwtV8SbceFokIBntxL0jPWrDnMr8qZFrwcDe703hOEdllZEwq4R2LY7j h1SXMEb+RgTqVq0bbRv7Xi+09SnphIVZuNKei8sejH3qw1xjQ/rT5FO8N1VEsq+41p6N6 PdZRapIXVCodNuQXL5u9NIVwE2kvlFnvQShQ8oDOnw3cMvbuHTJ0Qg9HOJ4geYY6PJNh1 HTPN8c6pfBRW+rDlxiS2UGmTn1Mn5qItZQC1UzJuuiPpiKzZ5LgIhGATQZA5ZkU+1Fg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=pm.me; spf=pass smtp.mailfrom=pm.me; dkim=pass header.d=pm.me header.i=@pm.me header.a=rsa-sha256 header.s=protonmail3 header.b=TMumDwx2; arc=none smtp.remote-ip=109.224.244.123 Received: from mail-244123.protonmail.ch (mail-244123.protonmail.ch [109.224.244.123]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1738C606A32C for ; Mon, 26 Oct 2026 00:10:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 1738C606A32C Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=pm.me Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pm.me Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=pm.me header.i=@pm.me header.a=rsa-sha256 header.s=protonmail3 header.b=TMumDwx2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pm.me; s=protonmail3; t=1792973456; x=1793232656; bh=ZcjPezzps46dzV2jP1tt2AUCN0jXr3QNikTRiI36eR4=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=TMumDwx2rdDouyoR9MQNtsIVkFWXLwdyM09q1A6+kP9yo8S5oJ77eQoBSP49LAuba +Wz5YnZlqOycvqpKczezK8uRm0xA4vi6sBD/HoZXsGIyKbs/tIoESjxaLZaMJmZc5U 3iUQCWoAdnTydSnhWkKklTZlmijOOfCLSq6ImI3J0pL/ocmQ7gg9pNZPnoFwD4vj9K 3HXeSWkJUk+E6n4ETphxo/PJkiCgnqF5obfNQMnzOVmdKDJPczC7XFSW51FMy5KnIQ ule2AziI1cNgCyTWa2jzRcBoCG/9TjHCeWelPsdTh1JaOtDTVhwr/1bVC3Z0BWs3HG 449s8mfj3aXNQ== Date: Mon, 26 Oct 2026 00:10:50 +0000 To: Jaroslav Kysela , Takashi Iwai , Clemens Ladisch From: x8svc Cc: linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 2/2] ALSA: ua101: Bound packet copies by the PCM buffer size Message-ID: <20261026001003.1067-3-enscrpt@pm.me> In-Reply-To: <20261026001003.1067-1-enscrpt@pm.me> References: <20261026001003.1067-1-enscrpt@pm.me> Feedback-ID: 48393780:user:proton X-Pm-Message-ID: 68af065fdc058ba39aaff5c85c7feb9bb533798d X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable copy_capture_data() and copy_playback_data() wrap the ring buffer position once and split the memcpy() in two at the buffer end, which is only correct when one packet holds at most buffer_size frames. The capture packet size is the device's (actual_length up to wMaxPacketSize, divided by 3 * bNrChannels from its own descriptor), the playback packet size is taken from the capture packets, and set_stream_hw() lets the PCM client pick period_bytes_min 1, periods_min 2 and a period time of 1.5 packet intervals: 9 frames at 44.1 kHz high speed, an 18-frame buffer. A device sending 672-byte mono 24-bit packets delivers 224 frames per packet. After the first packet buffer_pos is 206 and stays beyond buffer_size. On the next packet frames1 =3D buffer_size - buffer_pos wraps and memcpy() runs away: snd-ua101 2-1:1.0: invalid position: , pos =3D 206, buffer size =3D 18, period size =3D 9 BUG: KASAN: slab-out-of-bounds in capture_urb_complete+0x9eb/0xcb0 Read of size 4294966732 at addr ffff88800d73e7e0 by task vhci_rx/81 and for playback: BUG: KASAN: vmalloc-out-of-bounds in playback_work+0x789/0xac0 Read of size 4294966732 at addr ffffc9000002626a by task kworker/0:1H/80 Clamp the capture copy to buffer_size. On playback, copy at most one buffer and fill the rest of the packet with silence, so the URB length, the delay accounting and the data sent stay consistent. With that bound the single wrap and both memcpy() halves stay inside the buffer. A device whose packets do not fit the buffer never played correctly anyway. Reproduced on 7.3-rc7 with a USB/IP device presenting the UA-101 interface layout and a 672-byte isochronous endpoint. Fixes: 63978ab3e3e9 ("sound: add Edirol UA-101 support") Cc: stable@vger.kernel.org Signed-off-by: x8svc --- sound/usb/misc/ua101.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/sound/usb/misc/ua101.c b/sound/usb/misc/ua101.c index 58d8a3cdc8b9..bd8e0ed0ba5d 100644 --- a/sound/usb/misc/ua101.c +++ b/sound/usb/misc/ua101.c @@ -285,13 +285,29 @@ static void playback_work(struct work_struct *work) =09=09=09/* fill packet with data or silence */ =09=09=09urb->iso_frame_desc[0].length =3D =09=09=09=09frames * ua->playback.frame_bytes; -=09=09=09if (test_bit(ALSA_PLAYBACK_RUNNING, &ua->states)) +=09=09=09if (test_bit(ALSA_PLAYBACK_RUNNING, &ua->states)) { +=09=09=09=09/* +=09=09=09=09 * The packet size comes from the capture stream, +=09=09=09=09 * i.e. from the device, while the ring buffer can +=09=09=09=09 * be as small as two tiny periods. The single wrap +=09=09=09=09 * in copy_playback_data() is only valid for +=09=09=09=09 * frames <=3D buffer_size, so copy at most one +=09=09=09=09 * buffer and send silence for the rest. +=09=09=09=09 */ +=09=09=09=09unsigned int copy_frames =3D min(frames, +=09=09=09=09=09ua->playback.substream->runtime->buffer_size); + =09=09=09=09do_period_elapsed |=3D copy_playback_data(&ua->playback, =09=09=09=09=09=09=09=09=09urb, -=09=09=09=09=09=09=09=09=09frames); -=09=09=09else +=09=09=09=09=09=09=09=09=09copy_frames); +=09=09=09=09memset(urb->transfer_buffer + +=09=09=09=09 copy_frames * ua->playback.frame_bytes, 0, +=09=09=09=09 (frames - copy_frames) * +=09=09=09=09 ua->playback.frame_bytes); +=09=09=09} else { =09=09=09=09memset(urb->transfer_buffer, 0, =09=09=09=09 urb->iso_frame_desc[0].length); +=09=09=09} =20 =09=09=09/* and off you go ... */ =09=09=09err =3D usb_submit_urb(urb, GFP_ATOMIC); @@ -320,6 +336,13 @@ static bool copy_capture_data(struct ua101_stream *str= eam, struct urb *urb, =20 =09runtime =3D stream->substream->runtime; =09frame_bytes =3D stream->frame_bytes; +=09/* +=09 * A packet can carry up to max_packet_bytes, the device's +=09 * wMaxPacketSize, which may exceed the whole ring buffer; keep what +=09 * fits so the single wrap below stays valid. +=09 */ +=09if (unlikely(frames > runtime->buffer_size)) +=09=09frames =3D runtime->buffer_size; =09dest =3D runtime->dma_area + stream->buffer_pos * frame_bytes; =09if (stream->buffer_pos + frames <=3D runtime->buffer_size) { =09=09memcpy(dest, urb->transfer_buffer, frames * frame_bytes); --=20 2.56.0