From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794590485; b=VFg6fPiRHiT4EhZIiZmn6wcSqamAtadOZNEfArkeEGhvL0LDX31otkStHSy0k1m7gy9V 0WVFrQvVHvHEhuLPyorYmYDdftPYcXan5YYfsJOvYMj+obqHp1VWNl3gQfDYUVPPO50nI h3CiSabXy9c9fLvN3D+G+y2oC6j7htPlcE/RQ0w5Y/isfzJVR+pkij+Dw2hnVqto1U0Gy xIye5+mVpZ48A71yEvycK9X2xJsb1jToueBPjnguliuR7CDotufTsMvlys92GgSrduyWn pA86gSOEWe6HuSj5PAQFqac1mepm6KnMXgZohumWgXkBPtfDIixhBlj7AK8DxEjHU4g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794590485; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=i8v27y2Zbb9oIzFE/MlvJOxcYO0RFdQQzvGpSPgQvG8=; b=a4bx6sL7wAX9wswIP0NxxT1iYGYZtFIeFT1o6LLZfJf9qmwcCfefiLEBfEQSkiXUjp/l KCe36NK1rCkjnuCNn0JoUA8WozXjo70zDj0ARf3h/sGPnZWsHTHenDnslyx7T+6fQMnIP 7kv/mFw/W9XLupY2TtszkWB5sgA891ZrFgy5j0so5+JXp9HrggfNrcOfCF5eUODQK2PTl NvPQwmrHtJzDR/h/aW1mPPVaZ9msiXVfLgR8CVCHEOnpajoNqZ2Dy4UQsxahH+GpG6dCx GSLRw03p4o0DfQ8I2MELFuPD88c8reMvalFVHlIDXh4cFyRwhywa3bcePwtzrKTbmRw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=VTXfpOzB; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (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 5BEC6606B819; Fri, 13 Nov 2026 17:21:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=VTXfpOzB Received: by smtp.kernel.org (Postfix) with ESMTPSA id 086171F000C4; Fri, 13 Nov 2026 17:21:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794590485; bh=i8v27y2Zbb9oIzFE/MlvJOxcYO0RFdQQzvGpSPgQvG8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=VTXfpOzB9ilMvRoZPmVE0IrdJmb2SYP49Bovv898Osb/GQVtBQMkAV6UugjbSdCdE hoNBboljObXMlBfV8Aha02Vzlqn6RFIz8GOifS6P0OLAfx5gvA1B5/E7ikMkg/+2s9 MnO5IXSiFKS00OpMy1hSmKPH/Bud77b4QjWXQg5k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sinan Turunc , Takashi Iwai , Sasha Levin Subject: [PATCH 6.18 436/686] ALSA: usx2y: Guard the playback copy Date: Fri, 13 Nov 2026 10:49:29 -0500 Message-ID: <20261113153835.678791593@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153820.902362109@linuxfoundation.org> References: <20261113153820.902362109@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sinan Turunc [ Upstream commit e2c6de52ffacb2c0f4076884ee3fdb744735a4cb ] usx2y_urb_play_prepare() sums the packet lengths of a whole URB, copies that many frames with a single wrap, and sizes each playback packet from the capture packet's actual_length. Three things are unchecked: that the URB fits in the ring buffer, that a packet fits in the playback endpoint's maxpacksize, from which tmpbuf is allocated, and that actual_length is a whole number of frames. The ISO descriptors take the raw actual_length while transfer_buffer_length and the copies take count * stride, so a packet that is not a multiple of the stride makes the descriptors add up to more than the buffer, by up to stride - 1 bytes per packet. Return -EPIPE, as the existing packet-size check does, when the URB is larger than the buffer or a packet is larger than maxpacksize, and size each descriptor from whole frames, so the descriptors add up to transfer_buffer_length and each stays within maxpacksize. The buffer case is prevented by the previous patch and this is the guard for it; the other two depend only on the device. The first case is reachable on the unpatched driver with ordinary packets: on 7.3-rc7, a USB/IP device presenting the US-122 interface layout and sending 48-frame packets, with a 100-frame playback buffer (two 50-frame periods, inside the stock constraints), KASAN reports: BUG: KASAN: out-of-bounds in i_usx2y_urb_complete+0x79b/0x1ac0 Read of size 18446744073709551280 at addr ffff88800e6b02e0 by task vhci_rx/80 With both patches, the same device and a 200-frame playback buffer is refused at hw_params with EINVAL, and a 400-frame buffer plays for 30 s with the position advancing inside the buffer, no KASAN report and neither guard message. The maxpacksize check is not exercised: the emulated device reports the same wMaxPacketSize on both endpoints. The descriptor case is visible with capture packets of 195 bytes at stride 4 (48 frames and 3 bytes): without this change the four descriptors add up to 780 bytes for 768 bytes of data, and USB/IP's completion check refuses the URB ("total length of iso packets 780 not equal to actual length of buffer 768", -EPROTO), after which the driver stops the streams. With this patch every descriptor is 192 bytes, the descriptors add up to the data in every URB for 30 s, the position advances inside the buffer and KASAN reports nothing. The 48-frame playback run above is unchanged. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Sinan Turunc Link: https://patch.msgid.link/20261104122136.1518-3-enscrpt@pm.me Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/usb/usx2y/usbusx2yaudio.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/sound/usb/usx2y/usbusx2yaudio.c b/sound/usb/usx2y/usbusx2yaudio.c index 12b1c890812ba..f035add1e1b5a 100644 --- a/sound/usb/usx2y/usbusx2yaudio.c +++ b/sound/usb/usx2y/usbusx2yaudio.c @@ -118,14 +118,31 @@ static int usx2y_urb_play_prepare(struct snd_usx2y_substream *subs, __func__, counts); return -EPIPE; } + if (counts * usx2y->stride > subs->maxpacksize) { + dev_err_ratelimited(&usx2y->dev->dev, + "%s: packet of %i bytes exceeds maxpacksize %u\n", + __func__, counts * usx2y->stride, + subs->maxpacksize); + return -EPIPE; + } /* set up descriptor */ urb->iso_frame_desc[pack].offset = pack ? urb->iso_frame_desc[pack - 1].offset + urb->iso_frame_desc[pack - 1].length : 0; - urb->iso_frame_desc[pack].length = cap_urb->iso_frame_desc[pack].actual_length; + urb->iso_frame_desc[pack].length = counts * usx2y->stride; } if (atomic_read(&subs->state) >= STATE_PRERUNNING) { + /* + * The copy below wraps once, which needs count <= buffer_size. + * snd_usx2y_pcm_open() guarantees it; guard anyway. + */ + if (unlikely(count > runtime->buffer_size)) { + dev_err_ratelimited(&usx2y->dev->dev, + "%s: URB of %i frames exceeds %lu-frame buffer, stopping\n", + __func__, count, runtime->buffer_size); + return -EPIPE; + } if (subs->hwptr + count > runtime->buffer_size) { /* err, the transferred area goes over buffer boundary. * copy the data to the temp buffer. -- 2.53.0