From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B32F3414413; Wed, 23 Sep 2026 14:17:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790173060; cv=none; b=QqC28AfDVZkNHIZWQrgwDYwsOeTGUoX+aq4OoxmRLIN7id9C0I6t48r/XV5qgKEUJF8FcqvW4SwyWKMPLl3RD4P2fInBVeFNOhjqtvUzauUwc9eY11+/lyjoIhtK0hcygSEfUciWynZ4CtH0wvZrWZeWbIzdWZuWQsj0sBlWwxo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790173060; c=relaxed/simple; bh=zBlvSOLjM1P2UqCIf6NfY63i7lrfY2uIf106M+ln0z4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EioTddvoT7wHS01jwpqH0sAoSxynxNUMa64GvB11CN3gMe9DU5/n96DnGuf5YwYgAsc67c1YB/WTSaJeFPb7MFTAlP72wBvtoUahThLipZLrnlFDpG458vZ+nn7UJNn9D7PKfFHxuPHDtRjlyuTF/m9zozrc7EN8ysWedB2Xpao= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=iKANh9LY; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="iKANh9LY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1359A1F000FF; Wed, 23 Sep 2026 14:17:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790173058; bh=WirVVwuNxmyz+VQ+mCvfFZtC5l2InI8BwWp/mik6vhI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=iKANh9LYXkSCgv+iUg9TEvScDhfs3+L64rDczEzRgYapP7Ksgw3yxxh1EDD1Ql1+i DUWF9fj4ok21daV6VrjbSSYfGmUBUuCKnmBNk8qqLJze0vxaQekRBIVqqZvfWd6u8S cye1G9WrRKGynS6bjtxxb9o3CZtYMcm+ZIgc3jwA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, co+855929c2df672879@bugs.sh, Xiang Mei , Takashi Iwai , Sasha Levin Subject: [PATCH 7.2 139/438] ALSA: 6fire: fix OOB write from device-reported iso length Date: Wed, 23 Sep 2026 16:02:40 +0200 Message-ID: <20260923140648.379396499@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260923140644.756254324@linuxfoundation.org> References: <20260923140644.756254324@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiang Mei [ Upstream commit 1589afe2d099d3e817873bc474676968d7080410 ] usb6fire_pcm_in_urb_handler() sizes each outgoing isochronous packet as (actual_length - 4) / (in_n_analog << 2) * (out_n_analog << 2) + 4, where actual_length is the unsigned length the device reported for the matching IN packet. A packet completed with status 0 and actual_length < 4 wraps the subtraction to 0x7fffffec; a zero-length isochronous packet is legal on the bus, and the preceding loop rejects only non-zero status. The sum reaches memset() on out_urb->buffer, a 4832-byte object from kcalloc(PCM_MAX_PACKET_SIZE, PCM_N_PACKETS_PER_URB). Even without the wrap the result is out of bounds: at 88.2/96 kHz the 4-in/6-out scaling turns a full 420-byte IN packet into 628, so eight packets span 5024 bytes of that buffer. usb_submit_urb() rejects an over-long descriptor only after the memset() and the usb6fire_pcm_playback() copy of user PCM data have run. Guard the subtraction as the sibling usb6fire_pcm_capture() already does, and limit the frame count to what fits in rt->out_packet_size, the OUT endpoint's wMaxPacketSize. This bounds total_length by the buffer size while keeping each packet length aligned to a whole output frame. BUG: KASAN: out-of-bounds in usb6fire_pcm_in_urb_handler (sound/usb/6fire/pcm.c:338) Write of size 18446744073709551456 at addr ffff88802a3d0000 by task vhci_rx/5018 Call Trace: dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) print_report (mm/kasan/report.c:378 mm/kasan/report.c:482) kasan_report (mm/kasan/report.c:595) kasan_check_range (mm/kasan/generic.c:186 mm/kasan/generic.c:200) __asan_memset (mm/kasan/shadow.c:84) usb6fire_pcm_in_urb_handler (sound/usb/6fire/pcm.c:338) __usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1657) usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1741) vhci_rx_loop (drivers/usb/usbip/vhci_rx.c:107 drivers/usb/usbip/vhci_rx.c:242) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) Allocated by task 10: __kmalloc_cache_noprof (mm/slub.c:5563) usb6fire_pcm_init (sound/usb/6fire/pcm.c:560 sound/usb/6fire/pcm.c:595) usb6fire_chip_probe (sound/usb/6fire/chip.c:133) usb_probe_interface (drivers/usb/core/driver.c:399) The buggy address belongs to the object at ffff88802a3d0000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 0 bytes inside of 4832-byte region [ffff88802a3d0000, ffff88802a3d12e0) Kernel panic - not syncing: Fatal exception in interrupt Fixes: c6d43ba816d1 ("ALSA: usb/6fire - Driver for TerraTec DMX 6Fire USB") Reported-by: co+855929c2df672879@bugs.sh Closes: https://lore.kernel.org/all/gisnub8aWGLbyZLcDCSc7zWsHonMWGcyRgt5%40bugs.sh/ Assisted-by: LLM Signed-off-by: Xiang Mei Link: https://patch.msgid.link/20260914074324.3590843-1-xmei5@asu.edu Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/usb/6fire/pcm.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/sound/usb/6fire/pcm.c b/sound/usb/6fire/pcm.c index 21789db6657d3..0285d79ace0fc 100644 --- a/sound/usb/6fire/pcm.c +++ b/sound/usb/6fire/pcm.c @@ -335,11 +335,19 @@ static void usb6fire_pcm_in_urb_handler(struct urb *usb_urb) /* setup out urb structure */ for (i = 0; i < PCM_N_PACKETS_PER_URB; i++) { + unsigned int frames = 0; + isoc_out = &out_urb->instance->iso_frame_desc[i]; isoc_in = &in_urb->instance->iso_frame_desc[i]; + if (isoc_in->actual_length > 4) + frames = (isoc_in->actual_length - 4) + / (rt->in_n_analog << 2); + frames = min_t(unsigned int, frames, + (rt->out_packet_size - 4) + / (rt->out_n_analog << 2)); + isoc_out->offset = total_length; - isoc_out->length = (isoc_in->actual_length - 4) / (rt->in_n_analog << 2) - * (rt->out_n_analog << 2) + 4; + isoc_out->length = frames * (rt->out_n_analog << 2) + 4; isoc_out->status = 0; total_length += isoc_out->length; } -- 2.53.0