From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 BFF0D2D978C; Mon, 20 Apr 2026 16:04:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776701074; cv=none; b=lN2IGluy+99ROHyHBY2apqZDtFo+huPFlXSVl3M2G9fGzGj961z3TU62WEYYGTy15IfEyavFbaeGuW9xVra+d/AkmAey3es39FyvOAdIOlQt+YLrweJ2DGuszqOc30Y7F2AGJgvLPa9bRq+iPy+Bs14MYJbkfMLRh5jz+p0/OtM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776701074; c=relaxed/simple; bh=04AgJ4UYTcFnRjAVSx/tJSpOF1xQjbkwZYnyeBDLj5U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VjKNBxjpduCZwTPfJb8jmfuecQTR5EXaABT9C39Lll4ki2Y7bNC5KgHrP316LEPeAc1iDsADH0qPEnze/E8zsIMjQ+q1a5HW3V9TDJDcSKVMMVg4pwjwH7BBgPRY5R2j1awueHtLonVP2ubhzY3jHzufTTB0YVVV6ZSRieX/dVM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yxjWpcfS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="yxjWpcfS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5655BC19425; Mon, 20 Apr 2026 16:04:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776701074; bh=04AgJ4UYTcFnRjAVSx/tJSpOF1xQjbkwZYnyeBDLj5U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yxjWpcfS8FlrNNokxbKPiuOy04QjvFH3jq9cBUcoFZx3Ixzib8RKXTottJaXryQ3m m+xtraiBqmS9gNPUJTRLPWKtWEmYJWo172HAXwvLBqpevwYjrbsmL9pDpGsW+aweQ4 YkJiHIhSSO43TVbSjOO9HyKzV+hnrqea0ag78whc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , Shuah Khan , Nathan Rebello Subject: [PATCH 6.18 144/198] usbip: validate number_of_packets in usbip_pack_ret_submit() Date: Mon, 20 Apr 2026 17:42:03 +0200 Message-ID: <20260420153940.794249679@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420153935.605963767@linuxfoundation.org> References: <20260420153935.605963767@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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nathan Rebello commit 2ab833a16a825373aad2ba7d54b572b277e95b71 upstream. When a USB/IP client receives a RET_SUBMIT response, usbip_pack_ret_submit() unconditionally overwrites urb->number_of_packets from the network PDU. This value is subsequently used as the loop bound in usbip_recv_iso() and usbip_pad_iso() to iterate over urb->iso_frame_desc[], a flexible array whose size was fixed at URB allocation time based on the *original* number_of_packets from the CMD_SUBMIT. A malicious USB/IP server can set number_of_packets in the response to a value larger than what was originally submitted, causing a heap out-of-bounds write when usbip_recv_iso() writes to urb->iso_frame_desc[i] beyond the allocated region. KASAN confirmed this with kernel 7.0.0-rc5: BUG: KASAN: slab-out-of-bounds in usbip_recv_iso+0x46a/0x640 Write of size 4 at addr ffff888106351d40 by task vhci_rx/69 The buggy address is located 0 bytes to the right of allocated 320-byte region [ffff888106351c00, ffff888106351d40) The server side (stub_rx.c) and gadget side (vudc_rx.c) already validate number_of_packets in the CMD_SUBMIT path since commits c6688ef9f297 ("usbip: fix stub_rx: harden CMD_SUBMIT path to handle malicious input") and b78d830f0049 ("usbip: fix vudc_rx: harden CMD_SUBMIT path to handle malicious input"). The server side validates against USBIP_MAX_ISO_PACKETS because no URB exists yet at that point. On the client side we have the original URB, so we can use the tighter bound: the response must not exceed the original number_of_packets. This mirrors the existing validation of actual_length against transfer_buffer_length in usbip_recv_xbuff(), which checks the response value against the original allocation size. Kelvin Mbogo's series ("usb: usbip: fix integer overflow in usbip_recv_iso()", v2) hardens the receive-side functions themselves; this patch complements that work by catching the bad value at its source -- in usbip_pack_ret_submit() before the overwrite -- and using the tighter per-URB allocation bound rather than the global USBIP_MAX_ISO_PACKETS limit. Fix this by checking rpdu->number_of_packets against urb->number_of_packets in usbip_pack_ret_submit() before the overwrite. On violation, clamp to zero so that usbip_recv_iso() and usbip_pad_iso() safely return early. Fixes: 1325f85fa49f ("staging: usbip: bugfix add number of packets for isochronous frames") Cc: stable Acked-by: Shuah Khan Signed-off-by: Nathan Rebello Link: https://patch.msgid.link/20260402085259.234-1-nathan.c.rebello@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/usbip/usbip_common.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/drivers/usb/usbip/usbip_common.c +++ b/drivers/usb/usbip/usbip_common.c @@ -470,6 +470,18 @@ static void usbip_pack_ret_submit(struct urb->status = rpdu->status; urb->actual_length = rpdu->actual_length; urb->start_frame = rpdu->start_frame; + /* + * The number_of_packets field determines the length of + * iso_frame_desc[], which is a flexible array allocated + * at URB creation time. A response must never claim more + * packets than originally submitted; doing so would cause + * an out-of-bounds write in usbip_recv_iso() and + * usbip_pad_iso(). Clamp to zero on violation so both + * functions safely return early. + */ + if (rpdu->number_of_packets < 0 || + rpdu->number_of_packets > urb->number_of_packets) + rpdu->number_of_packets = 0; urb->number_of_packets = rpdu->number_of_packets; urb->error_count = rpdu->error_count; }