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 C5C2623183B; Thu, 19 Jun 2025 21:22:05 +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=1750368125; cv=none; b=oVJUAULnBOWuBLRoyNwf5wihv5EbZyt40q3JcXQmEXOv2ijZhcn3ZeZ8R47qTvr/cZqBHg6RmPVnbDPIOsfu57+St6DDH0qyBKwiBxfBLIBiFK3LymiUVMwElIjGVTR7T/UwX4ROdSyZZDYgUOFv9bp66hFZWTVJ5em7ecYRoW8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750368125; c=relaxed/simple; bh=pRuGfH2o8r29IBa31hoMcUPybgxpzd9xd7p/eTD4ucE=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=ajfDyKAHuaRzUKQc6AcoaiEvCieKEPULNL/tcPGH7NzyzPKxJrwn8QN7F4jnocAEd7pOQ3wLf55bIst3bw/IMhWzWMVHC21UOOUQlCv9R47ItpneOzWBwYZSSu/uv0s0WNqmYNBSSG88s7X1SyjliLhVdmOZ6qodL5bMFGV9XMw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QB7oRRku; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QB7oRRku" Received: by smtp.kernel.org (Postfix) with ESMTPS id 6067EC4CEEA; Thu, 19 Jun 2025 21:22:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750368125; bh=pRuGfH2o8r29IBa31hoMcUPybgxpzd9xd7p/eTD4ucE=; h=From:Date:Subject:To:Cc:Reply-To:From; b=QB7oRRkujF64rco7v1qJSFRQ2UuX/i+bueaLWm8EloYX302qLwPpi60nZiCv2LpFh b0DqWyUc3mEuw3RZ5fP0k0ZLuNKfRmR2LYyaXB8EPeBv+WVMwOFjx1XhLtP1o4bFPP 3FOfOmk1krrwGqGFisNi5MS7IcHV2SKrsZi3KhXugevEAnx3eXu/tKqswkB3gXv+FW xWBRJVLKsq2YlDhKlDNPXktdimQm4ainjzAAQCooQvyiX9YpCm6mqHgUetK5UD+D2H EVFoVU5Jq3bwimQqxyCSK3QW0bFN3hi1SSClf6B+5loLFs5KHPbYZNDgC/Ulh/SSkm 9VArDebKn7jQg== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5626BC7115A; Thu, 19 Jun 2025 21:22:05 +0000 (UTC) From: Dominique Martinet via B4 Relay Date: Fri, 20 Jun 2025 06:22:03 +0900 Subject: [PATCH v2] net/9p: Fix buffer overflow in USB transport layer Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20250620-9p-usb_overflow-v2-1-026c6109c7a1@codewreck.org> X-B4-Tracking: v=1; b=H4sIAHp/VGgC/y2NWw6CMBQFt0LutyV90Cb45T4MMQVu4RqgpFXUk O7dSvyck5yZHSIGwgjnYoeAG0XySwZ5KqAb7TIgoz4zSC41N5KzemXP2N78hsFN/sWkbl2nsW7 RKcivNaCj92G8NplHig8fPkdgE7/17xJGKKlVXRpVqYoJ1tuF4p1y9DLMlqay8zM0KaUvVTFZO 6UAAAA= X-Change-ID: 20250620-9p-usb_overflow-25bfc5e9bef3 To: Eric Van Hensbergen , Latchesar Ionkov , Christian Schoenebeck , Greg Kroah-Hartman , Michael Grzeschik Cc: stable@vger.kernel.org, Yuhao Jiang , security@kernel.org, v9fs@lists.linux.dev, linux-kernel@vger.kernel.org, Dominique Martinet X-Mailer: b4 0.15-dev-7be4f X-Developer-Signature: v=1; a=openpgp-sha256; l=2874; i=asmadeus@codewreck.org; h=from:subject:message-id; bh=sd75KIQYdSHcNYSxHvOsd/ZrBkByS+On5VAz8Wg9id0=; b=owEBbQKS/ZANAwAKAatOm+xqmOZwAcsmYgBoVH98nfmseHzKhOwth426LG3xCNHGuKrMrPYIS 6knofnzWnuJAjMEAAEKAB0WIQT8g9txgG5a3TOhiE6rTpvsapjmcAUCaFR/fAAKCRCrTpvsapjm cKyeD/oCJfejbpmPwkb/cnIW8YPsRFbmsDmvntEQHaill6n6KcyQB3v3oKHUGopejHFtiUl8TYQ NToXHtB3AKIWS7xpi4nHpHT+0QBUKW8TADf4peHz6SC9Mtnz3tUGLcrDMEFEjOBz9z+dQMfzEXT cLulWcIkJfGJQzNr0WON4ekRHI/EH0KSETffLJ5uedpG15CJPSypltjzs2RYIBtHyYiR6rcfSx6 /snUGfZrEbSz/XfTLB3LOdxrFPEk6Ue/lJ7i2A4ANJGxL9SNKoF7iOnzPBjqhvgENnn/XgWi1Td +eq24+g3eeygU8qsaYnmtRHZYGa9Tm6ea8a1yG7wBS234sgRNMOfKTjH5nbLmvTDM9uQrbYdb+W vMeOdDJfeTh9ebLmRxdHGBkdZvliQKm/l0uU6G/wJ8DRmprt+sun73E7h90Zd53/u39mH3kj/3i i1l2jIGgVbBCjbxa9Nhdo0cfQcv1EdYRviS7m5azPRYRwKrRxaVXEc0sx9ef3X/iYNpZiewb6J9 hxTVpZIe+YgQ1CTyAUlMWpv79xb/B8Ondu6yAX83B1+bfoZlJCRoThx2jtyR10yNjvRg11gY4Bj EDmfB3Zd6juPxcftwIgFSKK8fE1WgtERblihLOmKiO7xz+qjINPl/nurkKs7eF+xY7Zju1y4GX0 Vq4Nxjjs6kH9Neg== X-Developer-Key: i=asmadeus@codewreck.org; a=openpgp; fpr=B894379F662089525B3FB1B9333F1F391BBBB00A X-Endpoint-Received: by B4 Relay for asmadeus@codewreck.org/default with auth_id=435 X-Original-From: Dominique Martinet Reply-To: asmadeus@codewreck.org From: Dominique Martinet A buffer overflow vulnerability exists in the USB 9pfs transport layer where inconsistent size validation between packet header parsing and actual data copying allows a malicious USB host to overflow heap buffers. The issue occurs because: - usb9pfs_rx_header() validates only the declared size in packet header - usb9pfs_rx_complete() uses req->actual (actual received bytes) for memcpy This allows an attacker to craft packets with small declared size (bypassing validation) but large actual payload (triggering overflow in memcpy). Add validation in usb9pfs_rx_complete() to ensure req->actual does not exceed the buffer capacity before copying data. Reported-by: Yuhao Jiang Closes: https://lkml.kernel.org/r/20250616132539.63434-1-danisjiang@gmail.com Fixes: a3be076dc174 ("net/9p/usbg: Add new usb gadget function transport") Cc: stable@vger.kernel.org Signed-off-by: Dominique Martinet --- Not actually tested, I'll try to find time to figure out how to run with qemu for real this time... Changes in v2: - run through p9_client_cb() on error - Link to v1: https://lore.kernel.org/r/20250616132539.63434-1-danisjiang@gmail.com --- net/9p/trans_usbg.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/net/9p/trans_usbg.c b/net/9p/trans_usbg.c index 6b694f117aef296a66419fed5252305e7a1d0936..43078e0d4ca3f4063660f659d28452c81bef10b4 100644 --- a/net/9p/trans_usbg.c +++ b/net/9p/trans_usbg.c @@ -231,6 +231,8 @@ static void usb9pfs_rx_complete(struct usb_ep *ep, struct usb_request *req) struct f_usb9pfs *usb9pfs = ep->driver_data; struct usb_composite_dev *cdev = usb9pfs->function.config->cdev; struct p9_req_t *p9_rx_req; + unsigned int req_size = req->actual; + int status = REQ_STATUS_RCVD; if (req->status) { dev_err(&cdev->gadget->dev, "%s usb9pfs complete --> %d, %d/%d\n", @@ -242,11 +244,19 @@ static void usb9pfs_rx_complete(struct usb_ep *ep, struct usb_request *req) if (!p9_rx_req) return; - memcpy(p9_rx_req->rc.sdata, req->buf, req->actual); + if (req_size > p9_rx_req->rc.capacity) { + dev_err(&cdev->gadget->dev, + "%s received data size %u exceeds buffer capacity %zu\n", + ep->name, req_size, p9_rx_req->rc.capacity); + req_size = 0; + status = REQ_STATUS_ERROR; + } - p9_rx_req->rc.size = req->actual; + memcpy(p9_rx_req->rc.sdata, req->buf, req_size); - p9_client_cb(usb9pfs->client, p9_rx_req, REQ_STATUS_RCVD); + p9_rx_req->rc.size = req_sizel; + + p9_client_cb(usb9pfs->client, p9_rx_req, status); p9_req_put(usb9pfs->client, p9_rx_req); complete(&usb9pfs->received); --- base-commit: 74b4cc9b8780bfe8a3992c9ac0033bf22ac01f19 change-id: 20250620-9p-usb_overflow-25bfc5e9bef3 Best regards, -- Dominique Martinet