From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f181.google.com (mail-qk1-f181.google.com [209.85.222.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D1B803C2BAF for ; Tue, 12 May 2026 15:38:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778600315; cv=none; b=n5qb5KytK/A1mWFCxOc5xvmQJbLq8mcIaASAJX3mqLdtfeqRdmGSw0AUuZ5NRgPBCNG447QUY6ZoCgkUU/KyIA9rJQ7kZ1QSk3Tj1gH/WqWFGR0yqw5aOZst4wF3QOnX9k1YEj1uzQyT/BzI9s/Y3CN13KQo9NXQx3cdyr4v8kE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778600315; c=relaxed/simple; bh=h9bsPBYcOXqMfv+VjbAyojonmmoubV1MX83pq2oMIGQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=G5F+rqgD9XFN85sOD0vVlB5TNO2KAw0na1QcYPAziB3X9ddS5Stj+dj08kVQ7egL75j9E65JydCPTSxEn/LJh2PL2KBHQjzwHCdCucfs+jDwTnD6kUMeHItJD+EIYsiZDiYNPHAcqan24ED5+pF5dMMT7jyX4tdEjsLSoOZrZjo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=TRXrUCuL; arc=none smtp.client-ip=209.85.222.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="TRXrUCuL" Received: by mail-qk1-f181.google.com with SMTP id af79cd13be357-8cb5c9ba82bso813876185a.2 for ; Tue, 12 May 2026 08:38:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1778600313; x=1779205113; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=ZT0wrWmrJN0SJeayxN4+PzyvP8WgeUPSpw6VtORWwAU=; b=TRXrUCuL5qt+imjfrwEC7P9hkuSMXXElskCeFBD0WarzIy6Vi34JxGtvlKazRupPOe 2rrDg6Ov6u4irjIApiKdWC5MZH5bszFgFiI82hOvQtdoSZr1lYwy+zxfpT06G8M7DI4Y UwkebQZAjrLLgHQcmCI58m3ZPoNt6M3CqRVzsNOWtnKUtUCZXUmMrX0saw0Losw19LlJ xoAxDo/io9VbmTSQr8SrAN2TINoMMqiJDrW+yeS1OmZ1LwPiLoQLcgjLnKHwCP0189lI fd2Uf+xRHFtq5RQL/XO3le6dIfwni9IpDUFg7e2AGqdLpxnLBdUYX1QBtkc4BzqfnBna pQiw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778600313; x=1779205113; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=ZT0wrWmrJN0SJeayxN4+PzyvP8WgeUPSpw6VtORWwAU=; b=C67lP0CP+CBeUaKf8yroCFaYCWmzOzMOnKCKUnz6RjJpGHR0hztPiIpREnPOZtx7xa snDB7gk6EpAPo2FOrkOn0k/nxZ/JNyoJ43faXA8K8LM9+nCX4iwDeg8g+ncdfZhF9QFP TeGXPCS73vDm+u2yVJmX3LxNUJsj7ZGTjZfePaNLf3pktsDvap7LH8JKhhDrFYak7DuW ZWnEEHcnC1sYxAs7GxhJYdXREKLF6sg4zYZggOIZxwhzobv+1BL3+BjUPmum++nSkD45 NcQ5lS68ls5ur4mOrQhGczVXmokY3ejVrb4Pby/6eDm7bzGq5LcHYtbC/Och/ppRE2Eg mTqQ== X-Gm-Message-State: AOJu0YySxsEV85hcLsnY/kNMCMM+jypTTyyN8TOHTxhaWRLzRoePCJhm iYnlJWdw3SgKTYQgrSXLv7U4N4DQnyaJ4rr28ebOWnfA6HaYIE5rCOloySVHFw== X-Gm-Gg: Acq92OF0aNqNJAzyj1aBdtBAfdNdjqvMnBkGjXcX+M2LgDlgxBfjKjl9+pDHUxPnaLU ktLFf7jlWOLM6JgXM4S8vg9F5FmHnC95cIwgoXIVD69ofLkkc8OJ4kAU60s1gkMZ7KtKYhxf8jX AFnrT6Vtp9Hosbavlnbnbi8Ns6Jtw7v3ohAnZyRTaeU8MmM52UMKn6rwf8s9RI3am5mYuHz944p 71/XuJCKAC1S9cWzeB4RCR1VAva9aM0rC6dNox0HW46TlNJDI8Qks4cF2gK1uU9VdqjqW09SATC lViu0QZIoSE/JkuVuPnS+tNQCg5L5QSz2ls44dSttUOAe4xd4yq8CFwAX9qzPgaRhkLbh2AhTIi 7YRBTt15s7gGkk1wLmH8LCl8yDi0jBxasFD5UGombXNRwvYTTuPv4FxRXHuV8SotRLXC6FmvWhc DalI2zWzMEek6B21TMdZ/8bKCH3lTsKmtf68+o0OiMXQJcCuI2GjcvpQXWe1iopEYuYR/zX5HzK x51OpDHAxAOA5I= X-Received: by 2002:a05:620a:372a:b0:8f4:e8ce:8f4 with SMTP id af79cd13be357-90cfd34179emr518940485a.47.1778600312657; Tue, 12 May 2026 08:38:32 -0700 (PDT) Received: from jeremy.kali (srv1619992.hstgr.cloud. [2a02:4780:75:55a3::1]) by smtp.gmail.com with ESMTPSA id af79cd13be357-907b966f5f1sm1412826585a.8.2026.05.12.08.38.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 May 2026 08:38:32 -0700 (PDT) From: Jeremy Erazo To: Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v2] usb: gadget: composite: fix integer underflow in WebUSB GET_URL handling Date: Tue, 12 May 2026 15:38:25 +0000 Message-ID: <20260512153825.327038-1-mendozayt13@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026051237-delicacy-gallon-268c@gregkh> References: <2026051237-delicacy-gallon-268c@gregkh> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The WebUSB GET_URL handler in composite_setup() narrows landing_page_length to fit the host-supplied wLength using landing_page_length = w_length - WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH + landing_page_offset; If wLength is smaller than WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH the unsigned subtraction wraps, and the subsequent memcpy(url_descriptor->URL, cdev->landing_page + landing_page_offset, landing_page_length - landing_page_offset); ends up copying close to UINT_MAX bytes from cdev->landing_page into cdev->req->buf. KASAN reports a slab-out-of-bounds in composite_setup on the kmalloc-2k gadget_info allocation, and FORTIFY_SOURCE traps the memcpy as a 4294967293-byte field-spanning write into url_descriptor->URL (size 252). A USB host can reach this from a single SETUP packet against any gadget that has webusb/use=1 and a landingPage configured. Handle the small-wLength case before the math: when the host requested fewer bytes than the URL descriptor header, only the header is meaningful and no URL bytes need to be copied. Setting landing_page_length to landing_page_offset makes the existing memcpy a no-op and leaves the descriptor returned to the host unchanged for all larger wLength values. Fixes: 93c473948c58 ("usb: gadget: add WebUSB landing page support") Cc: stable@vger.kernel.org Signed-off-by: Jeremy Erazo --- drivers/usb/gadget/composite.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c index a902184bd..dc3664374 100644 --- a/drivers/usb/gadget/composite.c +++ b/drivers/usb/gadget/composite.c @@ -2172,7 +2172,10 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl) sizeof(url_descriptor->URL) - WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH + landing_page_offset); - if (w_length < WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH + landing_page_length) + if (w_length < WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH) + landing_page_length = landing_page_offset; + else if (w_length < + WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH + landing_page_length) landing_page_length = w_length - WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH + landing_page_offset; -- 2.53.0