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 890373B5F5D; Tue, 12 May 2026 14:38:09 +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=1778596689; cv=none; b=WLWAmjj7EJ9YIeaeYaipdkFuAUcM9YTZDXyAKco5O7Foak+7b78J8Cn+ZnfSg0qW/levV+zD5gEpqzEDCd8AswvRydrQrJtWoKb4X7IIP2N7IWGXQCAvfQazVGs+qlzH8YAR+1tTeeclVnfu6E/wCcVJYO/33LUXQRXMlxiAELA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778596689; c=relaxed/simple; bh=jbLD75OPWL6SVoyShglRzZ8g9b0hfzwobh3zc9lFvnE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZUIGp18qlKP0DmpYT1hqC10SYbuK2yPm6DaWpZ0N1mmT035NsO1n2E4HkOz6mHRQeYDh2a/OvWKaH+XWVdBPyiJKKLSJyTY4ccRUG3gQ9ZXhOusyo2nsTXqLIbCl9fk8gzcdFIxrzyFacZpMFaBzZesq4OPz+80RAxo68R1Ducs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UYrcBT9s; 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="UYrcBT9s" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1EB48C2BCB0; Tue, 12 May 2026 14:38:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778596689; bh=jbLD75OPWL6SVoyShglRzZ8g9b0hfzwobh3zc9lFvnE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UYrcBT9sp4yjXzDVwf/vTaxcqAsp3us210SJWzfIb+QqdOZk/kvUVnKrATPK8DA0z PNiFNzJ7X02hnSki/8k4hI04nvVAbb34hXRdgNCxcAmDdD59VxT2YUh+TnRxitcBBh ymiC3PJE6dFjsmU1SAgtVBe7rs27CnuI0JOzeVlc= Date: Tue, 12 May 2026 16:32:51 +0200 From: Greg Kroah-Hartman To: Sebastian EM Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] usb: gadget: composite: fix integer underflow in WebUSB GET_URL handling Message-ID: <2026051237-delicacy-gallon-268c@gregkh> References: <20260512014343.3770664-1-mendozayt13@gmail.com> <2026051221-glory-macaroni-dce6@gregkh> <2026051245-kangaroo-matriarch-8eed@gregkh> 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=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Tue, May 12, 2026 at 09:12:14AM -0500, Sebastian EM wrote: > 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 > --- > v2: > - Drop the self Reported-by tag. > - Add Fixes tag. > - Cc stable. > > 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 > > El mar, 12 may 2026 a las 8:29, Greg Kroah-Hartman (< > gregkh@linuxfoundation.org>) escribió: > > > On Tue, May 12, 2026 at 06:18:54AM -0500, Sebastian EM wrote: > > > Hi Greg, > > > > > > Thanks for the review. > > > > > > You are right; the self Reported-by tag does not belong there, so I > > dropped > > > it in v2. > > > > > > The introducing commit is: > > > > > > 93c473948c58 ("usb: gadget: add WebUSB landing page support") > > > > > > I also added: > > > > > > Cc: stable@vger.kernel.org > > > > > > since the issue was introduced with the WebUSB GET_URL handling path and > > > the fix is a small bounds/underflow fix suitable for stable kernels. > > > > > > v2 is attached as a plain patch: > > > > > > > > 0001-v2-usb-gadget-composite-fix-integer-underflow-in-WebUSB-GET_URL-handling.patch > > > > We can't take patches as attachments, just send this as a normal v2 > > patch. > > > > thanks, > > > > greg k-h > > Hi, This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him a patch that has triggered this response. He used to manually respond to these common problems, but in order to save his sanity (he kept writing the same thing over and over, yet to different people), I was created. Hopefully you will not take offence and will fix the problem in your patch and resubmit it so that it can be accepted into the Linux kernel tree. You are receiving this message because of the following common error(s) as indicated below: - Your patch is malformed (tabs converted to spaces, linewrapped, etc.) and can not be applied. Please read the file, Documentation/process/email-clients.rst in order to fix this. If you wish to discuss this problem further, or you have questions about how to resolve this issue, please feel free to respond to this email and Greg will reply once he has dug out from the pending patches received from other developers. thanks, greg k-h's patch email bot