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 5AF2533F586; Mon, 20 Apr 2026 16:10:14 +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=1776701414; cv=none; b=l/wxCYgdgktawvxtDlwEFppJvcgBjp6Y/M4rIcr9IHZinpkc5TsAe2v0wjs2S12ZtryeG3UVapMDa3jVruwj1YKXM8FegMn5h5lbO4DPZIO2uMrIF57mUNcudZW6G4Ypm82Izjf9lriNaWAaJ5/rGedlrhVhI0DRzkt7u2SpGNU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776701414; c=relaxed/simple; bh=Er64kUKQw5Eoy96PC19VHuuOiI5wpLgsYgojeQs6g/4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NgQ1W5ecsrG/e8e2WrctYspTnA8WyNPw9qFVjyDVcBUzvGTIfddLwiIu4ms9Gf3sze6EEbe1PWw80N1yzbgewDYjoD2cmqyYhLCX8Osl5dh1xNp7ZaHaRt342UzmfbqMeGz2QiG9Y+OTSowQelw2zHKs3AijjLMx8yFOVOPhpyw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=zyNRaF5p; 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="zyNRaF5p" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7228C2BCB7; Mon, 20 Apr 2026 16:10:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776701414; bh=Er64kUKQw5Eoy96PC19VHuuOiI5wpLgsYgojeQs6g/4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zyNRaF5pdMQT+xrNZnFuN6bKeMGJWiBN1YZfyoYdAedPB1jrxaqBxfhp5t48yDXJx SjnZbJBOJBrjd/VcZTUax7Epo6fJzjPx2h2/f04XGwGIgetgd3x2GT9wkkdJBLv5Rf 3ZumXiJu+iY/PDnguIgl3wWVZDTGUlMTmRdh7tao= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable Subject: [PATCH 6.12 104/162] usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb() Date: Mon, 20 Apr 2026 17:42:16 +0200 Message-ID: <20260420153930.807453800@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420153927.006696811@linuxfoundation.org> References: <20260420153927.006696811@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Greg Kroah-Hartman commit 8f993d30b95dc9557a8a96ceca11abed674c8acb upstream. The block_len read from the host-supplied NTB header is checked against ntb_max but has no lower bound. When block_len is smaller than opts->ndp_size, the bounds check of: ndp_index > (block_len - opts->ndp_size) will underflow producing a huge unsigned value that ndp_index can never exceed, defeating the check entirely. The same underflow occurs in the datagram index checks against block_len - opts->dpe_size. With those checks neutered, a malicious USB host can choose ndp_index and datagram offsets that point past the actual transfer, and the skb_put_data() copies adjacent kernel memory into the network skb. Fix this by rejecting block lengths that cannot hold at least the NTB header plus one NDP. This will make block_len - opts->ndp_size and block_len - opts->dpe_size both well-defined. Commit 8d2b1a1ec9f5 ("CDC-NCM: avoid overflow in sanity checking") fixed a related class of issues on the host side of NCM. Fixes: 2b74b0a04d3e ("USB: gadget: f_ncm: add bounds checks to ncm_unwrap_ntb()") Cc: stable Assisted-by: gregkh_clanker_t1000 Link: https://patch.msgid.link/2026040753-baffle-handheld-624d@gregkh Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_ncm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/usb/gadget/function/f_ncm.c +++ b/drivers/usb/gadget/function/f_ncm.c @@ -1209,8 +1209,8 @@ parse_ntb: block_len = get_ncm(&tmp, opts->block_length); /* (d)wBlockLength */ - if (block_len > ntb_max) { - INFO(port->func.config->cdev, "OUT size exceeded\n"); + if ((block_len < opts->nth_size + opts->ndp_size) || (block_len > ntb_max)) { + INFO(port->func.config->cdev, "Bad block length: %#X\n", block_len); goto err; }