From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 A119C2E7379; Sat, 30 May 2026 17:39:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780162785; cv=none; b=SDiF2lMTb9esPOBXwS8DliCW1weNRg5ruRurs1j29wN0GEdVqoBMaYXcykgtOkuJFEgiMaWQ6XidX1WLRmJnRhfLndV2f4kP2BBEd7e2jyM0jJ//Xd7VoPZMFPh0F0wXPAtaUDXIiOE1i7pIfcP8SH5RoL+Q+NazNzb3bljiBPE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780162785; c=relaxed/simple; bh=YfeDOeWqCcsGtNdodNMJBEgj1b37uzrD0+11vjcomo8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=la/nh9x8eangFbYQdiBMZuDCJF6G3uZJSR4gZbn4rQKApiO2TUTUFGwSRya4acUwDOQSkLe95mrJmdiOh+5Pxj2TvvWjhO2qdY8L6dC613SJ/T44pphiDkQUcPNJzjHlHf3nmLUR/45oTNwovh2m2hbjHF6rBqdJ8h+DduIh17Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mGiYOuym; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mGiYOuym" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E21E61F00893; Sat, 30 May 2026 17:39:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780162784; bh=xEE0ht7VY9oc7XRin9dSD8rw2UMtjtX4BzrMcpqAx3I=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mGiYOuymW3GxdimKoS6Lo+btzzX5X1Bp24MH4CrS2mBFEvuK9if2YQzr/x2A/Xl+a qBeWhn6GGuGaPNTLtu/yo5PsN0RzFraFsreL0CPd059KYw5lRpzqMmRBo8JMfqsbhe Y5fTQOHtLPUvDuz1L+cbGuAP9riBiRZyH+vcgH0Y= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable Subject: [PATCH 5.15 062/776] usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb() Date: Sat, 30 May 2026 17:56:16 +0200 Message-ID: <20260530160241.919245953@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160240.228940103@linuxfoundation.org> References: <20260530160240.228940103@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 5.15-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 @@ -1215,8 +1215,8 @@ 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; }