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 B1181217704; Sat, 30 May 2026 18:22:33 +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=1780165354; cv=none; b=gb3GHbOVX7ke5mRASAxn0OryctXCt581/Ak3bfYadWi3K5Tc6+U3DPRVZiC13GsAPOQxKNigPV9+rsRk0IiywSrHjPxTlbxDSAt0jgGiwgkcY5gDnbjPG3ELTh50kTjDjkc6jNT6Zps9OGMoWI3aJ2aMOrsZYGy9bRUaytWq8XY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780165354; c=relaxed/simple; bh=0aSysfY0QNO4MQ+uM+Ef66pYSQ/MQyhCgo4iujUZ3+s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=m/VVh7u98sBD6myrk+r2c21zdGWzm4As0fGaW/kJ7Cz3Ar1bxAaQAfNEAm5hl0NwKEg506nQ5gNmnX2XL2jVZmwByUiUowUZKwp5v3JNEfgfvknxVdt10QuSpu/MGL5KfzzpIf6NTnasgGhQaJq3x+58uRa3nFoVGB8tTYJpkBs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fg1Y/yvc; 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="fg1Y/yvc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 03BB71F00893; Sat, 30 May 2026 18:22:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780165353; bh=djMas0v1UMkTQ+r2rTXTEy4L/wg97MWH3utA0AHIDDY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=fg1Y/yvcQEI3s9Q1QDWD+O7mLjmAf6SOl2Fw2pcZx8Nl/SBf0k4pZqacuU3yUrb8+ M8XZ3taYwxLQ6C38LB9jihp/tUhbjFjhQ/SeJlx93Qei5PyQB+BOmu3qcFDmBLHeWG 0G58CxdwMnG2kdReQq4rahcQxqpkGh7I3q3KYeO0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable Subject: [PATCH 5.10 053/589] usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb() Date: Sat, 30 May 2026 17:58:54 +0200 Message-ID: <20260530160225.986715297@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160224.570625122@linuxfoundation.org> References: <20260530160224.570625122@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 5.10-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 @@ -1218,8 +1218,8 @@ 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; }