From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6155EC001E0 for ; Mon, 23 Oct 2023 11:07:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233419AbjJWLHn (ORCPT ); Mon, 23 Oct 2023 07:07:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55340 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233406AbjJWLHm (ORCPT ); Mon, 23 Oct 2023 07:07:42 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F7B5D6E for ; Mon, 23 Oct 2023 04:07:40 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E19DC433C7; Mon, 23 Oct 2023 11:07:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1698059259; bh=kSY42+fR68Adgo1EnYnYIec3S5fbAk3xpejJzPxmEpU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jyj10dIMxf82K2Q6ntOUW+gb93UwTDrAms36Pm3l94LfrFv2CS1SG2R57LWJvx3sz oXQ4kzYgtmYY+40efyPBwutDIheE3bOPhjTgIqsHcASHFYxVZ7He8973b4wxkXKMaT PEVMPjXp+jI/5RVydvaoi5+xvTj/nAS9tfHZ12cw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+01cdbc31e9c0ae9b33ac@syzkaller.appspotmail.com, syzbot+c99d835ff081ca30f986@syzkaller.appspotmail.com, Willem de Bruijn , Eric Dumazet , Jason Wang , "David S. Miller" Subject: [PATCH 6.5 091/241] net: more strict VIRTIO_NET_HDR_GSO_UDP_L4 validation Date: Mon, 23 Oct 2023 12:54:37 +0200 Message-ID: <20231023104836.111766102@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231023104833.832874523@linuxfoundation.org> References: <20231023104833.832874523@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Willem de Bruijn commit fc8b2a619469378717e7270d2a4e1ef93c585f7a upstream. Syzbot reported two new paths to hit an internal WARNING using the new virtio gso type VIRTIO_NET_HDR_GSO_UDP_L4. RIP: 0010:skb_checksum_help+0x4a2/0x600 net/core/dev.c:3260 skb len=64521 gso_size=344 and RIP: 0010:skb_warn_bad_offload+0x118/0x240 net/core/dev.c:3262 Older virtio types have historically had loose restrictions, leading to many entirely impractical fuzzer generated packets causing problems deep in the kernel stack. Ideally, we would have had strict validation for all types from the start. New virtio types can have tighter validation. Limit UDP GSO packets inserted via virtio to the same limits imposed by the UDP_SEGMENT socket interface: 1. must use checksum offload 2. checksum offload matches UDP header 3. no more segments than UDP_MAX_SEGMENTS 4. UDP GSO does not take modifier flags, notably SKB_GSO_TCP_ECN Fixes: 860b7f27b8f7 ("linux/virtio_net.h: Support USO offload in vnet header.") Reported-by: syzbot+01cdbc31e9c0ae9b33ac@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/0000000000005039270605eb0b7f@google.com/ Reported-by: syzbot+c99d835ff081ca30f986@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/0000000000005426680605eb0b9f@google.com/ Signed-off-by: Willem de Bruijn Reviewed-by: Eric Dumazet Acked-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/linux/virtio_net.h | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 7b4dd69555e4..27cc1d464321 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -3,8 +3,8 @@ #define _LINUX_VIRTIO_NET_H #include +#include #include -#include #include static inline bool virtio_net_hdr_match_proto(__be16 protocol, __u8 gso_type) @@ -151,9 +151,22 @@ retry: unsigned int nh_off = p_off; struct skb_shared_info *shinfo = skb_shinfo(skb); - /* UFO may not include transport header in gso_size. */ - if (gso_type & SKB_GSO_UDP) + switch (gso_type & ~SKB_GSO_TCP_ECN) { + case SKB_GSO_UDP: + /* UFO may not include transport header in gso_size. */ nh_off -= thlen; + break; + case SKB_GSO_UDP_L4: + if (!(hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM)) + return -EINVAL; + if (skb->csum_offset != offsetof(struct udphdr, check)) + return -EINVAL; + if (skb->len - p_off > gso_size * UDP_MAX_SEGMENTS) + return -EINVAL; + if (gso_type != SKB_GSO_UDP_L4) + return -EINVAL; + break; + } /* Kernel has a special handling for GSO_BY_FRAGS. */ if (gso_size == GSO_BY_FRAGS) -- 2.42.0