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 X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36511C43603 for ; Mon, 12 Apr 2021 09:31:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1566D6120F for ; Mon, 12 Apr 2021 09:31:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241737AbhDLJ0l (ORCPT ); Mon, 12 Apr 2021 05:26:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:57432 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239104AbhDLJC0 (ORCPT ); Mon, 12 Apr 2021 05:02:26 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A088A61283; Mon, 12 Apr 2021 09:01:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618218071; bh=pXS7HcrEri1qk/T2C4B0R49ir6M9TZCkcZPLOhAro5c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Yy1msW72bfh3qCwnlGExHWVb8ZD4KoT0teFjfd0b2d8c9TuHrHeKVpJPdbQNNjczB uh7qVN+23wB6hA0rBWzA3voPZjobMez5EIAQOiwBSWELAjGIu17CK2DTpXYfnDzGkc e9xmlYqW1IQsVAjDvz4fJzIWjM3yTWgkV71zgwWI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Balazs Nemeth , Willem de Bruijn , syzbot , "David S. Miller" Subject: [PATCH 5.11 061/210] net: ensure mac header is set in virtio_net_hdr_to_skb() Date: Mon, 12 Apr 2021 10:39:26 +0200 Message-Id: <20210412084018.030687595@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210412084016.009884719@linuxfoundation.org> References: <20210412084016.009884719@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet commit 61431a5907fc36d0738e9a547c7e1556349a03e9 upstream. Commit 924a9bc362a5 ("net: check if protocol extracted by virtio_net_hdr_set_proto is correct") added a call to dev_parse_header_protocol() but mac_header is not yet set. This means that eth_hdr() reads complete garbage, and syzbot complained about it [1] This patch resets mac_header earlier, to get more coverage about this change. Audit of virtio_net_hdr_to_skb() callers shows that this change should be safe. [1] BUG: KASAN: use-after-free in eth_header_parse_protocol+0xdc/0xe0 net/ethernet/eth.c:282 Read of size 2 at addr ffff888017a6200b by task syz-executor313/8409 CPU: 1 PID: 8409 Comm: syz-executor313 Not tainted 5.12.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232 __kasan_report mm/kasan/report.c:399 [inline] kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416 eth_header_parse_protocol+0xdc/0xe0 net/ethernet/eth.c:282 dev_parse_header_protocol include/linux/netdevice.h:3177 [inline] virtio_net_hdr_to_skb.constprop.0+0x99d/0xcd0 include/linux/virtio_net.h:83 packet_snd net/packet/af_packet.c:2994 [inline] packet_sendmsg+0x2325/0x52b0 net/packet/af_packet.c:3031 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:674 sock_no_sendpage+0xf3/0x130 net/core/sock.c:2860 kernel_sendpage.part.0+0x1ab/0x350 net/socket.c:3631 kernel_sendpage net/socket.c:3628 [inline] sock_sendpage+0xe5/0x140 net/socket.c:947 pipe_to_sendpage+0x2ad/0x380 fs/splice.c:364 splice_from_pipe_feed fs/splice.c:418 [inline] __splice_from_pipe+0x43e/0x8a0 fs/splice.c:562 splice_from_pipe fs/splice.c:597 [inline] generic_splice_sendpage+0xd4/0x140 fs/splice.c:746 do_splice_from fs/splice.c:767 [inline] do_splice+0xb7e/0x1940 fs/splice.c:1079 __do_splice+0x134/0x250 fs/splice.c:1144 __do_sys_splice fs/splice.c:1350 [inline] __se_sys_splice fs/splice.c:1332 [inline] __x64_sys_splice+0x198/0x250 fs/splice.c:1332 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 Fixes: 924a9bc362a5 ("net: check if protocol extracted by virtio_net_hdr_set_proto is correct") Signed-off-by: Eric Dumazet Cc: Balazs Nemeth Cc: Willem de Bruijn Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/linux/virtio_net.h | 2 ++ 1 file changed, 2 insertions(+) --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -62,6 +62,8 @@ static inline int virtio_net_hdr_to_skb( return -EINVAL; } + skb_reset_mac_header(skb); + if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { u16 start = __virtio16_to_cpu(little_endian, hdr->csum_start); u16 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);