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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 B6A3DC47409 for ; Mon, 10 Feb 2020 13:29:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 889FB2082F for ; Mon, 10 Feb 2020 13:29:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581341393; bh=oPJRys/4Q4T/6SEOih2NcNqCgQoCxVWGo3lcC09VXvM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uRQ2GJLS7YjlNYP6RpMxBE18whhOyD5X/mqW78lI10SqMGcSyOIHRCpopyxcCVadX Afsa/ML82pRnMMKf7A1wFhsEnghLBRbEuGxmTv6YBN2kHNAo//7mV9sYb68fw7woaJ do5gQ4Nt6HPW3qfj7jLr0JnXghKjSdoNMPM7/x4w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731294AbgBJN3w (ORCPT ); Mon, 10 Feb 2020 08:29:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:55324 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728322AbgBJMgS (ORCPT ); Mon, 10 Feb 2020 07:36:18 -0500 Received: from localhost (unknown [209.37.97.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9AB4F2085B; Mon, 10 Feb 2020 12:36:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338177; bh=oPJRys/4Q4T/6SEOih2NcNqCgQoCxVWGo3lcC09VXvM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sW6uUjimAhjGFAQvkISMfkp4khd7tl1Ji8ocZviATMjvoxrSyhWlESGLXGQguu1tU ZpJ3Ji4Cd8xAb2voWgZWMBdbvZPlfdTfueTfF1SjinxzEn2cnCu5ZCkVOxfHh1oimB V9RxVnqr2NmOB8svv/NydSVukdRSrjOPK+ZOic4A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , syzbot , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , "David S. Miller" Subject: [PATCH 4.19 166/195] bonding/alb: properly access headers in bond_alb_xmit() Date: Mon, 10 Feb 2020 04:33:44 -0800 Message-Id: <20200210122321.454024458@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200210122305.731206734@linuxfoundation.org> References: <20200210122305.731206734@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric Dumazet [ Upstream commit 38f88c45404293bbc027b956def6c10cbd45c616 ] syzbot managed to send an IPX packet through bond_alb_xmit() and af_packet and triggered a use-after-free. First, bond_alb_xmit() was using ipx_hdr() helper to reach the IPX header, but ipx_hdr() was using the transport offset instead of the network offset. In the particular syzbot report transport offset was 0xFFFF This patch removes ipx_hdr() since it was only (mis)used from bonding. Then we need to make sure IPv4/IPv6/IPX headers are pulled in skb->head before dereferencing anything. BUG: KASAN: use-after-free in bond_alb_xmit+0x153a/0x1590 drivers/net/bonding/bond_alb.c:1452 Read of size 2 at addr ffff8801ce56dfff by task syz-executor.2/18108 (if (ipx_hdr(skb)->ipx_checksum != IPX_NO_CHECKSUM) ...) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: [] __dump_stack lib/dump_stack.c:17 [inline] [] dump_stack+0x14d/0x20b lib/dump_stack.c:53 [] print_address_description+0x6f/0x20b mm/kasan/report.c:282 [] kasan_report_error mm/kasan/report.c:380 [inline] [] kasan_report mm/kasan/report.c:438 [inline] [] kasan_report.cold+0x8c/0x2a0 mm/kasan/report.c:422 [] __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:469 [] bond_alb_xmit+0x153a/0x1590 drivers/net/bonding/bond_alb.c:1452 [] __bond_start_xmit drivers/net/bonding/bond_main.c:4199 [inline] [] bond_start_xmit+0x4f4/0x1570 drivers/net/bonding/bond_main.c:4224 [] __netdev_start_xmit include/linux/netdevice.h:4525 [inline] [] netdev_start_xmit include/linux/netdevice.h:4539 [inline] [] xmit_one net/core/dev.c:3611 [inline] [] dev_hard_start_xmit+0x168/0x910 net/core/dev.c:3627 [] __dev_queue_xmit+0x1f55/0x33b0 net/core/dev.c:4238 [] dev_queue_xmit+0x18/0x20 net/core/dev.c:4278 [] packet_snd net/packet/af_packet.c:3226 [inline] [] packet_sendmsg+0x4919/0x70b0 net/packet/af_packet.c:3252 [] sock_sendmsg_nosec net/socket.c:673 [inline] [] sock_sendmsg+0x12c/0x160 net/socket.c:684 [] __sys_sendto+0x262/0x380 net/socket.c:1996 [] SYSC_sendto net/socket.c:2008 [inline] [] SyS_sendto+0x40/0x60 net/socket.c:2004 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Jay Vosburgh Cc: Veaceslav Falico Cc: Andy Gospodarek Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/bonding/bond_alb.c | 44 +++++++++++++++++++++++++++++------------ include/net/ipx.h | 5 ---- 2 files changed, 32 insertions(+), 17 deletions(-) --- a/drivers/net/bonding/bond_alb.c +++ b/drivers/net/bonding/bond_alb.c @@ -1399,26 +1399,31 @@ netdev_tx_t bond_alb_xmit(struct sk_buff bool do_tx_balance = true; u32 hash_index = 0; const u8 *hash_start = NULL; - struct ipv6hdr *ip6hdr; skb_reset_mac_header(skb); eth_data = eth_hdr(skb); switch (ntohs(skb->protocol)) { case ETH_P_IP: { - const struct iphdr *iph = ip_hdr(skb); + const struct iphdr *iph; if (is_broadcast_ether_addr(eth_data->h_dest) || - iph->daddr == ip_bcast || - iph->protocol == IPPROTO_IGMP) { + !pskb_network_may_pull(skb, sizeof(*iph))) { + do_tx_balance = false; + break; + } + iph = ip_hdr(skb); + if (iph->daddr == ip_bcast || iph->protocol == IPPROTO_IGMP) { do_tx_balance = false; break; } hash_start = (char *)&(iph->daddr); hash_size = sizeof(iph->daddr); - } break; - case ETH_P_IPV6: + } + case ETH_P_IPV6: { + const struct ipv6hdr *ip6hdr; + /* IPv6 doesn't really use broadcast mac address, but leave * that here just in case. */ @@ -1435,7 +1440,11 @@ netdev_tx_t bond_alb_xmit(struct sk_buff break; } - /* Additianally, DAD probes should not be tx-balanced as that + if (!pskb_network_may_pull(skb, sizeof(*ip6hdr))) { + do_tx_balance = false; + break; + } + /* Additionally, DAD probes should not be tx-balanced as that * will lead to false positives for duplicate addresses and * prevent address configuration from working. */ @@ -1445,17 +1454,26 @@ netdev_tx_t bond_alb_xmit(struct sk_buff break; } - hash_start = (char *)&(ipv6_hdr(skb)->daddr); - hash_size = sizeof(ipv6_hdr(skb)->daddr); + hash_start = (char *)&ip6hdr->daddr; + hash_size = sizeof(ip6hdr->daddr); break; - case ETH_P_IPX: - if (ipx_hdr(skb)->ipx_checksum != IPX_NO_CHECKSUM) { + } + case ETH_P_IPX: { + const struct ipxhdr *ipxhdr; + + if (pskb_network_may_pull(skb, sizeof(*ipxhdr))) { + do_tx_balance = false; + break; + } + ipxhdr = (struct ipxhdr *)skb_network_header(skb); + + if (ipxhdr->ipx_checksum != IPX_NO_CHECKSUM) { /* something is wrong with this packet */ do_tx_balance = false; break; } - if (ipx_hdr(skb)->ipx_type != IPX_TYPE_NCP) { + if (ipxhdr->ipx_type != IPX_TYPE_NCP) { /* The only protocol worth balancing in * this family since it has an "ARP" like * mechanism @@ -1464,9 +1482,11 @@ netdev_tx_t bond_alb_xmit(struct sk_buff break; } + eth_data = eth_hdr(skb); hash_start = (char *)eth_data->h_dest; hash_size = ETH_ALEN; break; + } case ETH_P_ARP: do_tx_balance = false; if (bond_info->rlb_enabled) --- a/include/net/ipx.h +++ b/include/net/ipx.h @@ -47,11 +47,6 @@ struct ipxhdr { /* From af_ipx.c */ extern int sysctl_ipx_pprop_broadcasting; -static __inline__ struct ipxhdr *ipx_hdr(struct sk_buff *skb) -{ - return (struct ipxhdr *)skb_transport_header(skb); -} - struct ipx_interface { /* IPX address */ __be32 if_netnum;