From patchwork Wed Jul 26 01:08:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yan Zhai X-Patchwork-Id: 706803 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 D8112EB64DD for ; Wed, 26 Jul 2023 01:08:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229746AbjGZBI0 (ORCPT ); Tue, 25 Jul 2023 21:08:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34994 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229987AbjGZBIZ (ORCPT ); Tue, 25 Jul 2023 21:08:25 -0400 Received: from mail-qk1-x72f.google.com (mail-qk1-x72f.google.com [IPv6:2607:f8b0:4864:20::72f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 36CBC268D for ; Tue, 25 Jul 2023 18:08:21 -0700 (PDT) Received: by mail-qk1-x72f.google.com with SMTP id af79cd13be357-7679ea01e16so538602885a.2 for ; Tue, 25 Jul 2023 18:08:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google; t=1690333700; x=1690938500; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=n0NtF3U2QeP9UCLELIDDLvHXTMrNEAe+2WmgLDwewEc=; b=Zwegie/aBtxLm5/hxoycUPRg/LkQ/+bpJIJPBs1adCSZnU6/M4XYi77KAHIkaUYFf5 5oiYrj8pSZiGiUIiSLGeDdPFyg85hpidIdlmu7QljlEKcwguPf2CD4c2jD2M9HiJpHkh c0rIWHce8o8oUAI6BuBWP529MRjgnrlaI7qpg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690333700; x=1690938500; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=n0NtF3U2QeP9UCLELIDDLvHXTMrNEAe+2WmgLDwewEc=; b=bWLqDImE15o3VUfIXKtkEx3zdvYTObXZED0mtNcpbiYOui8QTT+4I6M/Gp0uSfGmdj mJgpeN0T9xvrHyRkb/AovIqdoYe0HFTOn6PETNKxD6daKybxyVacll4CtZusutMsl6/X Wdf7qQkzzThej1Yuuvfwjjo0cnOv/TEdjyiDVZqul9y76DX8nBkETkfO94S9cXvDJfcH gAjfjtEMPA6W+ivmDYrapc7kUlfkS10zN0yKz9DxTO6OPnrijC8rk6mo2dwm/1xYR303 xb/qKthBpSZIPmSPtXCMA1OLAIUDjeIGJipOfDEScIdSrQDLR8LIzM81Lov2Q+CA7kBb bb+A== X-Gm-Message-State: ABy/qLaElw9jkXc1WcOokgoLsv13b78b0TiAl9Q95lRR98X8tPHxla5a ehkc4vr9xpVdjIzDVb5FFbsrVg== X-Google-Smtp-Source: APBJJlHootmHuQIc4Y64hnKm0eyRKTB4o0UGbqOkUA0SaKNL39yvmtLcwTImM1JUwqGGiCQBoMf6wA== X-Received: by 2002:a05:620a:e1e:b0:768:2472:d4ac with SMTP id y30-20020a05620a0e1e00b007682472d4acmr643965qkm.4.1690333700214; Tue, 25 Jul 2023 18:08:20 -0700 (PDT) Received: from debian.debian ([140.141.197.139]) by smtp.gmail.com with ESMTPSA id t4-20020a05620a004400b00767c8308329sm812377qkt.25.2023.07.25.18.08.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Jul 2023 18:08:19 -0700 (PDT) Date: Tue, 25 Jul 2023 18:08:17 -0700 From: Yan Zhai To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Mykola Lysenko , Shuah Khan , Yan Zhai , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-kselftest@vger.kernel.org, kernel-team@cloudflare.com, Jordan Griege , Markus Elfring , Jakub Sitnicki Subject: [PATCH v4 bpf 1/2] bpf: fix skb_do_redirect return values Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org skb_do_redirect returns various of values: error code (negative), 0 (success), and some positive status code, e.g. NET_XMIT_CN, NET_RX_DROP. Commit 3a0af8fd61f9 ("bpf: BPF for lightweight tunnel infrastructure") didn't check the return code correctly, so positive values are propagated back along call chain: ip_finish_output2 -> bpf_xmit -> run_lwt_bpf -> skb_do_redirect Inside ip_finish_output2, redirected skb will continue to neighbor subsystem as if LWTUNNEL_XMIT_CONTINUE is returned, despite that this skb could have been freed. The bug can trigger use-after-free warning and crashes kernel afterwards: https://gist.github.com/zhaiyan920/8fbac245b261fe316a7ef04c9b1eba48 Convert positive statuses from skb_do_redirect eliminates this issue. Fixes: 3a0af8fd61f9 ("bpf: BPF for lightweight tunnel infrastructure") Tested-by: Jakub Sitnicki Suggested-by: Markus Elfring Suggested-by: Stanislav Fomichev Reported-by: Jordan Griege Signed-off-by: Yan Zhai --- include/linux/netdevice.h | 2 ++ net/core/filter.c | 9 +++++++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index b828c7a75be2..520d808eec15 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -87,6 +87,8 @@ void netdev_sw_irq_coalesce_default_on(struct net_device *dev); #define NET_RX_SUCCESS 0 /* keep 'em coming, baby */ #define NET_RX_DROP 1 /* packet dropped */ +#define net_rx_errno(e) ((e) == NET_RX_DROP ? -ENOBUFS : (e)) + #define MAX_NEST_DEV 8 /* diff --git a/net/core/filter.c b/net/core/filter.c index 06ba0e56e369..564104543737 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2095,7 +2095,9 @@ static const struct bpf_func_proto bpf_csum_level_proto = { static inline int __bpf_rx_skb(struct net_device *dev, struct sk_buff *skb) { - return dev_forward_skb_nomtu(dev, skb); + int ret = dev_forward_skb_nomtu(dev, skb); + + return net_rx_errno(ret); } static inline int __bpf_rx_skb_no_mac(struct net_device *dev, @@ -2108,7 +2110,7 @@ static inline int __bpf_rx_skb_no_mac(struct net_device *dev, ret = netif_rx(skb); } - return ret; + return net_rx_errno(ret); } static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb) @@ -2129,6 +2131,9 @@ static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb) ret = dev_queue_xmit(skb); dev_xmit_recursion_dec(); + if (unlikely(ret > 0)) + ret = net_xmit_errno(ret); + return ret; } From patchwork Wed Jul 26 01:09:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yan Zhai X-Patchwork-Id: 707301 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 7692BEB64DD for ; Wed, 26 Jul 2023 01:09:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231202AbjGZBJT (ORCPT ); Tue, 25 Jul 2023 21:09:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229987AbjGZBJS (ORCPT ); Tue, 25 Jul 2023 21:09:18 -0400 Received: from mail-qt1-x836.google.com (mail-qt1-x836.google.com [IPv6:2607:f8b0:4864:20::836]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E5E30268D for ; Tue, 25 Jul 2023 18:09:15 -0700 (PDT) Received: by mail-qt1-x836.google.com with SMTP id d75a77b69052e-4039f0d140eso50796321cf.1 for ; Tue, 25 Jul 2023 18:09:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google; t=1690333755; x=1690938555; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=0j4SOStVYxHKXGyoHBk90Z9/7O0dfp1WmJmpO/HijKg=; b=sOVJjNqJxLUNOQKu8TUIs4EQXTFg4cyJ9WibcU6EPSNjZpSapC1e9ycnqVsUNFjzyD 9ZgMOAAmCDW3u4hbbP83OgjbUiZxD6av/PTe1NceH+6ufifpQsyofAHGSmkP0OQs9ErZ IWg0eW2mUmPiUpWXpw+zPfINGloxY602J4CSk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690333755; x=1690938555; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=0j4SOStVYxHKXGyoHBk90Z9/7O0dfp1WmJmpO/HijKg=; b=WoO4HKdHiiRrx7XyeL6leXXUKk9oFkcpfN+3vxWLvWnHIizdDq65n4bKVd7/PIYDQO LZkK3Ou/+iL9Pode0BnPp6ZQjxcL2Zerjwdn1I6tG+IQL2WRnfeRFHFHlNyT0ELK1MTw ooHU9xy89tkljwEF48rpqpxyyazL/44Dg8Yme4XBVpLs4jmDNbBRGq/DWhJxpbmwsTGl 9VM/Fdojnd33QH1id/6cxLE16q9WqmszeW2XVfDwekwjSThB+9pY6o7ZjR9xSzKo/rMb nxGQXqR1dsH5XiF8+/AsVwdHU0OCPH+mA8mUxgAkxFIqSfHsYrTh2vRMRcRlK6+i2ox1 XUKA== X-Gm-Message-State: ABy/qLZM8W6j++c645eELalkx414fF1DuR7GrhmNIwped9vxvricrqOW yXCd8L7jtWL/H4ZiXjIUa9bKUw== X-Google-Smtp-Source: APBJJlFUth/aSY8rBZymZAD3NLSJzY7rSe0GwigSDuaV3WLpvc5NGyNX5px/T+GiWiLtdzhGQYMlXA== X-Received: by 2002:a05:622a:1111:b0:402:2e84:f06e with SMTP id e17-20020a05622a111100b004022e84f06emr738486qty.27.1690333755005; Tue, 25 Jul 2023 18:09:15 -0700 (PDT) Received: from debian.debian ([140.141.197.139]) by smtp.gmail.com with ESMTPSA id b20-20020ac85414000000b0040541a8bd66sm4398523qtq.60.2023.07.25.18.09.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Jul 2023 18:09:14 -0700 (PDT) Date: Tue, 25 Jul 2023 18:09:12 -0700 From: Yan Zhai To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Mykola Lysenko , Shuah Khan , Yan Zhai , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-kselftest@vger.kernel.org, kernel-team@cloudflare.com, Jordan Griege , Markus Elfring , Jakub Sitnicki Subject: [PATCH v4 bpf 2/2] bpf: selftests: add lwt redirect regression test cases Message-ID: <9c4896b109a39c3fa088844addaa1737a84bbbb5.1690332693.git.yan@cloudflare.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Tests BPF redirect at the lwt xmit hook to ensure error handling are safe, i.e. won't panic the kernel. Tested-by: Jakub Sitnicki Suggested-by: Alexei Starovoitov Signed-off-by: Yan Zhai --- tools/testing/selftests/bpf/Makefile | 1 + .../selftests/bpf/progs/test_lwt_redirect.c | 66 +++++++ .../selftests/bpf/test_lwt_redirect.sh | 174 ++++++++++++++++++ 3 files changed, 241 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/test_lwt_redirect.c create mode 100755 tools/testing/selftests/bpf/test_lwt_redirect.sh diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 538df8fb8c42..e3a24d053793 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -66,6 +66,7 @@ TEST_PROGS := test_kmod.sh \ test_xdp_vlan_mode_generic.sh \ test_xdp_vlan_mode_native.sh \ test_lwt_ip_encap.sh \ + test_lwt_redirect.sh \ test_tcp_check_syncookie.sh \ test_tc_tunnel.sh \ test_tc_edt.sh \ diff --git a/tools/testing/selftests/bpf/progs/test_lwt_redirect.c b/tools/testing/selftests/bpf/progs/test_lwt_redirect.c new file mode 100644 index 000000000000..3674e101f68f --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_lwt_redirect.c @@ -0,0 +1,66 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include "bpf_tracing_net.h" + +/* We don't care about whether the packet can be received by network stack. + * Just care if the packet is sent to the correct device at correct direction + * and not panic the kernel. + */ +static __always_inline int prepend_dummy_mac(struct __sk_buff *skb) +{ + char mac[] = {0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0xf, + 0xe, 0xd, 0xc, 0xb, 0xa, 0x08, 0x00}; + + if (bpf_skb_change_head(skb, ETH_HLEN, 0)) { + bpf_printk("%s: fail to change head", __func__); + return -1; + } + + if (bpf_skb_store_bytes(skb, 0, mac, sizeof(mac), 0)) { + bpf_printk("%s: fail to update mac", __func__); + return -1; + } + + return 0; +} + +SEC("redir_ingress") +int test_lwt_redirect_in(struct __sk_buff *skb) +{ + if (prepend_dummy_mac(skb)) + return BPF_DROP; + + bpf_printk("Redirect skb to link %d ingress", skb->mark); + return bpf_redirect(skb->mark, BPF_F_INGRESS); +} + +SEC("redir_egress") +int test_lwt_redirect_out(struct __sk_buff *skb) +{ + if (prepend_dummy_mac(skb)) + return BPF_DROP; + + bpf_printk("Redirect skb to link %d egress", skb->mark); + return bpf_redirect(skb->mark, 0); +} + +SEC("redir_egress_nomac") +int test_lwt_redirect_out_nomac(struct __sk_buff *skb) +{ + int ret = bpf_redirect(skb->mark, 0); + + bpf_printk("Redirect skb to link %d egress nomac: %d", skb->mark, ret); + return ret; +} + +SEC("redir_ingress_nomac") +int test_lwt_redirect_in_nomac(struct __sk_buff *skb) +{ + int ret = bpf_redirect(skb->mark, BPF_F_INGRESS); + + bpf_printk("Redirect skb to link %d ingress nomac: %d", skb->mark, ret); + return ret; +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/test_lwt_redirect.sh b/tools/testing/selftests/bpf/test_lwt_redirect.sh new file mode 100755 index 000000000000..1b7b78b48174 --- /dev/null +++ b/tools/testing/selftests/bpf/test_lwt_redirect.sh @@ -0,0 +1,174 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# This regression test checks basic lwt redirect functionality, +# making sure the kernel would not crash when redirecting packets +# to a device, regardless its administration state: +# +# 1. redirect to a device egress/ingress should work normally +# 2. redirect to a device egress/ingress should not panic when target is down +# 3. redirect to a device egress/ingress should not panic when target carrier is down +# +# All test setup are simple: redirect ping packet via lwt xmit to cover above +# situations. We do not worry about specific device type, except for the two +# categories of devices that require MAC header and not require MAC header. For +# carrier down situation, we use a vlan device as upper link, and bring down its +# lower device. +# +# Kselftest framework requirement - SKIP code is 4. +ksft_skip=4 +BPF_FILE="test_lwt_redirect.bpf.o" +INGRESS_REDIR_IP=2.2.2.2 +EGRESS_REDIR_IP=3.3.3.3 +INGRESS_REDIR_IP_NOMAC=4.4.4.4 +EGRESS_REDIR_IP_NOMAC=5.5.5.5 +PASS=0 +FAIL=0 + +readonly NS1="ns1-$(mktemp -u XXXXXX)" + +msg="skip all tests:" +if [ $UID != 0 ]; then + echo $msg please run this as root >&2 + exit $ksft_skip +fi + +get_ip_direction() +{ + case $1 in + $INGRESS_REDIR_IP|$INGRESS_REDIR_IP_NOMAC) + echo ingress + ;; + $EGRESS_REDIR_IP|$EGRESS_REDIR_IP_NOMAC) + echo egress + ;; + *) + echo bug + ;; + esac +} + +test_pass() +{ + local testname=$1 + local direction=`get_ip_direction $2` + shift 2 + echo "Pass: $testname $direction $@" + PASS=$((PASS + 1)) +} + +test_fail() +{ + local testname=$1 + local direction=`get_ip_direction $2` + shift 2 + echo "Fail: $testname $direction $@" + FAIL=$((FAIL + 1)) +} + +setup() +{ + ip netns add $NS1 + + ip -n $NS1 link set lo up + ip -n $NS1 link add link_err type dummy + ip -n $NS1 link add link_w_mac type dummy + ip -n $NS1 link add link link_w_mac link_upper type vlan id 1 + ip -n $NS1 link add link_wo_mac type gre remote 4.3.2.1 local 1.2.3.4 + ip -n $NS1 link set link_err up + ip -n $NS1 link set link_w_mac up + ip -n $NS1 link set link_upper up + ip -n $NS1 link set link_wo_mac up + + ip -n $NS1 addr add dev lo 1.1.1.1/32 + + # link_err is only used to make sure packets are redirected instead of + # being routed + ip -n $NS1 route add $INGRESS_REDIR_IP encap bpf xmit \ + obj $BPF_FILE sec redir_ingress dev link_err + ip -n $NS1 route add $EGRESS_REDIR_IP encap bpf xmit \ + obj $BPF_FILE sec redir_egress dev link_err + ip -n $NS1 route add $INGRESS_REDIR_IP_NOMAC encap bpf xmit \ + obj $BPF_FILE sec redir_ingress_nomac dev link_err + ip -n $NS1 route add $EGRESS_REDIR_IP_NOMAC encap bpf xmit \ + obj $BPF_FILE sec redir_egress_nomac dev link_err +} + +cleanup_and_summary() +{ + ip netns del $NS1 + echo PASSED:$PASS FAILED:$FAIL + if [ $FAIL -ne 0 ]; then + exit 1 + else + exit 0 + fi +} + +test_redirect_normal() +{ + local test_name=${FUNCNAME[0]} + local link_name=$1 + local link_id=`ip netns exec $NS1 cat /sys/class/net/${link_name}/ifindex` + local dest=$2 + + ip netns exec $NS1 timeout 2 tcpdump -i ${link_name} -c 1 -n -p icmp >/dev/null 2>&1 & + local jobid=$! + sleep 1 + + # hack: mark indicates the link to redirect to + ip netns exec $NS1 ping -m $link_id $dest -c 1 -w 1 > /dev/null 2>&1 + wait $jobid + + if [ $? -ne 0 ]; then + test_fail $test_name $dest $link_name + else + test_pass $test_name $dest $link_name + fi +} + +test_redirect_no_panic_on_link_down() +{ + local test_name=${FUNCNAME[0]} + local link_name=$1 + local link_id=`ip netns exec $NS1 cat /sys/class/net/${link_name}/ifindex` + local dest=$2 + + ip -n $NS1 link set $link_name down + # hack: mark indicates the link to redirect to + ip netns exec $NS1 ping -m $link_id $dest -c 1 -w 1 >/dev/null 2>&1 + + test_pass $test_name $dest to $link_name + ip -n $NS1 link set $link_name up +} + +test_redirect_no_panic_on_link_carrier_down() +{ + local test_name=${FUNCNAME[0]} + local link_id=`ip netns exec $NS1 cat /sys/class/net/link_upper/ifindex` + local dest=$1 + + ip -n $NS1 link set link_w_mac down + # hack: mark indicates the link to redirect to + ip netns exec $NS1 ping -m $link_id $dest -c 1 -w 1 >/dev/null 2>&1 + + test_pass $test_name $dest to link_upper + ip -n $NS1 link set link_w_mac up +} + +setup + +echo "Testing lwt redirect to devices requiring MAC header" +for dest in $INGRESS_REDIR_IP $EGRESS_REDIR_IP; do + test_redirect_normal link_w_mac $dest + test_redirect_no_panic_on_link_down link_w_mac $dest + test_redirect_no_panic_on_link_carrier_down $dest +done + +echo "Testing lwt redirect to devices not requiring MAC header" +for dest in $INGRESS_REDIR_IP_NOMAC $EGRESS_REDIR_IP_NOMAC; do + test_redirect_normal link_wo_mac $dest + test_redirect_no_panic_on_link_down link_wo_mac $dest +done + +cleanup_and_summary