From patchwork Wed Dec 21 18:37:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin KaFai Lau X-Patchwork-Id: 13079120 X-Patchwork-Delegate: bpf@iogearbox.net 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 57D63C4332F for ; Wed, 21 Dec 2022 18:38:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234772AbiLUSiI (ORCPT ); Wed, 21 Dec 2022 13:38:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229491AbiLUSiH (ORCPT ); Wed, 21 Dec 2022 13:38:07 -0500 Received: from out-122.mta0.migadu.com (out-122.mta0.migadu.com [IPv6:2001:41d0:1004:224b::7a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CAD0526553 for ; Wed, 21 Dec 2022 10:38:05 -0800 (PST) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1671647884; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=UMACxTyzVoM2P9KX4+Qjzr02pwFD59T7YhG/VNphXBA=; b=T+0CsJfixcWc6VN3tev9vKnvh1ewJkZ0uCcqUzDr1L4K5UEr9BdBsg7BTWLmG3l0m7AlCK fvuJJAdFArYL/HED21J8DhttUYX59nGUvMCkVw+fy/JljyeypPPlZKcA3Hb2TR2baBruWl FmyDV44yHktw5HR5dhcsMV5eo9zEBNY= From: Martin KaFai Lau To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@meta.com, Jakub Kicinski Subject: [PATCH v3 bpf] selftests/bpf: Test bpf_skb_adjust_room on CHECKSUM_PARTIAL Date: Wed, 21 Dec 2022 10:37:57 -0800 Message-Id: <20221221183757.1470196-1-martin.lau@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Martin KaFai Lau When the bpf_skb_adjust_room() shrinks the skb such that its csum_start is invalid, the skb->ip_summed should be reset from CHECKSUM_PARTIAL to CHECKSUM_NONE. The commit 54c3f1a81421 ("bpf: pull before calling skb_postpull_rcsum()") fixed it. This patch adds a test to ensure the skb->ip_summed changed from CHECKSUM_PARTIAL to CHECKSUM_NONE after bpf_skb_adjust_room(). Cc: Jakub Kicinski Signed-off-by: Martin KaFai Lau --- v3: * Use ASSERT_TRUE and ASSERT_FALSE * On top of 'ip netns del', also call bpf_tc_hook_destroy() in case bpf_tc_hook_create() may allocate memory in the future. v2: Add test to DENYLIST.s390x due to kfunc usage tools/testing/selftests/bpf/DENYLIST.s390x | 1 + .../selftests/bpf/prog_tests/decap_sanity.c | 85 +++++++++++++++++++ .../selftests/bpf/progs/bpf_tracing_net.h | 6 ++ .../selftests/bpf/progs/decap_sanity.c | 68 +++++++++++++++ 4 files changed, 160 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/decap_sanity.c create mode 100644 tools/testing/selftests/bpf/progs/decap_sanity.c diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x index 585fcf73c731..3fc3e54b19aa 100644 --- a/tools/testing/selftests/bpf/DENYLIST.s390x +++ b/tools/testing/selftests/bpf/DENYLIST.s390x @@ -14,6 +14,7 @@ cgrp_kfunc # JIT does not support calling kernel f cgrp_local_storage # prog_attach unexpected error: -524 (trampoline) core_read_macros # unknown func bpf_probe_read#4 (overlapping) d_path # failed to auto-attach program 'prog_stat': -524 (trampoline) +decap_sanity # JIT does not support calling kernel function (kfunc) deny_namespace # failed to attach: ERROR: strerror_r(-524)=22 (trampoline) dummy_st_ops # test_run unexpected error: -524 (errno 524) (trampoline) fentry_fexit # fentry attach failed: -524 (trampoline) diff --git a/tools/testing/selftests/bpf/prog_tests/decap_sanity.c b/tools/testing/selftests/bpf/prog_tests/decap_sanity.c new file mode 100644 index 000000000000..0b2f73b88c53 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/decap_sanity.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#include +#include +#include +#include + +#include "test_progs.h" +#include "network_helpers.h" +#include "decap_sanity.skel.h" + +#define SYS(fmt, ...) \ + ({ \ + char cmd[1024]; \ + snprintf(cmd, sizeof(cmd), fmt, ##__VA_ARGS__); \ + if (!ASSERT_OK(system(cmd), cmd)) \ + goto fail; \ + }) + +#define NS_TEST "decap_sanity_ns" +#define IPV6_IFACE_ADDR "face::1" +#define UDP_TEST_PORT 7777 + +void test_decap_sanity(void) +{ + LIBBPF_OPTS(bpf_tc_hook, qdisc_hook, .attach_point = BPF_TC_EGRESS); + LIBBPF_OPTS(bpf_tc_opts, tc_attach); + struct nstoken *nstoken = NULL; + struct decap_sanity *skel; + struct sockaddr_in6 addr; + socklen_t addrlen; + char buf[128] = {}; + int sockfd, err; + + skel = decap_sanity__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel open_and_load")) + return; + + SYS("ip netns add %s", NS_TEST); + SYS("ip -net %s -6 addr add %s/128 dev lo nodad", NS_TEST, IPV6_IFACE_ADDR); + SYS("ip -net %s link set dev lo up", NS_TEST); + + nstoken = open_netns(NS_TEST); + if (!ASSERT_OK_PTR(nstoken, "open_netns")) + goto fail; + + qdisc_hook.ifindex = if_nametoindex("lo"); + if (!ASSERT_GT(qdisc_hook.ifindex, 0, "if_nametoindex lo")) + goto fail; + + err = bpf_tc_hook_create(&qdisc_hook); + if (!ASSERT_OK(err, "create qdisc hook")) + goto fail; + + tc_attach.prog_fd = bpf_program__fd(skel->progs.decap_sanity); + err = bpf_tc_attach(&qdisc_hook, &tc_attach); + if (!ASSERT_OK(err, "attach filter")) + goto fail; + + addrlen = sizeof(addr); + err = make_sockaddr(AF_INET6, IPV6_IFACE_ADDR, UDP_TEST_PORT, + (void *)&addr, &addrlen); + if (!ASSERT_OK(err, "make_sockaddr")) + goto fail; + sockfd = socket(AF_INET6, SOCK_DGRAM, 0); + if (!ASSERT_NEQ(sockfd, -1, "socket")) + goto fail; + err = sendto(sockfd, buf, sizeof(buf), 0, (void *)&addr, addrlen); + close(sockfd); + if (!ASSERT_EQ(err, sizeof(buf), "send")) + goto fail; + + ASSERT_TRUE(skel->bss->init_csum_partial, "init_csum_partial"); + ASSERT_TRUE(skel->bss->final_csum_none, "final_csum_none"); + ASSERT_FALSE(skel->bss->broken_csum_start, "broken_csum_start"); + +fail: + if (nstoken) { + bpf_tc_hook_destroy(&qdisc_hook); + close_netns(nstoken); + } + system("ip netns del " NS_TEST " >& /dev/null"); + decap_sanity__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h index b394817126cf..cfed4df490f3 100644 --- a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h +++ b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h @@ -50,6 +50,12 @@ #define ICSK_TIME_LOSS_PROBE 5 #define ICSK_TIME_REO_TIMEOUT 6 +#define ETH_HLEN 14 +#define ETH_P_IPV6 0x86DD + +#define CHECKSUM_NONE 0 +#define CHECKSUM_PARTIAL 3 + #define IFNAMSIZ 16 #define RTF_GATEWAY 0x0002 diff --git a/tools/testing/selftests/bpf/progs/decap_sanity.c b/tools/testing/selftests/bpf/progs/decap_sanity.c new file mode 100644 index 000000000000..b85113554cbf --- /dev/null +++ b/tools/testing/selftests/bpf/progs/decap_sanity.c @@ -0,0 +1,68 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#include "vmlinux.h" +#include "bpf_tracing_net.h" +#include +#include + +#define UDP_TEST_PORT 7777 + +void *bpf_cast_to_kern_ctx(void *) __ksym; +bool init_csum_partial = false; +bool final_csum_none = false; +bool broken_csum_start = false; + +static inline unsigned int skb_headlen(const struct sk_buff *skb) +{ + return skb->len - skb->data_len; +} + +static unsigned int skb_headroom(const struct sk_buff *skb) +{ + return skb->data - skb->head; +} + +static int skb_checksum_start_offset(const struct sk_buff *skb) +{ + return skb->csum_start - skb_headroom(skb); +} + +SEC("tc") +int decap_sanity(struct __sk_buff *skb) +{ + struct sk_buff *kskb; + struct ipv6hdr ip6h; + struct udphdr udph; + int err; + + if (skb->protocol != __bpf_constant_htons(ETH_P_IPV6)) + return TC_ACT_SHOT; + + if (bpf_skb_load_bytes(skb, ETH_HLEN, &ip6h, sizeof(ip6h))) + return TC_ACT_SHOT; + + if (ip6h.nexthdr != IPPROTO_UDP) + return TC_ACT_SHOT; + + if (bpf_skb_load_bytes(skb, ETH_HLEN + sizeof(ip6h), &udph, sizeof(udph))) + return TC_ACT_SHOT; + + if (udph.dest != __bpf_constant_htons(UDP_TEST_PORT)) + return TC_ACT_SHOT; + + kskb = bpf_cast_to_kern_ctx(skb); + init_csum_partial = (kskb->ip_summed == CHECKSUM_PARTIAL); + err = bpf_skb_adjust_room(skb, -(s32)(ETH_HLEN + sizeof(ip6h) + sizeof(udph)), + 1, BPF_F_ADJ_ROOM_FIXED_GSO); + if (err) + return TC_ACT_SHOT; + final_csum_none = (kskb->ip_summed == CHECKSUM_NONE); + if (kskb->ip_summed == CHECKSUM_PARTIAL && + (unsigned int)skb_checksum_start_offset(kskb) >= skb_headlen(kskb)) + broken_csum_start = true; + + return TC_ACT_SHOT; +} + +char __license[] SEC("license") = "GPL";