From bd6fecb9a99cceb949271c1821cfbad2b2db97c6 Mon Sep 17 00:00:00 2001 From: YiFei Zhu Date: Wed, 10 Jun 2020 13:41:40 -0500 Subject: selftests/bpf: Add cgroup_skb/egress test for load_bytes_relative When cgroup_skb/egress triggers the MAC header is not set. Added a test that asserts reading MAC header is a -EFAULT but NET header succeeds. The test result from within the eBPF program is stored in an 1-element array map that the userspace then reads and asserts on. Another assertion is added that reading from a large offset, past the end of packet, returns -EFAULT. Signed-off-by: YiFei Zhu Signed-off-by: Daniel Borkmann Reviewed-by: Stanislav Fomichev Link: https://lore.kernel.org/bpf/9028ccbea4385a620e69c0a104f469ffd655c01e.1591812755.git.zhuyifei@google.com --- .../selftests/bpf/prog_tests/load_bytes_relative.c | 71 ++++++++++++++++++++++ .../selftests/bpf/progs/load_bytes_relative.c | 48 +++++++++++++++ 2 files changed, 119 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/load_bytes_relative.c create mode 100644 tools/testing/selftests/bpf/progs/load_bytes_relative.c diff --git a/tools/testing/selftests/bpf/prog_tests/load_bytes_relative.c b/tools/testing/selftests/bpf/prog_tests/load_bytes_relative.c new file mode 100644 index 000000000000..c1168e4a9036 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/load_bytes_relative.c @@ -0,0 +1,71 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* + * Copyright 2020 Google LLC. + */ + +#include +#include + +void test_load_bytes_relative(void) +{ + int server_fd, cgroup_fd, prog_fd, map_fd, client_fd; + int err; + struct bpf_object *obj; + struct bpf_program *prog; + struct bpf_map *test_result; + __u32 duration = 0; + + __u32 map_key = 0; + __u32 map_value = 0; + + cgroup_fd = test__join_cgroup("/load_bytes_relative"); + if (CHECK_FAIL(cgroup_fd < 0)) + return; + + server_fd = start_server(AF_INET, SOCK_STREAM); + if (CHECK_FAIL(server_fd < 0)) + goto close_cgroup_fd; + + err = bpf_prog_load("./load_bytes_relative.o", BPF_PROG_TYPE_CGROUP_SKB, + &obj, &prog_fd); + if (CHECK_FAIL(err)) + goto close_server_fd; + + test_result = bpf_object__find_map_by_name(obj, "test_result"); + if (CHECK_FAIL(!test_result)) + goto close_bpf_object; + + map_fd = bpf_map__fd(test_result); + if (map_fd < 0) + goto close_bpf_object; + + prog = bpf_object__find_program_by_name(obj, "load_bytes_relative"); + if (CHECK_FAIL(!prog)) + goto close_bpf_object; + + err = bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_INET_EGRESS, + BPF_F_ALLOW_MULTI); + if (CHECK_FAIL(err)) + goto close_bpf_object; + + client_fd = connect_to_fd(AF_INET, SOCK_STREAM, server_fd); + if (CHECK_FAIL(client_fd < 0)) + goto close_bpf_object; + close(client_fd); + + err = bpf_map_lookup_elem(map_fd, &map_key, &map_value); + if (CHECK_FAIL(err)) + goto close_bpf_object; + + CHECK(map_value != 1, "bpf", "bpf program returned failure"); + +close_bpf_object: + bpf_object__close(obj); + +close_server_fd: + close(server_fd); + +close_cgroup_fd: + close(cgroup_fd); +} diff --git a/tools/testing/selftests/bpf/progs/load_bytes_relative.c b/tools/testing/selftests/bpf/progs/load_bytes_relative.c new file mode 100644 index 000000000000..dc1d04a7a3d6 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/load_bytes_relative.c @@ -0,0 +1,48 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* + * Copyright 2020 Google LLC. + */ + +#include +#include +#include +#include +#include + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, __u32); + __type(value, __u32); +} test_result SEC(".maps"); + +SEC("cgroup_skb/egress") +int load_bytes_relative(struct __sk_buff *skb) +{ + struct ethhdr eth; + struct iphdr iph; + + __u32 map_key = 0; + __u32 test_passed = 0; + + /* MAC header is not set by the time cgroup_skb/egress triggers */ + if (bpf_skb_load_bytes_relative(skb, 0, ð, sizeof(eth), + BPF_HDR_START_MAC) != -EFAULT) + goto fail; + + if (bpf_skb_load_bytes_relative(skb, 0, &iph, sizeof(iph), + BPF_HDR_START_NET)) + goto fail; + + if (bpf_skb_load_bytes_relative(skb, 0xffff, &iph, sizeof(iph), + BPF_HDR_START_NET) != -EFAULT) + goto fail; + + test_passed = 1; + +fail: + bpf_map_update_elem(&test_result, &map_key, &test_passed, BPF_ANY); + + return 1; +} -- cgit