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| author |   Stanislav Fomichev <sdf@google.com> | 2019-04-22 08:55:49 -0700 |
|---|---|---|
| committer |   Daniel Borkmann <daniel@iogearbox.net> | 2019-04-23 18:36:34 +0200 |
| commit | c9cb2c1e11cee75b3af5699add3302a3997f78e4 (patch) | |
| tree | 5223f0713124af66fc29f16bedae1c16c38a717f | |
| parent | net: pass net_device argument to the eth_get_headlen (diff) | |
| download | linux-dev-c9cb2c1e11cee75b3af5699add3302a3997f78e4.tar.xz linux-dev-c9cb2c1e11cee75b3af5699add3302a3997f78e4.zip | |
selftests/bpf: add flow dissector bpf_skb_load_bytes helper test
When flow dissector is called without skb, we want to make sure
bpf_skb_load_bytes invocations return error. Add small test which tries
to read single byte from a packet.
bpf_skb_load_bytes should always fail under BPF_PROG_TEST_RUN because
it was converted to the skb-less mode.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/flow_dissector_load_bytes.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/flow_dissector_load_bytes.c b/tools/testing/selftests/bpf/prog_tests/flow_dissector_load_bytes.c new file mode 100644 index 000000000000..dc5ef155ec28 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/flow_dissector_load_bytes.c @@ -0,0 +1,48 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <test_progs.h> + +void test_flow_dissector_load_bytes(void) +{ + struct bpf_flow_keys flow_keys; + __u32 duration = 0, retval, size; + struct bpf_insn prog[] = { + // BPF_REG_1 - 1st argument: context + // BPF_REG_2 - 2nd argument: offset, start at first byte + BPF_MOV64_IMM(BPF_REG_2, 0), + // BPF_REG_3 - 3rd argument: destination, reserve byte on stack + BPF_ALU64_REG(BPF_MOV, BPF_REG_3, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, -1), + // BPF_REG_4 - 4th argument: copy one byte + BPF_MOV64_IMM(BPF_REG_4, 1), + // bpf_skb_load_bytes(ctx, sizeof(pkt_v4), ptr, 1) + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, + BPF_FUNC_skb_load_bytes), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2), + // if (ret == 0) return BPF_DROP (2) + BPF_MOV64_IMM(BPF_REG_0, BPF_DROP), + BPF_EXIT_INSN(), + // if (ret != 0) return BPF_OK (0) + BPF_MOV64_IMM(BPF_REG_0, BPF_OK), + BPF_EXIT_INSN(), + }; + int fd, err; + + /* make sure bpf_skb_load_bytes is not allowed from skb-less context + */ + fd = bpf_load_program(BPF_PROG_TYPE_FLOW_DISSECTOR, prog, + ARRAY_SIZE(prog), "GPL", 0, NULL, 0); + CHECK(fd < 0, + "flow_dissector-bpf_skb_load_bytes-load", + "fd %d errno %d\n", + fd, errno); + + err = bpf_prog_test_run(fd, 1, &pkt_v4, sizeof(pkt_v4), + &flow_keys, &size, &retval, &duration); + CHECK(size != sizeof(flow_keys) || err || retval != 1, + "flow_dissector-bpf_skb_load_bytes", + "err %d errno %d retval %d duration %d size %u/%zu\n", + err, errno, retval, duration, size, sizeof(flow_keys)); + + if (fd >= -1) + close(fd); +} |