From: Eduard Zingerman eddyz87@gmail.com
commit 89ff40890d8f12a7d7e93fb602cc27562f3834f0 upstream.
Try different combinations of global functions replacement: - replace function that changes packet data with one that doesn't; - replace function that changes packet data with one that does; - replace function that doesn't change packet data with one that does; - replace function that doesn't change packet data with one that doesn't;
Signed-off-by: Eduard Zingerman eddyz87@gmail.com Link: https://lore.kernel.org/r/20241210041100.1898468-7-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Shung-Hsi Yu shung-hsi.yu@suse.com --- .../bpf/prog_tests/changes_pkt_data.c | 76 +++++++++++++++++++ .../selftests/bpf/progs/changes_pkt_data.c | 26 +++++++ .../bpf/progs/changes_pkt_data_freplace.c | 18 +++++ 3 files changed, 120 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/changes_pkt_data.c create mode 100644 tools/testing/selftests/bpf/progs/changes_pkt_data.c create mode 100644 tools/testing/selftests/bpf/progs/changes_pkt_data_freplace.c
diff --git a/tools/testing/selftests/bpf/prog_tests/changes_pkt_data.c b/tools/testing/selftests/bpf/prog_tests/changes_pkt_data.c new file mode 100644 index 000000000000..c0c7202f6c5c --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/changes_pkt_data.c @@ -0,0 +1,76 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "bpf/libbpf.h" +#include "changes_pkt_data_freplace.skel.h" +#include "changes_pkt_data.skel.h" +#include <test_progs.h> + +static void print_verifier_log(const char *log) +{ + if (env.verbosity >= VERBOSE_VERY) + fprintf(stdout, "VERIFIER LOG:\n=============\n%s=============\n", log); +} + +static void test_aux(const char *main_prog_name, const char *freplace_prog_name, bool expect_load) +{ + struct changes_pkt_data_freplace *freplace = NULL; + struct bpf_program *freplace_prog = NULL; + LIBBPF_OPTS(bpf_object_open_opts, opts); + struct changes_pkt_data *main = NULL; + char log[16*1024]; + int err; + + opts.kernel_log_buf = log; + opts.kernel_log_size = sizeof(log); + if (env.verbosity >= VERBOSE_SUPER) + opts.kernel_log_level = 1 | 2 | 4; + main = changes_pkt_data__open_opts(&opts); + if (!ASSERT_OK_PTR(main, "changes_pkt_data__open")) + goto out; + err = changes_pkt_data__load(main); + print_verifier_log(log); + if (!ASSERT_OK(err, "changes_pkt_data__load")) + goto out; + freplace = changes_pkt_data_freplace__open_opts(&opts); + if (!ASSERT_OK_PTR(freplace, "changes_pkt_data_freplace__open")) + goto out; + freplace_prog = bpf_object__find_program_by_name(freplace->obj, freplace_prog_name); + if (!ASSERT_OK_PTR(freplace_prog, "freplace_prog")) + goto out; + bpf_program__set_autoload(freplace_prog, true); + bpf_program__set_autoattach(freplace_prog, true); + bpf_program__set_attach_target(freplace_prog, + bpf_program__fd(main->progs.dummy), + main_prog_name); + err = changes_pkt_data_freplace__load(freplace); + print_verifier_log(log); + if (expect_load) { + ASSERT_OK(err, "changes_pkt_data_freplace__load"); + } else { + ASSERT_ERR(err, "changes_pkt_data_freplace__load"); + ASSERT_HAS_SUBSTR(log, "Extension program changes packet data", "error log"); + } + +out: + changes_pkt_data_freplace__destroy(freplace); + changes_pkt_data__destroy(main); +} + +/* There are two global subprograms in both changes_pkt_data.skel.h: + * - one changes packet data; + * - another does not. + * It is ok to freplace subprograms that change packet data with those + * that either do or do not. It is only ok to freplace subprograms + * that do not change packet data with those that do not as well. + * The below tests check outcomes for each combination of such freplace. + */ +void test_changes_pkt_data_freplace(void) +{ + if (test__start_subtest("changes_with_changes")) + test_aux("changes_pkt_data", "changes_pkt_data", true); + if (test__start_subtest("changes_with_doesnt_change")) + test_aux("changes_pkt_data", "does_not_change_pkt_data", true); + if (test__start_subtest("doesnt_change_with_changes")) + test_aux("does_not_change_pkt_data", "changes_pkt_data", false); + if (test__start_subtest("doesnt_change_with_doesnt_change")) + test_aux("does_not_change_pkt_data", "does_not_change_pkt_data", true); +} diff --git a/tools/testing/selftests/bpf/progs/changes_pkt_data.c b/tools/testing/selftests/bpf/progs/changes_pkt_data.c new file mode 100644 index 000000000000..f87da8e9d6b3 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/changes_pkt_data.c @@ -0,0 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> + +__noinline +long changes_pkt_data(struct __sk_buff *sk, __u32 len) +{ + return bpf_skb_pull_data(sk, len); +} + +__noinline __weak +long does_not_change_pkt_data(struct __sk_buff *sk, __u32 len) +{ + return 0; +} + +SEC("tc") +int dummy(struct __sk_buff *sk) +{ + changes_pkt_data(sk, 0); + does_not_change_pkt_data(sk, 0); + return 0; +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/changes_pkt_data_freplace.c b/tools/testing/selftests/bpf/progs/changes_pkt_data_freplace.c new file mode 100644 index 000000000000..0e525beb8603 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/changes_pkt_data_freplace.c @@ -0,0 +1,18 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> + +SEC("?freplace") +long changes_pkt_data(struct __sk_buff *sk, __u32 len) +{ + return bpf_skb_pull_data(sk, len); +} + +SEC("?freplace") +long does_not_change_pkt_data(struct __sk_buff *sk, __u32 len) +{ + return 0; +} + +char _license[] SEC("license") = "GPL";