On Thu, Mar 25, 2021 at 2:11 PM Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote:
>
> This adds a selftest to check that the verifier rejects a TCP CC struct_ops
> with a non-GPL license.
>
> v2:
> - Use a minimal struct_ops BPF program instead of rewriting bpf_dctcp's
> license in memory.
> - Check for the verifier reject message instead of just the return code.
>
> Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
> ---
> .../selftests/bpf/prog_tests/bpf_tcp_ca.c | 44 +++++++++++++++++++
> .../selftests/bpf/progs/bpf_nogpltcp.c | 19 ++++++++
> 2 files changed, 63 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/progs/bpf_nogpltcp.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
> index 37c5494a0381..a09c716528e1 100644
> --- a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
> @@ -6,6 +6,7 @@
> #include <test_progs.h>
> #include "bpf_dctcp.skel.h"
> #include "bpf_cubic.skel.h"
> +#include "bpf_nogpltcp.skel.h"
total nit, but my eyes can't read "nogpltcp"... wouldn't
"bpf_tcp_nogpl" be a bit easier?
>
> #define min(a, b) ((a) < (b) ? (a) : (b))
>
> @@ -227,10 +228,53 @@ static void test_dctcp(void)
> bpf_dctcp__destroy(dctcp_skel);
> }
>
> +static char *err_str = NULL;
> +static bool found = false;
> +
> +static int libbpf_debug_print(enum libbpf_print_level level,
> + const char *format, va_list args)
> +{
> + char *log_buf;
> +
> + if (level != LIBBPF_WARN ||
> + strcmp(format, "libbpf: \n%s\n")) {
> + vprintf(format, args);
> + return 0;
> + }
> +
> + log_buf = va_arg(args, char *);
> + if (!log_buf)
> + goto out;
> + if (err_str && strstr(log_buf, err_str) != NULL)
> + found = true;
> +out:
> + printf(format, log_buf);
> + return 0;
> +}
> +
> +static void test_invalid_license(void)
> +{
> + libbpf_print_fn_t old_print_fn = NULL;
> + struct bpf_nogpltcp *skel;
> +
> + err_str = "struct ops programs must have a GPL compatible license";
> + old_print_fn = libbpf_set_print(libbpf_debug_print);
> +
> + skel = bpf_nogpltcp__open_and_load();
> + if (CHECK(skel, "bpf_nogplgtcp__open_and_load()", "didn't fail\n"))
ASSERT_OK_PTR()
> + bpf_nogpltcp__destroy(skel);
you should destroy unconditionally
> +
> + CHECK(!found, "errmsg check", "expected string '%s'", err_str);
ASSERT_EQ(found, true, "expected_err_msg");
I can never be sure which way CHECK() is checking
> +
> + libbpf_set_print(old_print_fn);
> +}
> +
> void test_bpf_tcp_ca(void)
> {
> if (test__start_subtest("dctcp"))
> test_dctcp();
> if (test__start_subtest("cubic"))
> test_cubic();
> + if (test__start_subtest("invalid_license"))
> + test_invalid_license();
> }
> diff --git a/tools/testing/selftests/bpf/progs/bpf_nogpltcp.c b/tools/testing/selftests/bpf/progs/bpf_nogpltcp.c
> new file mode 100644
> index 000000000000..2ecd833dcd41
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/bpf_nogpltcp.c
> @@ -0,0 +1,19 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/bpf.h>
> +#include <linux/types.h>
> +#include <bpf/bpf_helpers.h>
> +#include <bpf/bpf_tracing.h>
> +#include "bpf_tcp_helpers.h"
> +
> +char _license[] SEC("license") = "X";
> +
> +void BPF_STRUCT_OPS(nogpltcp_init, struct sock *sk)
> +{
> +}
> +
> +SEC(".struct_ops")
> +struct tcp_congestion_ops bpf_nogpltcp = {
> + .init = (void *)nogpltcp_init,
> + .name = "bpf_nogpltcp",
> +};
> --
> 2.31.0
>
