We need to also export the kfunc set to the syscall program type, and then add a couple of eBPF programs that are testing those calls.
The first one checks for valid access, and the second one is OK from a static analysis point of view but fails at run time because we are trying to access outside of the allocated memory.
Signed-off-by: Benjamin Tissoires benjamin.tissoires@redhat.com
---
changes in v10: - use new definitions for tests in an array - add a new kfunc syscall_test_null_fail test
no changes in v9
no changes in v8
changes in v7: - add 1 more case to ensure we can read the entire sizeof(ctx) - add a test case for when the context is NULL
new in v6 --- net/bpf/test_run.c | 1 + .../selftests/bpf/prog_tests/kfunc_call.c | 128 ++++++++++++++++-- .../selftests/bpf/progs/kfunc_call_fail.c | 39 ++++++ .../selftests/bpf/progs/kfunc_call_test.c | 38 ++++++ 4 files changed, 197 insertions(+), 9 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/kfunc_call_fail.c
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 25d8ecf105aa..f16baf977a21 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -1634,6 +1634,7 @@ static int __init bpf_prog_test_run_init(void)
ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_prog_test_kfunc_set); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &bpf_prog_test_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &bpf_prog_test_kfunc_set); return ret ?: register_btf_id_dtor_kfuncs(bpf_prog_test_dtor_kfunc, ARRAY_SIZE(bpf_prog_test_dtor_kfunc), THIS_MODULE); diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c index 21e347f46c93..84798979f3a7 100644 --- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c @@ -2,6 +2,7 @@ /* Copyright (c) 2021 Facebook */ #include <test_progs.h> #include <network_helpers.h> +#include "kfunc_call_fail.skel.h" #include "kfunc_call_test.skel.h" #include "kfunc_call_test_subprog.skel.h" #include "kfunc_call_test_subprog.lskel.h" @@ -9,27 +10,68 @@
#include "cap_helpers.h"
+static size_t log_buf_sz = 1048576; /* 1 MB */ +static char obj_log_buf[1048576]; + +enum kfunc_test_type { + tc_test = 0, + syscall_test, + syscall_null_ctx_test, +}; + struct kfunc_test_params { const char *prog_name; int retval; + enum kfunc_test_type test_type; + const char *expected_err_msg; };
static struct kfunc_test_params kfunc_tests[] = { - {"kfunc_call_test1", 12}, - {"kfunc_call_test2", 3}, - {"kfunc_call_test_ref_btf_id", 0}, + /* failure cases: + * if retval is 0 -> the program will fail to load and the error message is an error + * if retval is not 0 -> the program can be loaded but running it will gives the + * provided return value. The error message is thus the one + * from a successful load + */ + {"kfunc_syscall_test_fail", -EINVAL, syscall_null_ctx_test, "processed 4 insns"}, + {"kfunc_syscall_test_null_fail", -EINVAL, syscall_null_ctx_test, "processed 4 insns"}, + + /* success cases */ + {"kfunc_call_test1", 12, tc_test, NULL}, + {"kfunc_call_test2", 3, tc_test, NULL}, + {"kfunc_call_test_ref_btf_id", 0, tc_test, NULL}, + {"kfunc_syscall_test", 0, syscall_test, NULL}, + {"kfunc_syscall_test_null", 0, syscall_null_ctx_test, NULL}, +}; + +struct syscall_test_args { + __u8 data[16]; + size_t size; };
static void verify_success(struct kfunc_test_params *param) { + LIBBPF_OPTS(bpf_test_run_opts, topts); struct kfunc_call_test *skel; struct bpf_program *prog; int prog_fd, err; - LIBBPF_OPTS(bpf_test_run_opts, topts, - .data_in = &pkt_v4, - .data_size_in = sizeof(pkt_v4), - .repeat = 1, - ); + struct syscall_test_args args = { + .size = 10, + }; + + switch (param->test_type) { + case syscall_test: + topts.ctx_in = &args; + topts.ctx_size_in = sizeof(args); + /* fallthrough */ + case syscall_null_ctx_test: + break; + case tc_test: + topts.data_in = &pkt_v4; + topts.data_size_in = sizeof(pkt_v4); + topts.repeat = 1; + break; + }
skel = kfunc_call_test__open_and_load(); if (!ASSERT_OK_PTR(skel, "skel")) @@ -50,6 +92,71 @@ static void verify_success(struct kfunc_test_params *param) kfunc_call_test__destroy(skel); }
+static void verify_fail(struct kfunc_test_params *param) +{ + LIBBPF_OPTS(bpf_object_open_opts, opts); + LIBBPF_OPTS(bpf_test_run_opts, topts); + struct bpf_program *prog; + struct kfunc_call_fail *skel; + int prog_fd, err; + struct syscall_test_args args = { + .size = 10, + }; + + opts.kernel_log_buf = obj_log_buf; + opts.kernel_log_size = log_buf_sz; + opts.kernel_log_level = 1; + + switch (param->test_type) { + case syscall_test: + topts.ctx_in = &args; + topts.ctx_size_in = sizeof(args); + /* fallthrough */ + case syscall_null_ctx_test: + break; + case tc_test: + topts.data_in = &pkt_v4; + topts.data_size_in = sizeof(pkt_v4); + break; + topts.repeat = 1; + } + + skel = kfunc_call_fail__open_opts(&opts); + if (!ASSERT_OK_PTR(skel, "kfunc_call_fail__open_opts")) + goto cleanup; + + prog = bpf_object__find_program_by_name(skel->obj, param->prog_name); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto cleanup; + + bpf_program__set_autoload(prog, true); + + err = kfunc_call_fail__load(skel); + if (!param->retval) { + /* the verifier is supposed to complain and refuses to load */ + if (!ASSERT_ERR(err, "unexpected load success")) + goto out_err; + + } else { + /* the program is loaded but must dynamically fail */ + if (!ASSERT_OK(err, "unexpected load error")) + goto out_err; + + prog_fd = bpf_program__fd(prog); + err = bpf_prog_test_run_opts(prog_fd, &topts); + if (!ASSERT_EQ(err, param->retval, param->prog_name)) + goto out_err; + } + +out_err: + if (!ASSERT_OK_PTR(strstr(obj_log_buf, param->expected_err_msg), "expected_err_msg")) { + fprintf(stderr, "Expected err_msg: %s\n", param->expected_err_msg); + fprintf(stderr, "Verifier output: %s\n", obj_log_buf); + } +cleanup: + kfunc_call_fail__destroy(skel); +} + static void test_main(void) { int i; @@ -58,7 +165,10 @@ static void test_main(void) if (!test__start_subtest(kfunc_tests[i].prog_name)) continue;
- verify_success(&kfunc_tests[i]); + if (!kfunc_tests[i].expected_err_msg) + verify_success(&kfunc_tests[i]); + else + verify_fail(&kfunc_tests[i]); } }
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_fail.c b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c new file mode 100644 index 000000000000..4168027f2ab1 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include <vmlinux.h> +#include <bpf/bpf_helpers.h> + +extern void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym; + +struct syscall_test_args { + __u8 data[16]; + size_t size; +}; + +SEC("?syscall") +int kfunc_syscall_test_fail(struct syscall_test_args *args) +{ + bpf_kfunc_call_test_mem_len_pass1(&args->data, sizeof(*args) + 1); + + return 0; +} + +SEC("?syscall") +int kfunc_syscall_test_null_fail(struct syscall_test_args *args) +{ + /* Must be called with args as a NULL pointer + * we do not check for it to have the verifier consider that + * the pointer might not be null, and so we can load it. + * + * So the following can not be added: + * + * if (args) + * return -22; + */ + + bpf_kfunc_call_test_mem_len_pass1(args, sizeof(*args)); + + return 0; +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/tools/testing/selftests/bpf/progs/kfunc_call_test.c index 5aecbb9fdc68..94c05267e5e7 100644 --- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c +++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c @@ -92,4 +92,42 @@ int kfunc_call_test_pass(struct __sk_buff *skb) return 0; }
+struct syscall_test_args { + __u8 data[16]; + size_t size; +}; + +SEC("syscall") +int kfunc_syscall_test(struct syscall_test_args *args) +{ + const int size = args->size; + + if (size > sizeof(args->data)) + return -7; /* -E2BIG */ + + bpf_kfunc_call_test_mem_len_pass1(&args->data, sizeof(args->data)); + bpf_kfunc_call_test_mem_len_pass1(&args->data, sizeof(*args)); + bpf_kfunc_call_test_mem_len_pass1(&args->data, size); + + return 0; +} + +SEC("syscall") +int kfunc_syscall_test_null(struct syscall_test_args *args) +{ + /* Must be called with args as a NULL pointer + * we do not check for it to have the verifier consider that + * the pointer might not be null, and so we can load it. + * + * So the following can not be added: + * + * if (args) + * return -22; + */ + + bpf_kfunc_call_test_mem_len_pass1(args, 0); + + return 0; +} + char _license[] SEC("license") = "GPL";