Commit ffd5cfca authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Daniel Borkmann

selftests/bpf: Excercise bpf_obj_get_info_by_fd for bpf2bpf

Apparently, no existing selftest covers it. Add a new one where
we load cgroup/bind4 program and attach fentry to it. Calling
bpf_obj_get_info_by_fd on the fentry program should return non-zero
btf_id/btf_obj_id instead of crashing the kernel.
Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220804201140.1340684-2-sdf@google.com
parent 6644aabb
......@@ -3,6 +3,7 @@
#include <test_progs.h>
#include <network_helpers.h>
#include <bpf/btf.h>
#include "bind4_prog.skel.h"
typedef int (*test_cb)(struct bpf_object *obj);
......@@ -407,6 +408,98 @@ static void test_func_replace_global_func(void)
prog_name, false, NULL);
}
static int find_prog_btf_id(const char *name, __u32 attach_prog_fd)
{
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
struct btf *btf;
int ret;
ret = bpf_obj_get_info_by_fd(attach_prog_fd, &info, &info_len);
if (ret)
return ret;
if (!info.btf_id)
return -EINVAL;
btf = btf__load_from_kernel_by_id(info.btf_id);
ret = libbpf_get_error(btf);
if (ret)
return ret;
ret = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
btf__free(btf);
return ret;
}
static int load_fentry(int attach_prog_fd, int attach_btf_id)
{
LIBBPF_OPTS(bpf_prog_load_opts, opts,
.expected_attach_type = BPF_TRACE_FENTRY,
.attach_prog_fd = attach_prog_fd,
.attach_btf_id = attach_btf_id,
);
struct bpf_insn insns[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
};
return bpf_prog_load(BPF_PROG_TYPE_TRACING,
"bind4_fentry",
"GPL",
insns,
ARRAY_SIZE(insns),
&opts);
}
static void test_fentry_to_cgroup_bpf(void)
{
struct bind4_prog *skel = NULL;
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
int cgroup_fd = -1;
int fentry_fd = -1;
int btf_id;
cgroup_fd = test__join_cgroup("/fentry_to_cgroup_bpf");
if (!ASSERT_GE(cgroup_fd, 0, "cgroup_fd"))
return;
skel = bind4_prog__open_and_load();
if (!ASSERT_OK_PTR(skel, "skel"))
goto cleanup;
skel->links.bind_v4_prog = bpf_program__attach_cgroup(skel->progs.bind_v4_prog, cgroup_fd);
if (!ASSERT_OK_PTR(skel->links.bind_v4_prog, "bpf_program__attach_cgroup"))
goto cleanup;
btf_id = find_prog_btf_id("bind_v4_prog", bpf_program__fd(skel->progs.bind_v4_prog));
if (!ASSERT_GE(btf_id, 0, "find_prog_btf_id"))
goto cleanup;
fentry_fd = load_fentry(bpf_program__fd(skel->progs.bind_v4_prog), btf_id);
if (!ASSERT_GE(fentry_fd, 0, "load_fentry"))
goto cleanup;
/* Make sure bpf_obj_get_info_by_fd works correctly when attaching
* to another BPF program.
*/
ASSERT_OK(bpf_obj_get_info_by_fd(fentry_fd, &info, &info_len),
"bpf_obj_get_info_by_fd");
ASSERT_EQ(info.btf_id, 0, "info.btf_id");
ASSERT_EQ(info.attach_btf_id, btf_id, "info.attach_btf_id");
ASSERT_GT(info.attach_btf_obj_id, 0, "info.attach_btf_obj_id");
cleanup:
if (cgroup_fd >= 0)
close(cgroup_fd);
if (fentry_fd >= 0)
close(fentry_fd);
bind4_prog__destroy(skel);
}
/* NOTE: affect other tests, must run in serial mode */
void serial_test_fexit_bpf2bpf(void)
{
......@@ -430,4 +523,6 @@ void serial_test_fexit_bpf2bpf(void)
test_fmod_ret_freplace();
if (test__start_subtest("func_replace_global_func"))
test_func_replace_global_func();
if (test__start_subtest("fentry_to_cgroup_bpf"))
test_fentry_to_cgroup_bpf();
}
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