From: Xu Kuohai Add test to check the return value when a BPF program exits with 0 for a boolean and an errno LSM hook. For each hook, two BPF programs are attached. The first program returns 0 without calling bpf_set_retval() to exercise the return value translation logic, while the second program reads the retval via bpf_get_retval(). Signed-off-by: Xu Kuohai --- .../selftests/bpf/prog_tests/lsm_cgroup.c | 79 +++++++++++++++++++ .../testing/selftests/bpf/progs/lsm_cgroup.c | 30 +++++++ 2 files changed, 109 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/lsm_cgroup.c b/tools/testing/selftests/bpf/prog_tests/lsm_cgroup.c index 6df25de8f080..41e867467f6c 100644 --- a/tools/testing/selftests/bpf/prog_tests/lsm_cgroup.c +++ b/tools/testing/selftests/bpf/prog_tests/lsm_cgroup.c @@ -2,6 +2,7 @@ #include #include +#include #include #include @@ -309,11 +310,89 @@ static void test_lsm_cgroup_nonvoid(void) lsm_cgroup_nonvoid__destroy(skel); } +static void test_lsm_cgroup_retval(void) +{ + struct lsm_cgroup *skel = NULL; + int skipcap_prog_fd1, skipcap_prog_fd2, socket_prog_fd1, socket_prog_fd2; + int cgroup_fd = -1; + int err, fd; + char tmpfile[] = "/tmp/test_lsm_cgroup_retval.XXXXXX"; + + fd = mkstemp(tmpfile); + if (!ASSERT_OK_FD(fd, "mkstemp")) + return; + close(fd); + + cgroup_fd = test__join_cgroup("/default_retval"); + if (!ASSERT_OK_FD(cgroup_fd, "join_cgroup")) + goto cleanup_tmpfile; + + skel = lsm_cgroup__open_and_load(); + if (!ASSERT_OK_PTR(skel, "open_and_load")) + goto cleanup_cgroup; + + skipcap_prog_fd1 = bpf_program__fd(skel->progs.skipcap_first); + skipcap_prog_fd2 = bpf_program__fd(skel->progs.skipcap_second); + socket_prog_fd1 = bpf_program__fd(skel->progs.socket_first); + socket_prog_fd2 = bpf_program__fd(skel->progs.socket_second); + + err = bpf_prog_attach(skipcap_prog_fd1, cgroup_fd, BPF_LSM_CGROUP, BPF_F_ALLOW_MULTI); + if (err == -ENOTSUPP) { + test__skip(); + goto cleanup_skeleton; + } + if (!ASSERT_OK(err, "attach first skipcap prog")) + goto cleanup_skeleton; + + err = bpf_prog_attach(skipcap_prog_fd2, cgroup_fd, BPF_LSM_CGROUP, BPF_F_ALLOW_MULTI); + if (!ASSERT_OK(err, "attach second skipcap prog")) + goto cleanup_skipcap1; + + err = bpf_prog_attach(socket_prog_fd1, cgroup_fd, BPF_LSM_CGROUP, BPF_F_ALLOW_MULTI); + if (!ASSERT_OK(err, "attach first sock_create prog")) + goto cleanup_skipcap2; + + err = bpf_prog_attach(socket_prog_fd2, cgroup_fd, BPF_LSM_CGROUP, BPF_F_ALLOW_MULTI); + if (!ASSERT_OK(err, "attach second sock_create prog")) + goto cleanup_sock_create1; + + /* trigger the bool hook by setxattr */ + err = setxattr(tmpfile, "user.test", "value", 5, 0); + if (!ASSERT_OK(err, "setxattr")) + goto cleanup_sock_create2; + + /* trigger the errno hook by creating a socket */ + fd = socket(AF_INET, SOCK_STREAM, 0); + if (!ASSERT_OK_FD(fd, "socket")) + goto cleanup_sock_create2; + close(fd); + + ASSERT_EQ(skel->data->skipcap_retval, 0, "bool_hook_retval_should_be_0"); + ASSERT_EQ(skel->data->socket_retval, -EPERM, "errno_hook_retval_should_be_EPERM"); + +cleanup_sock_create2: + bpf_prog_detach2(socket_prog_fd2, cgroup_fd, BPF_LSM_CGROUP); +cleanup_sock_create1: + bpf_prog_detach2(socket_prog_fd1, cgroup_fd, BPF_LSM_CGROUP); +cleanup_skipcap2: + bpf_prog_detach2(skipcap_prog_fd2, cgroup_fd, BPF_LSM_CGROUP); +cleanup_skipcap1: + bpf_prog_detach2(skipcap_prog_fd1, cgroup_fd, BPF_LSM_CGROUP); +cleanup_skeleton: + lsm_cgroup__destroy(skel); +cleanup_cgroup: + close(cgroup_fd); +cleanup_tmpfile: + unlink(tmpfile); +} + void test_lsm_cgroup(void) { if (test__start_subtest("functional")) test_lsm_cgroup_functional(); if (test__start_subtest("nonvoid")) test_lsm_cgroup_nonvoid(); + if (test__start_subtest("retval")) + test_lsm_cgroup_retval(); btf__free(btf); } diff --git a/tools/testing/selftests/bpf/progs/lsm_cgroup.c b/tools/testing/selftests/bpf/progs/lsm_cgroup.c index d7598538aa2d..3bfa479104be 100644 --- a/tools/testing/selftests/bpf/progs/lsm_cgroup.c +++ b/tools/testing/selftests/bpf/progs/lsm_cgroup.c @@ -35,6 +35,8 @@ int called_socket_bind; int called_socket_bind2; int called_socket_alloc; int called_socket_clone; +int skipcap_retval = -4095; +int socket_retval = -4095; static __always_inline int test_local_storage(void) { @@ -190,3 +192,31 @@ int BPF_PROG(socket_clone, struct sock *newsk, const struct request_sock *req) return 1; } + +SEC("lsm_cgroup/inode_xattr_skipcap") +int BPF_PROG(skipcap_first, const char *name) +{ + return 0; +} + +SEC("lsm_cgroup/inode_xattr_skipcap") +int BPF_PROG(skipcap_second, const char *name) +{ + skipcap_retval = bpf_get_retval(); + bpf_set_retval(0); + return 1; +} + +SEC("lsm_cgroup/socket_create") +int BPF_PROG(socket_first, int family, int type, int protocol, int kern) +{ + return 0; +} + +SEC("lsm_cgroup/socket_create") +int BPF_PROG(socket_second, int family, int type, int protocol, int kern) +{ + socket_retval = bpf_get_retval(); + bpf_set_retval(0); + return 1; +} -- 2.43.0