From: Roberto Sassu roberto.sassu@huawei.com
Add a test to ensure that bpf_lookup_user_key() creates a referenced special keyring when the KEY_LOOKUP_CREATE flag is passed to this function.
Ensure that the kfunc rejects invalid flags.
Ensure that a keyring can be obtained from bpf_lookup_system_key() when one of the pre-determined keyring IDs is provided.
The test is currently blacklisted for s390x (JIT does not support calling kernel function).
Signed-off-by: Roberto Sassu roberto.sassu@huawei.com --- tools/testing/selftests/bpf/DENYLIST.s390x | 1 + .../selftests/bpf/prog_tests/lookup_key.c | 112 ++++++++++++++++++ .../selftests/bpf/progs/test_lookup_key.c | 46 +++++++ 3 files changed, 159 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/lookup_key.c create mode 100644 tools/testing/selftests/bpf/progs/test_lookup_key.c
diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x index 168c5b287b5c..770c376c984d 100644 --- a/tools/testing/selftests/bpf/DENYLIST.s390x +++ b/tools/testing/selftests/bpf/DENYLIST.s390x @@ -71,3 +71,4 @@ cb_refs # expected error message unexpected err cgroup_hierarchical_stats # JIT does not support calling kernel function (kfunc) htab_update # failed to attach: ERROR: strerror_r(-524)=22 (trampoline) tracing_struct # failed to auto-attach: -524 (trampoline) +lookup_key # JIT does not support calling kernel function (kfunc) diff --git a/tools/testing/selftests/bpf/prog_tests/lookup_key.c b/tools/testing/selftests/bpf/prog_tests/lookup_key.c new file mode 100644 index 000000000000..68025e88f352 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/lookup_key.c @@ -0,0 +1,112 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu roberto.sassu@huawei.com + */ + +#include <linux/keyctl.h> +#include <test_progs.h> + +#include "test_lookup_key.skel.h" + +#define KEY_LOOKUP_CREATE 0x01 +#define KEY_LOOKUP_PARTIAL 0x02 + +static bool kfunc_not_supported; + +static int libbpf_print_cb(enum libbpf_print_level level, const char *fmt, + va_list args) +{ + char *func; + + if (strcmp(fmt, "libbpf: extern (func ksym) '%s': not found in kernel or module BTFs\n")) + return 0; + + func = va_arg(args, char *); + + if (strcmp(func, "bpf_lookup_user_key") && strcmp(func, "bpf_key_put") && + strcmp(func, "bpf_lookup_system_key")) + return 0; + + kfunc_not_supported = true; + return 0; +} + +void test_lookup_key(void) +{ + libbpf_print_fn_t old_print_cb; + struct test_lookup_key *skel; + __u32 next_id; + int ret; + + skel = test_lookup_key__open(); + if (!ASSERT_OK_PTR(skel, "test_lookup_key__open")) + return; + + old_print_cb = libbpf_set_print(libbpf_print_cb); + ret = test_lookup_key__load(skel); + libbpf_set_print(old_print_cb); + + if (ret < 0 && kfunc_not_supported) { + printf("%s:SKIP:bpf_lookup_*_key(), bpf_key_put() kfuncs not supported\n", + __func__); + test__skip(); + goto close_prog; + } + + if (!ASSERT_OK(ret, "test_lookup_key__load")) + goto close_prog; + + ret = test_lookup_key__attach(skel); + if (!ASSERT_OK(ret, "test_lookup_key__attach")) + goto close_prog; + + skel->bss->monitored_pid = getpid(); + skel->bss->key_serial = KEY_SPEC_THREAD_KEYRING; + + /* The thread-specific keyring does not exist, this test fails. */ + skel->bss->flags = 0; + + ret = bpf_prog_get_next_id(0, &next_id); + if (!ASSERT_LT(ret, 0, "bpf_prog_get_next_id")) + goto close_prog; + + /* Force creation of the thread-specific keyring, this test succeeds. */ + skel->bss->flags = KEY_LOOKUP_CREATE; + + ret = bpf_prog_get_next_id(0, &next_id); + if (!ASSERT_OK(ret, "bpf_prog_get_next_id")) + goto close_prog; + + /* Pass both lookup flags for parameter validation. */ + skel->bss->flags = KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL; + + ret = bpf_prog_get_next_id(0, &next_id); + if (!ASSERT_OK(ret, "bpf_prog_get_next_id")) + goto close_prog; + + /* Pass invalid flags. */ + skel->bss->flags = UINT64_MAX; + + ret = bpf_prog_get_next_id(0, &next_id); + if (!ASSERT_LT(ret, 0, "bpf_prog_get_next_id")) + goto close_prog; + + skel->bss->key_serial = 0; + skel->bss->key_id = 1; + + ret = bpf_prog_get_next_id(0, &next_id); + if (!ASSERT_OK(ret, "bpf_prog_get_next_id")) + goto close_prog; + + skel->bss->key_id = UINT32_MAX; + + ret = bpf_prog_get_next_id(0, &next_id); + ASSERT_LT(ret, 0, "bpf_prog_get_next_id"); + +close_prog: + skel->bss->monitored_pid = 0; + test_lookup_key__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/test_lookup_key.c b/tools/testing/selftests/bpf/progs/test_lookup_key.c new file mode 100644 index 000000000000..c73776990ae3 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_lookup_key.c @@ -0,0 +1,46 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu roberto.sassu@huawei.com + */ + +#include "vmlinux.h" +#include <errno.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +char _license[] SEC("license") = "GPL"; + +__u32 monitored_pid; +__u32 key_serial; +__u32 key_id; +__u64 flags; + +extern struct bpf_key *bpf_lookup_user_key(__u32 serial, __u64 flags) __ksym; +extern struct bpf_key *bpf_lookup_system_key(__u64 id) __ksym; +extern void bpf_key_put(struct bpf_key *key) __ksym; + +SEC("lsm.s/bpf") +int BPF_PROG(bpf, int cmd, union bpf_attr *attr, unsigned int size) +{ + struct bpf_key *bkey; + __u32 pid; + + pid = bpf_get_current_pid_tgid() >> 32; + if (pid != monitored_pid) + return 0; + + if (key_serial) + bkey = bpf_lookup_user_key(key_serial, flags); + else + bkey = bpf_lookup_system_key(key_id); + + if (!bkey) + return -ENOENT; + + bpf_key_put(bkey); + + return 0; +}