Add tests checking that programs calling destructive kfuncs can only do
so if they have BPF_F_DESTRUCTIVE flag set and CAP_SYS_BOOT
capabilities.
Signed-off-by: Artem Savkov <asavkov@xxxxxxxxxx>
---
net/bpf/test_run.c | 12 +++++-
.../selftests/bpf/prog_tests/kfunc_call.c | 41 +++++++++++++++++++
.../bpf/progs/kfunc_call_destructive.c | 14 +++++++
3 files changed, 66 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/bpf/progs/kfunc_call_destructive.c
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 2ca96acbc50a0..dc267fa308f92 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -691,6 +691,10 @@ noinline void bpf_kfunc_call_test_mem_len_fail2(u64 *mem, int len)
{
}
+noinline void bpf_kfunc_call_test_destructive(void)
+{
+}
+
__diag_pop();
ALLOW_ERROR_INJECTION(bpf_modify_return_test, ERRNO);
@@ -714,6 +718,7 @@ BTF_ID(func, bpf_kfunc_call_test_fail3)
BTF_ID(func, bpf_kfunc_call_test_mem_len_pass1)
BTF_ID(func, bpf_kfunc_call_test_mem_len_fail1)
BTF_ID(func, bpf_kfunc_call_test_mem_len_fail2)
+BTF_ID(func, bpf_kfunc_call_test_destructive)
BTF_SET_END(test_sk_check_kfunc_ids)
BTF_SET_START(test_sk_acquire_kfunc_ids)
@@ -738,6 +743,10 @@ BTF_SET_START(test_sk_kptr_acquire_kfunc_ids)
BTF_ID(func, bpf_kfunc_call_test_kptr_get)
BTF_SET_END(test_sk_kptr_acquire_kfunc_ids)
+BTF_SET_START(test_sk_destructive_kfunc_ids)
+BTF_ID(func, bpf_kfunc_call_test_destructive)
+BTF_SET_END(test_sk_destructive_kfunc_ids)
+
static void *bpf_test_init(const union bpf_attr *kattr, u32 user_size,
u32 size, u32 headroom, u32 tailroom)
{
@@ -1622,7 +1631,8 @@ static const struct btf_kfunc_id_set bpf_prog_test_kfunc_set = {
.acquire_set = &test_sk_acquire_kfunc_ids,
.release_set = &test_sk_release_kfunc_ids,
.ret_null_set = &test_sk_ret_null_kfunc_ids,
- .kptr_acquire_set = &test_sk_kptr_acquire_kfunc_ids
+ .kptr_acquire_set = &test_sk_kptr_acquire_kfunc_ids,
+ .destructive_set = &test_sk_destructive_kfunc_ids,
};
BTF_ID_LIST(bpf_prog_test_dtor_kfunc_ids)
diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
index c00eb974eb85e..1c2c4fdfba88b 100644
--- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
+++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
@@ -5,6 +5,9 @@
#include "kfunc_call_test.lskel.h"
#include "kfunc_call_test_subprog.skel.h"
#include "kfunc_call_test_subprog.lskel.h"
+#include "kfunc_call_destructive.skel.h"
+
+#include "cap_helpers.h"
static void test_main(void)
{
@@ -86,6 +89,41 @@ static void test_subprog_lskel(void)
kfunc_call_test_subprog_lskel__destroy(skel);
}
+static int test_destructive_open_and_load(int set_flag)
+{
+ struct kfunc_call_destructive *skel;
+ int err;
+
+ skel = kfunc_call_destructive__open();
+ if (!ASSERT_OK_PTR(skel, "prog_open"))
+ return -1;
+
+ if (set_flag)
+ bpf_program__set_flags(skel->progs.kfunc_destructive_test,
+ bpf_program__flags(skel->progs.kfunc_destructive_test) | BPF_F_DESTRUCTIVE);
+
+ err = kfunc_call_destructive__load(skel);
+
+ kfunc_call_destructive__destroy(skel);
+
+ return err;
+}
+
+static void test_destructive(void)
+{
+ __u64 save_caps = 0;
+
+ ASSERT_EQ(test_destructive_open_and_load(0), -13, "no_flag_failure");
+ ASSERT_OK(test_destructive_open_and_load(1), "succesful_load");
+
+ if (!ASSERT_OK(cap_disable_effective(1ULL << CAP_SYS_BOOT, &save_caps), "drop_caps"))
+ return;
+
+ ASSERT_EQ(test_destructive_open_and_load(1), -13, "no_caps_failure");
+
+ cap_enable_effective(save_caps, NULL);
+}
+
void test_kfunc_call(void)
{
if (test__start_subtest("main"))
@@ -96,4 +134,7 @@ void test_kfunc_call(void)
if (test__start_subtest("subprog_lskel"))
test_subprog_lskel();
+
+ if (test__start_subtest("destructive"))
+ test_destructive();
}
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c b/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c
new file mode 100644
index 0000000000000..767472bc5a97b
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+
+extern void bpf_kfunc_call_test_destructive(void) __ksym;
+
+SEC("tc")
+int kfunc_destructive_test(void)
+{
+ bpf_kfunc_call_test_destructive();
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.35.3
