1 files changed, 88 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_verify_pkcs7_sig.c b/tools/testing/selftests/bpf/progs/test_verify_pkcs7_sig.c
new file mode 100644
index 000000000000..f42e9f3831a1
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_verify_pkcs7_sig.c
@@ -0,0 +1,88 @@
+// 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>
+#include "bpf_kfuncs.h"
+
+#define MAX_DATA_SIZE (1024 * 1024)
+#define MAX_SIG_SIZE 1024
+
+__u32 monitored_pid;
+__u32 user_keyring_serial;
+__u64 system_keyring_id;
+
+struct data {
+	__u8 data[MAX_DATA_SIZE];
+	__u32 data_len;
+	__u8 sig[MAX_SIG_SIZE];
+	__u32 sig_len;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, __u32);
+	__type(value, struct data);
+} data_input SEC(".maps");
+
+char _license[] SEC("license") = "GPL";
+
+SEC("lsm.s/bpf")
+int BPF_PROG(bpf, int cmd, union bpf_attr *attr, unsigned int size)
+{
+	struct bpf_dynptr data_ptr, sig_ptr;
+	struct data *data_val;
+	struct bpf_key *trusted_keyring;
+	__u32 pid;
+	__u64 value;
+	int ret, zero = 0;
+
+	pid = bpf_get_current_pid_tgid() >> 32;
+	if (pid != monitored_pid)
+		return 0;
+
+	data_val = bpf_map_lookup_elem(&data_input, &zero);
+	if (!data_val)
+		return 0;
+
+	ret = bpf_probe_read_kernel(&value, sizeof(value), &attr->value);
+	if (ret)
+		return ret;
+
+	ret = bpf_copy_from_user(data_val, sizeof(struct data),
+				 (void *)(unsigned long)value);
+	if (ret)
+		return ret;
+
+	if (data_val->data_len > sizeof(data_val->data))
+		return -EINVAL;
+
+	bpf_dynptr_from_mem(data_val->data, data_val->data_len, 0, &data_ptr);
+
+	if (data_val->sig_len > sizeof(data_val->sig))
+		return -EINVAL;
+
+	bpf_dynptr_from_mem(data_val->sig, data_val->sig_len, 0, &sig_ptr);
+
+	if (user_keyring_serial)
+		trusted_keyring = bpf_lookup_user_key(user_keyring_serial, 0);
+	else
+		trusted_keyring = bpf_lookup_system_key(system_keyring_id);
+
+	if (!trusted_keyring)
+		return -ENOENT;
+
+	ret = bpf_verify_pkcs7_signature(&data_ptr, &sig_ptr, trusted_keyring);
+
+	bpf_key_put(trusted_keyring);
+
+	return ret;
+}