Add a simple C example

Signed-off-by: David Mulder <dmulder@samba.org>

example/.gitignore

@@ -0,0 +1 @@
+a.out

example/Makefile

@@ -0,0 +1,6 @@
+all:
+	cargo build
+	gcc -g msal_example.c -I../target/debug/include -L../target/debug -lmsal
+
+run:
+	LD_LIBRARY_PATH=../target/debug ./a.out

example/msal_example.c

@@ -0,0 +1,328 @@
+/*
+   Unix Azure Entra ID implementation
+   Copyright (C) David Mulder <dmulder@samba.org> 2024
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include <stdio.h>
+#include <msal.h>
+#include <string.h>
+#include <unistd.h>
+
+void strip_newline(char *str) {
+	int len = strlen(str);
+	if (str[len-1] == '\n') {
+		str[len-1] = '\0';
+	}
+}
+
+int main() {
+	BoxedDynTpm *tpm = NULL;
+	BrokerClientApplication *client = NULL;
+	LoadableMachineKey *loadable_machine_key = NULL;
+	MachineKey *machine_key = NULL;
+	EnrollAttrs *attrs = NULL;
+	MFAAuthContinue *flow = NULL;
+	UserToken *token = NULL;
+	UserToken *token0 = NULL;
+	LoadableMsOapxbcRsaKey *transport_key = NULL;
+	LoadableIdentityKey *cert_key = NULL;
+	LoadableIdentityKey *hello_key = NULL;
+	MSAL_ERROR err;
+	char* auth_value = NULL;
+	char *domain = NULL;
+	size_t len;
+	char *username = NULL;
+	char *password = NULL;
+	char *msg = NULL;
+	char *mfa_method = NULL;
+	char *device_id = NULL;
+	char *refresh_token = NULL;
+	char *access_token = NULL;
+	char *spn = NULL;
+	char *uuid = NULL;
+	bool mfa = false;
+	bool user_exists;
+
+	err = set_global_tracing_level(TRACE);
+	if (err != SUCCESS) {
+		printf("Failed setting the tracing level\n");
+		goto OUT;
+	}
+
+	err = tpm_init(NULL, &tpm);
+	if (err != SUCCESS) {
+		printf("Failed to initialize tpm!\n");
+		goto OUT;
+	}
+	auth_value_generate(&auth_value);
+	printf("auth_value: %s\n", auth_value);
+
+	err = tpm_machine_key_create(tpm, auth_value, &loadable_machine_key);
+	if (err != SUCCESS) {
+		printf("Failed to create loadable machine key!\n");
+		goto OUT;
+	}
+
+	err = tpm_machine_key_load(tpm,
+				   auth_value,
+				   loadable_machine_key,
+				   &machine_key);
+	if (err != SUCCESS) {
+		printf("Failed to load machine key!\n");
+		goto OUT;
+	}
+
+	err = broker_init(NULL, NULL, NULL, &client);
+	if (err != SUCCESS) {
+		printf("Failed to initialize the broker!\n");
+		goto OUT;
+	}
+
+	printf("Please enter your EntraID username: ");
+	getline(&username, &len, stdin);
+	strip_newline(username);
+
+	domain = strchr(username, '@');
+	if (domain != NULL) {
+		domain++;
+	} else {
+		printf("Failed to find the domain name from the user upn!\n");
+		goto OUT;
+	}
+
+	err = broker_check_user_exists(client, username, &user_exists);
+	if (err != SUCCESS) {
+		printf("Failed to check if the user exists!\n");
+		goto OUT;
+	}
+	if (user_exists) {
+		printf("User %s exists!\n", username);
+	} else {
+		printf("User %s does not exist!\n", username);
+		goto OUT;
+	}
+
+	password = getpass("Password: ");
+
+	err = broker_initiate_acquire_token_by_mfa_flow_for_device_enrollment(client,
+									      username,
+									      password,
+									      &flow);
+	if (err != SUCCESS) {
+		printf("Failed to initiate an mfa token acquire!\n");
+		goto OUT;
+	}
+
+	err = mfa_auth_continue_msg(flow, &msg);
+	if (err != SUCCESS) {
+		printf("Failed to fetch MFA auth message!\n");
+		goto OUT;
+	}
+	printf("%s", msg);
+	fflush(stdout);
+
+	err = mfa_auth_continue_mfa_method(flow, &mfa_method);
+	if (err != SUCCESS) {
+		printf("Failed to fetch MFA method!\n");
+		goto OUT;
+	}
+	if (strcmp(mfa_method, "PhoneAppOTP") == 0
+	 || strcmp(mfa_method, "OneWaySMS") == 0
+	 || strcmp(mfa_method, "ConsolidatedTelephony") == 0) {
+		char *otp = getpass("");
+		err = broker_acquire_token_by_mfa_flow(client,
+						       username,
+						       otp,
+						       0,
+						       flow,
+						       &token);
+		if (err != SUCCESS) {
+			printf("Failed to authenticate with otp!\n");
+			goto OUT;
+		}
+	} else {
+		printf("\n");
+		int polling_interval = mfa_auth_continue_polling_interval(flow);
+		int max_poll_attempts = mfa_auth_continue_max_poll_attempts(flow);
+		for (int i = 0; i < max_poll_attempts; i++) {
+			err = broker_acquire_token_by_mfa_flow(client,
+							       username,
+							       NULL,
+							       i,
+							       flow,
+							       &token);
+			if (err == MFA_POLL_CONTINUE) {
+				sleep(polling_interval/1000);
+			} else if (err == SUCCESS) {
+				break;
+			} else {
+				printf("Failed to authenticate when polling!\n");
+				goto OUT;
+			}
+		}
+	}
+	printf("Authentication was successful!\n");
+
+	err = enroll_attrs_init(domain,
+				"msal_example_c",
+				NULL,
+				0,
+				NULL,
+				&attrs);
+	if (err != SUCCESS) {
+		printf("Failed to create enrollment attributes!\n");
+		goto OUT;
+	}
+
+	err = broker_enroll_device(client,
+				   token,
+				   attrs,
+				   tpm,
+				   machine_key,
+				   &transport_key,
+				   &cert_key,
+				   &device_id);
+	if (err != SUCCESS) {
+		printf("Failed to enroll the device!\n");
+		goto OUT;
+	}
+	printf("Enrolled with device id: %s\n", device_id);
+
+	printf("Obtain PRT from enrollment refresh token\n");
+	err = user_token_refresh_token(token, &refresh_token);
+	if (err != SUCCESS) {
+		printf("Failed fetching refresh token\n");
+		goto OUT;
+	}
+	err = broker_acquire_token_by_refresh_token(client,
+						    refresh_token,
+						    NULL,
+						    0,
+						    NULL,
+						    tpm,
+						    machine_key,
+						    &token0);
+	if (err != SUCCESS) {
+		printf("Failed to acquire token by refresh token\n");
+		goto OUT;
+	}
+
+	err = user_token_access_token(token0, &access_token);
+	if (err != SUCCESS) {
+		printf("Failed fetching access token\n");
+		goto OUT;
+	}
+	err = user_token_spn(token0, &spn);
+	if (err != SUCCESS) {
+		printf("Failed fetching token spn\n");
+		goto OUT;
+	}
+	err = user_token_uuid(token0, &uuid);
+	if (err != SUCCESS) {
+		printf("Failed fetching token uuid\n");
+		goto OUT;
+	}
+	err = user_token_amr_mfa(token0, &mfa);
+	if (err != SUCCESS) {
+		printf("Failed fetching token amr_mfa\n");
+		goto OUT;
+	}
+	printf("access_token: %s, spn: %s, uuid: %s, mfa?: %d\n",
+	       access_token,
+	       spn,
+	       uuid,
+	       mfa);
+
+	printf("Provision hello key");
+	err = broker_provision_hello_for_business_key(client,
+						      token,
+						      tpm,
+						      machine_key,
+						      "123456",
+						      &hello_key);
+	if (err != SUCCESS) {
+		printf("Failed to provision a hello key!\n");
+		goto OUT;
+	}
+
+	printf("Acquire token via hello key\n");
+
+	user_token_free(token0);
+	err = broker_acquire_token_by_hello_for_business_key(client,
+							     username,
+							     hello_key,
+							     NULL,
+							     0,
+							     NULL,
+							     tpm,
+							     machine_key,
+							     "123456",
+							     &token0);
+	if (err != SUCCESS) {
+		printf("Failed to aquire a token using the provisioned hello key!\n");
+		goto OUT;
+	}
+
+	string_free(access_token);
+	err = user_token_access_token(token0, &access_token);
+	if (err != SUCCESS) {
+		printf("Failed fetching access token\n");
+		goto OUT;
+	}
+	string_free(spn);
+	err = user_token_spn(token0, &spn);
+	if (err != SUCCESS) {
+		printf("Failed fetching token spn\n");
+		goto OUT;
+	}
+	string_free(uuid);
+	err = user_token_uuid(token0, &uuid);
+	if (err != SUCCESS) {
+		printf("Failed fetching token uuid\n");
+		goto OUT;
+	}
+	err = user_token_amr_mfa(token0, &mfa);
+	if (err != SUCCESS) {
+		printf("Failed fetching token amr_mfa\n");
+		goto OUT;
+	}
+	printf("access_token: %s, spn: %s, uuid: %s, mfa?: %d\n",
+	       access_token,
+	       spn,
+	       uuid,
+	       mfa);
+
+OUT:
+	user_token_free(token);
+	user_token_free(token0);
+	mfa_auth_continue_free(flow);
+	string_free(auth_value);
+	loadable_machine_key_free(loadable_machine_key);
+	machine_key_free(machine_key);
+	broker_free(client);
+	tpm_free(tpm);
+	free(username);
+	string_free(msg);
+	string_free(mfa_method);
+	string_free(device_id);
+	loadable_ms_oapxbc_rsa_key_free(transport_key);
+	loadable_identity_key_free(cert_key);
+	loadable_identity_key_free(hello_key);
+	string_free(refresh_token);
+	string_free(access_token);
+	string_free(spn);
+	string_free(uuid);
+}