tango-tfe/plugin/business/ssl-policy/src/ssl_policy.cpp

#include <ssl_stream.h>
#include <tfe_utils.h>
#include <MESA/maat.h>
#include <cjson/cJSON.h>
#include <openssl/ssl.h>
#include <assert.h>
#include <tfe_resource.h>
#include <tfe_cmsg.h>

struct ssl_policy_enforcer
{
	struct maat *maat;
};

struct decryption_param
{
	uuid_t uuid;
	int ref_cnt;
	int bypass_ev_cert;
	int bypass_ct_cert;
	int bypass_mutual_auth;
	int bypass_pinning;
	int bypass_uninstall_cert_traffic;
	int bypass_protocol_errors;
	int no_verify_cn;
	int no_verify_issuer;
	int no_verify_self_signed;
	int no_verify_expry_date;
	int block_fake_cert;
	int ssl_min_version;
	int ssl_max_version;
	int allow_http2;
	int mirror_client_version;
};

static void profile_param_dup_cb(const char *table_name, void **to, void **from, long argl, void *argp)
{
	struct decryption_param *param = (struct decryption_param *)*from;
	if (param)
	{
		__sync_add_and_fetch(&(param->ref_cnt), 1);
		*to = param;
	}
	else
	{
		*to = NULL;
	}
	return;
}

static void profile_param_free_cb(const char *table_name, void **ad, long argl, void *argp)
{
	struct decryption_param *param = (struct decryption_param *)*ad;
	if (param == NULL)
	{
		return;
	}

	if ((__sync_sub_and_fetch(&param->ref_cnt, 1) == 0))
	{
		char uuid_str[UUID_STRING_SIZE];
		uuid_unparse(param->uuid, uuid_str);
		TFE_LOG_INFO(g_default_logger, "Del decryption profile: %s", uuid_str);

		free(param);
		*ad = NULL;
	}
}

static void profile_param_free(struct decryption_param *param)
{
	profile_param_free_cb(NULL, (void **)&param, 0, NULL);
}

static void profile_param_new_cb(const char *table_name, const char *key, const char *table_line, void **ad, long argl, void *argp)
{
	int ret = 0;
	cJSON *json = NULL;
	cJSON *object = NULL;
	cJSON *exclusions = NULL;
	cJSON *cert_verify = NULL;
	cJSON *approach = NULL;
	cJSON *ssl_ver = NULL;
	cJSON *item = NULL;
	struct decryption_param *param = NULL;

	char *json_str = strdup(table_line);
	json = cJSON_Parse(json_str);
	if (json == NULL)
	{
		TFE_LOG_ERROR(g_default_logger, "Invalid decryption parameter: (invalid json format) %s", table_line);
		goto error_out;
	}

	param = ALLOC(struct decryption_param, 1);
	param->ref_cnt = 1;
	param->bypass_mutual_auth = 1;
	param->bypass_pinning = 1;
	param->mirror_client_version = 1;
	uuid_parse(key, param->uuid);

	object = cJSON_GetObjectItem(json, "decryption");
	if (!object || !cJSON_IsObject(object))
	{
		TFE_LOG_ERROR(g_default_logger, "Invalid decryption parameter: (invalid decryption param) %s", table_line);
		goto error_out;
	}

	exclusions = cJSON_GetObjectItem(object, "dynamic_bypass");
	if (exclusions)
	{
		item = cJSON_GetObjectItem(exclusions, "ev_cert");
		if (item && item->type == cJSON_Number)
		{
			param->bypass_ev_cert = item->valueint;
		}
		item = cJSON_GetObjectItem(exclusions, "cert_transparency");
		if (item && item->type == cJSON_Number)
		{
			param->bypass_ct_cert = item->valueint;
		}
		item = cJSON_GetObjectItem(exclusions, "mutual_authentication");
		if (item && item->type == cJSON_Number)
		{
			param->bypass_mutual_auth = item->valueint;
		}
		item = cJSON_GetObjectItem(exclusions, "cert_pinning");
		if (item && item->type == cJSON_Number)
		{
			param->bypass_pinning = item->valueint;
		}
		item = cJSON_GetObjectItem(exclusions, "protocol_errors");
		if (item && item->type == cJSON_Number)
		{
			param->bypass_protocol_errors = item->valueint;
		}
		item = cJSON_GetObjectItem(exclusions, "trusted_root_cert_is_not_installed_on_client");
		if (item && item->type == cJSON_Number)
		{
			param->bypass_uninstall_cert_traffic = item->valueint;
		}
	}
	ssl_ver = cJSON_GetObjectItem(object, "protocol_version");
	if (ssl_ver)
	{
		item = cJSON_GetObjectItem(ssl_ver, "mirror_client");
		if (item && item->type == cJSON_Number)
		{
			param->mirror_client_version = item->valueint;
		}
		if (!param->mirror_client_version)
		{
			item = cJSON_GetObjectItem(ssl_ver, "min");
			if (item && item->type == cJSON_String)
			{
				param->ssl_min_version = sslver_str2num(item->valuestring);
			}
			item = cJSON_GetObjectItem(ssl_ver, "max");
			if (item && item->type == cJSON_String)
			{
				param->ssl_max_version = sslver_str2num(item->valuestring);
			}
			if (param->ssl_min_version < 0 || param->ssl_max_version < 0)
			{
				param->mirror_client_version = 1;
				TFE_LOG_ERROR(g_default_logger, "Invalid intercept parameter: ssl version = %s", item->valuestring);
			}
		}
		item = cJSON_GetObjectItem(ssl_ver, "allow_http2");
		if (item && item->type == cJSON_Number)
		{
			param->allow_http2 = item->valueint;
		}
	}
	cert_verify = cJSON_GetObjectItem(object, "certificate_checks");
	if (cert_verify)
	{
		approach = cJSON_GetObjectItem(cert_verify, "approach");
		if (approach)
		{
			item = cJSON_GetObjectItem(approach, "cn");
			if (item && item->type == cJSON_Number && item->valueint == 0)
			{
				param->no_verify_cn = 1;
			}
			item = cJSON_GetObjectItem(approach, "issuer");
			if (item && item->type == cJSON_Number && item->valueint == 0)
			{
				param->no_verify_issuer = 1;
			}
			item = cJSON_GetObjectItem(approach, "self-signed");
			if (item && item->type == cJSON_Number && item->valueint == 0)
			{
				param->no_verify_self_signed = 1;
			}
			item = cJSON_GetObjectItem(approach, "expiration");
			if (item && item->type == cJSON_Number && item->valueint == 0)
			{
				param->no_verify_expry_date = 1;
			}
		}
		item = cJSON_GetObjectItem(cert_verify, "fail_action");
		if (item && item->type == cJSON_String)
		{
			if (0 == strcasecmp(item->valuestring, "Fail-Close"))
			{
				param->block_fake_cert = 1;
			}
		}
	}

	*ad = param;
	TFE_LOG_INFO(g_default_logger, "Add decryption profile: %s", key);

	cJSON_Delete(json);
	free(json_str);

error_out:
	if (json)
	{
		cJSON_Delete(json);
	}
	if (json_str)
	{
		free(json_str);
	}
	if (param)
	{
		free(param);
	}
	return;
}

struct ssl_policy_enforcer *ssl_policy_enforcer_create()
{
	UNUSED int ret = 0;
	struct ssl_policy_enforcer *enforcer = ALLOC(struct ssl_policy_enforcer, 1);
	enforcer->maat = tfe_get_maat_handle();
	ret = maat_plugin_table_ex_schema_register(enforcer->maat,
											   "PXY_PROFILE_DECRYPTION",
											   profile_param_new_cb,
											   profile_param_free_cb,
											   profile_param_dup_cb,
											   0,
											   enforcer);
	assert(ret == 0);
	return enforcer;
}
enum ssl_stream_action ssl_policy_enforce(struct ssl_stream *upstream, void *u_para)
{
	UNUSED struct ssl_policy_enforcer *enforcer = (struct ssl_policy_enforcer *)u_para;
	enum ssl_stream_action action = SSL_ACTION_PASSTHROUGH;
	UNUSED int ret = 0;
	char sni[512];
	char addr_string[512];
	char rule_uuid_str[UUID_STRING_SIZE];
	char decrypted_uuid_str[UUID_STRING_SIZE];

	uuid_t rule_uuid;
	uuid_t decrypted_uuid;
	uuid_t trusted_keyring_uuid;
	uuid_t untrusted_keyring_uuid;
	ssl_stream_get_policy_id(upstream, &rule_uuid);
	ssl_stream_get_decrypted_profile_id(upstream, &decrypted_uuid);
	ssl_stream_get_trusted_keyring_profile_id(upstream, &trusted_keyring_uuid);
	ssl_stream_get_untrusted_keyring_profile_id(upstream, &untrusted_keyring_uuid);

	ssl_stream_get_string_opt(upstream, SSL_STREAM_OPT_SNI, sni, sizeof(sni));
	ssl_stream_get_string_opt(upstream, SSL_STREAM_OPT_ADDR, addr_string, sizeof(addr_string));

	uuid_unparse(rule_uuid, rule_uuid_str);
	uuid_unparse(decrypted_uuid, decrypted_uuid_str);
	TFE_LOG_DEBUG(g_default_logger, "%s %s enforce policy %s", addr_string, sni, rule_uuid_str);

	struct decryption_param *profile_param = (struct decryption_param *)maat_plugin_table_get_ex_data(enforcer->maat, "PXY_PROFILE_DECRYPTION", (const char *)&decrypted_uuid, sizeof(uuid_t));
	if (profile_param == NULL)
	{
		TFE_LOG_INFO(g_default_logger, "Failed to get decryption parameter of profile %s.", decrypted_uuid_str);
		ssl_stream_set_cmsg_string(upstream, TFE_CMSG_SSL_PASSTHROUGH_REASON, "Invalid Decryption Param");
		return SSL_ACTION_PASSTHROUGH;
	}
	int pinning_staus = 0, is_ev = 0, is_ct = 0, is_mauth = 0, has_error = 0, ja3_pinning_status = 0;
	if (!profile_param->mirror_client_version)
	{
		ret = ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_PROTOCOL_MIN_VERSION, profile_param->ssl_min_version);
		assert(ret == 0);
		ret = ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_PROTOCOL_MAX_VERSION, profile_param->ssl_max_version);
		assert(ret == 0);
	}
	if (profile_param->allow_http2)
	{
		ret = ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_ENABLE_ALPN, 1);
		assert(ret == 0);
	}
	ret = ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_NO_VERIFY_COMMON_NAME, profile_param->no_verify_cn);
	assert(ret == 0);
	ret = ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_NO_VERIFY_ISSUER, profile_param->no_verify_issuer);
	assert(ret == 0);
	ret = ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_NO_VERIFY_SELF_SIGNED, profile_param->no_verify_self_signed);
	assert(ret == 0);
	ret = ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_NO_VERIFY_EXPIRY_DATE, profile_param->no_verify_expry_date);
	assert(ret == 0);
	if (profile_param->block_fake_cert)
	{
		ret = ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_BLOCK_FAKE_CERT, 1);
		assert(ret == 0);
	}
	ret = ssl_stream_set_uuid_opt(upstream, SSL_STREAM_OPT_KEYRING_FOR_TRUSTED, &trusted_keyring_uuid);
	assert(ret == 0);
	ret = ssl_stream_set_uuid_opt(upstream, SSL_STREAM_OPT_KEYRING_FOR_UNTRUSTED, &untrusted_keyring_uuid);
	assert(ret == 0);
	ret = ssl_stream_get_integer_opt(upstream, SSL_STREAM_OPT_PINNING_STATUS, &pinning_staus);
	assert(ret == 0);
	ret = ssl_stream_get_integer_opt(upstream, SSL_STREAM_OPT_JA3_PINNING_STATUS, &ja3_pinning_status);
	assert(ret == 0);
	ret = ssl_stream_get_integer_opt(upstream, SSL_STREAM_OPT_IS_EV_CERT, &is_ev);
	assert(ret == 0);
	ret = ssl_stream_get_integer_opt(upstream, SSL_STREAM_OPT_IS_MUTUAL_AUTH, &is_mauth);
	assert(ret == 0);
	ret = ssl_stream_get_integer_opt(upstream, SSL_STREAM_OPT_IS_CT_CERT, &is_ct);
	assert(ret == 0);
	ret = ssl_stream_get_integer_opt(upstream, SSL_STREAM_OPT_HAS_PROTOCOL_ERRORS, &has_error);
	assert(ret == 0);

	if (pinning_staus == 1 && ja3_pinning_status == JA3_PINNING_STATUS_NOT_PINNING && profile_param->bypass_uninstall_cert_traffic)
	{
		action = SSL_ACTION_PASSTHROUGH;
		ssl_stream_set_cmsg_string(upstream, TFE_CMSG_SSL_PASSTHROUGH_REASON, "Certificate Not Installed");
		TFE_LOG_DEBUG(g_default_logger, "%s %s enforce policy %s, action PASSTHROUGH due to Certificate Not Installed", addr_string, sni, rule_uuid_str);
	}
	else if ((pinning_staus == 1 || ja3_pinning_status == JA3_PINNING_STATUS_IS_PINNING) && ja3_pinning_status != JA3_PINNING_STATUS_NOT_PINNING && profile_param->bypass_pinning)
	{
		action = SSL_ACTION_PASSTHROUGH;
		ssl_stream_set_cmsg_string(upstream, TFE_CMSG_SSL_PASSTHROUGH_REASON, "Certificate Pinning");
		TFE_LOG_DEBUG(g_default_logger, "%s %s enforce policy %s, action PASSTHROUGH due to Certificate Pinning", addr_string, sni, rule_uuid_str);
	}
	else if (is_mauth && profile_param->bypass_mutual_auth)
	{
		action = SSL_ACTION_PASSTHROUGH;
		ssl_stream_set_cmsg_string(upstream, TFE_CMSG_SSL_PASSTHROUGH_REASON, "Mutual Authentication");
		TFE_LOG_DEBUG(g_default_logger, "%s %s enforce policy %s, action PASSTHROUGH due to Mutual Authentication", addr_string, sni, rule_uuid_str);
	}
	else if (is_ev && profile_param->bypass_ev_cert)
	{
		action = SSL_ACTION_PASSTHROUGH;
		ssl_stream_set_cmsg_string(upstream, TFE_CMSG_SSL_PASSTHROUGH_REASON, "EV Certificate");
		TFE_LOG_DEBUG(g_default_logger, "%s %s enforce policy %s, action PASSTHROUGH due to EV Certificate", addr_string, sni, rule_uuid_str);
	}
	else if (is_ct && profile_param->bypass_ct_cert)
	{
		action = SSL_ACTION_PASSTHROUGH;
		ssl_stream_set_cmsg_string(upstream, TFE_CMSG_SSL_PASSTHROUGH_REASON, "Certificate Transparency");
		TFE_LOG_DEBUG(g_default_logger, "%s %s enforce policy %s, action PASSTHROUGH due to Certificate Transparency", addr_string, sni, rule_uuid_str);
	}
	else if (has_error && profile_param->bypass_protocol_errors)
	{
		action = SSL_ACTION_PASSTHROUGH;
		ssl_stream_set_cmsg_string(upstream, TFE_CMSG_SSL_PASSTHROUGH_REASON, "Protocol Errors");
		TFE_LOG_DEBUG(g_default_logger, "%s %s enforce policy %s, action PASSTHROUGH due to Protocol Errors", addr_string, sni, rule_uuid_str);
	}
	else
	{
		action = SSL_ACTION_INTERCEPT;
	}

	profile_param_free(profile_param);
	profile_param = NULL;
	return action;
}