tango-tfe/platform/src/ssl_policy.cpp

#include <ssl_stream.h>
#include <ssl_utils.h>
#include <tfe_utils.h>
#include <openssl/ssl.h>
#include <MESA/Maat_rule.h>
#include <cjson/cJSON.h>

struct ssl_policy_enforcer
{
	Maat_feather_t maat;
	int table_id;
	void* logger;
};
struct intercept_param
{
	int policy_id;
	int ref_cnt;
	int keyring;
	int bypass_ev_cert;
	int bypass_ct_cert;
	int bypass_mutual_auth;
	int bypass_pinning;
	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 mirror_client_version;
	int decrypt_mirror_enabled;
	int mirror_profile_id;
};

void intercept_param_dup_cb(int table_id, MAAT_PLUGIN_EX_DATA* to, MAAT_PLUGIN_EX_DATA* from, long argl, void* argp)
{
	struct intercept_param* param= (struct intercept_param*) *from;
	param->ref_cnt++;
	*to = param;
	return;
}
void intercept_param_new_cb(int table_id, const char* key, const char* table_line, MAAT_PLUGIN_EX_DATA* ad, long argl, void* argp)
{
	int ret=0;
	size_t intercept_user_region_offset=0, len=0;
	char* json_str=NULL;
	cJSON *json=NULL, *exclusions=NULL, *cert_verify=NULL, *approach=NULL, *ssl_ver=NULL, *item=NULL;
	struct intercept_param* param=NULL;

	struct ssl_policy_enforcer* enforcer=(struct ssl_policy_enforcer*)argp;
	ret=Maat_helper_read_column(table_line, 7, &intercept_user_region_offset, &len);
	if(ret<0)
	{	
		TFE_LOG_ERROR(enforcer->logger, "Get intercept user region: %s", table_line);
		return;
	}	
	json_str=ALLOC(char, len+1);
	memcpy(json_str, table_line+intercept_user_region_offset, len);	
	json=cJSON_Parse(json_str);
	if(json==NULL)
	{
		TFE_LOG_ERROR(enforcer->logger, "Invalid intercept parameter: id = %s", key);
		goto error_out;
	}
	param=ALLOC(struct intercept_param, 1);	
	param->policy_id=atoi(key);
	param->ref_cnt=1;
	param->bypass_mutual_auth=1;
	param->bypass_pinning=1;
	
	item=cJSON_GetObjectItem(json, "keyring");
	if(item && item->type==cJSON_Number) param->keyring=item->valueint;
	
	exclusions=cJSON_GetObjectItem(json, "exclusions");
	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, "client_cert_req");
		if(item && item->type==cJSON_Number) param->bypass_mutual_auth=item->valueint;
		item=cJSON_GetObjectItem(exclusions, "pinning");
		if(item && item->type==cJSON_Number) param->bypass_pinning=item->valueint;
	}
	cert_verify=cJSON_GetObjectItem(json, "cert_verify");
	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(exclusions, "fail_method");
		if(item && item->type==cJSON_String)
		{
			if(0==strcasecmp(item->string, "Fail-Close"))
			{
				param->block_fake_cert=1;
			}
		}
	}
	ssl_ver=cJSON_GetObjectItem(json, "ssl_ver");
	if(ssl_ver)
	{		
		item=cJSON_GetObjectItem(ssl_ver, "mirror_client");	
		if(item && item->type==cJSON_String) 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->string);
			item=cJSON_GetObjectItem(ssl_ver, "max");	
			if(item && item->type==cJSON_String) param->ssl_max_version=sslver_str2num(item->string);
		}
	}
	*ad=param;
	TFE_LOG_INFO(enforcer->logger, "Add intercept policy: %d", param->policy_id);
error_out:	
	cJSON_Delete(json);
	free(json_str);
	return;
}
void intercept_param_free_cb(int table_id, MAAT_PLUGIN_EX_DATA* ad, long argl, void* argp)
{
	struct ssl_policy_enforcer* enforcer=(struct ssl_policy_enforcer*)argp;
	struct intercept_param* param= (struct intercept_param*) *ad;
	param->ref_cnt--;
	if(param->ref_cnt==0)
	{
		free(param);
		TFE_LOG_INFO(enforcer->logger, "Del intercept policy %d", param->policy_id);
		free(*ad);
		*ad=NULL;
	}
}
void intercept_param_free(struct intercept_param* param)
{
	intercept_param_free_cb(0, (void**)&param, 0, NULL);
	return;
}
struct ssl_policy_enforcer* ssl_policy_enforcer_create(Maat_feather_t maat, void* logger)
{
	struct ssl_policy_enforcer* enforcer=ALLOC(struct ssl_policy_enforcer, 1);
	enforcer->maat=maat;
	enforcer->logger=logger;
	enforcer->table_id=Maat_table_register(enforcer->maat, "PXY_INTERCEPT_COMPILE");
	int ret=Maat_plugin_EX_register(enforcer->maat, 
							enforcer->table_id,
							intercept_param_new_cb,							
							intercept_param_free_cb,
							intercept_param_dup_cb,
							NULL,
							0,
							enforcer);
	assert(ret==1);
	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;
	struct intercept_param *param=NULL;
	enum ssl_stream_action action=SSL_ACTION_PASSTHROUGH;
	UNUSED int ret=0;
	int policy_id=0;
	char policy_id_str[16]={0};
	snprintf(policy_id_str, sizeof(policy_id_str), "%d", policy_id);
	param=(struct intercept_param *)Maat_plugin_get_EX_data(enforcer->maat, enforcer->table_id, policy_id_str);
	if(param==NULL)
	{
		TFE_LOG_INFO(enforcer->logger, "Failed to get intercept parameter of policy %d.", param->policy_id);
		return SSL_ACTION_PASSTHROUGH;
	}
	int pinning_staus=0, is_ev=0, is_ct=0, is_mauth=0;
 	if(!param->mirror_client_version)
	{
		ret=ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_PROTOCOL_MIN_VERSION, SSL3_VERSION);
		ret=ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_PROTOCOL_MIN_VERSION, TLS1_3_VERSION);
	}
	ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_NO_VERIFY_COMMON_NAME, param->no_verify_cn);
	ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_NO_VERIFY_ISSUER, param->no_verify_issuer);
	ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_NO_VERIFY_SELF_SIGNED, param->no_verify_self_signed);
	ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_NO_VERIFY_EXPIRY_DATE, param->no_verify_expry_date);
	if(param->block_fake_cert)
	{
		ret=ssl_stream_set_integer_opt(upstream, SSL_STREAM_OPT_BLOCK_FAKE_CERT, 1);
	}
	ret=ssl_stream_get_integer_opt(upstream, SSL_STREAM_OPT_PINNING_STATUS, &pinning_staus);
	assert(ret==1);
	ret=ssl_stream_get_integer_opt(upstream, SSL_STREAM_OPT_IS_EV_CERT, &is_ev);
	assert(ret==1);
	ret=ssl_stream_get_integer_opt(upstream, SSL_STREAM_OPT_IS_MUTUAL_AUTH, &is_mauth);
	ret=ssl_stream_get_integer_opt(upstream, SSL_STREAM_OPT_IS_CT_CERT, &is_ct);
	assert(ret=1);
	if( (pinning_staus>1 && param->bypass_pinning) ||
		(is_mauth && param->bypass_mutual_auth) ||
		(is_ev && param->bypass_ev_cert) ||
		(is_ct && param->bypass_ct_cert) )
	{
		action=SSL_ACTION_PASSTHROUGH;
	}
	else
	{
		action=SSL_ACTION_INTERCEPT;
	}
	intercept_param_free(param);
	param=NULL;
	return action;
}