/********************************************************************* * * File : $Source: /cvsroot/ijbswa/current/ssl.c,v $ * * Purpose : File with TLS/SSL extension. Contains methods for * creating, using and closing TLS/SSL connections * using mbedTLS. * * Copyright : Written by and Copyright (c) 2017-2020 Vaclav Svec. FIT CVUT. * Copyright (C) 2018-2024 by Fabian Keil * * This program is free software; you can redistribute it * and/or modify it under the terms of the GNU General * Public License as published by the Free Software * Foundation; either version 2 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 General Public * License for more details. * * The GNU General Public License should be included with * this file. If not, you can view it at * http://www.gnu.org/copyleft/gpl.html * or write to the Free Software Foundation, Inc., 59 * Temple Place - Suite 330, Boston, MA 02111-1307, USA. * *********************************************************************/ #include #include #if !defined(MBEDTLS_CONFIG_FILE) # include "mbedtls/config.h" #else # include MBEDTLS_CONFIG_FILE #endif #include "mbedtls/sha256.h" #include "mbedtls/pem.h" #include "mbedtls/base64.h" #include "mbedtls/error.h" #include "mbedtls/oid.h" #include "mbedtls/asn1write.h" #include "config.h" #include "project.h" #include "miscutil.h" #include "errlog.h" #include "jcc.h" #include "ssl.h" #include "ssl_common.h" #include "encode.h" /* * Macros for searching begin and end of certificates. * Necessary to convert structure mbedtls_x509_crt to crt file. */ #define PEM_BEGIN_CRT "-----BEGIN CERTIFICATE-----\n" #define PEM_END_CRT "-----END CERTIFICATE-----\n" #define VALID_DATETIME_FMT "%Y%m%d%H%M%S" #define VALID_DATETIME_BUFLEN 15 /* * Macros for ssl.c */ #define CERTIFICATE_BUF_SIZE 16384 /* Size of buffer to save certificate. Value 4096 is mbedtls library buffer size for certificate in DER form */ #define PRIVATE_KEY_BUF_SIZE 16000 /* Size of buffer to save private key. Value 16000 is taken from mbed TLS library examples. */ #define CERT_SIGNATURE_ALGORITHM MBEDTLS_MD_SHA256 /* The MD algorithm to use for the signature */ #define CERT_PARAM_COMMON_NAME CERT_PARAM_COMMON_NAME_FCODE"=" #define CERT_PARAM_ORGANIZATION ","CERT_PARAM_ORGANIZATION_FCODE"=" #define CERT_PARAM_ORG_UNIT ","CERT_PARAM_ORG_UNIT_FCODE"=" #define CERT_PARAM_COUNTRY ","CERT_PARAM_COUNTRY_FCODE"="CERT_PARAM_COUNTRY_CODE /* * Properties of key for generating */ typedef struct { mbedtls_pk_type_t type; /* type of key to generate */ int rsa_keysize; /* length of key in bits */ char *key_file_path; /* filename of the key file */ } key_options; /* Variables for one common RNG for all SSL use */ static mbedtls_ctr_drbg_context ctr_drbg; static mbedtls_entropy_context entropy; static int rng_seeded; static int generate_host_certificate(struct client_state *csp); static int host_to_hash(struct client_state *csp); static int ssl_verify_callback(void *data, mbedtls_x509_crt *crt, int depth, uint32_t *flags); static void free_client_ssl_structures(struct client_state *csp); static void free_server_ssl_structures(struct client_state *csp); static int seed_rng(struct client_state *csp); static int *get_ciphersuites_from_string(const char *ciphersuites_string); /********************************************************************* * * Function : is_ssl_pending * * Description : Tests if there are some waiting data on ssl connection. * Only considers data that has actually been received * locally and ignores data that is still on the fly * or has not yet been sent by the remote end. * * Parameters : * 1 : ssl_attr = SSL context to test * * Returns : 0 => No data are pending * >0 => Pending data length * *********************************************************************/ extern size_t is_ssl_pending(struct ssl_attr *ssl_attr) { mbedtls_ssl_context *ssl = &ssl_attr->mbedtls_attr.ssl; if (ssl == NULL) { return 0; } return mbedtls_ssl_get_bytes_avail(ssl); } /********************************************************************* * * Function : ssl_send_data * * Description : Sends the content of buf (for n bytes) to given SSL * connection context. * * Parameters : * 1 : ssl_attr = SSL context to send data to * 2 : buf = Pointer to data to be sent * 3 : len = Length of data to be sent to the SSL context * * Returns : Length of sent data or negative value on error. * *********************************************************************/ extern int ssl_send_data(struct ssl_attr *ssl_attr, const unsigned char *buf, size_t len) { mbedtls_ssl_context *ssl = &ssl_attr->mbedtls_attr.ssl; int ret = 0; size_t max_fragment_size = 0; /* Maximal length of data in one SSL fragment*/ int send_len = 0; /* length of one data part to send */ int pos = 0; /* Position of unsent part in buffer */ if (len == 0) { return 0; } /* Getting maximal length of data sent in one fragment */ max_fragment_size = mbedtls_ssl_get_max_frag_len(ssl); /* * Whole buffer must be sent in many fragments, because each fragment * has its maximal length. */ while (pos < len) { /* Compute length of data, that can be send in next fragment */ if ((pos + (int)max_fragment_size) > len) { send_len = (int)len - pos; } else { send_len = (int)max_fragment_size; } log_error(LOG_LEVEL_WRITING, "TLS on socket %d: %N", ssl_attr->mbedtls_attr.socket_fd.fd, send_len, buf+pos); /* * Sending one part of the buffer */ while ((ret = mbedtls_ssl_write(ssl, (const unsigned char *)(buf + pos), (size_t)send_len)) < 0) { if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) { char err_buf[ERROR_BUF_SIZE]; mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Sending data on socket %d over TLS/SSL failed: %s", ssl_attr->mbedtls_attr.socket_fd.fd, err_buf); return -1; } } /* Adding count of sent bytes to position in buffer */ pos = pos + send_len; } return (int)len; } /********************************************************************* * * Function : ssl_recv_data * * Description : Receives data from given SSL context and puts * it into buffer. * * Parameters : * 1 : ssl_attr = SSL context to receive data from * 2 : buf = Pointer to buffer where data will be written * 3 : max_length = Maximum number of bytes to read * * Returns : Number of bytes read, 0 for EOF, or -1 * on error. * *********************************************************************/ extern int ssl_recv_data(struct ssl_attr *ssl_attr, unsigned char *buf, size_t max_length) { mbedtls_ssl_context *ssl = &ssl_attr->mbedtls_attr.ssl; int ret = 0; memset(buf, 0, max_length); /* * Receiving data from SSL context into buffer */ do { ret = mbedtls_ssl_read(ssl, buf, max_length); } while (ret == MBEDTLS_ERR_SSL_WANT_READ || ret == MBEDTLS_ERR_SSL_WANT_WRITE); if (ret < 0) { char err_buf[ERROR_BUF_SIZE]; if (ret == MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY) { log_error(LOG_LEVEL_CONNECT, "The peer notified us that " "the connection on socket %d is going to be closed", ssl_attr->mbedtls_attr.socket_fd.fd); return 0; } mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Receiving data on socket %d over TLS/SSL failed: %s", ssl_attr->mbedtls_attr.socket_fd.fd, err_buf); return -1; } log_error(LOG_LEVEL_RECEIVED, "TLS from socket %d: %N", ssl_attr->mbedtls_attr.socket_fd.fd, ret, buf); return ret; } /********************************************************************* * * Function : create_client_ssl_connection * * Description : Creates TLS/SSL secured connection with client * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : 0 on success, negative value if connection wasn't created * successfully. * *********************************************************************/ extern int create_client_ssl_connection(struct client_state *csp) { struct ssl_attr *ssl_attr = &csp->ssl_client_attr; /* Paths to certificates file and key file */ char *key_file = NULL; char *ca_file = NULL; char *cert_file = NULL; int ret = 0; char err_buf[ERROR_BUF_SIZE]; /* * Initializing mbedtls structures for TLS/SSL connection */ mbedtls_net_init(&(ssl_attr->mbedtls_attr.socket_fd)); mbedtls_ssl_init(&(ssl_attr->mbedtls_attr.ssl)); mbedtls_ssl_config_init(&(ssl_attr->mbedtls_attr.conf)); mbedtls_x509_crt_init(&(ssl_attr->mbedtls_attr.server_cert)); mbedtls_pk_init(&(ssl_attr->mbedtls_attr.prim_key)); #if defined(MBEDTLS_SSL_CACHE_C) mbedtls_ssl_cache_init(&(ssl_attr->mbedtls_attr.cache)); #endif /* * Preparing hash of host for creating certificates */ ret = host_to_hash(csp); if (ret != 0) { log_error(LOG_LEVEL_ERROR, "Generating hash of host failed: %d", ret); ret = -1; goto exit; } /* * Preparing paths to certificates files and key file */ ca_file = csp->config->ca_cert_file; cert_file = make_certs_path(csp->config->certificate_directory, (const char *)csp->http->hash_of_host_hex, CERT_FILE_TYPE); key_file = make_certs_path(csp->config->certificate_directory, (const char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE); if (cert_file == NULL || key_file == NULL) { ret = -1; goto exit; } /* * Generating certificate for requested host. Mutex to prevent * certificate and key inconsistence must be locked. */ privoxy_mutex_lock(&certificate_mutex); ret = generate_host_certificate(csp); privoxy_mutex_unlock(&certificate_mutex); if (ret < 0) { log_error(LOG_LEVEL_ERROR, "generate_host_certificate failed: %d", ret); ret = -1; goto exit; } /* * Seed the RNG */ ret = seed_rng(csp); if (ret != 0) { ret = -1; goto exit; } /* * Loading CA file, webpage certificate and key files */ ret = mbedtls_x509_crt_parse_file(&(ssl_attr->mbedtls_attr.server_cert), cert_file); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Loading webpage certificate %s failed: %s", cert_file, err_buf); ret = -1; goto exit; } ret = mbedtls_x509_crt_parse_file(&(ssl_attr->mbedtls_attr.server_cert), ca_file); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Loading CA certificate %s failed: %s", ca_file, err_buf); ret = -1; goto exit; } ret = mbedtls_pk_parse_keyfile(&(ssl_attr->mbedtls_attr.prim_key), key_file, NULL); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Loading and parsing webpage certificate private key %s failed: %s", key_file, err_buf); ret = -1; goto exit; } /* * Setting SSL parameters */ ret = mbedtls_ssl_config_defaults(&(ssl_attr->mbedtls_attr.conf), MBEDTLS_SSL_IS_SERVER, MBEDTLS_SSL_TRANSPORT_STREAM, MBEDTLS_SSL_PRESET_DEFAULT); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_config_defaults failed: %s", err_buf); ret = -1; goto exit; } mbedtls_ssl_conf_rng(&(ssl_attr->mbedtls_attr.conf), mbedtls_ctr_drbg_random, &ctr_drbg); #if defined(MBEDTLS_SSL_CACHE_C) mbedtls_ssl_conf_session_cache(&(ssl_attr->mbedtls_attr.conf), &(ssl_attr->mbedtls_attr.cache), mbedtls_ssl_cache_get, mbedtls_ssl_cache_set); #endif /* * Setting certificates */ ret = mbedtls_ssl_conf_own_cert(&(ssl_attr->mbedtls_attr.conf), &(ssl_attr->mbedtls_attr.server_cert), &(ssl_attr->mbedtls_attr.prim_key)); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_conf_own_cert failed: %s", err_buf); ret = -1; goto exit; } if (csp->config->cipher_list != NULL) { ssl_attr->mbedtls_attr.ciphersuites_list = get_ciphersuites_from_string(csp->config->cipher_list); if (ssl_attr->mbedtls_attr.ciphersuites_list == NULL) { log_error(LOG_LEVEL_ERROR, "Setting the cipher list '%s' for the client connection failed", csp->config->cipher_list); ret = -1; goto exit; } mbedtls_ssl_conf_ciphersuites(&(ssl_attr->mbedtls_attr.conf), ssl_attr->mbedtls_attr.ciphersuites_list); } ret = mbedtls_ssl_setup(&(ssl_attr->mbedtls_attr.ssl), &(ssl_attr->mbedtls_attr.conf)); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_setup failed: %s", err_buf); ret = -1; goto exit; } mbedtls_ssl_set_bio(&(ssl_attr->mbedtls_attr.ssl), &(ssl_attr->mbedtls_attr.socket_fd), mbedtls_net_send, mbedtls_net_recv, NULL); mbedtls_ssl_session_reset(&(ssl_attr->mbedtls_attr.ssl)); /* * Setting socket fd in mbedtls_net_context structure. This structure * can't be set by mbedtls functions, because we already have created * a TCP connection when this function is called. */ ssl_attr->mbedtls_attr.socket_fd.fd = csp->cfd; /* * Handshake with client */ log_error(LOG_LEVEL_CONNECT, "Performing the TLS/SSL handshake with client. Hash of host: %s", csp->http->hash_of_host_hex); while ((ret = mbedtls_ssl_handshake(&(ssl_attr->mbedtls_attr.ssl))) != 0) { if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "medtls_ssl_handshake with client failed: %s", err_buf); ret = -1; goto exit; } } log_error(LOG_LEVEL_CONNECT, "Client successfully connected over %s (%s).", mbedtls_ssl_get_version(&(ssl_attr->mbedtls_attr.ssl)), mbedtls_ssl_get_ciphersuite(&(ssl_attr->mbedtls_attr.ssl))); csp->ssl_with_client_is_opened = 1; exit: /* * Freeing allocated paths to files */ freez(cert_file); freez(key_file); /* Freeing structures if connection wasn't created successfully */ if (ret < 0) { free_client_ssl_structures(csp); } return ret; } /********************************************************************* * * Function : close_client_ssl_connection * * Description : Closes TLS/SSL connection with client. This function * checks if this connection is already created. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : N/A * *********************************************************************/ extern void close_client_ssl_connection(struct client_state *csp) { struct ssl_attr *ssl_attr = &csp->ssl_client_attr; int ret = 0; if (csp->ssl_with_client_is_opened == 0) { return; } /* * Notifying the peer that the connection is being closed. */ do { ret = mbedtls_ssl_close_notify(&(ssl_attr->mbedtls_attr.ssl)); } while (ret == MBEDTLS_ERR_SSL_WANT_WRITE); free_client_ssl_structures(csp); csp->ssl_with_client_is_opened = 0; } /********************************************************************* * * Function : free_client_ssl_structures * * Description : Frees structures used for SSL communication with * client. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : N/A * *********************************************************************/ static void free_client_ssl_structures(struct client_state *csp) { struct ssl_attr *ssl_attr = &csp->ssl_client_attr; /* * We can't use function mbedtls_net_free, because this function * inter alia close TCP connection on set fd. Instead of this * function, we change fd to -1, which is the same what does * rest of mbedtls_net_free function. */ ssl_attr->mbedtls_attr.socket_fd.fd = -1; /* Freeing mbedtls structures */ mbedtls_x509_crt_free(&(ssl_attr->mbedtls_attr.server_cert)); mbedtls_pk_free(&(ssl_attr->mbedtls_attr.prim_key)); mbedtls_ssl_free(&(ssl_attr->mbedtls_attr.ssl)); freez(ssl_attr->mbedtls_attr.ciphersuites_list); mbedtls_ssl_config_free(&(ssl_attr->mbedtls_attr.conf)); #if defined(MBEDTLS_SSL_CACHE_C) mbedtls_ssl_cache_free(&(ssl_attr->mbedtls_attr.cache)); #endif } /********************************************************************* * * Function : create_server_ssl_connection * * Description : Creates TLS/SSL secured connection with server. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : 0 on success, negative value if connection wasn't created * successfully. * *********************************************************************/ extern int create_server_ssl_connection(struct client_state *csp) { struct ssl_attr *ssl_attr = &csp->ssl_server_attr; int ret = 0; char err_buf[ERROR_BUF_SIZE]; char *trusted_cas_file = NULL; int auth_mode = MBEDTLS_SSL_VERIFY_REQUIRED; csp->server_cert_verification_result = SSL_CERT_NOT_VERIFIED; csp->server_certs_chain.next = NULL; /* Setting path to file with trusted CAs */ trusted_cas_file = csp->config->trusted_cas_file; /* * Initializing mbedtls structures for TLS/SSL connection */ mbedtls_net_init(&(ssl_attr->mbedtls_attr.socket_fd)); mbedtls_ssl_init(&(ssl_attr->mbedtls_attr.ssl)); mbedtls_ssl_config_init(&(ssl_attr->mbedtls_attr.conf)); mbedtls_x509_crt_init(&(ssl_attr->mbedtls_attr.ca_cert)); /* * Setting socket fd in mbedtls_net_context structure. This structure * can't be set by mbedtls functions, because we already have created * TCP connection when calling this function. */ ssl_attr->mbedtls_attr.socket_fd.fd = csp->server_connection.sfd; /* * Seed the RNG */ ret = seed_rng(csp); if (ret != 0) { ret = -1; goto exit; } /* * Loading file with trusted CAs */ ret = mbedtls_x509_crt_parse_file(&(ssl_attr->mbedtls_attr.ca_cert), trusted_cas_file); if (ret < 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Loading trusted CAs file %s failed: %s", trusted_cas_file, err_buf); ret = -1; goto exit; } /* * Set TLS/SSL options */ ret = mbedtls_ssl_config_defaults(&(ssl_attr->mbedtls_attr.conf), MBEDTLS_SSL_IS_CLIENT, MBEDTLS_SSL_TRANSPORT_STREAM, MBEDTLS_SSL_PRESET_DEFAULT); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_config_defaults failed: %s", err_buf); ret = -1; goto exit; } /* * Setting how strict should certificate verification be and other * parameters for certificate verification */ if (csp->dont_verify_certificate) { auth_mode = MBEDTLS_SSL_VERIFY_NONE; } mbedtls_ssl_conf_authmode(&(ssl_attr->mbedtls_attr.conf), auth_mode); mbedtls_ssl_conf_ca_chain(&(ssl_attr->mbedtls_attr.conf), &(ssl_attr->mbedtls_attr.ca_cert), NULL); /* Setting callback function for certificates verification */ mbedtls_ssl_conf_verify(&(ssl_attr->mbedtls_attr.conf), ssl_verify_callback, (void *)csp); mbedtls_ssl_conf_rng(&(ssl_attr->mbedtls_attr.conf), mbedtls_ctr_drbg_random, &ctr_drbg); if (csp->config->cipher_list != NULL) { ssl_attr->mbedtls_attr.ciphersuites_list = get_ciphersuites_from_string(csp->config->cipher_list); if (ssl_attr->mbedtls_attr.ciphersuites_list == NULL) { log_error(LOG_LEVEL_ERROR, "Setting the cipher list '%s' for the server connection failed", csp->config->cipher_list); ret = -1; goto exit; } mbedtls_ssl_conf_ciphersuites(&(ssl_attr->mbedtls_attr.conf), ssl_attr->mbedtls_attr.ciphersuites_list); } ret = mbedtls_ssl_setup(&(ssl_attr->mbedtls_attr.ssl), &(ssl_attr->mbedtls_attr.conf)); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_setup failed: %s", err_buf); ret = -1; goto exit; } /* * Set the hostname to check against the received server certificate */ ret = mbedtls_ssl_set_hostname(&(ssl_attr->mbedtls_attr.ssl), csp->http->host); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_set_hostname failed: %s", err_buf); ret = -1; goto exit; } mbedtls_ssl_set_bio(&(ssl_attr->mbedtls_attr.ssl), &(ssl_attr->mbedtls_attr.socket_fd), mbedtls_net_send, mbedtls_net_recv, NULL); /* * Handshake with server */ log_error(LOG_LEVEL_CONNECT, "Performing the TLS/SSL handshake with the server"); while ((ret = mbedtls_ssl_handshake(&(ssl_attr->mbedtls_attr.ssl))) != 0) { if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED) { char reason[INVALID_CERT_INFO_BUF_SIZE]; csp->server_cert_verification_result = mbedtls_ssl_get_verify_result(&(ssl_attr->mbedtls_attr.ssl)); mbedtls_x509_crt_verify_info(reason, sizeof(reason), "", csp->server_cert_verification_result); /* Log the reason without the trailing new line */ log_error(LOG_LEVEL_ERROR, "X509 certificate verification for %s failed: %N", csp->http->hostport, strlen(reason)-1, reason); ret = -1; } else { log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_handshake with server failed: %s", err_buf); free_certificate_chain(csp); ret = -1; } goto exit; } } log_error(LOG_LEVEL_CONNECT, "Server successfully connected over %s (%s).", mbedtls_ssl_get_version(&(ssl_attr->mbedtls_attr.ssl)), mbedtls_ssl_get_ciphersuite(&(ssl_attr->mbedtls_attr.ssl))); /* * Server certificate chain is valid, so we can clean * chain, because we will not send it to client. */ free_certificate_chain(csp); csp->ssl_with_server_is_opened = 1; csp->server_cert_verification_result = mbedtls_ssl_get_verify_result(&(ssl_attr->mbedtls_attr.ssl)); exit: /* Freeing structures if connection wasn't created successfully */ if (ret < 0) { free_server_ssl_structures(csp); } return ret; } /********************************************************************* * * Function : close_server_ssl_connection * * Description : Closes TLS/SSL connection with server. This function * checks if this connection is already opened. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : N/A * *********************************************************************/ extern void close_server_ssl_connection(struct client_state *csp) { struct ssl_attr *ssl_attr = &csp->ssl_server_attr; int ret = 0; if (csp->ssl_with_server_is_opened == 0) { return; } /* * Notifying the peer that the connection is being closed. */ do { ret = mbedtls_ssl_close_notify(&(ssl_attr->mbedtls_attr.ssl)); } while (ret == MBEDTLS_ERR_SSL_WANT_WRITE); free_server_ssl_structures(csp); csp->ssl_with_server_is_opened = 0; } /********************************************************************* * * Function : free_server_ssl_structures * * Description : Frees structures used for SSL communication with server * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : N/A * *********************************************************************/ static void free_server_ssl_structures(struct client_state *csp) { struct ssl_attr *ssl_attr = &csp->ssl_server_attr; /* * We can't use function mbedtls_net_free, because this function * inter alia close TCP connection on set fd. Instead of this * function, we change fd to -1, which is the same what does * rest of mbedtls_net_free function. */ ssl_attr->mbedtls_attr.socket_fd.fd = -1; mbedtls_x509_crt_free(&(ssl_attr->mbedtls_attr.ca_cert)); mbedtls_ssl_free(&(ssl_attr->mbedtls_attr.ssl)); freez(ssl_attr->mbedtls_attr.ciphersuites_list); mbedtls_ssl_config_free(&(ssl_attr->mbedtls_attr.conf)); } /*====================== Certificates ======================*/ /********************************************************************* * * Function : write_certificate * * Description : Writes certificate into file. * * Parameters : * 1 : crt = certificate to write into file * 2 : output_file = path to save certificate file * 3 : f_rng = mbedtls_ctr_drbg_random * 4 : p_rng = mbedtls_ctr_drbg_context * * Returns : Length of written certificate on success or negative value * on error * *********************************************************************/ static int write_certificate(mbedtls_x509write_cert *crt, const char *output_file, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng) { FILE *f = NULL; size_t len = 0; unsigned char cert_buf[CERTIFICATE_BUF_SIZE + 1]; /* Buffer for certificate in PEM format + terminating NULL */ int ret = 0; char err_buf[ERROR_BUF_SIZE]; memset(cert_buf, 0, sizeof(cert_buf)); /* * Writing certificate into PEM string. If buffer is too small, function * returns specific error and no buffer overflow can happen. */ if ((ret = mbedtls_x509write_crt_pem(crt, cert_buf, sizeof(cert_buf) - 1, f_rng, p_rng)) != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Writing certificate into buffer failed: %s", err_buf); return -1; } len = strlen((char *)cert_buf); /* * Saving certificate into file */ if ((f = fopen(output_file, "w")) == NULL) { log_error(LOG_LEVEL_ERROR, "Opening file %s to save certificate failed", output_file); return -1; } if (fwrite(cert_buf, 1, len, f) != len) { log_error(LOG_LEVEL_ERROR, "Writing certificate into file %s failed", output_file); fclose(f); return -1; } fclose(f); return (int)len; } /********************************************************************* * * Function : write_private_key * * Description : Writes private key into file and copies saved * content into given pointer to string. If function * returns 0 for success, this copy must be freed by * caller. * * Parameters : * 1 : key = key to write into file * 2 : ret_buf = pointer to string with created key file content * 3 : key_file_path = path where to save key file * * Returns : Length of written private key on success or negative value * on error * *********************************************************************/ static int write_private_key(mbedtls_pk_context *key, unsigned char **ret_buf, const char *key_file_path) { size_t len = 0; /* Length of created key */ FILE *f = NULL; /* File to save certificate */ int ret = 0; char err_buf[ERROR_BUF_SIZE]; /* Initializing buffer for key file content */ *ret_buf = zalloc_or_die(PRIVATE_KEY_BUF_SIZE + 1); /* * Writing private key into PEM string */ if ((ret = mbedtls_pk_write_key_pem(key, *ret_buf, PRIVATE_KEY_BUF_SIZE)) != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Writing private key into PEM string failed: %s", err_buf); ret = -1; goto exit; } len = strlen((char *)*ret_buf); /* * Saving key into file */ if ((f = fopen(key_file_path, "wb")) == NULL) { log_error(LOG_LEVEL_ERROR, "Opening file %s to save private key failed: %E", key_file_path); ret = -1; goto exit; } if (fwrite(*ret_buf, 1, len, f) != len) { fclose(f); log_error(LOG_LEVEL_ERROR, "Writing private key into file %s failed", key_file_path); ret = -1; goto exit; } fclose(f); exit: if (ret < 0) { freez(*ret_buf); *ret_buf = NULL; return ret; } return (int)len; } /********************************************************************* * * Function : generate_key * * Description : Tests if private key for host saved in csp already * exists. If this file doesn't exists, a new key is * generated and saved in a file. The generated key is also * copied into given parameter key_buf, which must be then * freed by caller. If file with key exists, key_buf * contain NULL and no private key is generated. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : key_buf = buffer to save new generated key * * Returns : -1 => Error while generating private key * 0 => Key already exists * >0 => Length of generated private key * *********************************************************************/ static int generate_key(struct client_state *csp, unsigned char **key_buf) { mbedtls_pk_context key; key_options key_opt; int ret = 0; char err_buf[ERROR_BUF_SIZE]; key_opt.key_file_path = NULL; /* * Initializing structures for key generating */ mbedtls_pk_init(&key); /* * Preparing path for key file and other properties for generating key */ key_opt.type = MBEDTLS_PK_RSA; key_opt.rsa_keysize = RSA_KEYSIZE; key_opt.key_file_path = make_certs_path(csp->config->certificate_directory, (char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE); if (key_opt.key_file_path == NULL) { ret = -1; goto exit; } /* * Test if key already exists. If so, we don't have to create it again. */ if (file_exists(key_opt.key_file_path) == 1) { ret = 0; goto exit; } /* * Seed the RNG */ ret = seed_rng(csp); if (ret != 0) { ret = -1; goto exit; } /* * Setting attributes of private key and generating it */ if ((ret = mbedtls_pk_setup(&key, mbedtls_pk_info_from_type(key_opt.type))) != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_pk_setup failed: %s", err_buf); ret = -1; goto exit; } ret = mbedtls_rsa_gen_key(mbedtls_pk_rsa(key), mbedtls_ctr_drbg_random, &ctr_drbg, (unsigned)key_opt.rsa_keysize, RSA_KEY_PUBLIC_EXPONENT); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Key generating failed: %s", err_buf); ret = -1; goto exit; } /* * Exporting private key into file */ if ((ret = write_private_key(&key, key_buf, key_opt.key_file_path)) < 0) { log_error(LOG_LEVEL_ERROR, "Writing private key into file %s failed", key_opt.key_file_path); ret = -1; goto exit; } exit: /* * Freeing used variables */ freez(key_opt.key_file_path); mbedtls_pk_free(&key); return ret; } /********************************************************************* * * Function : ssl_certificate_is_invalid * * Description : Checks whether or not a certificate is valid. * Currently only checks that the certificate can be * parsed and that the "valid to" date is in the future. * * Parameters : * 1 : cert_file = The certificate to check * * Returns : 0 => The certificate is valid. * 1 => The certificate is invalid * *********************************************************************/ static int ssl_certificate_is_invalid(const char *cert_file) { mbedtls_x509_crt cert; int ret; mbedtls_x509_crt_init(&cert); ret = mbedtls_x509_crt_parse_file(&cert, cert_file); if (ret != 0) { char err_buf[ERROR_BUF_SIZE]; mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Loading certificate %s to check validity failed: %s", cert_file, err_buf); mbedtls_x509_crt_free(&cert); return 1; } if (mbedtls_x509_time_is_past(&cert.valid_to)) { mbedtls_x509_crt_free(&cert); return 1; } mbedtls_x509_crt_free(&cert); return 0; } /********************************************************************* * * Function : set_subject_alternative_name * * Description : Sets the Subject Alternative Name extension to a cert * * Parameters : * 1 : cert = The certificate to modify * 2 : hostname = The hostname to add * * Returns : <0 => Error while creating certificate. * 0 => It worked * *********************************************************************/ static int set_subject_alternative_name(mbedtls_x509write_cert *cert, const char *hostname) { char err_buf[ERROR_BUF_SIZE]; int ret; char *subject_alternative_name; size_t subject_alternative_name_len; #define MBEDTLS_SUBJECT_ALTERNATIVE_NAME_MAX_LEN 255 unsigned char san_buf[MBEDTLS_SUBJECT_ALTERNATIVE_NAME_MAX_LEN + 1]; unsigned char *c; int len; subject_alternative_name_len = strlen(hostname) + 1; subject_alternative_name = zalloc_or_die(subject_alternative_name_len); strlcpy(subject_alternative_name, hostname, subject_alternative_name_len); memset(san_buf, 0, sizeof(san_buf)); c = san_buf + sizeof(san_buf); len = 0; ret = mbedtls_asn1_write_raw_buffer(&c, san_buf, (const unsigned char *)subject_alternative_name, strlen(subject_alternative_name)); if (ret < 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_asn1_write_raw_buffer() failed: %s", err_buf); goto exit; } len += ret; ret = mbedtls_asn1_write_len(&c, san_buf, strlen(subject_alternative_name)); if (ret < 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_asn1_write_len() failed: %s", err_buf); goto exit; } len += ret; ret = mbedtls_asn1_write_tag(&c, san_buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC | 2); if (ret < 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_asn1_write_tag() failed: %s", err_buf); goto exit; } len += ret; ret = mbedtls_asn1_write_len(&c, san_buf, (size_t)len); if (ret < 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_asn1_write_len() failed: %s", err_buf); goto exit; } len += ret; ret = mbedtls_asn1_write_tag(&c, san_buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE); if (ret < 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_asn1_write_tag() failed: %s", err_buf); goto exit; } len += ret; ret = mbedtls_x509write_crt_set_extension(cert, MBEDTLS_OID_SUBJECT_ALT_NAME, MBEDTLS_OID_SIZE(MBEDTLS_OID_SUBJECT_ALT_NAME), 0, san_buf + sizeof(san_buf) - len, (size_t)len); if (ret < 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_x509write_crt_set_extension() failed: %s", err_buf); } exit: freez(subject_alternative_name); return ret; } /********************************************************************* * * Function : generate_host_certificate * * Description : Creates certificate file in presetted directory. * If certificate already exists, no other certificate * will be created. Subject of certificate is named * by csp->http->host from parameter. This function also * triggers generating of private key for new certificate. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : -1 => Error while creating certificate. * 0 => Certificate already exists. * >0 => Length of created certificate. * *********************************************************************/ static int generate_host_certificate(struct client_state *csp) { mbedtls_x509_crt issuer_cert; mbedtls_pk_context loaded_issuer_key, loaded_subject_key; mbedtls_pk_context *issuer_key = &loaded_issuer_key; mbedtls_pk_context *subject_key = &loaded_subject_key; mbedtls_x509write_cert cert; mbedtls_mpi serial; unsigned char *key_buf = NULL; /* Buffer for created key */ int ret = 0; char err_buf[ERROR_BUF_SIZE]; cert_options cert_opt; char cert_valid_from[VALID_DATETIME_BUFLEN]; char cert_valid_to[VALID_DATETIME_BUFLEN]; /* Paths to keys and certificates needed to create certificate */ cert_opt.issuer_key = NULL; cert_opt.subject_key = NULL; cert_opt.issuer_crt = NULL; cert_opt.output_file = make_certs_path(csp->config->certificate_directory, (const char *)csp->http->hash_of_host_hex, CERT_FILE_TYPE); if (cert_opt.output_file == NULL) { return -1; } cert_opt.subject_key = make_certs_path(csp->config->certificate_directory, (const char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE); if (cert_opt.subject_key == NULL) { freez(cert_opt.output_file); return -1; } if (enforce_sane_certificate_state(cert_opt.output_file, cert_opt.subject_key)) { freez(cert_opt.output_file); freez(cert_opt.subject_key); return -1; } if (file_exists(cert_opt.output_file) == 1) { /* The file exists, but is it valid? */ if (ssl_certificate_is_invalid(cert_opt.output_file)) { log_error(LOG_LEVEL_CONNECT, "Certificate %s is no longer valid. Removing it.", cert_opt.output_file); if (unlink(cert_opt.output_file)) { log_error(LOG_LEVEL_ERROR, "Failed to unlink %s: %E", cert_opt.output_file); freez(cert_opt.output_file); freez(cert_opt.subject_key); return -1; } if (unlink(cert_opt.subject_key)) { log_error(LOG_LEVEL_ERROR, "Failed to unlink %s: %E", cert_opt.subject_key); freez(cert_opt.output_file); freez(cert_opt.subject_key); return -1; } } else { freez(cert_opt.output_file); freez(cert_opt.subject_key); return 0; } } /* * Create key for requested host */ int subject_key_len = generate_key(csp, &key_buf); if (subject_key_len < 0) { freez(cert_opt.output_file); freez(cert_opt.subject_key); log_error(LOG_LEVEL_ERROR, "Key generating failed"); return -1; } /* * Initializing structures for certificate generating */ mbedtls_x509write_crt_init(&cert); mbedtls_x509write_crt_set_md_alg(&cert, CERT_SIGNATURE_ALGORITHM); mbedtls_pk_init(&loaded_issuer_key); mbedtls_pk_init(&loaded_subject_key); mbedtls_mpi_init(&serial); mbedtls_x509_crt_init(&issuer_cert); /* * Presetting parameters for certificate. We must compute total length * of parameters. */ size_t cert_params_len = strlen(CERT_PARAM_COMMON_NAME) + strlen(CERT_PARAM_ORGANIZATION) + strlen(CERT_PARAM_COUNTRY) + strlen(CERT_PARAM_ORG_UNIT) + 3 * strlen(csp->http->host) + 1; char cert_params[cert_params_len]; memset(cert_params, 0, cert_params_len); /* * Converting unsigned long serial number to char * serial number. * We must compute length of serial number in string + terminating null. */ unsigned long certificate_serial = get_certificate_serial(csp); unsigned long certificate_serial_time = (unsigned long)time(NULL); int serial_num_size = snprintf(NULL, 0, "%lu%lu", certificate_serial_time, certificate_serial) + 1; if (serial_num_size <= 0) { serial_num_size = 1; } char serial_num_text[serial_num_size]; /* Buffer for serial number */ ret = snprintf(serial_num_text, (size_t)serial_num_size, "%lu%lu", certificate_serial_time, certificate_serial); if (ret < 0 || ret >= serial_num_size) { log_error(LOG_LEVEL_ERROR, "Converting certificate serial number into string failed"); ret = -1; goto exit; } /* * Preparing parameters for certificate */ strlcpy(cert_params, CERT_PARAM_COMMON_NAME, cert_params_len); strlcat(cert_params, csp->http->host, cert_params_len); strlcat(cert_params, CERT_PARAM_ORGANIZATION, cert_params_len); strlcat(cert_params, csp->http->host, cert_params_len); strlcat(cert_params, CERT_PARAM_ORG_UNIT, cert_params_len); strlcat(cert_params, csp->http->host, cert_params_len); strlcat(cert_params, CERT_PARAM_COUNTRY, cert_params_len); cert_opt.issuer_crt = csp->config->ca_cert_file; cert_opt.issuer_key = csp->config->ca_key_file; if (get_certificate_valid_from_date(cert_valid_from, sizeof(cert_valid_from), VALID_DATETIME_FMT) || get_certificate_valid_to_date(cert_valid_to, sizeof(cert_valid_to), VALID_DATETIME_FMT)) { log_error(LOG_LEVEL_ERROR, "Generating one of the validity dates failed"); ret = -1; goto exit; } cert_opt.subject_pwd = CERT_SUBJECT_PASSWORD; cert_opt.issuer_pwd = csp->config->ca_password; cert_opt.subject_name = cert_params; cert_opt.not_before = cert_valid_from; cert_opt.not_after = cert_valid_to; cert_opt.serial = serial_num_text; cert_opt.is_ca = 0; cert_opt.max_pathlen = -1; /* * Test if the private key was already created. * XXX: Can this still happen? */ if (subject_key_len == 0) { log_error(LOG_LEVEL_ERROR, "Subject key was already created"); ret = 0; goto exit; } /* * Seed the PRNG */ ret = seed_rng(csp); if (ret != 0) { ret = -1; goto exit; } /* * Parse serial to MPI */ ret = mbedtls_mpi_read_string(&serial, 10, cert_opt.serial); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_mpi_read_string failed: %s", err_buf); ret = -1; goto exit; } /* * Loading certificates */ ret = mbedtls_x509_crt_parse_file(&issuer_cert, cert_opt.issuer_crt); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Loading issuer certificate %s failed: %s", cert_opt.issuer_crt, err_buf); ret = -1; goto exit; } ret = mbedtls_x509_dn_gets(cert_opt.issuer_name, sizeof(cert_opt.issuer_name), &issuer_cert.subject); if (ret < 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_x509_dn_gets failed: %s", err_buf); ret = -1; goto exit; } /* * Loading keys from file or from buffer */ if (key_buf != NULL && subject_key_len > 0) { /* Key was created in this function and is stored in buffer */ ret = mbedtls_pk_parse_key(&loaded_subject_key, key_buf, (size_t)(subject_key_len + 1), (unsigned const char *) cert_opt.subject_pwd, strlen(cert_opt.subject_pwd)); } else { /* Key wasn't created in this function, because it already existed */ ret = mbedtls_pk_parse_keyfile(&loaded_subject_key, cert_opt.subject_key, cert_opt.subject_pwd); } if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Parsing subject key %s failed: %s", cert_opt.subject_key, err_buf); ret = -1; goto exit; } ret = mbedtls_pk_parse_keyfile(&loaded_issuer_key, cert_opt.issuer_key, cert_opt.issuer_pwd); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Parsing issuer key %s failed: %s", cert_opt.issuer_key, err_buf); ret = -1; goto exit; } /* * Check if key and issuer certificate match */ if (!mbedtls_pk_can_do(&issuer_cert.pk, MBEDTLS_PK_RSA) || mbedtls_mpi_cmp_mpi(&mbedtls_pk_rsa(issuer_cert.pk)->N, &mbedtls_pk_rsa(*issuer_key)->N) != 0 || mbedtls_mpi_cmp_mpi(&mbedtls_pk_rsa(issuer_cert.pk)->E, &mbedtls_pk_rsa(*issuer_key)->E) != 0) { log_error(LOG_LEVEL_ERROR, "Issuer key doesn't match issuer certificate"); ret = -1; goto exit; } mbedtls_x509write_crt_set_subject_key(&cert, subject_key); mbedtls_x509write_crt_set_issuer_key(&cert, issuer_key); /* * Setting parameters of signed certificate */ ret = mbedtls_x509write_crt_set_subject_name(&cert, cert_opt.subject_name); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Setting subject name in signed certificate failed: %s", err_buf); ret = -1; goto exit; } ret = mbedtls_x509write_crt_set_issuer_name(&cert, cert_opt.issuer_name); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Setting issuer name in signed certificate failed: %s", err_buf); ret = -1; goto exit; } ret = mbedtls_x509write_crt_set_serial(&cert, &serial); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Setting serial number in signed certificate failed: %s", err_buf); ret = -1; goto exit; } ret = mbedtls_x509write_crt_set_validity(&cert, cert_opt.not_before, cert_opt.not_after); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Setting validity in signed certificate failed: %s", err_buf); ret = -1; goto exit; } /* * Setting the basicConstraints extension for certificate */ ret = mbedtls_x509write_crt_set_basic_constraints(&cert, cert_opt.is_ca, cert_opt.max_pathlen); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "Setting the basicConstraints extension " "in signed certificate failed: %s", err_buf); ret = -1; goto exit; } #if defined(MBEDTLS_SHA1_C) /* Setting the subjectKeyIdentifier extension for certificate */ ret = mbedtls_x509write_crt_set_subject_key_identifier(&cert); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_x509write_crt_set_subject_key_" "identifier failed: %s", err_buf); ret = -1; goto exit; } /* Setting the authorityKeyIdentifier extension for certificate */ ret = mbedtls_x509write_crt_set_authority_key_identifier(&cert); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_x509write_crt_set_authority_key_" "identifier failed: %s", err_buf); ret = -1; goto exit; } #endif /* MBEDTLS_SHA1_C */ if (!host_is_ip_address(csp->http->host) && set_subject_alternative_name(&cert, csp->http->host)) { /* Errors are already logged by set_subject_alternative_name() */ ret = -1; goto exit; } /* * Writing certificate into file */ ret = write_certificate(&cert, cert_opt.output_file, mbedtls_ctr_drbg_random, &ctr_drbg); if (ret < 0) { log_error(LOG_LEVEL_ERROR, "Writing certificate into file failed"); goto exit; } exit: /* * Freeing used structures */ mbedtls_x509write_crt_free(&cert); mbedtls_pk_free(&loaded_subject_key); mbedtls_pk_free(&loaded_issuer_key); mbedtls_mpi_free(&serial); mbedtls_x509_crt_free(&issuer_cert); freez(cert_opt.subject_key); freez(cert_opt.output_file); freez(key_buf); return ret; } /********************************************************************* * * Function : ssl_verify_callback * * Description : This is a callback function for certificate verification. * It's called once for each certificate in the server's * certificate trusted chain and prepares information about * the certificate. The information can be used to inform * the user about invalid certificates. * * Parameters : * 1 : csp_void = Current client state (buffers, headers, etc...) * 2 : crt = certificate from trusted chain * 3 : depth = depth in trusted chain * 4 : flags = certificate flags * * Returns : 0 on success and negative value on error * *********************************************************************/ static int ssl_verify_callback(void *csp_void, mbedtls_x509_crt *crt, int depth, uint32_t *flags) { struct client_state *csp = (struct client_state *)csp_void; struct certs_chain *last = &(csp->server_certs_chain); size_t olen = 0; int ret = 0; size_t pem_buffer_length; /* * Searching for last item in certificates linked list */ while (last->next != NULL) { last = last->next; } /* * Preparing next item in linked list for next certificate */ last->next = malloc_or_die(sizeof(struct certs_chain)); last->next->next = NULL; memset(last->next->info_buf, 0, sizeof(last->next->info_buf)); last->next->file_buf = NULL; ret = mbedtls_pem_write_buffer(PEM_BEGIN_CRT, PEM_END_CRT, crt->raw.p, crt->raw.len, NULL, 0, &olen); if (MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL != ret) { log_error(LOG_LEVEL_ERROR, "Failed to figure out the required X509 PEM certificate buffer size"); return -1; } pem_buffer_length = olen; last->file_buf = malloc(pem_buffer_length); if (last->file_buf == NULL) { log_error(LOG_LEVEL_ERROR, "Failed to allocate %lu bytes to store the X509 PEM certificate", pem_buffer_length); return -1; } /* * Saving certificate file into buffer */ if ((ret = mbedtls_pem_write_buffer(PEM_BEGIN_CRT, PEM_END_CRT, crt->raw.p, crt->raw.len, (unsigned char *)last->file_buf, pem_buffer_length, &olen)) != 0) { char err_buf[ERROR_BUF_SIZE]; mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_pem_write_buffer() failed: %s", err_buf); return(ret); } /* * Saving certificate information into buffer */ { char buf[CERT_INFO_BUF_SIZE]; char *encoded_text; #define CERT_INFO_PREFIX "" mbedtls_x509_crt_info(buf, sizeof(buf), CERT_INFO_PREFIX, crt); encoded_text = html_encode(buf); if (encoded_text == NULL) { log_error(LOG_LEVEL_ERROR, "Failed to HTML-encode the certificate information"); return -1; } strlcpy(last->info_buf, encoded_text, sizeof(last->info_buf)); freez(encoded_text); } return 0; } /********************************************************************* * * Function : host_to_hash * * Description : Creates a sha256 hash from host name. The host name * is taken from the csp structure and stored into it. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : -1 => Error while creating hash * 0 => Hash created successfully * *********************************************************************/ static int host_to_hash(struct client_state *csp) { mbedtls_sha256((unsigned char *)csp->http->host, strlen(csp->http->host), csp->http->hash_of_host, 0); return create_hexadecimal_hash_of_host(csp); } /********************************************************************* * * Function : seed_rng * * Description : Seeding the RNG for all SSL uses * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : -1 => RNG wasn't seed successfully * 0 => RNG is seeded successfully * *********************************************************************/ static int seed_rng(struct client_state *csp) { int ret = 0; char err_buf[ERROR_BUF_SIZE]; if (rng_seeded == 0) { privoxy_mutex_lock(&ssl_init_mutex); if (rng_seeded == 0) { mbedtls_ctr_drbg_init(&ctr_drbg); mbedtls_entropy_init(&entropy); ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func, &entropy, NULL, 0); if (ret != 0) { mbedtls_strerror(ret, err_buf, sizeof(err_buf)); log_error(LOG_LEVEL_ERROR, "mbedtls_ctr_drbg_seed failed: %s", err_buf); privoxy_mutex_unlock(&ssl_init_mutex); return -1; } rng_seeded = 1; } privoxy_mutex_unlock(&ssl_init_mutex); } return 0; } /********************************************************************* * * Function : ssl_base64_encode * * Description : Encode a buffer into base64 format. * * Parameters : * 1 : dst = Destination buffer * 2 : dlen = Destination buffer length * 3 : olen = Number of bytes written * 4 : src = Source buffer * 5 : slen = Amount of data to be encoded * * Returns : 0 on success, error code othervise * *********************************************************************/ extern int ssl_base64_encode(unsigned char *dst, size_t dlen, size_t *olen, const unsigned char *src, size_t slen) { return mbedtls_base64_encode(dst, dlen, olen, src, slen); } /********************************************************************* * * Function : ssl_crt_verify_info * * Description : Returns an informational string about the verification * status of a certificate. * * Parameters : * 1 : buf = Buffer to write to * 2 : size = Maximum size of buffer * 3 : csp = client state * * Returns : N/A * *********************************************************************/ extern void ssl_crt_verify_info(char *buf, size_t size, struct client_state *csp) { char *last_byte; mbedtls_x509_crt_verify_info(buf, size, "", csp->server_cert_verification_result); last_byte = buf + strlen(buf)-1; if (*last_byte == '\n') { /* Overwrite trailing new line character */ *last_byte = '\0'; } } #ifdef FEATURE_GRACEFUL_TERMINATION /********************************************************************* * * Function : ssl_release * * Description : Release all SSL resources * * Parameters : * * Returns : N/A * *********************************************************************/ extern void ssl_release(void) { if (rng_seeded == 1) { mbedtls_ctr_drbg_free(&ctr_drbg); mbedtls_entropy_free(&entropy); } } #endif /* def FEATURE_GRACEFUL_TERMINATION */ /********************************************************************* * * Function : get_ciphersuites_from_string * * Description : Converts a string of ciphersuite names to * an array of ciphersuite ids. * * Parameters : * 1 : ciphersuites_string = String containing allowed * ciphersuites. * * Returns : Array of ciphersuite ids * *********************************************************************/ static int *get_ciphersuites_from_string(const char *parameter_string) { char *ciphersuites_index; char *item_end; char *ciphersuites_string; int *ciphersuite_ids; size_t count = 2; int index = 0; const char separator = ':'; size_t parameter_len = strlen(parameter_string); ciphersuites_string = zalloc_or_die(parameter_len + 1); strlcpy(ciphersuites_string, parameter_string, parameter_len + 1); ciphersuites_index = ciphersuites_string; while (*ciphersuites_index) { if (*ciphersuites_index++ == separator) { ++count; } } ciphersuite_ids = zalloc_or_die(count * sizeof(int)); ciphersuites_index = ciphersuites_string; do { item_end = strchr(ciphersuites_index, separator); if (item_end != NULL) { *item_end = '\0'; } ciphersuite_ids[index] = mbedtls_ssl_get_ciphersuite_id(ciphersuites_index); if (ciphersuite_ids[index] == 0) { log_error(LOG_LEVEL_ERROR, "Failed to get ciphersuite id for %s", ciphersuites_index); freez(ciphersuite_ids); freez(ciphersuites_string); return NULL; } ciphersuites_index = item_end + 1; index++; } while (item_end != NULL); ciphersuite_ids[index] = 0; freez(ciphersuites_string); return ciphersuite_ids; }