X-Git-Url: http://www.privoxy.org/gitweb/?p=privoxy.git;a=blobdiff_plain;f=ssl.c;h=634f76a2fad060de91d23f7ac1ee729b410fd7ae;hp=2f6dc51e3777f64189d8a86c1826117abd2be8e1;hb=da6d6e7115b36cd4e03460c9c49a212edacb159a;hpb=14f7edff7951eb3e664baed36a4b4b5c666a1937 diff --git a/ssl.c b/ssl.c index 2f6dc51e..634f76a2 100644 --- a/ssl.c +++ b/ssl.c @@ -6,7 +6,7 @@ * creating, using and closing TLS/SSL connections. * * Copyright : Written by and Copyright (c) 2017 Vaclav Svec. FIT CVUT. - * Copyright (C) 2018-2019 by Fabian Keil + * Copyright (C) 2018-2020 by Fabian Keil * * This program is free software; you can redistribute it * and/or modify it under the terms of the GNU General @@ -41,6 +41,8 @@ #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" @@ -65,8 +67,6 @@ #define PRIVATE_KEY_BUF_SIZE 16000 /* Size of buffer to save private key. Value 16000 is taken from mbed TLS library examples. */ #define RSA_KEY_PUBLIC_EXPONENT 65537 /* Public exponent for RSA private key generating */ #define RSA_KEYSIZE 2048 /* Size of generated RSA keys */ -#define GENERATED_CERT_VALID_FROM "20100101000000" /* Date and time, which will be set in generated certificates as parameter valid from */ -#define GENERATED_CERT_VALID_TO "20401231235959" /* Date and time, which will be set in generated certificates as parameter valid to */ #define CERT_SIGNATURE_ALGORITHM MBEDTLS_MD_SHA256 /* The MD algorithm to use for the signature */ #define CERT_SERIAL_NUM_LENGTH 4 /* Bytes of hash to be used for creating serial number of certificate. Min=2 and max=16 */ #define INVALID_CERT_INFO_BUF_SIZE 2048 /* Size of buffer for message with information about reason of certificate invalidity. Data after the end of buffer will not be saved */ @@ -113,7 +113,6 @@ static int file_exists(const char *path); 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_certificate_chain(struct client_state *csp); -static unsigned int get_certificate_mutex_id(struct client_state *csp); static unsigned long get_certificate_serial(struct client_state *csp); static void free_client_ssl_structures(struct client_state *csp); static void free_server_ssl_structures(struct client_state *csp); @@ -163,7 +162,10 @@ extern int server_use_ssl(const struct client_state *csp) * * Function : is_ssl_pending * - * Description : Tests if there are some waiting data on ssl connection + * 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 = SSL context to test @@ -229,6 +231,8 @@ extern int ssl_send_data(mbedtls_ssl_context *ssl, const unsigned char *buf, siz send_len = (int)max_fragment_size; } + log_error(LOG_LEVEL_WRITING, "TLS: %N", send_len, buf+pos); + /* * Sending one part of the buffer */ @@ -302,6 +306,8 @@ extern int ssl_recv_data(mbedtls_ssl_context *ssl, unsigned char *buf, size_t ma return -1; } + log_error(LOG_LEVEL_RECEIVED, "TLS: %N", ret, buf); + return ret; } @@ -433,19 +439,18 @@ extern int create_client_ssl_connection(struct client_state *csp) * Generating certificate for requested host. Mutex to prevent * certificate and key inconsistence must be locked. */ - unsigned int cert_mutex_id = get_certificate_mutex_id(csp); - privoxy_mutex_lock(&(certificates_mutexes[cert_mutex_id])); + privoxy_mutex_lock(&certificate_mutex); ret = generate_webpage_certificate(csp); if (ret < 0) { log_error(LOG_LEVEL_ERROR, "Generate_webpage_certificate failed: %d", ret); - privoxy_mutex_unlock(&(certificates_mutexes[cert_mutex_id])); + privoxy_mutex_unlock(&certificate_mutex); ret = -1; goto exit; } - privoxy_mutex_unlock(&(certificates_mutexes[cert_mutex_id])); + privoxy_mutex_unlock(&certificate_mutex); /* * Seed the RNG @@ -798,7 +803,7 @@ extern int create_server_ssl_connection(struct client_state *csp) * Handshake with server */ log_error(LOG_LEVEL_CONNECT, - "Performing the TLS/SSL handshake with server"); + "Performing the TLS/SSL handshake with the server"); while ((ret = mbedtls_ssl_handshake(&(csp->mbedtls_server_attr.ssl))) != 0) { @@ -809,17 +814,24 @@ extern int create_server_ssl_connection(struct client_state *csp) if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED) { - log_error(LOG_LEVEL_ERROR, - "Server certificate verification failed: %s", err_buf); + char reason[INVALID_CERT_INFO_BUF_SIZE]; + csp->server_cert_verification_result = mbedtls_ssl_get_verify_result(&(csp->mbedtls_server_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; @@ -903,7 +915,7 @@ static void free_server_ssl_structures(struct client_state *csp) * function, we change fd to -1, which is the same what does * rest of mbedtls_net_free function. */ - csp->mbedtls_client_attr.socket_fd.fd = -1; + csp->mbedtls_server_attr.socket_fd.fd = -1; mbedtls_x509_crt_free(&(csp->mbedtls_server_attr.ca_cert)); mbedtls_ssl_free(&(csp->mbedtls_server_attr.ssl)); @@ -1193,6 +1205,257 @@ exit: } +/********************************************************************* + * + * 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 : generate_certificate_valid_date + * + * Description : Turns a time_t into the format expected by mbedTLS. + * + * Parameters : + * 1 : time_spec = The timestamp to convert + * 2 : buffer = The buffer to write the date to + * 3 : buffer_size = The size of the buffer + * + * Returns : 0 => The conversion worked + * 1 => The conversion failed + * + *********************************************************************/ +static int generate_certificate_valid_date(time_t time_spec, char *buffer, + size_t buffer_size) +{ + struct tm valid_date; + size_t ret; + +#ifndef HAVE_GMTIME_R +#error HTTP inspection currently requires gmtime_r() which seems to be missing +#endif + if (NULL == gmtime_r(&time_spec, &valid_date)) + { + return 1; + } + + ret = strftime(buffer, buffer_size, "%Y%m%d%H%M%S", &valid_date); + if (ret != 14) + { + return 1; + } + + return 0; + +} + + +/********************************************************************* + * + * Function : get_certificate_valid_from_date + * + * Description : Generates a "valid from" date in the format + * expected by mbedTLS. + * + * Parameters : + * 1 : buffer = The buffer to write the date to + * 2 : buffer_size = The size of the buffer + * + * Returns : 0 => The generation worked + * 1 => The generation failed + * + *********************************************************************/ +static int get_certificate_valid_from_date(char *buffer, size_t buffer_size) +{ + time_t time_spec; + + time_spec = time(NULL); + /* 1 month in the past */ + time_spec -= 30 * 24 * 60 * 60; + + return generate_certificate_valid_date(time_spec, buffer, buffer_size); + +} + + +/********************************************************************* + * + * Function : get_certificate_valid_to_date + * + * Description : Generates a "valid to" date in the format + * expected by mbedTLS. + * + * Parameters : + * 1 : buffer = The buffer to write the date to + * 2 : buffer_size = The size of the buffer + * + * Returns : 0 => The generation worked + * 1 => The generation failed + * + *********************************************************************/ +static int get_certificate_valid_to_date(char *buffer, size_t buffer_size) +{ + time_t time_spec; + + time_spec = time(NULL); + /* Three months in the future */ + time_spec += 90 * 24 * 60 * 60; + + return generate_certificate_valid_date(time_spec, buffer, buffer_size); + +} + + +/********************************************************************* + * + * 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_webpage_certificate @@ -1225,12 +1488,66 @@ static int generate_webpage_certificate(struct client_state *csp) int ret = 0; char err_buf[ERROR_BUF_SIZE]; cert_options cert_opt; + char cert_valid_from[15]; + char cert_valid_to[15]; /* 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 = 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 (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 @@ -1238,6 +1555,8 @@ static int generate_webpage_certificate(struct client_state *csp) 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; } @@ -1268,14 +1587,17 @@ static int generate_webpage_certificate(struct client_state *csp) * We must compute length of serial number in string + terminating null. */ unsigned long certificate_serial = get_certificate_serial(csp); - int serial_num_size = snprintf(NULL, 0, "%lu", certificate_serial) + 1; + 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", certificate_serial); + 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, @@ -1297,13 +1619,11 @@ static int generate_webpage_certificate(struct client_state *csp) cert_opt.issuer_crt = csp->config->ca_cert_file; cert_opt.issuer_key = csp->config->ca_key_file; - cert_opt.subject_key = make_certs_path(csp->config->certificate_directory, - (const char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE); - 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.subject_key == NULL || cert_opt.output_file == NULL) + if (get_certificate_valid_from_date(cert_valid_from, sizeof(cert_valid_from)) + || get_certificate_valid_to_date(cert_valid_to, sizeof(cert_valid_to))) { + log_error(LOG_LEVEL_ERROR, "Generating one of the validity dates failed"); ret = -1; goto exit; } @@ -1311,17 +1631,19 @@ static int generate_webpage_certificate(struct client_state *csp) 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 = GENERATED_CERT_VALID_FROM; - cert_opt.not_after = GENERATED_CERT_VALID_TO; + 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 certificate exists and private key was already created + * Test if the private key was already created. + * XXX: Can this still happen? */ - if (file_exists(cert_opt.output_file) == 1 && subject_key_len == 0) + if (subject_key_len == 0) { + log_error(LOG_LEVEL_ERROR, "Subject key was already created"); ret = 0; goto exit; } @@ -1509,6 +1831,13 @@ static int generate_webpage_certificate(struct client_state *csp) } #endif /* MBEDTLS_SHA1_C */ + if (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 */ @@ -1542,7 +1871,7 @@ exit: * * Function : make_certs_path * - * Description : Creates path to file from three pieces. This fuction + * Description : Creates path to file from three pieces. This function * takes parameters and puts them in one new mallocated * char * in correct order. Returned variable must be freed * by caller. This function is mainly used for creating @@ -1617,29 +1946,6 @@ static char *make_certs_path(const char *conf_dir, const char *file_name, } -/********************************************************************* - * - * Function : get_certificate_mutex_id - * - * Description : Computes mutex id from host name hash. This hash must - * be already saved in csp structure - * - * Parameters : - * 1 : csp = Current client state (buffers, headers, etc...) - * - * Returns : Mutex id for given host name - * - *********************************************************************/ -static unsigned int get_certificate_mutex_id(struct client_state *csp) { -#ifdef LIMIT_MUTEX_NUMBER - return (unsigned int)(csp->http->hash_of_host[0] % 32); -#else - return (unsigned int)(csp->http->hash_of_host[1] - + 256 * (int)csp->http->hash_of_host[0]); -#endif /* LIMIT_MUTEX_NUMBER */ -} - - /********************************************************************* * * Function : get_certificate_serial @@ -1654,20 +1960,12 @@ static unsigned int get_certificate_mutex_id(struct client_state *csp) { * Returns : Serial number for new certificate * *********************************************************************/ -static unsigned long get_certificate_serial(struct client_state *csp) { +static unsigned long get_certificate_serial(struct client_state *csp) +{ unsigned long exp = 1; unsigned long serial = 0; int i = CERT_SERIAL_NUM_LENGTH; - /* Length of hash is 16 bytes, we must avoid to read next chars */ - if (i > 16) - { - i = 16; - } - if (i < 2) - { - i = 2; - } for (; i >= 0; i--) { @@ -1703,7 +2001,7 @@ extern void ssl_send_certificate_error(struct client_state *csp) "HTTP/1.1 200 OK\r\n" "Content-Type: text/html\r\n" "Connection: close\r\n\r\n" - "

Invalid server certificate

Reason: "; + "

Server certificate verification failed

Reason: "; const char message_end[] = "\r\n\r\n"; char reason[INVALID_CERT_INFO_BUF_SIZE]; memset(reason, 0, sizeof(reason)); @@ -1778,11 +2076,6 @@ extern void ssl_send_certificate_error(struct client_state *csp) */ ssl_send_data(&(csp->mbedtls_client_attr.ssl), (const unsigned char *)message, strlen(message)); - /* - * Waiting before closing connection. Some browsers don't show received - * message if there isn't this delay. - */ - sleep(1); free_certificate_chain(csp); } @@ -1793,10 +2086,10 @@ extern void ssl_send_certificate_error(struct client_state *csp) * Function : ssl_verify_callback * * Description : This is a callback function for certificate verification. - * It's called for all certificates in server certificate - * trusted chain and it's preparing information about this - * certificates. Prepared informations can be used to inform - * user about invalid certificates. + * 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...) @@ -1838,6 +2131,12 @@ static int ssl_verify_callback(void *csp_void, mbedtls_x509_crt *crt, crt->raw.p, crt->raw.len, (unsigned char *)last->file_buf, sizeof(last->file_buf)-1, &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); } @@ -1877,14 +2176,11 @@ static void free_certificate_chain(struct client_state *csp) csp->server_certs_chain.next = NULL; /* Freeing memory in whole linked list */ - if (cert != NULL) + while (cert != NULL) { - do - { - struct certs_chain *cert_for_free = cert; - cert = cert->next; - freez(cert_for_free); - } while (cert != NULL); + struct certs_chain *cert_for_free = cert; + cert = cert->next; + freez(cert_for_free); } } @@ -1934,9 +2230,7 @@ static int host_to_hash(struct client_state *csp) int ret = 0; #if !defined(MBEDTLS_MD5_C) - log_error(LOG_LEVEL_ERROR, "MBEDTLS_MD5_C is not defined. Can't create" - "MD5 hash for certificate and key name."); - return -1; +#error mbedTLS needs to be compiled with md5 support #else memset(csp->http->hash_of_host, 0, sizeof(csp->http->hash_of_host)); mbedtls_md5((unsigned char *)csp->http->host, strlen(csp->http->host),