| /** |
| * \file session_tls.c |
| * \author Radek Krejci <rkrejci@cesnet.cz> |
| * \author Michal Vasko <mvasko@cesnet.cz> |
| * \brief libnetconf2 - TLS specific session transport functions |
| * |
| * This source is compiled only with libssl. |
| * |
| * Copyright (c) 2015 CESNET, z.s.p.o. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * 3. Neither the name of the Company nor the names of its contributors |
| * may be used to endorse or promote products derived from this |
| * software without specific prior written permission. |
| * |
| */ |
| |
| #include <assert.h> |
| #include <errno.h> |
| #include <pwd.h> |
| #include <sys/types.h> |
| #include <string.h> |
| #include <unistd.h> |
| |
| #include <libyang/libyang.h> |
| |
| #include "libnetconf.h" |
| #include "session.h" |
| |
| /* TLS certificate verification error messages */ |
| static const char* verify_ret_msg[] = { |
| "ok", |
| "", |
| "unable to get issuer certificate", |
| "unable to get certificate CRL", |
| "unable to decrypt certificate's signature", |
| "unable to decrypt CRL's signature", |
| "unable to decode issuer public key", |
| "certificate signature failure", |
| "CRL signature failure", |
| "certificate is not yet valid", |
| "certificate has expired", |
| "CRL is not yet valid", |
| "CRL has expired", |
| "format error in certificate's notBefore field", |
| "format error in certificate's notAfter field", |
| "format error in CRL's lastUpdate field", |
| "format error in CRL's nextUpdate field", |
| "out of memory", |
| "self signed certificate", |
| "self signed certificate in certificate chain", |
| "unable to get local issuer certificate", |
| "unable to verify the first certificate", |
| "certificate chain too long", |
| "certificate revoked", |
| "invalid CA certificate", |
| "path length constraint exceeded", |
| "unsupported certificate purpose", |
| "certificate not trusted", |
| "certificate rejected", |
| "subject issuer mismatch", |
| "authority and subject key identifier mismatch", |
| "authority and issuer serial number mismatch", |
| "key usage does not include certificate signing" |
| }; |
| |
| static struct nc_tls_auth_opts tls_opts; |
| |
| /* internal functions from session.c */ |
| struct nc_session *connect_init(struct ly_ctx *ctx); |
| int connect_getsocket(const char* host, unsigned short port); |
| int handshake(struct nc_session *session); |
| |
| static int |
| tlsauth_verify_callback(int preverify_ok, X509_STORE_CTX *x509_ctx) |
| { |
| X509_STORE_CTX store_ctx; |
| X509_OBJECT obj; |
| X509_NAME *subject, *issuer; |
| X509 *cert; |
| X509_CRL *crl; |
| X509_REVOKED *revoked; |
| EVP_PKEY *pubkey; |
| int i, n, rc; |
| ASN1_TIME *next_update = NULL; |
| |
| if (!preverify_ok) { |
| return 0; |
| } |
| |
| cert = X509_STORE_CTX_get_current_cert(x509_ctx); |
| subject = X509_get_subject_name(cert); |
| issuer = X509_get_issuer_name(cert); |
| |
| /* try to retrieve a CRL corresponding to the _subject_ of |
| * the current certificate in order to verify it's integrity */ |
| memset((char *)&obj, 0, sizeof obj); |
| X509_STORE_CTX_init(&store_ctx, tls_opts.tls_store, NULL, NULL); |
| rc = X509_STORE_get_by_subject(&store_ctx, X509_LU_CRL, subject, &obj); |
| X509_STORE_CTX_cleanup(&store_ctx); |
| crl = obj.data.crl; |
| if (rc > 0 && crl) { |
| next_update = X509_CRL_get_nextUpdate(crl); |
| |
| /* verify the signature on this CRL */ |
| pubkey = X509_get_pubkey(cert); |
| if (X509_CRL_verify(crl, pubkey) <= 0) { |
| X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_CRL_SIGNATURE_FAILURE); |
| X509_OBJECT_free_contents(&obj); |
| if (pubkey) { |
| EVP_PKEY_free(pubkey); |
| } |
| return 0; /* fail */ |
| } |
| if (pubkey) { |
| EVP_PKEY_free(pubkey); |
| } |
| |
| /* check date of CRL to make sure it's not expired */ |
| if (!next_update) { |
| X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD); |
| X509_OBJECT_free_contents(&obj); |
| return 0; /* fail */ |
| } |
| if (X509_cmp_current_time(next_update) < 0) { |
| X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_CRL_HAS_EXPIRED); |
| X509_OBJECT_free_contents(&obj); |
| return 0; /* fail */ |
| } |
| X509_OBJECT_free_contents(&obj); |
| } |
| |
| /* try to retrieve a CRL corresponding to the _issuer_ of |
| * the current certificate in order to check for revocation */ |
| memset((char *)&obj, 0, sizeof obj); |
| X509_STORE_CTX_init(&store_ctx, tls_opts.tls_store, NULL, NULL); |
| rc = X509_STORE_get_by_subject(&store_ctx, X509_LU_CRL, issuer, &obj); |
| X509_STORE_CTX_cleanup(&store_ctx); |
| crl = obj.data.crl; |
| if (rc > 0 && crl) { |
| /* check if the current certificate is revoked by this CRL */ |
| n = sk_X509_REVOKED_num(X509_CRL_get_REVOKED(crl)); |
| for (i = 0; i < n; i++) { |
| revoked = sk_X509_REVOKED_value(X509_CRL_get_REVOKED(crl), i); |
| if (ASN1_INTEGER_cmp(revoked->serialNumber, X509_get_serialNumber(cert)) == 0) { |
| ERR("Certificate revoked!"); |
| X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_CERT_REVOKED); |
| X509_OBJECT_free_contents(&obj); |
| return 0; /* fail */ |
| } |
| } |
| X509_OBJECT_free_contents(&obj); |
| } |
| |
| return 1; /* success */ |
| } |
| |
| API int |
| nc_client_init_tls(const char *client_cert, const char *client_key, const char *ca_file, const char *ca_dir, |
| const char *crl_file, const char *crl_dir) |
| { |
| const char *key_ = client_key; |
| X509_LOOKUP *lookup; |
| |
| if (tls_opts.tls_ctx) { |
| ERR("TLS context already initialized!"); |
| return EXIT_FAILURE; |
| } |
| |
| /* init libssl */ |
| SSL_load_error_strings(); |
| ERR_load_BIO_strings(); |
| SSL_library_init(); |
| |
| if (!client_cert) { |
| return EXIT_SUCCESS; |
| } |
| |
| /* prepare global SSL context, allow only mandatory TLS 1.2 */ |
| if (!(tls_opts.tls_ctx = SSL_CTX_new(TLSv1_2_client_method()))) { |
| ERR("Unable to create OpenSSL context (%s)", ERR_reason_error_string(ERR_get_error())); |
| return EXIT_FAILURE; |
| } |
| |
| if (crl_file || crl_dir) { |
| /* set the revocation store with the correct paths for the callback */ |
| tls_opts.tls_store = X509_STORE_new(); |
| tls_opts.tls_store->cache = 0; |
| |
| if (crl_file) { |
| if (!(lookup = X509_STORE_add_lookup(tls_opts.tls_store, X509_LOOKUP_file()))) { |
| ERR("Failed to add lookup method to CRL checking."); |
| return EXIT_FAILURE; |
| } |
| if (X509_LOOKUP_add_dir(lookup, crl_file, X509_FILETYPE_PEM) != 1) { |
| ERR("Failed to add the revocation lookup file \"%s\".", crl_file); |
| return EXIT_FAILURE; |
| } |
| } |
| |
| if (crl_dir) { |
| if (!(lookup = X509_STORE_add_lookup(tls_opts.tls_store, X509_LOOKUP_hash_dir()))) { |
| ERR("Failed to add lookup method to CRL checking."); |
| return EXIT_FAILURE; |
| } |
| if (X509_LOOKUP_add_dir(lookup, crl_dir, X509_FILETYPE_PEM) != 1) { |
| ERR("Failed to add the revocation lookup directory \"%s\".", crl_dir); |
| return EXIT_FAILURE; |
| } |
| } |
| |
| SSL_CTX_set_verify(tls_opts.tls_ctx, SSL_VERIFY_PEER, tlsauth_verify_callback); |
| } else { |
| /* CRL checking will be skipped */ |
| SSL_CTX_set_verify(tls_opts.tls_ctx, SSL_VERIFY_PEER, NULL); |
| } |
| |
| /* get peer certificate */ |
| if (SSL_CTX_use_certificate_file(tls_opts.tls_ctx, client_cert, SSL_FILETYPE_PEM) != 1) { |
| ERR("Loading a peer certificate from \'%s\' failed (%s).", client_cert, ERR_reason_error_string(ERR_get_error())); |
| return EXIT_FAILURE; |
| } |
| |
| if (!key_) { |
| /* |
| * if the file with private key not specified, expect that the private |
| * key is stored altogether with the certificate |
| */ |
| key_ = client_cert; |
| } |
| if (SSL_CTX_use_PrivateKey_file(tls_opts.tls_ctx, key_, SSL_FILETYPE_PEM) != 1) { |
| ERR("Loading the client certificate from \'%s\' failed (%s).", key_, ERR_reason_error_string(ERR_get_error())); |
| return EXIT_FAILURE; |
| } |
| |
| if (!SSL_CTX_load_verify_locations(tls_opts.tls_ctx, ca_file, ca_dir)) { |
| ERR("Failed to load the locations of trusted CA certificates (%s).", ERR_reason_error_string(ERR_get_error())); |
| return EXIT_FAILURE; |
| } |
| |
| return EXIT_SUCCESS; |
| } |
| |
| API void |
| nc_client_destroy_tls() |
| { |
| CRYPTO_THREADID crypto_tid; |
| |
| SSL_CTX_free(tls_opts.tls_ctx); |
| |
| EVP_cleanup(); |
| CRYPTO_cleanup_all_ex_data(); |
| ERR_free_strings(); |
| sk_SSL_COMP_free(SSL_COMP_get_compression_methods()); |
| CRYPTO_THREADID_current(&crypto_tid); |
| ERR_remove_thread_state(&crypto_tid); |
| } |
| |
| API struct nc_session * |
| nc_connect_tls(const char *host, unsigned short port, const char *username, struct ly_ctx *ctx) |
| { |
| struct passwd *pw; |
| struct nc_session *session = NULL; |
| int sock, verify; |
| |
| /* was init called? */ |
| if (!tls_opts.tls_ctx) { |
| ERR("TLS context was not initialized!"); |
| return NULL; |
| } |
| |
| /* process parameters */ |
| if (!host || strisempty(host)) { |
| host = "localhost"; |
| } |
| |
| if (!port) { |
| port = NC_PORT_TLS; |
| } |
| |
| if (!username) { |
| pw = getpwuid(getuid()); |
| if (pw) { |
| username = pw->pw_name; |
| } |
| } |
| |
| /* prepare session structure */ |
| session = connect_init(ctx); |
| if (!session) { |
| return NULL; |
| } |
| session->ti_type = NC_TI_OPENSSL; |
| |
| /* transport lock */ |
| session->ti_lock = malloc(sizeof *session->ti_lock); |
| if (!session->ti_lock) { |
| ERRMEM; |
| goto fail; |
| } |
| pthread_mutex_init(session->ti_lock, NULL); |
| |
| /* fill the session */ |
| session->username = lydict_insert(session->ctx, username, 0); |
| session->host = lydict_insert(session->ctx, host, 0); |
| session->port = port; |
| if (!(session->ti.tls = SSL_new(tls_opts.tls_ctx))) { |
| ERR("Failed to create new TLS session structure (%s)", ERR_reason_error_string(ERR_get_error())); |
| goto fail; |
| } |
| |
| /* create and assign socket */ |
| sock = connect_getsocket(host, port); |
| if (sock == -1) { |
| goto fail; |
| } |
| SSL_set_fd(session->ti.tls, sock); |
| |
| /* set the SSL_MODE_AUTO_RETRY flag to allow OpenSSL perform re-handshake automatically */ |
| SSL_set_mode(session->ti.tls, SSL_MODE_AUTO_RETRY); |
| |
| /* connect and perform the handshake */ |
| if (SSL_connect(session->ti.tls) != 1) { |
| ERR("Connecting over TLS failed (%s).", ERR_reason_error_string(ERR_get_error())); |
| goto fail; |
| } |
| |
| /* check certificate verification result */ |
| verify = SSL_get_verify_result(session->ti.tls); |
| switch (verify) { |
| case X509_V_OK: |
| VRB("Server certificate successfully verified."); |
| break; |
| default: |
| WRN("Server certificate verification problem (%s).", verify_ret_msg[verify]); |
| } |
| |
| /* NETCONF handshake */ |
| if (handshake(session)) { |
| goto fail; |
| } |
| |
| session->status = NC_STATUS_RUNNING; |
| return session; |
| |
| fail: |
| nc_session_free(session); |
| return NULL; |
| } |
| |
| API struct nc_session * |
| nc_connect_libssl(SSL *tls, struct ly_ctx *ctx) |
| { |
| struct nc_session *session; |
| |
| /* check TLS session status */ |
| if (!tls || !SSL_is_init_finished(tls)) { |
| ERR("Supplied TLS session is not fully connected!"); |
| return NULL; |
| } |
| |
| /* prepare session structure */ |
| session = connect_init(ctx); |
| if (!session) { |
| return NULL; |
| } |
| session->ti_type = NC_TI_OPENSSL; |
| |
| /* transport lock */ |
| session->ti_lock = malloc(sizeof *session->ti_lock); |
| if (!session->ti_lock) { |
| ERRMEM; |
| goto fail; |
| } |
| pthread_mutex_init(session->ti_lock, NULL); |
| |
| session->ti.tls = tls; |
| |
| if (!ctx) { |
| ctx = session->ctx; |
| } |
| |
| /* NETCONF handshake */ |
| if (handshake(session)) { |
| goto fail; |
| } |
| |
| session->status = NC_STATUS_RUNNING; |
| return session; |
| |
| fail: |
| nc_session_free(session); |
| return NULL; |
| } |
| |