/*------------------------------------------------------------------------- * * fe-secure-openssl.c * OpenSSL support * * * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * src/interfaces/libpq/fe-secure-openssl.c * * NOTES * * We don't provide informational callbacks here (like * info_cb() in be-secure.c), since there's no good mechanism to * display such information to the user. * *------------------------------------------------------------------------- */ #include "postgres_fe.h" #include #include #include #include "libpq-fe.h" #include "fe-auth.h" #include "fe-secure-common.h" #include "libpq-int.h" #include "common/openssl.h" #ifdef WIN32 #include "win32.h" #else #include #include #include #include #ifdef HAVE_NETINET_TCP_H #include #endif #include #endif #include #ifdef ENABLE_THREAD_SAFETY #ifdef WIN32 #include "pthread-win32.h" #else #include #endif #endif #include #include #ifdef USE_SSL_ENGINE #include #endif #include static int verify_cb(int ok, X509_STORE_CTX *ctx); static int openssl_verify_peer_name_matches_certificate_name(PGconn *conn, ASN1_STRING *name, char **store_name); static void destroy_ssl_system(void); static int initialize_SSL(PGconn *conn); static PostgresPollingStatusType open_client_SSL(PGconn *); static char *SSLerrmessage(unsigned long ecode); static void SSLerrfree(char *buf); static int PQssl_passwd_cb(char *buf, int size, int rwflag, void *userdata); static int my_sock_read(BIO *h, char *buf, int size); static int my_sock_write(BIO *h, const char *buf, int size); static BIO_METHOD *my_BIO_s_socket(void); static int my_SSL_set_fd(PGconn *conn, int fd); static bool pq_init_ssl_lib = true; static bool pq_init_crypto_lib = true; static bool ssl_lib_initialized = false; #ifdef ENABLE_THREAD_SAFETY static long ssl_open_connections = 0; #ifndef WIN32 static pthread_mutex_t ssl_config_mutex = PTHREAD_MUTEX_INITIALIZER; #else static pthread_mutex_t ssl_config_mutex = NULL; static long win32_ssl_create_mutex = 0; #endif #endif /* ENABLE_THREAD_SAFETY */ static PQsslKeyPassHook_type PQsslKeyPassHook = NULL; static int ssl_protocol_version_to_openssl(const char *protocol); /* ------------------------------------------------------------ */ /* Procedures common to all secure sessions */ /* ------------------------------------------------------------ */ void pgtls_init_library(bool do_ssl, int do_crypto) { #ifdef ENABLE_THREAD_SAFETY /* * Disallow changing the flags while we have open connections, else we'd * get completely confused. */ if (ssl_open_connections != 0) return; #endif pq_init_ssl_lib = do_ssl; pq_init_crypto_lib = do_crypto; } PostgresPollingStatusType pgtls_open_client(PGconn *conn) { /* First time through? */ if (conn->ssl == NULL) { /* * Create a connection-specific SSL object, and load client * certificate, private key, and trusted CA certs. */ if (initialize_SSL(conn) != 0) { /* initialize_SSL already put a message in conn->errorMessage */ pgtls_close(conn); return PGRES_POLLING_FAILED; } } /* Begin or continue the actual handshake */ return open_client_SSL(conn); } ssize_t pgtls_read(PGconn *conn, void *ptr, size_t len) { ssize_t n; int result_errno = 0; char sebuf[PG_STRERROR_R_BUFLEN]; int err; unsigned long ecode; rloop: /* * Prepare to call SSL_get_error() by clearing thread's OpenSSL error * queue. In general, the current thread's error queue must be empty * before the TLS/SSL I/O operation is attempted, or SSL_get_error() will * not work reliably. Since the possibility exists that other OpenSSL * clients running in the same thread but not under our control will fail * to call ERR_get_error() themselves (after their own I/O operations), * pro-actively clear the per-thread error queue now. */ SOCK_ERRNO_SET(0); ERR_clear_error(); n = SSL_read(conn->ssl, ptr, len); err = SSL_get_error(conn->ssl, n); /* * Other clients of OpenSSL may fail to call ERR_get_error(), but we * always do, so as to not cause problems for OpenSSL clients that don't * call ERR_clear_error() defensively. Be sure that this happens by * calling now. SSL_get_error() relies on the OpenSSL per-thread error * queue being intact, so this is the earliest possible point * ERR_get_error() may be called. */ ecode = (err != SSL_ERROR_NONE || n < 0) ? ERR_get_error() : 0; switch (err) { case SSL_ERROR_NONE: if (n < 0) { /* Not supposed to happen, so we don't translate the msg */ printfPQExpBuffer(&conn->errorMessage, "SSL_read failed but did not provide error information\n"); /* assume the connection is broken */ result_errno = ECONNRESET; } break; case SSL_ERROR_WANT_READ: n = 0; break; case SSL_ERROR_WANT_WRITE: /* * Returning 0 here would cause caller to wait for read-ready, * which is not correct since what SSL wants is wait for * write-ready. The former could get us stuck in an infinite * wait, so don't risk it; busy-loop instead. */ goto rloop; case SSL_ERROR_SYSCALL: if (n < 0) { result_errno = SOCK_ERRNO; if (result_errno == EPIPE || result_errno == ECONNRESET) printfPQExpBuffer(&conn->errorMessage, libpq_gettext( "server closed the connection unexpectedly\n" "\tThis probably means the server terminated abnormally\n" "\tbefore or while processing the request.\n")); else printfPQExpBuffer(&conn->errorMessage, libpq_gettext("SSL SYSCALL error: %s\n"), SOCK_STRERROR(result_errno, sebuf, sizeof(sebuf))); } else { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("SSL SYSCALL error: EOF detected\n")); /* assume the connection is broken */ result_errno = ECONNRESET; n = -1; } break; case SSL_ERROR_SSL: { char *errm = SSLerrmessage(ecode); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("SSL error: %s\n"), errm); SSLerrfree(errm); /* assume the connection is broken */ result_errno = ECONNRESET; n = -1; break; } case SSL_ERROR_ZERO_RETURN: /* * Per OpenSSL documentation, this error code is only returned for * a clean connection closure, so we should not report it as a * server crash. */ printfPQExpBuffer(&conn->errorMessage, libpq_gettext("SSL connection has been closed unexpectedly\n")); result_errno = ECONNRESET; n = -1; break; default: printfPQExpBuffer(&conn->errorMessage, libpq_gettext("unrecognized SSL error code: %d\n"), err); /* assume the connection is broken */ result_errno = ECONNRESET; n = -1; break; } /* ensure we return the intended errno to caller */ SOCK_ERRNO_SET(result_errno); return n; } bool pgtls_read_pending(PGconn *conn) { return SSL_pending(conn->ssl) > 0; } ssize_t pgtls_write(PGconn *conn, const void *ptr, size_t len) { ssize_t n; int result_errno = 0; char sebuf[PG_STRERROR_R_BUFLEN]; int err; unsigned long ecode; SOCK_ERRNO_SET(0); ERR_clear_error(); n = SSL_write(conn->ssl, ptr, len); err = SSL_get_error(conn->ssl, n); ecode = (err != SSL_ERROR_NONE || n < 0) ? ERR_get_error() : 0; switch (err) { case SSL_ERROR_NONE: if (n < 0) { /* Not supposed to happen, so we don't translate the msg */ printfPQExpBuffer(&conn->errorMessage, "SSL_write failed but did not provide error information\n"); /* assume the connection is broken */ result_errno = ECONNRESET; } break; case SSL_ERROR_WANT_READ: /* * Returning 0 here causes caller to wait for write-ready, which * is not really the right thing, but it's the best we can do. */ n = 0; break; case SSL_ERROR_WANT_WRITE: n = 0; break; case SSL_ERROR_SYSCALL: if (n < 0) { result_errno = SOCK_ERRNO; if (result_errno == EPIPE || result_errno == ECONNRESET) printfPQExpBuffer(&conn->errorMessage, libpq_gettext( "server closed the connection unexpectedly\n" "\tThis probably means the server terminated abnormally\n" "\tbefore or while processing the request.\n")); else printfPQExpBuffer(&conn->errorMessage, libpq_gettext("SSL SYSCALL error: %s\n"), SOCK_STRERROR(result_errno, sebuf, sizeof(sebuf))); } else { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("SSL SYSCALL error: EOF detected\n")); /* assume the connection is broken */ result_errno = ECONNRESET; n = -1; } break; case SSL_ERROR_SSL: { char *errm = SSLerrmessage(ecode); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("SSL error: %s\n"), errm); SSLerrfree(errm); /* assume the connection is broken */ result_errno = ECONNRESET; n = -1; break; } case SSL_ERROR_ZERO_RETURN: /* * Per OpenSSL documentation, this error code is only returned for * a clean connection closure, so we should not report it as a * server crash. */ printfPQExpBuffer(&conn->errorMessage, libpq_gettext("SSL connection has been closed unexpectedly\n")); result_errno = ECONNRESET; n = -1; break; default: printfPQExpBuffer(&conn->errorMessage, libpq_gettext("unrecognized SSL error code: %d\n"), err); /* assume the connection is broken */ result_errno = ECONNRESET; n = -1; break; } /* ensure we return the intended errno to caller */ SOCK_ERRNO_SET(result_errno); return n; } #ifdef HAVE_X509_GET_SIGNATURE_NID char * pgtls_get_peer_certificate_hash(PGconn *conn, size_t *len) { X509 *peer_cert; const EVP_MD *algo_type; unsigned char hash[EVP_MAX_MD_SIZE]; /* size for SHA-512 */ unsigned int hash_size; int algo_nid; char *cert_hash; *len = 0; if (!conn->peer) return NULL; peer_cert = conn->peer; /* * Get the signature algorithm of the certificate to determine the hash * algorithm to use for the result. */ if (!OBJ_find_sigid_algs(X509_get_signature_nid(peer_cert), &algo_nid, NULL)) { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not determine server certificate signature algorithm\n")); return NULL; } /* * The TLS server's certificate bytes need to be hashed with SHA-256 if * its signature algorithm is MD5 or SHA-1 as per RFC 5929 * (https://tools.ietf.org/html/rfc5929#section-4.1). If something else * is used, the same hash as the signature algorithm is used. */ switch (algo_nid) { case NID_md5: case NID_sha1: algo_type = EVP_sha256(); break; default: algo_type = EVP_get_digestbynid(algo_nid); if (algo_type == NULL) { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not find digest for NID %s\n"), OBJ_nid2sn(algo_nid)); return NULL; } break; } if (!X509_digest(peer_cert, algo_type, hash, &hash_size)) { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not generate peer certificate hash\n")); return NULL; } /* save result */ cert_hash = malloc(hash_size); if (cert_hash == NULL) { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("out of memory\n")); return NULL; } memcpy(cert_hash, hash, hash_size); *len = hash_size; return cert_hash; } #endif /* HAVE_X509_GET_SIGNATURE_NID */ /* ------------------------------------------------------------ */ /* OpenSSL specific code */ /* ------------------------------------------------------------ */ /* * Certificate verification callback * * This callback allows us to log intermediate problems during * verification, but there doesn't seem to be a clean way to get * our PGconn * structure. So we can't log anything! * * This callback also allows us to override the default acceptance * criteria (e.g., accepting self-signed or expired certs), but * for now we accept the default checks. */ static int verify_cb(int ok, X509_STORE_CTX *ctx) { return ok; } /* * OpenSSL-specific wrapper around * pq_verify_peer_name_matches_certificate_name(), converting the ASN1_STRING * into a plain C string. */ static int openssl_verify_peer_name_matches_certificate_name(PGconn *conn, ASN1_STRING *name_entry, char **store_name) { int len; const unsigned char *namedata; /* Should not happen... */ if (name_entry == NULL) { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("SSL certificate's name entry is missing\n")); return -1; } /* * GEN_DNS can be only IA5String, equivalent to US ASCII. */ #ifdef HAVE_ASN1_STRING_GET0_DATA namedata = ASN1_STRING_get0_data(name_entry); #else namedata = ASN1_STRING_data(name_entry); #endif len = ASN1_STRING_length(name_entry); /* OK to cast from unsigned to plain char, since it's all ASCII. */ return pq_verify_peer_name_matches_certificate_name(conn, (const char *) namedata, len, store_name); } /* * Verify that the server certificate matches the hostname we connected to. * * The certificate's Common Name and Subject Alternative Names are considered. */ int pgtls_verify_peer_name_matches_certificate_guts(PGconn *conn, int *names_examined, char **first_name) { STACK_OF(GENERAL_NAME) *peer_san; int i; int rc = 0; /* * First, get the Subject Alternative Names (SANs) from the certificate, * and compare them against the originally given hostname. */ peer_san = (STACK_OF(GENERAL_NAME) *) X509_get_ext_d2i(conn->peer, NID_subject_alt_name, NULL, NULL); if (peer_san) { int san_len = sk_GENERAL_NAME_num(peer_san); for (i = 0; i < san_len; i++) { const GENERAL_NAME *name = sk_GENERAL_NAME_value(peer_san, i); if (name->type == GEN_DNS) { char *alt_name; (*names_examined)++; rc = openssl_verify_peer_name_matches_certificate_name(conn, name->d.dNSName, &alt_name); if (alt_name) { if (!*first_name) *first_name = alt_name; else free(alt_name); } } if (rc != 0) break; } sk_GENERAL_NAME_free(peer_san); } /* * If there is no subjectAltName extension of type dNSName, check the * Common Name. * * (Per RFC 2818 and RFC 6125, if the subjectAltName extension of type * dNSName is present, the CN must be ignored.) */ if (*names_examined == 0) { X509_NAME *subject_name; subject_name = X509_get_subject_name(conn->peer); if (subject_name != NULL) { int cn_index; cn_index = X509_NAME_get_index_by_NID(subject_name, NID_commonName, -1); if (cn_index >= 0) { (*names_examined)++; rc = openssl_verify_peer_name_matches_certificate_name( conn, X509_NAME_ENTRY_get_data( X509_NAME_get_entry(subject_name, cn_index)), first_name); } } } return rc; } #if defined(ENABLE_THREAD_SAFETY) && defined(HAVE_CRYPTO_LOCK) /* * Callback functions for OpenSSL internal locking. (OpenSSL 1.1.0 * does its own locking, and doesn't need these anymore. The * CRYPTO_lock() function was removed in 1.1.0, when the callbacks * were made obsolete, so we assume that if CRYPTO_lock() exists, * the callbacks are still required.) */ static unsigned long pq_threadidcallback(void) { /* * This is not standards-compliant. pthread_self() returns pthread_t, and * shouldn't be cast to unsigned long, but CRYPTO_set_id_callback requires * it, so we have to do it. */ return (unsigned long) pthread_self(); } static pthread_mutex_t *pq_lockarray; static void pq_lockingcallback(int mode, int n, const char *file, int line) { if (mode & CRYPTO_LOCK) { if (pthread_mutex_lock(&pq_lockarray[n])) PGTHREAD_ERROR("failed to lock mutex"); } else { if (pthread_mutex_unlock(&pq_lockarray[n])) PGTHREAD_ERROR("failed to unlock mutex"); } } #endif /* ENABLE_THREAD_SAFETY && HAVE_CRYPTO_LOCK */ /* * Initialize SSL library. * * In threadsafe mode, this includes setting up libcrypto callback functions * to do thread locking. * * If the caller has told us (through PQinitOpenSSL) that he's taking care * of libcrypto, we expect that callbacks are already set, and won't try to * override it. */ int pgtls_init(PGconn *conn) { #ifdef ENABLE_THREAD_SAFETY #ifdef WIN32 /* Also see similar code in fe-connect.c, default_threadlock() */ if (ssl_config_mutex == NULL) { while (InterlockedExchange(&win32_ssl_create_mutex, 1) == 1) /* loop, another thread own the lock */ ; if (ssl_config_mutex == NULL) { if (pthread_mutex_init(&ssl_config_mutex, NULL)) return -1; } InterlockedExchange(&win32_ssl_create_mutex, 0); } #endif if (pthread_mutex_lock(&ssl_config_mutex)) return -1; #ifdef HAVE_CRYPTO_LOCK if (pq_init_crypto_lib) { /* * If necessary, set up an array to hold locks for libcrypto. * libcrypto will tell us how big to make this array. */ if (pq_lockarray == NULL) { int i; pq_lockarray = malloc(sizeof(pthread_mutex_t) * CRYPTO_num_locks()); if (!pq_lockarray) { pthread_mutex_unlock(&ssl_config_mutex); return -1; } for (i = 0; i < CRYPTO_num_locks(); i++) { if (pthread_mutex_init(&pq_lockarray[i], NULL)) { free(pq_lockarray); pq_lockarray = NULL; pthread_mutex_unlock(&ssl_config_mutex); return -1; } } } if (ssl_open_connections++ == 0) { /* * These are only required for threaded libcrypto applications, * but make sure we don't stomp on them if they're already set. */ if (CRYPTO_get_id_callback() == NULL) CRYPTO_set_id_callback(pq_threadidcallback); if (CRYPTO_get_locking_callback() == NULL) CRYPTO_set_locking_callback(pq_lockingcallback); } } #endif /* HAVE_CRYPTO_LOCK */ #endif /* ENABLE_THREAD_SAFETY */ if (!ssl_lib_initialized) { if (pq_init_ssl_lib) { #ifdef HAVE_OPENSSL_INIT_SSL OPENSSL_init_ssl(OPENSSL_INIT_LOAD_CONFIG, NULL); #else OPENSSL_config(NULL); SSL_library_init(); SSL_load_error_strings(); #endif } ssl_lib_initialized = true; } #ifdef ENABLE_THREAD_SAFETY pthread_mutex_unlock(&ssl_config_mutex); #endif return 0; } /* * This function is needed because if the libpq library is unloaded * from the application, the callback functions will no longer exist when * libcrypto is used by other parts of the system. For this reason, * we unregister the callback functions when the last libpq * connection is closed. (The same would apply for OpenSSL callbacks * if we had any.) * * Callbacks are only set when we're compiled in threadsafe mode, so * we only need to remove them in this case. They are also not needed * with OpenSSL 1.1.0 anymore. */ static void destroy_ssl_system(void) { #if defined(ENABLE_THREAD_SAFETY) && defined(HAVE_CRYPTO_LOCK) /* Mutex is created in pgtls_init() */ if (pthread_mutex_lock(&ssl_config_mutex)) return; if (pq_init_crypto_lib && ssl_open_connections > 0) --ssl_open_connections; if (pq_init_crypto_lib && ssl_open_connections == 0) { /* * No connections left, unregister libcrypto callbacks, if no one * registered different ones in the meantime. */ if (CRYPTO_get_locking_callback() == pq_lockingcallback) CRYPTO_set_locking_callback(NULL); if (CRYPTO_get_id_callback() == pq_threadidcallback) CRYPTO_set_id_callback(NULL); /* * We don't free the lock array. If we get another connection in this * process, we will just re-use them with the existing mutexes. * * This means we leak a little memory on repeated load/unload of the * library. */ } pthread_mutex_unlock(&ssl_config_mutex); #endif } /* * Create per-connection SSL object, and load the client certificate, * private key, and trusted CA certs. * * Returns 0 if OK, -1 on failure (with a message in conn->errorMessage). */ static int initialize_SSL(PGconn *conn) { SSL_CTX *SSL_context; struct stat buf; char homedir[MAXPGPATH]; char fnbuf[MAXPGPATH]; char sebuf[PG_STRERROR_R_BUFLEN]; bool have_homedir; bool have_cert; bool have_rootcert; EVP_PKEY *pkey = NULL; /* * We'll need the home directory if any of the relevant parameters are * defaulted. If pqGetHomeDirectory fails, act as though none of the * files could be found. */ if (!(conn->sslcert && strlen(conn->sslcert) > 0) || !(conn->sslkey && strlen(conn->sslkey) > 0) || !(conn->sslrootcert && strlen(conn->sslrootcert) > 0) || !(conn->sslcrl && strlen(conn->sslcrl) > 0)) have_homedir = pqGetHomeDirectory(homedir, sizeof(homedir)); else /* won't need it */ have_homedir = false; /* * Create a new SSL_CTX object. * * We used to share a single SSL_CTX between all connections, but it was * complicated if connections used different certificates. So now we * create a separate context for each connection, and accept the overhead. */ SSL_context = SSL_CTX_new(SSLv23_method()); if (!SSL_context) { char *err = SSLerrmessage(ERR_get_error()); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not create SSL context: %s\n"), err); SSLerrfree(err); return -1; } /* * Delegate the client cert password prompt to the libpq wrapper * callback if any is defined. * * If the application hasn't installed its own and the sslpassword * parameter is non-null, we install ours now to make sure we * supply PGconn->sslpassword to OpenSSL instead of letting it * prompt on stdin. * * This will replace OpenSSL's default PEM_def_callback (which * prompts on stdin), but we're only setting it for this SSL * context so it's harmless. */ if (PQsslKeyPassHook || (conn->sslpassword && strlen(conn->sslpassword) > 0)) { SSL_CTX_set_default_passwd_cb(SSL_context, PQssl_passwd_cb); SSL_CTX_set_default_passwd_cb_userdata(SSL_context, conn); } /* Disable old protocol versions */ SSL_CTX_set_options(SSL_context, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3); /* Set the minimum and maximum protocol versions if necessary */ if (conn->sslminprotocolversion && strlen(conn->sslminprotocolversion) != 0) { int ssl_min_ver; ssl_min_ver = ssl_protocol_version_to_openssl(conn->sslminprotocolversion); if (ssl_min_ver == -1) { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("invalid value \"%s\" for minimum version of SSL protocol\n"), conn->sslminprotocolversion); return -1; } if (!SSL_CTX_set_min_proto_version(SSL_context, ssl_min_ver)) { char *err = SSLerrmessage(ERR_get_error()); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not set minimum version of SSL protocol: %s\n"), err); return -1; } } if (conn->sslmaxprotocolversion && strlen(conn->sslmaxprotocolversion) != 0) { int ssl_max_ver; ssl_max_ver = ssl_protocol_version_to_openssl(conn->sslmaxprotocolversion); if (ssl_max_ver == -1) { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("invalid value \"%s\" for maximum version of SSL protocol\n"), conn->sslmaxprotocolversion); return -1; } if (!SSL_CTX_set_max_proto_version(SSL_context, ssl_max_ver)) { char *err = SSLerrmessage(ERR_get_error()); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not set maximum version of SSL protocol: %s\n"), err); return -1; } } /* * Disable OpenSSL's moving-write-buffer sanity check, because it causes * unnecessary failures in nonblocking send cases. */ SSL_CTX_set_mode(SSL_context, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER); /* * If the root cert file exists, load it so we can perform certificate * verification. If sslmode is "verify-full" we will also do further * verification after the connection has been completed. */ if (conn->sslrootcert && strlen(conn->sslrootcert) > 0) strlcpy(fnbuf, conn->sslrootcert, sizeof(fnbuf)); else if (have_homedir) snprintf(fnbuf, sizeof(fnbuf), "%s/%s", homedir, ROOT_CERT_FILE); else fnbuf[0] = '\0'; if (fnbuf[0] != '\0' && stat(fnbuf, &buf) == 0) { X509_STORE *cvstore; if (SSL_CTX_load_verify_locations(SSL_context, fnbuf, NULL) != 1) { char *err = SSLerrmessage(ERR_get_error()); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not read root certificate file \"%s\": %s\n"), fnbuf, err); SSLerrfree(err); SSL_CTX_free(SSL_context); return -1; } if ((cvstore = SSL_CTX_get_cert_store(SSL_context)) != NULL) { if (conn->sslcrl && strlen(conn->sslcrl) > 0) strlcpy(fnbuf, conn->sslcrl, sizeof(fnbuf)); else if (have_homedir) snprintf(fnbuf, sizeof(fnbuf), "%s/%s", homedir, ROOT_CRL_FILE); else fnbuf[0] = '\0'; /* Set the flags to check against the complete CRL chain */ if (fnbuf[0] != '\0' && X509_STORE_load_locations(cvstore, fnbuf, NULL) == 1) { X509_STORE_set_flags(cvstore, X509_V_FLAG_CRL_CHECK | X509_V_FLAG_CRL_CHECK_ALL); } /* if not found, silently ignore; we do not require CRL */ ERR_clear_error(); } have_rootcert = true; } else { /* * stat() failed; assume root file doesn't exist. If sslmode is * verify-ca or verify-full, this is an error. Otherwise, continue * without performing any server cert verification. */ if (conn->sslmode[0] == 'v') /* "verify-ca" or "verify-full" */ { /* * The only way to reach here with an empty filename is if * pqGetHomeDirectory failed. That's a sufficiently unusual case * that it seems worth having a specialized error message for it. */ if (fnbuf[0] == '\0') printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not get home directory to locate root certificate file\n" "Either provide the file or change sslmode to disable server certificate verification.\n")); else printfPQExpBuffer(&conn->errorMessage, libpq_gettext("root certificate file \"%s\" does not exist\n" "Either provide the file or change sslmode to disable server certificate verification.\n"), fnbuf); SSL_CTX_free(SSL_context); return -1; } have_rootcert = false; } /* Read the client certificate file */ if (conn->sslcert && strlen(conn->sslcert) > 0) strlcpy(fnbuf, conn->sslcert, sizeof(fnbuf)); else if (have_homedir) snprintf(fnbuf, sizeof(fnbuf), "%s/%s", homedir, USER_CERT_FILE); else fnbuf[0] = '\0'; if (fnbuf[0] == '\0') { /* no home directory, proceed without a client cert */ have_cert = false; } else if (stat(fnbuf, &buf) != 0) { /* * If file is not present, just go on without a client cert; server * might or might not accept the connection. Any other error, * however, is grounds for complaint. */ if (errno != ENOENT && errno != ENOTDIR) { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not open certificate file \"%s\": %s\n"), fnbuf, strerror_r(errno, sebuf, sizeof(sebuf))); SSL_CTX_free(SSL_context); return -1; } have_cert = false; } else { /* * Cert file exists, so load it. Since OpenSSL doesn't provide the * equivalent of "SSL_use_certificate_chain_file", we have to load it * into the SSL context, rather than the SSL object. */ if (SSL_CTX_use_certificate_chain_file(SSL_context, fnbuf) != 1) { char *err = SSLerrmessage(ERR_get_error()); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not read certificate file \"%s\": %s\n"), fnbuf, err); SSLerrfree(err); SSL_CTX_free(SSL_context); return -1; } /* need to load the associated private key, too */ have_cert = true; } /* * The SSL context is now loaded with the correct root and client * certificates. Create a connection-specific SSL object. The private key * is loaded directly into the SSL object. (We could load the private key * into the context, too, but we have done it this way historically, and * it doesn't really matter.) */ if (!(conn->ssl = SSL_new(SSL_context)) || !SSL_set_app_data(conn->ssl, conn) || !my_SSL_set_fd(conn, conn->sock)) { char *err = SSLerrmessage(ERR_get_error()); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not establish SSL connection: %s\n"), err); SSLerrfree(err); SSL_CTX_free(SSL_context); return -1; } conn->ssl_in_use = true; /* * SSL contexts are reference counted by OpenSSL. We can free it as soon * as we have created the SSL object, and it will stick around for as long * as it's actually needed. */ SSL_CTX_free(SSL_context); SSL_context = NULL; /* * Read the SSL key. If a key is specified, treat it as an engine:key * combination if there is colon present - we don't support files with * colon in the name. The exception is if the second character is a colon, * in which case it can be a Windows filename with drive specification. */ if (have_cert && conn->sslkey && strlen(conn->sslkey) > 0) { #ifdef USE_SSL_ENGINE if (strchr(conn->sslkey, ':') #ifdef WIN32 && conn->sslkey[1] != ':' #endif ) { /* Colon, but not in second character, treat as engine:key */ char *engine_str = strdup(conn->sslkey); char *engine_colon; if (engine_str == NULL) { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("out of memory\n")); return -1; } /* cannot return NULL because we already checked before strdup */ engine_colon = strchr(engine_str, ':'); *engine_colon = '\0'; /* engine_str now has engine name */ engine_colon++; /* engine_colon now has key name */ conn->engine = ENGINE_by_id(engine_str); if (conn->engine == NULL) { char *err = SSLerrmessage(ERR_get_error()); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not load SSL engine \"%s\": %s\n"), engine_str, err); SSLerrfree(err); free(engine_str); return -1; } if (ENGINE_init(conn->engine) == 0) { char *err = SSLerrmessage(ERR_get_error()); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not initialize SSL engine \"%s\": %s\n"), engine_str, err); SSLerrfree(err); ENGINE_free(conn->engine); conn->engine = NULL; free(engine_str); return -1; } pkey = ENGINE_load_private_key(conn->engine, engine_colon, NULL, NULL); if (pkey == NULL) { char *err = SSLerrmessage(ERR_get_error()); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not read private SSL key \"%s\" from engine \"%s\": %s\n"), engine_colon, engine_str, err); SSLerrfree(err); ENGINE_finish(conn->engine); ENGINE_free(conn->engine); conn->engine = NULL; free(engine_str); return -1; } if (SSL_use_PrivateKey(conn->ssl, pkey) != 1) { char *err = SSLerrmessage(ERR_get_error()); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not load private SSL key \"%s\" from engine \"%s\": %s\n"), engine_colon, engine_str, err); SSLerrfree(err); ENGINE_finish(conn->engine); ENGINE_free(conn->engine); conn->engine = NULL; free(engine_str); return -1; } free(engine_str); fnbuf[0] = '\0'; /* indicate we're not going to load from a * file */ } else #endif /* USE_SSL_ENGINE */ { /* PGSSLKEY is not an engine, treat it as a filename */ strlcpy(fnbuf, conn->sslkey, sizeof(fnbuf)); } } else if (have_homedir) { /* No PGSSLKEY specified, load default file */ snprintf(fnbuf, sizeof(fnbuf), "%s/%s", homedir, USER_KEY_FILE); } else fnbuf[0] = '\0'; if (have_cert && fnbuf[0] != '\0') { /* read the client key from file */ if (stat(fnbuf, &buf) != 0) { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("certificate present, but not private key file \"%s\"\n"), fnbuf); return -1; } #ifndef WIN32 if (!S_ISREG(buf.st_mode) || buf.st_mode & (S_IRWXG | S_IRWXO)) { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("private key file \"%s\" has group or world access; permissions should be u=rw (0600) or less\n"), fnbuf); return -1; } #endif if (SSL_use_PrivateKey_file(conn->ssl, fnbuf, SSL_FILETYPE_PEM) != 1) { char *err = SSLerrmessage(ERR_get_error()); /* * We'll try to load the file in DER (binary ASN.1) format, and if * that fails too, report the original error. This could mask * issues where there's something wrong with a DER-format cert, but * we'd have to duplicate openssl's format detection to be smarter * than this. We can't just probe for a leading -----BEGIN because * PEM can have leading non-matching lines and blanks. OpenSSL * doesn't expose its get_name(...) and its PEM routines don't * differentiate between failure modes in enough detail to let us * tell the difference between "not PEM, try DER" and "wrong * password". */ if (SSL_use_PrivateKey_file(conn->ssl, fnbuf, SSL_FILETYPE_ASN1) != 1) { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("could not load private key file \"%s\": %s\n"), fnbuf, err); SSLerrfree(err); return -1; } SSLerrfree(err); } } /* verify that the cert and key go together */ if (have_cert && SSL_check_private_key(conn->ssl) != 1) { char *err = SSLerrmessage(ERR_get_error()); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("certificate does not match private key file \"%s\": %s\n"), fnbuf, err); SSLerrfree(err); return -1; } /* * If a root cert was loaded, also set our certificate verification * callback. */ if (have_rootcert) SSL_set_verify(conn->ssl, SSL_VERIFY_PEER, verify_cb); /* * Set compression option if necessary. */ if (conn->sslcompression && conn->sslcompression[0] == '0') SSL_set_options(conn->ssl, SSL_OP_NO_COMPRESSION); else SSL_clear_options(conn->ssl, SSL_OP_NO_COMPRESSION); return 0; } /* * Attempt to negotiate SSL connection. */ static PostgresPollingStatusType open_client_SSL(PGconn *conn) { int r; ERR_clear_error(); r = SSL_connect(conn->ssl); if (r <= 0) { int err = SSL_get_error(conn->ssl, r); unsigned long ecode; ecode = ERR_get_error(); switch (err) { case SSL_ERROR_WANT_READ: return PGRES_POLLING_READING; case SSL_ERROR_WANT_WRITE: return PGRES_POLLING_WRITING; case SSL_ERROR_SYSCALL: { char sebuf[PG_STRERROR_R_BUFLEN]; if (r == -1) printfPQExpBuffer(&conn->errorMessage, libpq_gettext("SSL SYSCALL error: %s\n"), SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf))); else printfPQExpBuffer(&conn->errorMessage, libpq_gettext("SSL SYSCALL error: EOF detected\n")); pgtls_close(conn); return PGRES_POLLING_FAILED; } case SSL_ERROR_SSL: { char *err = SSLerrmessage(ecode); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("SSL error: %s\n"), err); SSLerrfree(err); pgtls_close(conn); return PGRES_POLLING_FAILED; } default: printfPQExpBuffer(&conn->errorMessage, libpq_gettext("unrecognized SSL error code: %d\n"), err); pgtls_close(conn); return PGRES_POLLING_FAILED; } } /* * We already checked the server certificate in initialize_SSL() using * SSL_CTX_set_verify(), if root.crt exists. */ /* get server certificate */ conn->peer = SSL_get_peer_certificate(conn->ssl); if (conn->peer == NULL) { char *err; err = SSLerrmessage(ERR_get_error()); printfPQExpBuffer(&conn->errorMessage, libpq_gettext("certificate could not be obtained: %s\n"), err); SSLerrfree(err); pgtls_close(conn); return PGRES_POLLING_FAILED; } if (!pq_verify_peer_name_matches_certificate(conn)) { pgtls_close(conn); return PGRES_POLLING_FAILED; } /* SSL handshake is complete */ return PGRES_POLLING_OK; } void pgtls_close(PGconn *conn) { bool destroy_needed = false; if (conn->ssl) { /* * We can't destroy everything SSL-related here due to the possible * later calls to OpenSSL routines which may need our thread * callbacks, so set a flag here and check at the end. */ destroy_needed = true; SSL_shutdown(conn->ssl); SSL_free(conn->ssl); conn->ssl = NULL; conn->ssl_in_use = false; } if (conn->peer) { X509_free(conn->peer); conn->peer = NULL; } #ifdef USE_SSL_ENGINE if (conn->engine) { ENGINE_finish(conn->engine); ENGINE_free(conn->engine); conn->engine = NULL; } #endif /* * This will remove our SSL locking hooks, if this is the last SSL * connection, which means we must wait to call it until after all SSL * calls have been made, otherwise we can end up with a race condition and * possible deadlocks. * * See comments above destroy_ssl_system(). */ if (destroy_needed) destroy_ssl_system(); } /* * Obtain reason string for passed SSL errcode * * ERR_get_error() is used by caller to get errcode to pass here. * * Some caution is needed here since ERR_reason_error_string will * return NULL if it doesn't recognize the error code. We don't * want to return NULL ever. */ static char ssl_nomem[] = "out of memory allocating error description"; #define SSL_ERR_LEN 128 static char * SSLerrmessage(unsigned long ecode) { const char *errreason; char *errbuf; errbuf = malloc(SSL_ERR_LEN); if (!errbuf) return ssl_nomem; if (ecode == 0) { snprintf(errbuf, SSL_ERR_LEN, libpq_gettext("no SSL error reported")); return errbuf; } errreason = ERR_reason_error_string(ecode); if (errreason != NULL) { strlcpy(errbuf, errreason, SSL_ERR_LEN); return errbuf; } snprintf(errbuf, SSL_ERR_LEN, libpq_gettext("SSL error code %lu"), ecode); return errbuf; } static void SSLerrfree(char *buf) { if (buf != ssl_nomem) free(buf); } /* ------------------------------------------------------------ */ /* SSL information functions */ /* ------------------------------------------------------------ */ /* * Return pointer to OpenSSL object. */ void * PQgetssl(PGconn *conn) { if (!conn) return NULL; return conn->ssl; } void * PQsslStruct(PGconn *conn, const char *struct_name) { if (!conn) return NULL; if (strcmp(struct_name, "OpenSSL") == 0) return conn->ssl; return NULL; } const char *const * PQsslAttributeNames(PGconn *conn) { static const char *const result[] = { "library", "key_bits", "cipher", "compression", "protocol", NULL }; return result; } const char * PQsslAttribute(PGconn *conn, const char *attribute_name) { if (!conn) return NULL; if (conn->ssl == NULL) return NULL; if (strcmp(attribute_name, "library") == 0) return "OpenSSL"; if (strcmp(attribute_name, "key_bits") == 0) { static char sslbits_str[12]; int sslbits; SSL_get_cipher_bits(conn->ssl, &sslbits); snprintf(sslbits_str, sizeof(sslbits_str), "%d", sslbits); return sslbits_str; } if (strcmp(attribute_name, "cipher") == 0) return SSL_get_cipher(conn->ssl); if (strcmp(attribute_name, "compression") == 0) return SSL_get_current_compression(conn->ssl) ? "on" : "off"; if (strcmp(attribute_name, "protocol") == 0) return SSL_get_version(conn->ssl); return NULL; /* unknown attribute */ } /* * Private substitute BIO: this does the sending and receiving using * pqsecure_raw_write() and pqsecure_raw_read() instead, to allow those * functions to disable SIGPIPE and give better error messages on I/O errors. * * These functions are closely modelled on the standard socket BIO in OpenSSL; * see sock_read() and sock_write() in OpenSSL's crypto/bio/bss_sock.c. * XXX OpenSSL 1.0.1e considers many more errcodes than just EINTR as reasons * to retry; do we need to adopt their logic for that? */ #ifndef HAVE_BIO_GET_DATA #define BIO_get_data(bio) (bio->ptr) #define BIO_set_data(bio, data) (bio->ptr = data) #endif static BIO_METHOD *my_bio_methods; static int my_sock_read(BIO *h, char *buf, int size) { int res; res = pqsecure_raw_read((PGconn *) BIO_get_data(h), buf, size); BIO_clear_retry_flags(h); if (res < 0) { /* If we were interrupted, tell caller to retry */ switch (SOCK_ERRNO) { #ifdef EAGAIN case EAGAIN: #endif #if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN)) case EWOULDBLOCK: #endif case EINTR: BIO_set_retry_read(h); break; default: break; } } return res; } static int my_sock_write(BIO *h, const char *buf, int size) { int res; res = pqsecure_raw_write((PGconn *) BIO_get_data(h), buf, size); BIO_clear_retry_flags(h); if (res <= 0) { /* If we were interrupted, tell caller to retry */ switch (SOCK_ERRNO) { #ifdef EAGAIN case EAGAIN: #endif #if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN)) case EWOULDBLOCK: #endif case EINTR: BIO_set_retry_write(h); break; default: break; } } return res; } static BIO_METHOD * my_BIO_s_socket(void) { if (!my_bio_methods) { BIO_METHOD *biom = (BIO_METHOD *) BIO_s_socket(); #ifdef HAVE_BIO_METH_NEW int my_bio_index; my_bio_index = BIO_get_new_index(); if (my_bio_index == -1) return NULL; my_bio_methods = BIO_meth_new(my_bio_index, "libpq socket"); if (!my_bio_methods) return NULL; /* * As of this writing, these functions never fail. But check anyway, * like OpenSSL's own examples do. */ if (!BIO_meth_set_write(my_bio_methods, my_sock_write) || !BIO_meth_set_read(my_bio_methods, my_sock_read) || !BIO_meth_set_gets(my_bio_methods, BIO_meth_get_gets(biom)) || !BIO_meth_set_puts(my_bio_methods, BIO_meth_get_puts(biom)) || !BIO_meth_set_ctrl(my_bio_methods, BIO_meth_get_ctrl(biom)) || !BIO_meth_set_create(my_bio_methods, BIO_meth_get_create(biom)) || !BIO_meth_set_destroy(my_bio_methods, BIO_meth_get_destroy(biom)) || !BIO_meth_set_callback_ctrl(my_bio_methods, BIO_meth_get_callback_ctrl(biom))) { BIO_meth_free(my_bio_methods); my_bio_methods = NULL; return NULL; } #else my_bio_methods = malloc(sizeof(BIO_METHOD)); if (!my_bio_methods) return NULL; memcpy(my_bio_methods, biom, sizeof(BIO_METHOD)); my_bio_methods->bread = my_sock_read; my_bio_methods->bwrite = my_sock_write; #endif } return my_bio_methods; } /* This should exactly match OpenSSL's SSL_set_fd except for using my BIO */ static int my_SSL_set_fd(PGconn *conn, int fd) { int ret = 0; BIO *bio; BIO_METHOD *bio_method; bio_method = my_BIO_s_socket(); if (bio_method == NULL) { SSLerr(SSL_F_SSL_SET_FD, ERR_R_BUF_LIB); goto err; } bio = BIO_new(bio_method); if (bio == NULL) { SSLerr(SSL_F_SSL_SET_FD, ERR_R_BUF_LIB); goto err; } BIO_set_data(bio, conn); SSL_set_bio(conn->ssl, bio, bio); BIO_set_fd(bio, fd, BIO_NOCLOSE); ret = 1; err: return ret; } /* * This is the default handler to return a client cert password from * conn->sslpassword. Apps may install it explicitly if they want to * prevent openssl from ever prompting on stdin. */ int PQdefaultSSLKeyPassHook(char *buf, int size, PGconn *conn) { if (conn->sslpassword) { if (strlen(conn->sslpassword) + 1 > size) fprintf(stderr, libpq_gettext("WARNING: sslpassword truncated")); strncpy(buf, conn->sslpassword, size); buf[size-1] = '\0'; return strlen(buf); } else { buf[0] = '\0'; return 0; } } PQsslKeyPassHook_type PQgetSSLKeyPassHook(void) { return PQsslKeyPassHook; } void PQsetSSLKeyPassHook(PQsslKeyPassHook_type hook) { PQsslKeyPassHook = hook; } /* * Supply a password to decrypt a client certificate. * * This must match OpenSSL type pem_passwd_cb. */ static int PQssl_passwd_cb(char *buf, int size, int rwflag, void *userdata) { PGconn *conn = userdata; if (PQsslKeyPassHook) return PQsslKeyPassHook(buf, size, conn); else return PQdefaultSSLKeyPassHook(buf, size, conn); } /* * Convert TLS protocol version string to OpenSSL values * * If a version is passed that is not supported by the current OpenSSL version, * then we return -1. If a non-negative value is returned, subsequent code can * assume it is working with a supported version. * * Note: this is rather similar to the backend routine in be-secure-openssl.c, * so make sure to update both routines if changing this one. */ static int ssl_protocol_version_to_openssl(const char *protocol) { if (pg_strcasecmp("TLSv1", protocol) == 0) return TLS1_VERSION; #ifdef TLS1_1_VERSION if (pg_strcasecmp("TLSv1.1", protocol) == 0) return TLS1_1_VERSION; #endif #ifdef TLS1_2_VERSION if (pg_strcasecmp("TLSv1.2", protocol) == 0) return TLS1_2_VERSION; #endif #ifdef TLS1_3_VERSION if (pg_strcasecmp("TLSv1.3", protocol) == 0) return TLS1_3_VERSION; #endif return -1; }