/*------------------------------------------------------------------------- * * be-secure-openssl.c * functions for OpenSSL support in the backend. * * * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * src/backend/libpq/be-secure-openssl.c * * Since the server static private key ($DataDir/server.key) * will normally be stored unencrypted so that the database * backend can restart automatically, it is important that * we select an algorithm that continues to provide confidentiality * even if the attacker has the server's private key. Ephemeral * DH (EDH) keys provide this and more (Perfect Forward Secrecy * aka PFS). * * N.B., the static private key should still be protected to * the largest extent possible, to minimize the risk of * impersonations. * * Another benefit of EDH is that it allows the backend and * clients to use DSA keys. DSA keys can only provide digital * signatures, not encryption, and are often acceptable in * jurisdictions where RSA keys are unacceptable. * * The downside to EDH is that it makes it impossible to * use ssldump(1) if there's a problem establishing an SSL * session. In this case you'll need to temporarily disable * EDH by commenting out the callback. * *------------------------------------------------------------------------- */ #include "postgres.h" #include #include #include #include #include #include #include #include #ifdef HAVE_NETINET_TCP_H #include #include #endif #include #include #include #ifndef OPENSSL_NO_ECDH #include #endif #include "libpq/libpq.h" #include "miscadmin.h" #include "storage/latch.h" #include "tcop/tcopprot.h" #include "utils/memutils.h" 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(Port *port, int fd); static DH *load_dh_file(int keylength); static DH *load_dh_buffer(const char *, size_t); static DH *generate_dh_parameters(int prime_len, int generator); static DH *tmp_dh_cb(SSL *s, int is_export, int keylength); static int verify_cb(int, X509_STORE_CTX *); static void info_cb(const SSL *ssl, int type, int args); static void initialize_ecdh(void); static const char *SSLerrmessage(unsigned long ecode); static char *X509_NAME_to_cstring(X509_NAME *name); static SSL_CTX *SSL_context = NULL; /* ------------------------------------------------------------ */ /* Hardcoded values */ /* ------------------------------------------------------------ */ /* * Hardcoded DH parameters, used in ephemeral DH keying. * As discussed above, EDH protects the confidentiality of * sessions even if the static private key is compromised, * so we are *highly* motivated to ensure that we can use * EDH even if the DBA... or an attacker... deletes the * $DataDir/dh*.pem files. * * We could refuse SSL connections unless a good DH parameter * file exists, but some clients may quietly renegotiate an * unsecured connection without fully informing the user. * Very uncool. * * Alternatively, the backend could attempt to load these files * on startup if SSL is enabled - and refuse to start if any * do not exist - but this would tend to piss off DBAs. * * If you want to create your own hardcoded DH parameters * for fun and profit, review "Assigned Number for SKIP * Protocols" (http://www.skip-vpn.org/spec/numbers.html) * for suggestions. */ static const char file_dh512[] = "-----BEGIN DH PARAMETERS-----\n\ MEYCQQD1Kv884bEpQBgRjXyEpwpy1obEAxnIByl6ypUM2Zafq9AKUJsCRtMIPWak\n\ XUGfnHy9iUsiGSa6q6Jew1XpKgVfAgEC\n\ -----END DH PARAMETERS-----\n"; static const char file_dh1024[] = "-----BEGIN DH PARAMETERS-----\n\ MIGHAoGBAPSI/VhOSdvNILSd5JEHNmszbDgNRR0PfIizHHxbLY7288kjwEPwpVsY\n\ jY67VYy4XTjTNP18F1dDox0YbN4zISy1Kv884bEpQBgRjXyEpwpy1obEAxnIByl6\n\ ypUM2Zafq9AKUJsCRtMIPWakXUGfnHy9iUsiGSa6q6Jew1XpL3jHAgEC\n\ -----END DH PARAMETERS-----\n"; static const char file_dh2048[] = "-----BEGIN DH PARAMETERS-----\n\ MIIBCAKCAQEA9kJXtwh/CBdyorrWqULzBej5UxE5T7bxbrlLOCDaAadWoxTpj0BV\n\ 89AHxstDqZSt90xkhkn4DIO9ZekX1KHTUPj1WV/cdlJPPT2N286Z4VeSWc39uK50\n\ T8X8dryDxUcwYc58yWb/Ffm7/ZFexwGq01uejaClcjrUGvC/RgBYK+X0iP1YTknb\n\ zSC0neSRBzZrM2w4DUUdD3yIsxx8Wy2O9vPJI8BD8KVbGI2Ou1WMuF040zT9fBdX\n\ Q6MdGGzeMyEstSr/POGxKUAYEY18hKcKctaGxAMZyAcpesqVDNmWn6vQClCbAkbT\n\ CD1mpF1Bn5x8vYlLIhkmuquiXsNV6TILOwIBAg==\n\ -----END DH PARAMETERS-----\n"; static const char file_dh4096[] = "-----BEGIN DH PARAMETERS-----\n\ MIICCAKCAgEA+hRyUsFN4VpJ1O8JLcCo/VWr19k3BCgJ4uk+d+KhehjdRqNDNyOQ\n\ l/MOyQNQfWXPeGKmOmIig6Ev/nm6Nf9Z2B1h3R4hExf+zTiHnvVPeRBhjdQi81rt\n\ Xeoh6TNrSBIKIHfUJWBh3va0TxxjQIs6IZOLeVNRLMqzeylWqMf49HsIXqbcokUS\n\ Vt1BkvLdW48j8PPv5DsKRN3tloTxqDJGo9tKvj1Fuk74A+Xda1kNhB7KFlqMyN98\n\ VETEJ6c7KpfOo30mnK30wqw3S8OtaIR/maYX72tGOno2ehFDkq3pnPtEbD2CScxc\n\ alJC+EL7RPk5c/tgeTvCngvc1KZn92Y//EI7G9tPZtylj2b56sHtMftIoYJ9+ODM\n\ sccD5Piz/rejE3Ome8EOOceUSCYAhXn8b3qvxVI1ddd1pED6FHRhFvLrZxFvBEM9\n\ ERRMp5QqOaHJkM+Dxv8Cj6MqrCbfC4u+ZErxodzuusgDgvZiLF22uxMZbobFWyte\n\ OvOzKGtwcTqO/1wV5gKkzu1ZVswVUQd5Gg8lJicwqRWyyNRczDDoG9jVDxmogKTH\n\ AaqLulO7R8Ifa1SwF2DteSGVtgWEN8gDpN3RBmmPTDngyF2DHb5qmpnznwtFKdTL\n\ KWbuHn491xNO25CQWMtem80uKw+pTnisBRF/454n1Jnhub144YRBoN8CAQI=\n\ -----END DH PARAMETERS-----\n"; /* ------------------------------------------------------------ */ /* Public interface */ /* ------------------------------------------------------------ */ /* * Initialize global SSL context. */ void be_tls_init(void) { struct stat buf; STACK_OF(X509_NAME) *root_cert_list = NULL; if (!SSL_context) { #if OPENSSL_VERSION_NUMBER >= 0x10100000L OPENSSL_init_ssl(OPENSSL_INIT_LOAD_CONFIG, NULL); #else OPENSSL_config(NULL); SSL_library_init(); SSL_load_error_strings(); #endif /* * We use SSLv23_method() because it can negotiate use of the highest * mutually supported protocol version, while alternatives like * TLSv1_2_method() permit only one specific version. Note that we * don't actually allow SSL v2 or v3, only TLS protocols (see below). */ SSL_context = SSL_CTX_new(SSLv23_method()); if (!SSL_context) ereport(FATAL, (errmsg("could not create SSL context: %s", SSLerrmessage(ERR_get_error())))); /* * 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); /* * Load and verify server's certificate and private key */ if (SSL_CTX_use_certificate_chain_file(SSL_context, ssl_cert_file) != 1) ereport(FATAL, (errcode(ERRCODE_CONFIG_FILE_ERROR), errmsg("could not load server certificate file \"%s\": %s", ssl_cert_file, SSLerrmessage(ERR_get_error())))); if (stat(ssl_key_file, &buf) != 0) ereport(FATAL, (errcode_for_file_access(), errmsg("could not access private key file \"%s\": %m", ssl_key_file))); if (!S_ISREG(buf.st_mode)) ereport(FATAL, (errcode(ERRCODE_CONFIG_FILE_ERROR), errmsg("private key file \"%s\" is not a regular file", ssl_key_file))); /* * Refuse to load files owned by users other than us or root. * * XXX surely we can check this on Windows somehow, too. */ #if !defined(WIN32) && !defined(__CYGWIN__) if (buf.st_uid != geteuid() && buf.st_uid != 0) ereport(FATAL, (errcode(ERRCODE_CONFIG_FILE_ERROR), errmsg("private key file \"%s\" must be owned by the database user or root", ssl_key_file))); #endif /* * Require no public access to key file. If the file is owned by us, * require mode 0600 or less. If owned by root, require 0640 or less * to allow read access through our gid, or a supplementary gid that * allows to read system-wide certificates. * * XXX temporarily suppress check when on Windows, because there may * not be proper support for Unix-y file permissions. Need to think * of a reasonable check to apply on Windows. (See also the data * directory permission check in postmaster.c) */ #if !defined(WIN32) && !defined(__CYGWIN__) if ((buf.st_uid == geteuid() && buf.st_mode & (S_IRWXG | S_IRWXO)) || (buf.st_uid == 0 && buf.st_mode & (S_IWGRP | S_IXGRP | S_IRWXO))) ereport(FATAL, (errcode(ERRCODE_CONFIG_FILE_ERROR), errmsg("private key file \"%s\" has group or world access", ssl_key_file), errdetail("File must have permissions u=rw (0600) or less if owned by the database user, or permissions u=rw,g=r (0640) or less if owned by root."))); #endif if (SSL_CTX_use_PrivateKey_file(SSL_context, ssl_key_file, SSL_FILETYPE_PEM) != 1) ereport(FATAL, (errmsg("could not load private key file \"%s\": %s", ssl_key_file, SSLerrmessage(ERR_get_error())))); if (SSL_CTX_check_private_key(SSL_context) != 1) ereport(FATAL, (errmsg("check of private key failed: %s", SSLerrmessage(ERR_get_error())))); } /* set up ephemeral DH keys, and disallow SSL v2/v3 while at it */ SSL_CTX_set_tmp_dh_callback(SSL_context, tmp_dh_cb); SSL_CTX_set_options(SSL_context, SSL_OP_SINGLE_DH_USE | SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3); /* set up ephemeral ECDH keys */ initialize_ecdh(); /* set up the allowed cipher list */ if (SSL_CTX_set_cipher_list(SSL_context, SSLCipherSuites) != 1) elog(FATAL, "could not set the cipher list (no valid ciphers available)"); /* Let server choose order */ if (SSLPreferServerCiphers) SSL_CTX_set_options(SSL_context, SSL_OP_CIPHER_SERVER_PREFERENCE); /* * Load CA store, so we can verify client certificates if needed. */ if (ssl_ca_file[0]) { if (SSL_CTX_load_verify_locations(SSL_context, ssl_ca_file, NULL) != 1 || (root_cert_list = SSL_load_client_CA_file(ssl_ca_file)) == NULL) ereport(FATAL, (errmsg("could not load root certificate file \"%s\": %s", ssl_ca_file, SSLerrmessage(ERR_get_error())))); } /*---------- * Load the Certificate Revocation List (CRL). * http://searchsecurity.techtarget.com/sDefinition/0,,sid14_gci803160,00.html *---------- */ if (ssl_crl_file[0]) { X509_STORE *cvstore = SSL_CTX_get_cert_store(SSL_context); if (cvstore) { /* Set the flags to check against the complete CRL chain */ if (X509_STORE_load_locations(cvstore, ssl_crl_file, NULL) == 1) { /* OpenSSL 0.96 does not support X509_V_FLAG_CRL_CHECK */ #ifdef X509_V_FLAG_CRL_CHECK X509_STORE_set_flags(cvstore, X509_V_FLAG_CRL_CHECK | X509_V_FLAG_CRL_CHECK_ALL); #else ereport(LOG, (errmsg("SSL certificate revocation list file \"%s\" ignored", ssl_crl_file), errdetail("SSL library does not support certificate revocation lists."))); #endif } else ereport(FATAL, (errmsg("could not load SSL certificate revocation list file \"%s\": %s", ssl_crl_file, SSLerrmessage(ERR_get_error())))); } } if (ssl_ca_file[0]) { /* * Always ask for SSL client cert, but don't fail if it's not * presented. We might fail such connections later, depending on what * we find in pg_hba.conf. */ SSL_CTX_set_verify(SSL_context, (SSL_VERIFY_PEER | SSL_VERIFY_CLIENT_ONCE), verify_cb); /* Set flag to remember CA store is successfully loaded */ ssl_loaded_verify_locations = true; /* * Tell OpenSSL to send the list of root certs we trust to clients in * CertificateRequests. This lets a client with a keystore select the * appropriate client certificate to send to us. */ SSL_CTX_set_client_CA_list(SSL_context, root_cert_list); } } /* * Attempt to negotiate SSL connection. */ int be_tls_open_server(Port *port) { int r; int err; int waitfor; unsigned long ecode; Assert(!port->ssl); Assert(!port->peer); if (!(port->ssl = SSL_new(SSL_context))) { ereport(COMMERROR, (errcode(ERRCODE_PROTOCOL_VIOLATION), errmsg("could not initialize SSL connection: %s", SSLerrmessage(ERR_get_error())))); return -1; } if (!my_SSL_set_fd(port, port->sock)) { ereport(COMMERROR, (errcode(ERRCODE_PROTOCOL_VIOLATION), errmsg("could not set SSL socket: %s", SSLerrmessage(ERR_get_error())))); return -1; } port->ssl_in_use = true; aloop: /* * 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. An extension may have failed to clear the * per-thread error queue following another call to an OpenSSL I/O * routine. */ ERR_clear_error(); r = SSL_accept(port->ssl); if (r <= 0) { err = SSL_get_error(port->ssl, r); /* * Other clients of OpenSSL in the backend 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_get_error(); switch (err) { case SSL_ERROR_WANT_READ: case SSL_ERROR_WANT_WRITE: /* not allowed during connection establishment */ Assert(!port->noblock); /* * No need to care about timeouts/interrupts here. At this * point authentication_timeout still employs * StartupPacketTimeoutHandler() which directly exits. */ if (err == SSL_ERROR_WANT_READ) waitfor = WL_SOCKET_READABLE; else waitfor = WL_SOCKET_WRITEABLE; WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0); goto aloop; case SSL_ERROR_SYSCALL: if (r < 0) ereport(COMMERROR, (errcode_for_socket_access(), errmsg("could not accept SSL connection: %m"))); else ereport(COMMERROR, (errcode(ERRCODE_PROTOCOL_VIOLATION), errmsg("could not accept SSL connection: EOF detected"))); break; case SSL_ERROR_SSL: ereport(COMMERROR, (errcode(ERRCODE_PROTOCOL_VIOLATION), errmsg("could not accept SSL connection: %s", SSLerrmessage(ecode)))); break; case SSL_ERROR_ZERO_RETURN: ereport(COMMERROR, (errcode(ERRCODE_PROTOCOL_VIOLATION), errmsg("could not accept SSL connection: EOF detected"))); break; default: ereport(COMMERROR, (errcode(ERRCODE_PROTOCOL_VIOLATION), errmsg("unrecognized SSL error code: %d", err))); break; } return -1; } /* Get client certificate, if available. */ port->peer = SSL_get_peer_certificate(port->ssl); /* and extract the Common Name from it. */ port->peer_cn = NULL; port->peer_cert_valid = false; if (port->peer != NULL) { int len; len = X509_NAME_get_text_by_NID(X509_get_subject_name(port->peer), NID_commonName, NULL, 0); if (len != -1) { char *peer_cn; peer_cn = MemoryContextAlloc(TopMemoryContext, len + 1); r = X509_NAME_get_text_by_NID(X509_get_subject_name(port->peer), NID_commonName, peer_cn, len + 1); peer_cn[len] = '\0'; if (r != len) { /* shouldn't happen */ pfree(peer_cn); return -1; } /* * Reject embedded NULLs in certificate common name to prevent * attacks like CVE-2009-4034. */ if (len != strlen(peer_cn)) { ereport(COMMERROR, (errcode(ERRCODE_PROTOCOL_VIOLATION), errmsg("SSL certificate's common name contains embedded null"))); pfree(peer_cn); return -1; } port->peer_cn = peer_cn; } port->peer_cert_valid = true; } ereport(DEBUG2, (errmsg("SSL connection from \"%s\"", port->peer_cn ? port->peer_cn : "(anonymous)"))); /* set up debugging/info callback */ SSL_CTX_set_info_callback(SSL_context, info_cb); return 0; } /* * Close SSL connection. */ void be_tls_close(Port *port) { if (port->ssl) { SSL_shutdown(port->ssl); SSL_free(port->ssl); port->ssl = NULL; port->ssl_in_use = false; } if (port->peer) { X509_free(port->peer); port->peer = NULL; } if (port->peer_cn) { pfree(port->peer_cn); port->peer_cn = NULL; } } /* * Read data from a secure connection. */ ssize_t be_tls_read(Port *port, void *ptr, size_t len, int *waitfor) { ssize_t n; int err; unsigned long ecode; errno = 0; ERR_clear_error(); n = SSL_read(port->ssl, ptr, len); err = SSL_get_error(port->ssl, n); ecode = (err != SSL_ERROR_NONE || n < 0) ? ERR_get_error() : 0; switch (err) { case SSL_ERROR_NONE: /* a-ok */ break; case SSL_ERROR_WANT_READ: *waitfor = WL_SOCKET_READABLE; errno = EWOULDBLOCK; n = -1; break; case SSL_ERROR_WANT_WRITE: *waitfor = WL_SOCKET_WRITEABLE; errno = EWOULDBLOCK; n = -1; break; case SSL_ERROR_SYSCALL: /* leave it to caller to ereport the value of errno */ if (n != -1) { errno = ECONNRESET; n = -1; } break; case SSL_ERROR_SSL: ereport(COMMERROR, (errcode(ERRCODE_PROTOCOL_VIOLATION), errmsg("SSL error: %s", SSLerrmessage(ecode)))); /* fall through */ case SSL_ERROR_ZERO_RETURN: errno = ECONNRESET; n = -1; break; default: ereport(COMMERROR, (errcode(ERRCODE_PROTOCOL_VIOLATION), errmsg("unrecognized SSL error code: %d", err))); errno = ECONNRESET; n = -1; break; } return n; } /* * Write data to a secure connection. */ ssize_t be_tls_write(Port *port, void *ptr, size_t len, int *waitfor) { ssize_t n; int err; unsigned long ecode; errno = 0; ERR_clear_error(); n = SSL_write(port->ssl, ptr, len); err = SSL_get_error(port->ssl, n); ecode = (err != SSL_ERROR_NONE || n < 0) ? ERR_get_error() : 0; switch (err) { case SSL_ERROR_NONE: /* a-ok */ break; case SSL_ERROR_WANT_READ: *waitfor = WL_SOCKET_READABLE; errno = EWOULDBLOCK; n = -1; break; case SSL_ERROR_WANT_WRITE: *waitfor = WL_SOCKET_WRITEABLE; errno = EWOULDBLOCK; n = -1; break; case SSL_ERROR_SYSCALL: /* leave it to caller to ereport the value of errno */ if (n != -1) { errno = ECONNRESET; n = -1; } break; case SSL_ERROR_SSL: ereport(COMMERROR, (errcode(ERRCODE_PROTOCOL_VIOLATION), errmsg("SSL error: %s", SSLerrmessage(ecode)))); /* fall through */ case SSL_ERROR_ZERO_RETURN: errno = ECONNRESET; n = -1; break; default: ereport(COMMERROR, (errcode(ERRCODE_PROTOCOL_VIOLATION), errmsg("unrecognized SSL error code: %d", err))); errno = ECONNRESET; n = -1; break; } return n; } /* ------------------------------------------------------------ */ /* Internal functions */ /* ------------------------------------------------------------ */ /* * Private substitute BIO: this does the sending and receiving using send() and * recv() instead. This is so that we can enable and disable interrupts * just while calling recv(). We cannot have interrupts occurring while * the bulk of openssl runs, because it uses malloc() and possibly other * non-reentrant libc facilities. We also need to call send() and recv() * directly so it gets passed through the socket/signals layer on Win32. * * 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? */ #if OPENSSL_VERSION_NUMBER < 0x10100000L #define BIO_get_data(bio) (bio->ptr) #define BIO_set_data(bio, data) (bio->ptr = data) #endif static BIO_METHOD *my_bio_methods = NULL; static int my_sock_read(BIO *h, char *buf, int size) { int res = 0; if (buf != NULL) { res = secure_raw_read(((Port *) BIO_get_data(h)), buf, size); BIO_clear_retry_flags(h); if (res <= 0) { /* If we were interrupted, tell caller to retry */ if (errno == EINTR || errno == EWOULDBLOCK || errno == EAGAIN) { BIO_set_retry_read(h); } } } return res; } static int my_sock_write(BIO *h, const char *buf, int size) { int res = 0; res = secure_raw_write(((Port *) BIO_get_data(h)), buf, size); BIO_clear_retry_flags(h); if (res <= 0) { /* If we were interrupted, tell caller to retry */ if (errno == EINTR || errno == EWOULDBLOCK || errno == EAGAIN) { BIO_set_retry_write(h); } } return res; } static BIO_METHOD * my_BIO_s_socket(void) { if (!my_bio_methods) { BIO_METHOD *biom = (BIO_METHOD *) BIO_s_socket(); #if OPENSSL_VERSION_NUMBER >= 0x10100000L 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, "PostgreSQL backend socket"); if (!my_bio_methods) return NULL; 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(Port *port, 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, port); BIO_set_fd(bio, fd, BIO_NOCLOSE); SSL_set_bio(port->ssl, bio, bio); ret = 1; err: return ret; } /* * Load precomputed DH parameters. * * To prevent "downgrade" attacks, we perform a number of checks * to verify that the DBA-generated DH parameters file contains * what we expect it to contain. */ static DH * load_dh_file(int keylength) { FILE *fp; char fnbuf[MAXPGPATH]; DH *dh = NULL; int codes; /* attempt to open file. It's not an error if it doesn't exist. */ snprintf(fnbuf, sizeof(fnbuf), "dh%d.pem", keylength); if ((fp = fopen(fnbuf, "r")) == NULL) return NULL; /* flock(fileno(fp), LOCK_SH); */ dh = PEM_read_DHparams(fp, NULL, NULL, NULL); /* flock(fileno(fp), LOCK_UN); */ fclose(fp); /* is the prime the correct size? */ if (dh != NULL && 8 * DH_size(dh) < keylength) { elog(LOG, "DH errors (%s): %d bits expected, %d bits found", fnbuf, keylength, 8 * DH_size(dh)); dh = NULL; } /* make sure the DH parameters are usable */ if (dh != NULL) { if (DH_check(dh, &codes) == 0) { elog(LOG, "DH_check error (%s): %s", fnbuf, SSLerrmessage(ERR_get_error())); return NULL; } if (codes & DH_CHECK_P_NOT_PRIME) { elog(LOG, "DH error (%s): p is not prime", fnbuf); return NULL; } if ((codes & DH_NOT_SUITABLE_GENERATOR) && (codes & DH_CHECK_P_NOT_SAFE_PRIME)) { elog(LOG, "DH error (%s): neither suitable generator or safe prime", fnbuf); return NULL; } } return dh; } /* * Load hardcoded DH parameters. * * To prevent problems if the DH parameters files don't even * exist, we can load DH parameters hardcoded into this file. */ static DH * load_dh_buffer(const char *buffer, size_t len) { BIO *bio; DH *dh = NULL; bio = BIO_new_mem_buf((char *) buffer, len); if (bio == NULL) return NULL; dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL); if (dh == NULL) ereport(DEBUG2, (errmsg_internal("DH load buffer: %s", SSLerrmessage(ERR_get_error())))); BIO_free(bio); return dh; } /* * Generate DH parameters. * * Last resort if we can't load precomputed nor hardcoded * parameters. */ static DH * generate_dh_parameters(int prime_len, int generator) { DH *dh; if ((dh = DH_new()) == NULL) return NULL; if (DH_generate_parameters_ex(dh, prime_len, generator, NULL)) return dh; DH_free(dh); return NULL; } /* * Generate an ephemeral DH key. Because this can take a long * time to compute, we can use precomputed parameters of the * common key sizes. * * Since few sites will bother to precompute these parameter * files, we also provide a fallback to the parameters provided * by the OpenSSL project. * * These values can be static (once loaded or computed) since * the OpenSSL library can efficiently generate random keys from * the information provided. */ static DH * tmp_dh_cb(SSL *s, int is_export, int keylength) { DH *r = NULL; static DH *dh = NULL; static DH *dh512 = NULL; static DH *dh1024 = NULL; static DH *dh2048 = NULL; static DH *dh4096 = NULL; switch (keylength) { case 512: if (dh512 == NULL) dh512 = load_dh_file(keylength); if (dh512 == NULL) dh512 = load_dh_buffer(file_dh512, sizeof file_dh512); r = dh512; break; case 1024: if (dh1024 == NULL) dh1024 = load_dh_file(keylength); if (dh1024 == NULL) dh1024 = load_dh_buffer(file_dh1024, sizeof file_dh1024); r = dh1024; break; case 2048: if (dh2048 == NULL) dh2048 = load_dh_file(keylength); if (dh2048 == NULL) dh2048 = load_dh_buffer(file_dh2048, sizeof file_dh2048); r = dh2048; break; case 4096: if (dh4096 == NULL) dh4096 = load_dh_file(keylength); if (dh4096 == NULL) dh4096 = load_dh_buffer(file_dh4096, sizeof file_dh4096); r = dh4096; break; default: if (dh == NULL) dh = load_dh_file(keylength); r = dh; } /* this may take a long time, but it may be necessary... */ if (r == NULL || 8 * DH_size(r) < keylength) { ereport(DEBUG2, (errmsg_internal("DH: generating parameters (%d bits)", keylength))); r = generate_dh_parameters(keylength, DH_GENERATOR_2); } return r; } /* * Certificate verification callback * * This callback allows us to log intermediate problems during * verification, but for now we'll see if the final error message * contains enough information. * * 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; } /* * This callback is used to copy SSL information messages * into the PostgreSQL log. */ static void info_cb(const SSL *ssl, int type, int args) { switch (type) { case SSL_CB_HANDSHAKE_START: ereport(DEBUG4, (errmsg_internal("SSL: handshake start"))); break; case SSL_CB_HANDSHAKE_DONE: ereport(DEBUG4, (errmsg_internal("SSL: handshake done"))); break; case SSL_CB_ACCEPT_LOOP: ereport(DEBUG4, (errmsg_internal("SSL: accept loop"))); break; case SSL_CB_ACCEPT_EXIT: ereport(DEBUG4, (errmsg_internal("SSL: accept exit (%d)", args))); break; case SSL_CB_CONNECT_LOOP: ereport(DEBUG4, (errmsg_internal("SSL: connect loop"))); break; case SSL_CB_CONNECT_EXIT: ereport(DEBUG4, (errmsg_internal("SSL: connect exit (%d)", args))); break; case SSL_CB_READ_ALERT: ereport(DEBUG4, (errmsg_internal("SSL: read alert (0x%04x)", args))); break; case SSL_CB_WRITE_ALERT: ereport(DEBUG4, (errmsg_internal("SSL: write alert (0x%04x)", args))); break; } } static void initialize_ecdh(void) { #ifndef OPENSSL_NO_ECDH EC_KEY *ecdh; int nid; nid = OBJ_sn2nid(SSLECDHCurve); if (!nid) ereport(FATAL, (errmsg("ECDH: unrecognized curve name: %s", SSLECDHCurve))); ecdh = EC_KEY_new_by_curve_name(nid); if (!ecdh) ereport(FATAL, (errmsg("ECDH: could not create key"))); SSL_CTX_set_options(SSL_context, SSL_OP_SINGLE_ECDH_USE); SSL_CTX_set_tmp_ecdh(SSL_context, ecdh); EC_KEY_free(ecdh); #endif } /* * 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 const char * SSLerrmessage(unsigned long ecode) { const char *errreason; static char errbuf[32]; if (ecode == 0) return _("no SSL error reported"); errreason = ERR_reason_error_string(ecode); if (errreason != NULL) return errreason; snprintf(errbuf, sizeof(errbuf), _("SSL error code %lu"), ecode); return errbuf; } /* * Return information about the SSL connection */ int be_tls_get_cipher_bits(Port *port) { int bits; if (port->ssl) { SSL_get_cipher_bits(port->ssl, &bits); return bits; } else return 0; } bool be_tls_get_compression(Port *port) { if (port->ssl) return (SSL_get_current_compression(port->ssl) != NULL); else return false; } void be_tls_get_version(Port *port, char *ptr, size_t len) { if (port->ssl) strlcpy(ptr, SSL_get_version(port->ssl), len); else ptr[0] = '\0'; } void be_tls_get_cipher(Port *port, char *ptr, size_t len) { if (port->ssl) strlcpy(ptr, SSL_get_cipher(port->ssl), len); else ptr[0] = '\0'; } void be_tls_get_peerdn_name(Port *port, char *ptr, size_t len) { if (port->peer) strlcpy(ptr, X509_NAME_to_cstring(X509_get_subject_name(port->peer)), len); else ptr[0] = '\0'; } /* * Convert an X509 subject name to a cstring. * */ static char * X509_NAME_to_cstring(X509_NAME *name) { BIO *membuf = BIO_new(BIO_s_mem()); int i, nid, count = X509_NAME_entry_count(name); X509_NAME_ENTRY *e; ASN1_STRING *v; const char *field_name; size_t size; char nullterm; char *sp; char *dp; char *result; (void) BIO_set_close(membuf, BIO_CLOSE); for (i = 0; i < count; i++) { e = X509_NAME_get_entry(name, i); nid = OBJ_obj2nid(X509_NAME_ENTRY_get_object(e)); v = X509_NAME_ENTRY_get_data(e); field_name = OBJ_nid2sn(nid); if (!field_name) field_name = OBJ_nid2ln(nid); BIO_printf(membuf, "/%s=", field_name); ASN1_STRING_print_ex(membuf, v, ((ASN1_STRFLGS_RFC2253 & ~ASN1_STRFLGS_ESC_MSB) | ASN1_STRFLGS_UTF8_CONVERT)); } /* ensure null termination of the BIO's content */ nullterm = '\0'; BIO_write(membuf, &nullterm, 1); size = BIO_get_mem_data(membuf, &sp); dp = pg_any_to_server(sp, size - 1, PG_UTF8); result = pstrdup(dp); if (dp != sp) pfree(dp); BIO_free(membuf); return result; }