/* Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License, version 2.0, as published by the Free Software Foundation. This program is also distributed with certain software (including but not limited to OpenSSL) that is licensed under separate terms, as designated in a particular file or component or in included license documentation. The authors of MySQL hereby grant you an additional permission to link the program and your derivative works with the separately licensed software that they have included with MySQL. Without limiting anything contained in the foregoing, this file, which is part of C Driver for MySQL (Connector/C), is also subject to the Universal FOSS Exception, version 1.0, a copy of which can be found at http://oss.oracle.com/licenses/universal-foss-exception. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0, for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ /* Note that we can't have assertion on file descriptors; The reason for this is that during mysql shutdown, another thread can close a file we are working on. In this case we should just return read errors from the file descriptior. */ #include #include #include "my_dbug.h" #include "my_inttypes.h" #include "my_io.h" #include "mysql/psi/mysql_socket.h" #include "vio/vio_priv.h" /* clang-format off */ /** @page page_protocol_basic_tls TLS The MySQL Protocol also supports encryption and authentication via TLS. The encryption is transparent to the rest of the protocol and is applied after the data is compressed right before the data is written to the network layer. The TLS suppport is announced in @ref page_protocol_connection_phase_packets_protocol_handshake sent by the server via ::CLIENT_SSL and is enabled if the client returns the same capability. For an unencrypted connection the server starts with its @ref page_protocol_connection_phase_packets_protocol_handshake : ~~~~~~~ 36 00 00 00 0a 35 2e 35 2e 32 2d 6d 32 00 52 00 6....5.5.2-m2.R. 00 00 22 3d 4e 50 29 75 39 56 00 ff ff 08 02 00 .."=NP)u9V...... 00 00 00 00 00 00 00 00 00 00 00 00 00 29 64 40 .............)d@ 52 5c 55 78 7a 7c 21 29 4b 00 R\Uxz|!)K. ~~~~~~~ ... and the client returns its @ref page_protocol_connection_phase_packets_protocol_handshake_response ~~~~~~~ 3a 00 00 01 05 a6 03 00 00 00 00 01 08 00 00 00 :............... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 72 6f 6f 74 00 14 14 63 6b 70 99 8a ....root...ckp.. b6 9e 96 87 a2 30 9a 40 67 2b 83 38 85 4b .....0.@g+.8.K ~~~~~~~ If client wants to do TLS and the server supports it, it would send a @ref page_protocol_connection_phase_packets_protocol_ssl_request with ::CLIENT_SSL capability enabled. ~~~~~~~ 20 00 00 01 05 ae 03 00 00 00 00 01 08 00 00 00 ............... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 .... ~~~~~~~ Then the rest of the communication is swithed to TLS: ~~~~~~~ 16 03 01 00 5e 01 00 00 5a 03 01 4c a3 49 2e 7a ....^...Z..L.I.z b5 06 75 68 5c 30 36 73 f1 82 79 70 58 4c 64 bb ..uh\06s..ypXLd. 47 7e 90 cd 9b 30 c5 66 65 da 35 00 00 2c 00 39 G~...0.fe.5..,.9 00 38 00 35 00 16 00 13 00 0a 00 33 00 32 00 2f .8.5.......3.2./ 00 9a 00 99 00 96 00 05 00 04 00 15 00 12 00 09 ................ 00 14 00 11 00 08 00 06 00 03 02 01 00 00 04 00 ................ 23 00 00 #.. ~~~~~~~ The preceding packet is from SSL_connect() which does the [TLS handshake](https://en.wikipedia.org/wiki/Transport_Layer_Security#TLS_handshake) Once the TLS tunnel is established the normal communication continues starting with the client sending the @ref page_protocol_connection_phase_packets_protocol_handshake_response See @ref sect_protocol_connection_phase_initial_handshake_ssl_handshake for a diagram of the exchange. @sa cli_establish_ssl, parse_client_handshake_packet */ /* clang-format on */ #ifdef HAVE_OPENSSL #ifndef DBUG_OFF static void report_errors(SSL *ssl) { unsigned long l; const char *file; const char *data; int line, flags = 0; char buf[512]; DBUG_TRACE; while ((l = ERR_get_error_line_data(&file, &line, &data, &flags))) { DBUG_PRINT("error", ("OpenSSL: %s:%s:%d:%s\n", ERR_error_string(l, buf), file, line, (flags & ERR_TXT_STRING) ? data : "")); } if (ssl) DBUG_PRINT("error", ("error: %s", ERR_error_string(SSL_get_error(ssl, l), buf))); DBUG_PRINT("info", ("socket_errno: %d", socket_errno)); } #endif /** Obtain the equivalent system error status for the last SSL I/O operation. @param ssl_error The result code of the failed TLS/SSL I/O operation. */ static void ssl_set_sys_error(int ssl_error) { int error = 0; switch (ssl_error) { case SSL_ERROR_ZERO_RETURN: error = SOCKET_ECONNRESET; break; case SSL_ERROR_WANT_READ: case SSL_ERROR_WANT_WRITE: #ifdef SSL_ERROR_WANT_CONNECT case SSL_ERROR_WANT_CONNECT: #endif #ifdef SSL_ERROR_WANT_ACCEPT case SSL_ERROR_WANT_ACCEPT: #endif error = SOCKET_EWOULDBLOCK; break; case SSL_ERROR_SSL: /* Protocol error. */ #ifdef EPROTO error = EPROTO; #else error = SOCKET_ECONNRESET; #endif break; case SSL_ERROR_SYSCALL: case SSL_ERROR_NONE: default: break; }; /* Set error status to a equivalent of the SSL error. */ if (error) { #ifdef _WIN32 WSASetLastError(error); #else errno = error; #endif } } /** Check if an operation should be retried and handle errors This function does the following: - it indicates whether a SSL I/O operation must be retried later; - if DBUG is enabled it prints all the errors in the thread's queue to DBUG - it clears the OpenSSL error queue, thus the next OpenSSL-operation can be performed even after failed OpenSSL-call. Note that this is not done for SSL_ERROR_WANT_READ/SSL_ERROR_WANT_WRITE since these are not treated as errors and a call to the function is retried. When SSL_ERROR_SSL is returned the ERR code of the top error in the queue is peeked and returned to the caller so they can call ERR_error_string_n() and retrieve the right error message. @param vio VIO object representing a SSL connection. @param ret Value returned by a SSL I/O function. @param [out] event The type of I/O event to wait/retry. @param [out] ssl_errno_holder The SSL error code. @return Whether a SSL I/O operation should be deferred. @retval true Temporary failure, retry operation. @retval false Indeterminate failure. */ static bool ssl_should_retry(Vio *vio, int ret, enum enum_vio_io_event *event, unsigned long *ssl_errno_holder) { int ssl_error, err_error; SSL *ssl = static_cast(vio->ssl_arg); bool should_retry = true; /* Retrieve the result for the SSL I/O operation. */ ssl_error = SSL_get_error(ssl, ret); /* Retrieve the result for the SSL I/O operation. */ switch (ssl_error) { case SSL_ERROR_WANT_READ: err_error = ssl_error; // for backward compatibility. *event = VIO_IO_EVENT_READ; break; case SSL_ERROR_WANT_WRITE: err_error = ssl_error; // for backward compatibility. *event = VIO_IO_EVENT_WRITE; break; default: /* first save the top ERR error */ err_error = ERR_get_error(); /* now report all remaining errors on and/or clear the error stack */ #ifndef DBUG_OFF /* Debug build */ /* Note: the OpenSSL error queue gets cleared in report_errors(). */ report_errors(ssl); #else /* Release build */ ERR_clear_error(); #endif should_retry = false; ssl_set_sys_error(ssl_error); break; } *ssl_errno_holder = err_error; return should_retry; } size_t vio_ssl_read(Vio *vio, uchar *buf, size_t size) { int ret; SSL *ssl = static_cast(vio->ssl_arg); unsigned long ssl_errno_not_used; DBUG_TRACE; while (1) { enum enum_vio_io_event event; /* Check that the SSL thread's error queue is cleared. Otherwise SSL_read() returns an error from the error queue, when SSL_read() failed because it would block. */ DBUG_ASSERT(ERR_peek_error() == 0); ret = SSL_read(ssl, buf, (int)size); if (ret >= 0) break; /* Process the SSL I/O error. */ if (!ssl_should_retry(vio, ret, &event, &ssl_errno_not_used)) break; if (!vio->is_blocking_flag) { switch (event) { case VIO_IO_EVENT_READ: return VIO_SOCKET_WANT_READ; case VIO_IO_EVENT_WRITE: return VIO_SOCKET_WANT_WRITE; default: return VIO_SOCKET_ERROR; } } /* Attempt to wait for an I/O event. */ if (vio_socket_io_wait(vio, event)) break; } return ret < 0 ? -1 : ret; } size_t vio_ssl_write(Vio *vio, const uchar *buf, size_t size) { int ret; SSL *ssl = static_cast(vio->ssl_arg); unsigned long ssl_errno_not_used; DBUG_TRACE; while (1) { enum enum_vio_io_event event; /* check that the SSL thread's error queue is cleared. Otherwise SSL_write() returns an error from the error queue, when SSL_write() failed because it would block. */ DBUG_ASSERT(ERR_peek_error() == 0); ret = SSL_write(ssl, buf, (int)size); if (ret >= 0) break; /* Process the SSL I/O error. */ if (!ssl_should_retry(vio, ret, &event, &ssl_errno_not_used)) break; if (!vio->is_blocking_flag) { switch (event) { case VIO_IO_EVENT_READ: return VIO_SOCKET_WANT_READ; case VIO_IO_EVENT_WRITE: return VIO_SOCKET_WANT_WRITE; default: return VIO_SOCKET_ERROR; } } /* Attempt to wait for an I/O event. */ if (vio_socket_io_wait(vio, event)) break; } return ret < 0 ? -1 : ret; } int vio_ssl_shutdown(Vio *vio) { int r = 0; SSL *ssl = (SSL *)vio->ssl_arg; DBUG_TRACE; if (ssl) { /* THE SSL standard says that SSL sockets must send and receive a close_notify alert on socket shutdown to avoid truncation attacks. However, this can cause problems since we often hold a lock during shutdown and this IO can take an unbounded amount of time to complete. Since our packets are self describing with length, we aren't vunerable to these attacks. Therefore, we just shutdown by closing the socket (quiet shutdown). */ SSL_set_quiet_shutdown(ssl, 1); switch ((r = SSL_shutdown(ssl))) { case 1: /* Shutdown successful */ break; case 0: /* Shutdown not yet finished - since the socket is going to be closed there is no need to call SSL_shutdown() a second time to wait for the other side to respond */ break; default: /* Shutdown failed */ DBUG_PRINT("vio_error", ("SSL_shutdown() failed, error: %d", SSL_get_error(ssl, r))); break; } } return vio_shutdown(vio); } void vio_ssl_delete(Vio *vio) { if (!vio) return; /* It must be safe to delete null pointer */ if (vio->inactive == false) vio_ssl_shutdown(vio); /* Still open, close connection first */ if (vio->ssl_arg) { SSL_free((SSL *)vio->ssl_arg); vio->ssl_arg = 0; } #if OPENSSL_VERSION_NUMBER < 0x10100000L ERR_remove_thread_state(0); #endif /* OPENSSL_VERSION_NUMBER < 0x10100000L */ vio_delete(vio); } /** SSL handshake handler. */ extern "C" { typedef int (*ssl_handshake_func_t)(SSL *); } /** Loop and wait until a SSL handshake is completed. @param vio VIO object representing a SSL connection. @param ssl SSL structure for the connection. @param func SSL handshake handler. @param [out] ssl_errno_holder The SSL error code. @return Return value is 1 on success. */ static size_t ssl_handshake_loop(Vio *vio, SSL *ssl, ssl_handshake_func_t func, unsigned long *ssl_errno_holder) { DBUG_TRACE; size_t ret = -1; vio->ssl_arg = ssl; /* Initiate the SSL handshake. */ while (1) { enum enum_vio_io_event event; /* check that the SSL thread's error queue is cleared. Otherwise SSL-handshake-function returns an error from the error queue, when the function failed because it would block. */ DBUG_ASSERT(ERR_peek_error() == 0); int handshake_ret; handshake_ret = func(ssl); if (handshake_ret >= 1) { ret = 0; break; } /* Process the SSL I/O error. */ if (!ssl_should_retry(vio, handshake_ret, &event, ssl_errno_holder)) break; if (!vio->is_blocking_flag) { switch (event) { case VIO_IO_EVENT_READ: return VIO_SOCKET_WANT_READ; case VIO_IO_EVENT_WRITE: return VIO_SOCKET_WANT_WRITE; default: return VIO_SOCKET_ERROR; } } /* Wait for I/O so that the handshake can proceed. */ if (vio_socket_io_wait(vio, event)) break; } vio->ssl_arg = NULL; return ret; } static int ssl_do(struct st_VioSSLFd *ptr, Vio *vio, long timeout, ssl_handshake_func_t func, unsigned long *ssl_errno_holder, SSL **sslptr) { SSL *ssl = nullptr; my_socket sd = mysql_socket_getfd(vio->mysql_socket); /* Declared here to make compiler happy */ #if !defined(DBUG_OFF) int j, n; #endif DBUG_TRACE; DBUG_PRINT("enter", ("ptr: %p, sd: %d ctx: %p", ptr, sd, ptr->ssl_context)); if (!sslptr) { sslptr = &ssl; } if (*sslptr == nullptr) { if (!(ssl = SSL_new(ptr->ssl_context))) { DBUG_PRINT("error", ("SSL_new failure")); *ssl_errno_holder = ERR_get_error(); return 1; } DBUG_PRINT("info", ("ssl: %p timeout: %ld", ssl, timeout)); SSL_clear(ssl); SSL_SESSION_set_timeout(SSL_get_session(ssl), timeout); SSL_set_fd(ssl, sd); #if defined(SSL_OP_NO_COMPRESSION) SSL_set_options(ssl, SSL_OP_NO_COMPRESSION); /* OpenSSL >= 1.0 only */ #elif OPENSSL_VERSION_NUMBER >= 0x00908000L /* workaround for OpenSSL 0.9.8 */ sk_SSL_COMP_zero(SSL_COMP_get_compression_methods()); #endif #if !defined(DBUG_OFF) { STACK_OF(SSL_COMP) *ssl_comp_methods = NULL; ssl_comp_methods = SSL_COMP_get_compression_methods(); n = sk_SSL_COMP_num(ssl_comp_methods); DBUG_PRINT("info", ("Available compression methods:\n")); if (n == 0) DBUG_PRINT("info", ("NONE\n")); else for (j = 0; j < n; j++) { SSL_COMP *c = sk_SSL_COMP_value(ssl_comp_methods, j); #if OPENSSL_VERSION_NUMBER < 0x10100000L DBUG_PRINT("info", (" %d: %s\n", c->id, c->name)); #else /* OPENSSL_VERSION_NUMBER < 0x10100000L */ DBUG_PRINT("info", (" %d: %s\n", SSL_COMP_get_id(c), SSL_COMP_get0_name(c))); #endif /* OPENSSL_VERSION_NUMBER < 0x10100000L */ } } #endif *sslptr = ssl; } else { ssl = *sslptr; } size_t loop_ret; if ((loop_ret = ssl_handshake_loop(vio, ssl, func, ssl_errno_holder))) { if (loop_ret != VIO_SOCKET_ERROR) { return (int)loop_ret; // Don't free SSL } DBUG_PRINT("error", ("SSL_connect/accept failure")); SSL_free(ssl); *sslptr = nullptr; return (int)VIO_SOCKET_ERROR; } /* Connection succeeded. Install new function handlers, change type, set sd to the fd used when connecting and set pointer to the SSL structure */ if (vio_reset(vio, VIO_TYPE_SSL, SSL_get_fd(ssl), ssl, 0)) return 1; if (sslptr != &ssl) { *sslptr = nullptr; } #ifndef DBUG_OFF { /* Print some info about the peer */ X509 *cert; char buf[512]; DBUG_PRINT("info", ("SSL connection succeeded")); DBUG_PRINT("info", ("Using cipher: '%s'", SSL_get_cipher_name(ssl))); if ((cert = SSL_get_peer_certificate(ssl))) { DBUG_PRINT("info", ("Peer certificate:")); X509_NAME_oneline(X509_get_subject_name(cert), buf, sizeof(buf)); DBUG_PRINT("info", ("\t subject: '%s'", buf)); X509_NAME_oneline(X509_get_issuer_name(cert), buf, sizeof(buf)); DBUG_PRINT("info", ("\t issuer: '%s'", buf)); X509_free(cert); } else DBUG_PRINT("info", ("Peer does not have certificate.")); if (SSL_get_shared_ciphers(ssl, buf, sizeof(buf))) { DBUG_PRINT("info", ("shared_ciphers: '%s'", buf)); } else DBUG_PRINT("info", ("no shared ciphers!")); } #endif return 0; } int sslaccept(struct st_VioSSLFd *ptr, Vio *vio, long timeout, unsigned long *ssl_errno_holder) { DBUG_TRACE; int ret = ssl_do(ptr, vio, timeout, SSL_accept, ssl_errno_holder, nullptr); return ret; } int sslconnect(struct st_VioSSLFd *ptr, Vio *vio, long timeout, unsigned long *ssl_errno_holder, SSL **ssl) { DBUG_TRACE; int ret = ssl_do(ptr, vio, timeout, SSL_connect, ssl_errno_holder, ssl); return ret; } bool vio_ssl_has_data(Vio *vio) { return SSL_pending(static_cast(vio->ssl_arg)) > 0 ? true : false; } #endif /* HAVE_OPENSSL */