diff options
Diffstat (limited to 'src/interfaces/libpq/fe-secure-openssl.c')
| -rw-r--r-- | src/interfaces/libpq/fe-secure-openssl.c | 1468 |
1 files changed, 1468 insertions, 0 deletions
diff --git a/src/interfaces/libpq/fe-secure-openssl.c b/src/interfaces/libpq/fe-secure-openssl.c new file mode 100644 index 00000000000..f950fc3bc3c --- /dev/null +++ b/src/interfaces/libpq/fe-secure-openssl.c @@ -0,0 +1,1468 @@ +/*------------------------------------------------------------------------- + * + * fe-secure-openssl.c + * OpenSSL support + * + * + * Portions Copyright (c) 1996-2014, 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 <signal.h> +#include <fcntl.h> +#include <ctype.h> + +#include "libpq-fe.h" +#include "fe-auth.h" +#include "libpq-int.h" + +#ifdef WIN32 +#include "win32.h" +#else +#include <sys/socket.h> +#include <unistd.h> +#include <netdb.h> +#include <netinet/in.h> +#ifdef HAVE_NETINET_TCP_H +#include <netinet/tcp.h> +#endif +#include <arpa/inet.h> +#endif + +#include <sys/stat.h> + +#ifdef ENABLE_THREAD_SAFETY +#ifdef WIN32 +#include "pthread-win32.h" +#else +#include <pthread.h> +#endif +#endif + +#include <openssl/ssl.h> +#if (SSLEAY_VERSION_NUMBER >= 0x00907000L) +#include <openssl/conf.h> +#endif +#ifdef USE_SSL_ENGINE +#include <openssl/engine.h> +#endif + +static bool verify_peer_name_matches_certificate(PGconn *); +static int verify_cb(int ok, X509_STORE_CTX *ctx); +static void destroy_ssl_system(void); +static int initialize_SSL(PGconn *conn); +static PostgresPollingStatusType open_client_SSL(PGconn *); +static char *SSLerrmessage(void); +static void SSLerrfree(char *buf); + +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; + +/* + * SSL_context is currently shared between threads and therefore we need to be + * careful to lock around any usage of it when providing thread safety. + * ssl_config_mutex is the mutex that we use to protect it. + */ +static SSL_CTX *SSL_context = NULL; + +#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 */ + + +/* ------------------------------------------------------------ */ +/* Procedures common to all secure sessions */ +/* ------------------------------------------------------------ */ + +/* + * Exported function to allow application to tell us it's already + * initialized OpenSSL and/or libcrypto. + */ +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; +} + +/* + * Begin or continue negotiating a secure session. + */ +PostgresPollingStatusType +pgtls_open_client(PGconn *conn) +{ + /* First time through? */ + if (conn->ssl == NULL) + { +#ifdef ENABLE_THREAD_SAFETY + int rc; +#endif + +#ifdef ENABLE_THREAD_SAFETY + if ((rc = pthread_mutex_lock(&ssl_config_mutex))) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("could not acquire mutex: %s\n"), strerror(rc)); + return PGRES_POLLING_FAILED; + } +#endif + /* Create a connection-specific SSL object */ + if (!(conn->ssl = SSL_new(SSL_context)) || + !SSL_set_app_data(conn->ssl, conn) || + !my_SSL_set_fd(conn, conn->sock)) + { + char *err = SSLerrmessage(); + + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("could not establish SSL connection: %s\n"), + err); + SSLerrfree(err); +#ifdef ENABLE_THREAD_SAFETY + pthread_mutex_unlock(&ssl_config_mutex); +#endif + pgtls_close(conn); + + return PGRES_POLLING_FAILED; + } + conn->ssl_in_use = true; + +#ifdef ENABLE_THREAD_SAFETY + pthread_mutex_unlock(&ssl_config_mutex); +#endif + + /* + * 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); +} + +/* + * Read data from a secure connection. + * + * On failure, this function is responsible for putting a suitable message + * into conn->errorMessage. The caller must still inspect errno, but only + * to determine whether to continue/retry after error. + */ +ssize_t +pgtls_read(PGconn *conn, void *ptr, size_t len) +{ + ssize_t n; + int result_errno = 0; + char sebuf[256]; + int err; + +rloop: + SOCK_ERRNO_SET(0); + n = SSL_read(conn->ssl, ptr, len); + err = SSL_get_error(conn->ssl, n); + 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(); + + 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; +} + +/* + * Write data to a secure connection. + * + * On failure, this function is responsible for putting a suitable message + * into conn->errorMessage. The caller must still inspect errno, but only + * to determine whether to continue/retry after error. + */ +ssize_t +pgtls_write(PGconn *conn, const void *ptr, size_t len) +{ + ssize_t n; + int result_errno = 0; + char sebuf[256]; + int err; + + SOCK_ERRNO_SET(0); + n = SSL_write(conn->ssl, ptr, len); + err = SSL_get_error(conn->ssl, n); + 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(); + + 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; +} + +/* ------------------------------------------------------------ */ +/* 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; +} + + +/* + * Check if a wildcard certificate matches the server hostname. + * + * The rule for this is: + * 1. We only match the '*' character as wildcard + * 2. We match only wildcards at the start of the string + * 3. The '*' character does *not* match '.', meaning that we match only + * a single pathname component. + * 4. We don't support more than one '*' in a single pattern. + * + * This is roughly in line with RFC2818, but contrary to what most browsers + * appear to be implementing (point 3 being the difference) + * + * Matching is always case-insensitive, since DNS is case insensitive. + */ +static int +wildcard_certificate_match(const char *pattern, const char *string) +{ + int lenpat = strlen(pattern); + int lenstr = strlen(string); + + /* If we don't start with a wildcard, it's not a match (rule 1 & 2) */ + if (lenpat < 3 || + pattern[0] != '*' || + pattern[1] != '.') + return 0; + + if (lenpat > lenstr) + /* If pattern is longer than the string, we can never match */ + return 0; + + if (pg_strcasecmp(pattern + 1, string + lenstr - lenpat + 1) != 0) + + /* + * If string does not end in pattern (minus the wildcard), we don't + * match + */ + return 0; + + if (strchr(string, '.') < string + lenstr - lenpat) + + /* + * If there is a dot left of where the pattern started to match, we + * don't match (rule 3) + */ + return 0; + + /* String ended with pattern, and didn't have a dot before, so we match */ + return 1; +} + + +/* + * Verify that common name resolves to peer. + */ +static bool +verify_peer_name_matches_certificate(PGconn *conn) +{ + char *peer_cn; + int r; + int len; + bool result; + + /* + * If told not to verify the peer name, don't do it. Return true + * indicating that the verification was successful. + */ + if (strcmp(conn->sslmode, "verify-full") != 0) + return true; + + /* + * Extract the common name from the certificate. + * + * XXX: Should support alternate names here + */ + /* First find out the name's length and allocate a buffer for it. */ + len = X509_NAME_get_text_by_NID(X509_get_subject_name(conn->peer), + NID_commonName, NULL, 0); + if (len == -1) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("could not get server common name from server certificate\n")); + return false; + } + peer_cn = malloc(len + 1); + if (peer_cn == NULL) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("out of memory\n")); + return false; + } + + r = X509_NAME_get_text_by_NID(X509_get_subject_name(conn->peer), + NID_commonName, peer_cn, len + 1); + if (r != len) + { + /* Got different length than on the first call. Shouldn't happen. */ + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("could not get server common name from server certificate\n")); + free(peer_cn); + return false; + } + peer_cn[len] = '\0'; + + /* + * Reject embedded NULLs in certificate common name to prevent attacks + * like CVE-2009-4034. + */ + if (len != strlen(peer_cn)) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("SSL certificate's common name contains embedded null\n")); + free(peer_cn); + return false; + } + + /* + * We got the peer's common name. Now compare it against the originally + * given hostname. + */ + if (!(conn->pghost && conn->pghost[0] != '\0')) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("host name must be specified for a verified SSL connection\n")); + result = false; + } + else + { + if (pg_strcasecmp(peer_cn, conn->pghost) == 0) + /* Exact name match */ + result = true; + else if (wildcard_certificate_match(peer_cn, conn->pghost)) + /* Matched wildcard certificate */ + result = true; + else + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("server common name \"%s\" does not match host name \"%s\"\n"), + peer_cn, conn->pghost); + result = false; + } + } + + free(peer_cn); + return result; +} + +#ifdef ENABLE_THREAD_SAFETY +/* + * Callback functions for OpenSSL internal locking + */ + +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 */ + +/* + * Initialize SSL system, in particular creating the SSL_context object + * that will be shared by all SSL-using connections in this process. + * + * 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. + * + * The conn parameter is only used to be able to pass back an error + * message - no connection-local setup is made here. + * + * Returns 0 if OK, -1 on failure (with a message in conn->errorMessage). + */ +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; + + 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 */ + CRYPTO_set_id_callback(pq_threadidcallback); + CRYPTO_set_locking_callback(pq_lockingcallback); + } + } +#endif /* ENABLE_THREAD_SAFETY */ + + if (!SSL_context) + { + if (pq_init_ssl_lib) + { +#if SSLEAY_VERSION_NUMBER >= 0x00907000L + OPENSSL_config(NULL); +#endif + SSL_library_init(); + SSL_load_error_strings(); + } + + /* + * 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) + { + char *err = SSLerrmessage(); + + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("could not create SSL context: %s\n"), + err); + SSLerrfree(err); +#ifdef ENABLE_THREAD_SAFETY + pthread_mutex_unlock(&ssl_config_mutex); +#endif + return -1; + } + + /* Disable old protocol versions */ + SSL_CTX_set_options(SSL_context, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3); + + /* + * 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); + } + +#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. + */ +static void +destroy_ssl_system(void) +{ +#ifdef ENABLE_THREAD_SAFETY + /* Mutex is created in initialize_ssl_system() */ + 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 */ + CRYPTO_set_locking_callback(NULL); + CRYPTO_set_id_callback(NULL); + + /* + * We don't free the lock array or the SSL_context. 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 +} + +/* + * Initialize (potentially) per-connection SSL data, namely the + * client certificate, private key, and trusted CA certs. + * + * conn->ssl must already be created. It receives the connection's client + * certificate and private key. Note however that certificates also get + * loaded into the SSL_context object, and are therefore accessible to all + * connections in this process. This should be OK as long as there aren't + * any hash collisions among the certs. + * + * Returns 0 if OK, -1 on failure (with a message in conn->errorMessage). + */ +static int +initialize_SSL(PGconn *conn) +{ + struct stat buf; + char homedir[MAXPGPATH]; + char fnbuf[MAXPGPATH]; + char sebuf[256]; + bool have_homedir; + bool have_cert; + 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; + + /* Read the client certificate file */ + if (conn->sslcert && strlen(conn->sslcert) > 0) + strncpy(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, pqStrerror(errno, sebuf, sizeof(sebuf))); + 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 actually have to + * load the file twice. The first call loads any extra certs after + * the first one into chain-cert storage associated with the + * SSL_context. The second call loads the first cert (only) into the + * SSL object, where it will be correctly paired with the private key + * we load below. We do it this way so that each connection + * understands which subject cert to present, in case different + * sslcert settings are used for different connections in the same + * process. + * + * NOTE: This function may also modify our SSL_context and therefore + * we have to lock around this call and any places where we use the + * SSL_context struct. + */ +#ifdef ENABLE_THREAD_SAFETY + int rc; + + if ((rc = pthread_mutex_lock(&ssl_config_mutex))) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("could not acquire mutex: %s\n"), strerror(rc)); + return -1; + } +#endif + if (SSL_CTX_use_certificate_chain_file(SSL_context, fnbuf) != 1) + { + char *err = SSLerrmessage(); + + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("could not read certificate file \"%s\": %s\n"), + fnbuf, err); + SSLerrfree(err); + +#ifdef ENABLE_THREAD_SAFETY + pthread_mutex_unlock(&ssl_config_mutex); +#endif + return -1; + } + + if (SSL_use_certificate_file(conn->ssl, fnbuf, SSL_FILETYPE_PEM) != 1) + { + char *err = SSLerrmessage(); + + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("could not read certificate file \"%s\": %s\n"), + fnbuf, err); + SSLerrfree(err); +#ifdef ENABLE_THREAD_SAFETY + pthread_mutex_unlock(&ssl_config_mutex); +#endif + return -1; + } + + /* need to load the associated private key, too */ + have_cert = true; + +#ifdef ENABLE_THREAD_SAFETY + pthread_mutex_unlock(&ssl_config_mutex); +#endif + } + + /* + * 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(); + + 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(); + + 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(); + + 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(); + + 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 */ + strncpy(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(); + + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("could not load private key file \"%s\": %s\n"), + fnbuf, err); + SSLerrfree(err); + return -1; + } + } + + /* verify that the cert and key go together */ + if (have_cert && + SSL_check_private_key(conn->ssl) != 1) + { + char *err = SSLerrmessage(); + + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("certificate does not match private key file \"%s\": %s\n"), + fnbuf, err); + SSLerrfree(err); + return -1; + } + + /* + * 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) + strncpy(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; + +#ifdef ENABLE_THREAD_SAFETY + int rc; + + if ((rc = pthread_mutex_lock(&ssl_config_mutex))) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("could not acquire mutex: %s\n"), strerror(rc)); + return -1; + } +#endif + if (SSL_CTX_load_verify_locations(SSL_context, fnbuf, NULL) != 1) + { + char *err = SSLerrmessage(); + + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("could not read root certificate file \"%s\": %s\n"), + fnbuf, err); + SSLerrfree(err); +#ifdef ENABLE_THREAD_SAFETY + pthread_mutex_unlock(&ssl_config_mutex); +#endif + return -1; + } + + if ((cvstore = SSL_CTX_get_cert_store(SSL_context)) != NULL) + { + if (conn->sslcrl && strlen(conn->sslcrl) > 0) + strncpy(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) + { + /* 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 + char *err = SSLerrmessage(); + + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("SSL library does not support CRL certificates (file \"%s\")\n"), + fnbuf); + SSLerrfree(err); +#ifdef ENABLE_THREAD_SAFETY + pthread_mutex_unlock(&ssl_config_mutex); +#endif + return -1; +#endif + } + /* if not found, silently ignore; we do not require CRL */ + } +#ifdef ENABLE_THREAD_SAFETY + pthread_mutex_unlock(&ssl_config_mutex); +#endif + + SSL_set_verify(conn->ssl, SSL_VERIFY_PEER, verify_cb); + } + 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); + return -1; + } + } + + /* + * If the OpenSSL version used supports it (from 1.0.0 on) and the user + * requested it, disable SSL compression. + */ +#ifdef SSL_OP_NO_COMPRESSION + if (conn->sslcompression && conn->sslcompression[0] == '0') + { + SSL_set_options(conn->ssl, SSL_OP_NO_COMPRESSION); + } +#endif + + return 0; +} + +/* + * Attempt to negotiate SSL connection. + */ +static PostgresPollingStatusType +open_client_SSL(PGconn *conn) +{ + int r; + + r = SSL_connect(conn->ssl); + if (r <= 0) + { + int err = SSL_get_error(conn->ssl, r); + + 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[256]; + + 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(); + + 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 = SSLerrmessage(); + + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("certificate could not be obtained: %s\n"), + err); + SSLerrfree(err); + pgtls_close(conn); + return PGRES_POLLING_FAILED; + } + + if (!verify_peer_name_matches_certificate(conn)) + { + pgtls_close(conn); + return PGRES_POLLING_FAILED; + } + + /* SSL handshake is complete */ + return PGRES_POLLING_OK; +} + +/* + * Close SSL connection. + */ +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 last SSL error + * + * 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(void) +{ + unsigned long errcode; + const char *errreason; + char *errbuf; + + errbuf = malloc(SSL_ERR_LEN); + if (!errbuf) + return ssl_nomem; + errcode = ERR_get_error(); + if (errcode == 0) + { + snprintf(errbuf, SSL_ERR_LEN, libpq_gettext("no SSL error reported")); + return errbuf; + } + errreason = ERR_reason_error_string(errcode); + if (errreason != NULL) + { + strlcpy(errbuf, errreason, SSL_ERR_LEN); + return errbuf; + } + snprintf(errbuf, SSL_ERR_LEN, libpq_gettext("SSL error code %lu"), errcode); + return errbuf; +} + +static void +SSLerrfree(char *buf) +{ + if (buf != ssl_nomem) + free(buf); +} + +/* + * Return pointer to OpenSSL object. + */ +void * +PQgetssl(PGconn *conn) +{ + if (!conn) + return NULL; + return conn->ssl; +} + + +/* + * 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? + */ + +static bool my_bio_initialized = false; +static BIO_METHOD my_bio_methods; + +static int +my_sock_read(BIO *h, char *buf, int size) +{ + int res; + int save_errno; + + res = pqsecure_raw_read((PGconn *) h->ptr, buf, size); + save_errno = errno; + BIO_clear_retry_flags(h); + if (res < 0) + { + switch (save_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; + } + } + + errno = save_errno; + return res; +} + +static int +my_sock_write(BIO *h, const char *buf, int size) +{ + int res; + int save_errno; + + res = pqsecure_raw_write((PGconn *) h->ptr, buf, size); + save_errno = errno; + BIO_clear_retry_flags(h); + if (res <= 0) + { + if (save_errno == EINTR) + { + BIO_set_retry_write(h); + } + } + + return res; +} + +static BIO_METHOD * +my_BIO_s_socket(void) +{ + if (!my_bio_initialized) + { + memcpy(&my_bio_methods, BIO_s_socket(), sizeof(BIO_METHOD)); + my_bio_methods.bread = my_sock_read; + my_bio_methods.bwrite = my_sock_write; + my_bio_initialized = true; + } + 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 = NULL; + + bio = BIO_new(my_BIO_s_socket()); + if (bio == NULL) + { + SSLerr(SSL_F_SSL_SET_FD, ERR_R_BUF_LIB); + goto err; + } + /* Use 'ptr' to store pointer to PGconn */ + bio->ptr = conn; + + SSL_set_bio(conn->ssl, bio, bio); + BIO_set_fd(bio, fd, BIO_NOCLOSE); + ret = 1; +err: + return ret; +} |