[#70] TLS support: pgagroal - PostgreSQL

Initial support for TLS connections to PostgreSQL, but
doesn't support pooling so we will keep the issue open until fixed

doc/ARCHITECTURE.md

@@ -151,6 +151,7 @@ struct worker_io
    int server_fd;        /* The server descriptor */
    int slot;             /* The slot */
    SSL* client_ssl;      /* The client SSL context */
+   SSL* server_ssl;      /* The server SSL context */
    void* shmem;          /* The shared memory segment */
    void* pipeline_shmem; /* The shared memory segment for the pipeline */
 };

doc/CONFIGURATION.md

@@ -73,6 +73,7 @@ __Danger zone__
 | host | | String | Yes | The address of the PostgreSQL instance |
 | port | | Int | Yes | The port of the PostgreSQL instance |
 | primary | | Bool | No | Identify the instance as primary (hint) |
+| tls | `off` | Bool | No | Enable Transport Layer Security (TLS) support (Experimental - no pooling) |
 
 Note, that if `host` starts with a `/` it represents a path and `pgagroal` will connect using a Unix Domain Socket.
 

doc/man/pgagroal.conf.5.rst

@@ -154,6 +154,9 @@ port
 primary
   Identify the instance as the primary instance (hint)
 
+tls
+  Enable Transport Layer Security (TLS) support (Experimental - no pooling). Default is off
+
 REPORTING BUGS
 ==============
 

src/include/pgagroal.h

@@ -155,6 +155,7 @@ struct server
    char name[MISC_LENGTH]; /**< The name of the server */
    char host[MISC_LENGTH]; /**< The host name of the server */
    int port;               /**< The port of the server */
+   bool tls;               /**< Use TLS if possible */
    atomic_schar state;     /**< The state of the server */
 } __attribute__ ((aligned (64)));
 

src/include/pool.h

@@ -37,6 +37,7 @@ extern "C" {
 
 #include <stdbool.h>
 #include <stdlib.h>
+#include <openssl/ssl.h>
 
 /**
  * Get a connection
@@ -45,27 +46,30 @@ extern "C" {
  * @param reuse Should a slot be reused
  * @param transaction_mode Obtain a connection in transaction mode
  * @param slot The resulting slot
+ * @param ssl The resulting SSL (can be NULL)
  * @return 0 upon success, 1 if pool is full, otherwise 2
  */
 int
-pgagroal_get_connection(char* username, char* database, bool reuse, bool transaction_mode, int* slot);
+pgagroal_get_connection(char* username, char* database, bool reuse, bool transaction_mode, int* slot, SSL** ssl);
 
 /**
  * Return a connection
  * @param slot The slot
+ * @param ssl The SSL connection (can be NULL)
  * @param transaction_mode Is the connection returned in transaction mode
  * @return 0 upon success, otherwise 1
  */
 int
-pgagroal_return_connection(int slot, bool transaction_mode);
+pgagroal_return_connection(int slot, SSL* ssl, bool transaction_mode);
 
 /**
  * Kill a connection
  * @param slot The slot
+ * @param ssl The SSL connection (can be NULL)
  * @return 0 upon success, otherwise 1
  */
 int
-pgagroal_kill_connection(int slot);
+pgagroal_kill_connection(int slot, SSL* ssl);
 
 /**
  * Perform idle timeout

src/include/security.h

@@ -45,21 +45,23 @@ extern "C" {
  * @param address The client address
  * @param slot The resulting slot
  * @param client_ssl The client SSL context
+ * @param server_ssl The server SSL context
  * @return 0 upon success, otherwise 1
  */
 int
-pgagroal_authenticate(int client_fd, char* address, int* slot, SSL** client_ssl);
+pgagroal_authenticate(int client_fd, char* address, int* slot, SSL** client_ssl, SSL** server_ssl);
 
 /**
  * Authenticate a prefill connection
  * @param username The user name
  * @param password The password
  * @param database The database
  * @param slot The resulting slot
+ * @param server_ssl The server SSL context
  * @return 0 upon success, otherwise 1
  */
 int
-pgagroal_prefill_auth(char* username, char* password, char* database, int* slot);
+pgagroal_prefill_auth(char* username, char* password, char* database, int* slot, SSL** server_ssl);
 
 /**
  * Authenticate a remote management user

src/include/server.h

@@ -36,6 +36,7 @@ extern "C" {
 #include <pgagroal.h>
 
 #include <stdlib.h>
+#include <openssl/ssl.h>
 
 /**
  * Get the primary server
@@ -49,10 +50,11 @@ pgagroal_get_primary(int* server);
  * Update the server state
  * @param slot The slot
  * @param socket The descriptor
+ * @param ssl The SSL connection
  * @return 0 upon success, otherwise 1
  */
 int
-pgagroal_update_server_state(int slot, int socket);
+pgagroal_update_server_state(int slot, int socket, SSL* ssl);
 
 /**
  * Print the state of the servers

src/include/worker.h

@@ -56,6 +56,7 @@ struct worker_io
    int server_fd;        /**< The server descriptor */
    int slot;             /**< The slot */
    SSL* client_ssl;      /**< The client SSL context */
+   SSL* server_ssl;      /**< The server SSL context */
 };
 
 extern volatile int running;

src/libpgagroal/configuration.c

@@ -363,6 +363,13 @@ pgagroal_read_configuration(void* shm, char* filename)
                         unknown = true;
                      }
                   }
+                  else if (strlen(section) > 0)
+                  {
+                     if (as_bool(value, &srv.tls))
+                     {
+                        unknown = true;
+                     }
+                  }
                   else
                   {
                      unknown = true;
@@ -1020,6 +1027,15 @@ pgagroal_validate_configuration(void* shm, bool has_unix_socket, bool has_main_s
          }
       }
 
+      for (int i = 0; i < config->number_of_servers; i++)
+      {
+         if (config->servers[i].tls)
+         {
+            pgagroal_log_fatal("pgagroal: Transaction pipeline does not support TLS to a server");
+            return 1;
+         }
+      }
+
       if (config->blocking_timeout > 0)
       {
          pgagroal_log_warn("pgagroal: Using blocking_timeout for the transaction pipeline is not recommended");

src/libpgagroal/management.c

@@ -255,7 +255,7 @@ pgagroal_management_transfer_connection(int32_t slot)
    if (cmptr)
       free(cmptr);
    pgagroal_disconnect(fd);
-   pgagroal_kill_connection(slot);
+   pgagroal_kill_connection(slot, NULL);
 
    return 1;
 }
@@ -1105,7 +1105,7 @@ pgagroal_management_client_fd(int32_t slot, pid_t pid)
 error:
    free(cmptr);
    pgagroal_disconnect(fd);
-   pgagroal_kill_connection(slot);
+   pgagroal_kill_connection(slot, NULL);
 
    return 1;
 }

src/libpgagroal/message.c

@@ -1349,11 +1349,17 @@ ssl_write_message(SSL* ssl, struct message* msg)
                keep_write = true;
                break;
             case SSL_ERROR_SYSCALL:
-               pgagroal_log_error("SSL_ERROR_SYSCALL: %s (%d)", strerror(errno), SSL_get_fd(ssl));
+               pgagroal_log_error("SSL_ERROR_SYSCALL: FD %d", SSL_get_fd(ssl));
+               pgagroal_log_error("%s", ERR_error_string(err, NULL));
+               pgagroal_log_error("%s", ERR_lib_error_string(err));
+               pgagroal_log_error("%s", ERR_reason_error_string(err));
                errno = 0;
                break;
             case SSL_ERROR_SSL:
-               pgagroal_log_error("SSL_ERROR_SSL: %s (%d)", strerror(errno), SSL_get_fd(ssl));
+               pgagroal_log_error("SSL_ERROR_SSL: FD %d", SSL_get_fd(ssl));
+               pgagroal_log_error("%s", ERR_error_string(err, NULL));
+               pgagroal_log_error("%s", ERR_lib_error_string(err));
+               pgagroal_log_error("%s", ERR_reason_error_string(err));
                errno = 0;
                break;
          }

src/libpgagroal/pipeline_perf.c

@@ -121,7 +121,14 @@ performance_client(struct ev_loop *loop, struct ev_io *watcher, int revents)
    {
       if (likely(msg->kind != 'X'))
       {
-         status = pgagroal_write_socket_message(wi->server_fd, msg);
+         if (wi->server_ssl == NULL)
+         {
+            status = pgagroal_write_socket_message(wi->server_fd, msg);
+         }
+         else
+         {
+            status = pgagroal_write_ssl_message(wi->server_ssl, msg);
+         }
          if (unlikely(status != MESSAGE_STATUS_OK))
          {
             goto server_error;
@@ -195,7 +202,14 @@ performance_server(struct ev_loop *loop, struct ev_io *watcher, int revents)
 
    wi = (struct worker_io*)watcher;
 
-   status = pgagroal_read_socket_message(wi->server_fd, &msg);
+   if (wi->server_ssl == NULL)
+   {
+      status = pgagroal_read_socket_message(wi->server_fd, &msg);
+   }
+   else
+   {
+      status = pgagroal_read_ssl_message(wi->server_ssl, &msg);
+   }
    if (likely(status == MESSAGE_STATUS_OK))
    {
       status = pgagroal_write_socket_message(wi->client_fd, msg);

src/libpgagroal/pipeline_session.c

@@ -300,7 +300,14 @@ session_client(struct ev_loop *loop, struct ev_io *watcher, int revents)
             }
          }
 
-         status = pgagroal_write_socket_message(wi->server_fd, msg);
+         if (wi->server_ssl == NULL)
+         {
+            status = pgagroal_write_socket_message(wi->server_fd, msg);
+         }
+         else
+         {
+            status = pgagroal_write_ssl_message(wi->server_ssl, msg);
+         }
          if (unlikely(status == MESSAGE_STATUS_ERROR))
          {
             if (config->failover)
@@ -401,7 +408,14 @@ session_server(struct ev_loop *loop, struct ev_io *watcher, int revents)
 
    client_active(wi->slot);
 
-   status = pgagroal_read_socket_message(wi->server_fd, &msg);
+   if (wi->server_ssl == NULL)
+   {
+      status = pgagroal_read_socket_message(wi->server_fd, &msg);
+   }
+   else
+   {
+      status = pgagroal_read_ssl_message(wi->server_ssl, &msg);
+   }
    if (likely(status == MESSAGE_STATUS_OK))
    {
       pgagroal_prometheus_network_received_add(msg->length);

src/libpgagroal/pipeline_transaction.c

@@ -134,7 +134,7 @@ transaction_start(struct ev_loop* loop, struct worker_io* w)
    pgagroal_tracking_event_slot(TRACKER_TX_RETURN_CONNECTION_START, w->slot);
 
    is_new = config->connections[w->slot].new;
-   pgagroal_return_connection(w->slot, true);
+   pgagroal_return_connection(w->slot, w->server_ssl, true);
 
    w->server_fd = -1;
    w->slot = -1;
@@ -176,7 +176,7 @@ transaction_stop(struct ev_loop* loop, struct worker_io* w)
 
       ev_io_stop(loop, (struct ev_io*)&server_io);
       pgagroal_tracking_event_slot(TRACKER_TX_RETURN_CONNECTION_STOP, w->slot);
-      pgagroal_return_connection(slot, true);
+      pgagroal_return_connection(slot, w->server_ssl, true);
       slot = -1;
    }
 
@@ -197,6 +197,7 @@ static void
 transaction_client(struct ev_loop* loop, struct ev_io* watcher, int revents)
 {
    int status = MESSAGE_STATUS_ERROR;
+   SSL* s_ssl = NULL;
    struct worker_io* wi = NULL;
    struct message* msg = NULL;
    struct configuration* config = NULL;
@@ -208,13 +209,14 @@ transaction_client(struct ev_loop* loop, struct ev_io* watcher, int revents)
    if (slot == -1)
    {
       pgagroal_tracking_event_basic(TRACKER_TX_GET_CONNECTION, &username[0], &database[0]);
-      if (pgagroal_get_connection(&username[0], &database[0], true, true, &slot))
+      if (pgagroal_get_connection(&username[0], &database[0], true, true, &slot, &s_ssl))
       {
          pgagroal_write_pool_full(wi->client_ssl, wi->client_fd);
          goto get_error;
       }
 
       wi->server_fd = config->connections[slot].fd;
+      wi->server_ssl = s_ssl;
       wi->slot = slot;
 
       memcpy(&config->connections[slot].appname[0], &appname[0], MAX_APPLICATION_NAME);
@@ -224,6 +226,7 @@ transaction_client(struct ev_loop* loop, struct ev_io* watcher, int revents)
       server_io.server_fd = config->connections[slot].fd;
       server_io.slot = slot;
       server_io.client_ssl = wi->client_ssl;
+      server_io.server_ssl = wi->server_ssl;
 
       fatal = false;
 
@@ -292,7 +295,14 @@ transaction_client(struct ev_loop* loop, struct ev_io* watcher, int revents)
             }
          }
 
-         status = pgagroal_write_socket_message(wi->server_fd, msg);
+         if (wi->server_ssl == NULL)
+         {
+            status = pgagroal_write_socket_message(wi->server_fd, msg);
+         }
+         else
+         {
+            status = pgagroal_write_ssl_message(wi->server_ssl, msg);
+         }
          if (unlikely(status == MESSAGE_STATUS_ERROR))
          {
             if (config->failover)
@@ -399,7 +409,14 @@ transaction_server(struct ev_loop *loop, struct ev_io *watcher, int revents)
       goto client_error;
    }
 
-   status = pgagroal_read_socket_message(wi->server_fd, &msg);
+   if (wi->server_ssl == NULL)
+   {
+      status = pgagroal_read_socket_message(wi->server_fd, &msg);
+   }
+   else
+   {
+      status = pgagroal_read_ssl_message(wi->server_ssl, &msg);
+   }
    if (likely(status == MESSAGE_STATUS_OK))
    {
       pgagroal_prometheus_network_received_add(msg->length);
@@ -474,12 +491,12 @@ transaction_server(struct ev_loop *loop, struct ev_io *watcher, int revents)
 
             if (deallocate)
             {
-               pgagroal_write_deallocate_all(NULL, wi->server_fd);
+               pgagroal_write_deallocate_all(wi->server_ssl, wi->server_fd);
                deallocate = false;
             }
 
             pgagroal_tracking_event_slot(TRACKER_TX_RETURN_CONNECTION, slot);
-            if (pgagroal_return_connection(slot, true))
+            if (pgagroal_return_connection(slot, wi->server_ssl, true))
             {
                goto return_error;
             }