contrib/auth_delay/auth_delay.c

   1 /* -------------------------------------------------------------------------
   2  *
   3  * auth_delay.c
   4  *
   5  * Copyright (c) 2010-2025, PostgreSQL Global Development Group
   6  *
   7  * IDENTIFICATION
   8  *              contrib/auth_delay/auth_delay.c
   9  *
  10  * -------------------------------------------------------------------------
  11  */
  12 #include "postgres.h"
  13
  14 #include <limits.h>
  15
  16 #include "libpq/auth.h"
  17 #include "utils/guc.h"
  18
  19 PG_MODULE_MAGIC;
  20
  21 /* GUC Variables */
  22 static int      auth_delay_milliseconds = 0;
  23
  24 /* Original Hook */
  25 static ClientAuthentication_hook_type original_client_auth_hook = NULL;
  26
  27 /*
  28  * Check authentication
  29  */
  30 static void
  31 auth_delay_checks(Port *port, int status)
  32 {
  33         /*
  34          * Any other plugins which use ClientAuthentication_hook.
  35          */
  36         if (original_client_auth_hook)
  37                 original_client_auth_hook(port, status);
  38
  39         /*
  40          * Inject a short delay if authentication failed.
  41          */
  42         if (status != STATUS_OK)
  43         {
  44                 pg_usleep(1000L * auth_delay_milliseconds);
  45         }
  46 }
  47
  48 /*
  49  * Module Load Callback
  50  */
  51 void
  52 _PG_init(void)
  53 {
  54         /* Define custom GUC variables */
  55         DefineCustomIntVariable("auth_delay.milliseconds",
  56                                                         "Milliseconds to delay before reporting authentication failure",
  57                                                         NULL,
  58                                                         &auth_delay_milliseconds,
  59                                                         0,
  60                                                         0, INT_MAX / 1000,
  61                                                         PGC_SIGHUP,
  62                                                         GUC_UNIT_MS,
  63                                                         NULL,
  64                                                         NULL,
  65                                                         NULL);
  66
  67         MarkGUCPrefixReserved("auth_delay");
  68
  69         /* Install Hooks */
  70         original_client_auth_hook = ClientAuthentication_hook;
  71         ClientAuthentication_hook = auth_delay_checks;
  72 }