contrib/auth_delay/auth_delay.c

   1 /* -------------------------------------------------------------------------
   2  *
   3  * auth_delay.c
   4  *
   5  * Copyright (c) 2010-2024, 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 "port.h"
  18 #include "utils/guc.h"
  19 #include "utils/timestamp.h"
  20
  21 PG_MODULE_MAGIC;
  22
  23 /* GUC Variables */
  24 static int      auth_delay_milliseconds = 0;
  25
  26 /* Original Hook */
  27 static ClientAuthentication_hook_type original_client_auth_hook = NULL;
  28
  29 /*
  30  * Check authentication
  31  */
  32 static void
  33 auth_delay_checks(Port *port, int status)
  34 {
  35         /*
  36          * Any other plugins which use ClientAuthentication_hook.
  37          */
  38         if (original_client_auth_hook)
  39                 original_client_auth_hook(port, status);
  40
  41         /*
  42          * Inject a short delay if authentication failed.
  43          */
  44         if (status != STATUS_OK)
  45         {
  46                 pg_usleep(1000L * auth_delay_milliseconds);
  47         }
  48 }
  49
  50 /*
  51  * Module Load Callback
  52  */
  53 void
  54 _PG_init(void)
  55 {
  56         /* Define custom GUC variables */
  57         DefineCustomIntVariable("auth_delay.milliseconds",
  58                                                         "Milliseconds to delay before reporting authentication failure",
  59                                                         NULL,
  60                                                         &auth_delay_milliseconds,
  61                                                         0,
  62                                                         0, INT_MAX / 1000,
  63                                                         PGC_SIGHUP,
  64                                                         GUC_UNIT_MS,
  65                                                         NULL,
  66                                                         NULL,
  67                                                         NULL);
  68
  69         MarkGUCPrefixReserved("auth_delay");
  70
  71         /* Install Hooks */
  72         original_client_auth_hook = ClientAuthentication_hook;
  73         ClientAuthentication_hook = auth_delay_checks;
  74 }