contrib/auth_delay/auth_delay.c

   1 /* -------------------------------------------------------------------------
   2  *
   3  * auth_delay.c
   4  *
   5  * Copyright (c) 2010-2022, 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 void            _PG_init(void);
  24
  25 /* GUC Variables */
  26 static int      auth_delay_milliseconds;
  27
  28 /* Original Hook */
  29 static ClientAuthentication_hook_type original_client_auth_hook = NULL;
  30
  31 /*
  32  * Check authentication
  33  */
  34 static void
  35 auth_delay_checks(Port *port, int status)
  36 {
  37         /*
  38          * Any other plugins which use ClientAuthentication_hook.
  39          */
  40         if (original_client_auth_hook)
  41                 original_client_auth_hook(port, status);
  42
  43         /*
  44          * Inject a short delay if authentication failed.
  45          */
  46         if (status != STATUS_OK)
  47         {
  48                 pg_usleep(1000L * auth_delay_milliseconds);
  49         }
  50 }
  51
  52 /*
  53  * Module Load Callback
  54  */
  55 void
  56 _PG_init(void)
  57 {
  58         /* Define custom GUC variables */
  59         DefineCustomIntVariable("auth_delay.milliseconds",
  60                                                         "Milliseconds to delay before reporting authentication failure",
  61                                                         NULL,
  62                                                         &auth_delay_milliseconds,
  63                                                         0,
  64                                                         0, INT_MAX / 1000,
  65                                                         PGC_SIGHUP,
  66                                                         GUC_UNIT_MS,
  67                                                         NULL,
  68                                                         NULL,
  69                                                         NULL);
  70
  71         EmitWarningsOnPlaceholders("auth_delay");
  72
  73         /* Install Hooks */
  74         original_client_auth_hook = ClientAuthentication_hook;
  75         ClientAuthentication_hook = auth_delay_checks;
  76 }