contrib/chkpass/chkpass.c

   1 /*
   2  * PostgreSQL type definitions for chkpass
   3  * Written by D'Arcy J.M. Cain
   4  * darcy@druid.net
   5  * http://www.druid.net/darcy/
   6  *
   7  * $PostgreSQL$
   8  * best viewed with tabs set to 4
   9  */
  10
  11 #include "postgres.h"
  12
  13 #include <time.h>
  14 #include <unistd.h>
  15 #ifdef HAVE_CRYPT_H
  16 #include <crypt.h>
  17 #endif
  18
  19 #include "fmgr.h"
  20 #include "utils/builtins.h"
  21
  22 PG_MODULE_MAGIC;
  23
  24 /*
  25  * This type encrypts it's input unless the first character is a colon.
  26  * The output is the encrypted form with a leading colon.  The output
  27  * format is designed to allow dump and reload operations to work as
  28  * expected without doing special tricks.
  29  */
  30
  31
  32 /*
  33  * This is the internal storage format for CHKPASSs.
  34  * 15 is all I need but add a little buffer
  35  */
  36
  37 typedef struct chkpass
  38 {
  39         char            password[16];
  40 }       chkpass;
  41
  42 /*
  43  * Various forward declarations:
  44  */
  45
  46 Datum           chkpass_in(PG_FUNCTION_ARGS);
  47 Datum           chkpass_out(PG_FUNCTION_ARGS);
  48 Datum           chkpass_rout(PG_FUNCTION_ARGS);
  49
  50 /* Only equal or not equal make sense */
  51 Datum           chkpass_eq(PG_FUNCTION_ARGS);
  52 Datum           chkpass_ne(PG_FUNCTION_ARGS);
  53
  54
  55 /* This function checks that the password is a good one
  56  * It's just a placeholder for now */
  57 static int
  58 verify_pass(const char *str)
  59 {
  60         return 0;
  61 }
  62
  63 /*
  64  * CHKPASS reader.
  65  */
  66 PG_FUNCTION_INFO_V1(chkpass_in);
  67 Datum
  68 chkpass_in(PG_FUNCTION_ARGS)
  69 {
  70         char       *str = PG_GETARG_CSTRING(0);
  71         chkpass    *result;
  72         char            mysalt[4];
  73         static char salt_chars[] =
  74         "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  75
  76         /* special case to let us enter encrypted passwords */
  77         if (*str == ':')
  78         {
  79                 result = (chkpass *) palloc(sizeof(chkpass));
  80                 strlcpy(result->password, str + 1, 13 + 1);
  81                 PG_RETURN_POINTER(result);
  82         }
  83
  84         if (verify_pass(str) != 0)
  85                 ereport(ERROR,
  86                                 (errcode(ERRCODE_DATA_EXCEPTION),
  87                                  errmsg("password \"%s\" is weak", str)));
  88
  89         result = (chkpass *) palloc(sizeof(chkpass));
  90
  91         mysalt[0] = salt_chars[random() & 0x3f];
  92         mysalt[1] = salt_chars[random() & 0x3f];
  93         mysalt[2] = 0;                          /* technically the terminator is not necessary
  94                                                                  * but I like to play safe */
  95         strcpy(result->password, crypt(str, mysalt));
  96         PG_RETURN_POINTER(result);
  97 }
  98
  99 /*
 100  * CHKPASS output function.
 101  * Just like any string but we know it is max 15 (13 plus colon and terminator.)
 102  */
 103
 104 PG_FUNCTION_INFO_V1(chkpass_out);
 105 Datum
 106 chkpass_out(PG_FUNCTION_ARGS)
 107 {
 108         chkpass    *password = (chkpass *) PG_GETARG_POINTER(0);
 109         char       *result;
 110
 111         result = (char *) palloc(16);
 112         result[0] = ':';
 113         strcpy(result + 1, password->password);
 114
 115         PG_RETURN_CSTRING(result);
 116 }
 117
 118
 119 /*
 120  * special output function that doesn't output the colon
 121  */
 122
 123 PG_FUNCTION_INFO_V1(chkpass_rout);
 124 Datum
 125 chkpass_rout(PG_FUNCTION_ARGS)
 126 {
 127         chkpass    *password = (chkpass *) PG_GETARG_POINTER(0);
 128
 129         PG_RETURN_TEXT_P(cstring_to_text(password->password));
 130 }
 131
 132
 133 /*
 134  * Boolean tests
 135  */
 136
 137 PG_FUNCTION_INFO_V1(chkpass_eq);
 138 Datum
 139 chkpass_eq(PG_FUNCTION_ARGS)
 140 {
 141         chkpass    *a1 = (chkpass *) PG_GETARG_POINTER(0);
 142         text       *a2 = PG_GETARG_TEXT_PP(1);
 143         char            str[9];
 144
 145         text_to_cstring_buffer(a2, str, sizeof(str));
 146         PG_RETURN_BOOL(strcmp(a1->password, crypt(str, a1->password)) == 0);
 147 }
 148
 149 PG_FUNCTION_INFO_V1(chkpass_ne);
 150 Datum
 151 chkpass_ne(PG_FUNCTION_ARGS)
 152 {
 153         chkpass    *a1 = (chkpass *) PG_GETARG_POINTER(0);
 154         text       *a2 = PG_GETARG_TEXT_PP(1);
 155         char            str[9];
 156
 157         text_to_cstring_buffer(a2, str, sizeof(str));
 158         PG_RETURN_BOOL(strcmp(a1->password, crypt(str, a1->password)) != 0);
 159 }