src/src/auths/plaintext.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2018 */
   6 /* Copyright (c) The Exim Maintainers 2020 */
   7 /* See the file NOTICE for conditions of use and distribution. */
   8
   9 #include "../exim.h"
  10 #include "plaintext.h"
  11
  12
  13 /* Options specific to the plaintext authentication mechanism. */
  14
  15 optionlist auth_plaintext_options[] = {
  16   { "client_ignore_invalid_base64", opt_bool,
  17       OPT_OFF(auth_plaintext_options_block, client_ignore_invalid_base64) },
  18   { "client_send",        opt_stringptr,
  19       OPT_OFF(auth_plaintext_options_block, client_send) },
  20   { "server_prompts",     opt_stringptr,
  21       OPT_OFF(auth_plaintext_options_block, server_prompts) }
  22 };
  23
  24 /* Size of the options list. An extern variable has to be used so that its
  25 address can appear in the tables drtables.c. */
  26
  27 int auth_plaintext_options_count =
  28   sizeof(auth_plaintext_options)/sizeof(optionlist);
  29
  30 /* Default private options block for the plaintext authentication method. */
  31
  32 auth_plaintext_options_block auth_plaintext_option_defaults = {
  33   NULL,              /* server_prompts */
  34   NULL,              /* client_send */
  35   FALSE              /* client_ignore_invalid_base64 */
  36 };
  37
  38
  39 #ifdef MACRO_PREDEF
  40
  41 /* Dummy values */
  42 void auth_plaintext_init(auth_instance *ablock) {}
  43 int auth_plaintext_server(auth_instance *ablock, uschar *data) {return 0;}
  44 int auth_plaintext_client(auth_instance *ablock, void * sx, int timeout,
  45     uschar *buffer, int buffsize) {return 0;}
  46
  47 #else   /*!MACRO_PREDEF*/
  48
  49
  50
  51 /*************************************************
  52 *          Initialization entry point            *
  53 *************************************************/
  54
  55 /* Called for each instance, after its options have been read, to
  56 enable consistency checks to be done, or anything else that needs
  57 to be set up. */
  58
  59 void
  60 auth_plaintext_init(auth_instance *ablock)
  61 {
  62 auth_plaintext_options_block *ob =
  63   (auth_plaintext_options_block *)(ablock->options_block);
  64 if (ablock->public_name == NULL) ablock->public_name = ablock->name;
  65 if (ablock->server_condition != NULL) ablock->server = TRUE;
  66 if (ob->client_send != NULL) ablock->client = TRUE;
  67 }
  68
  69
  70
  71 /*************************************************
  72 *             Server entry point                 *
  73 *************************************************/
  74
  75 /* For interface, see auths/README */
  76
  77 int
  78 auth_plaintext_server(auth_instance * ablock, uschar * data)
  79 {
  80 auth_plaintext_options_block * ob =
  81   (auth_plaintext_options_block *)(ablock->options_block);
  82 const uschar * prompts = ob->server_prompts;
  83 uschar * s;
  84 int number = 1;
  85 int rc;
  86 int sep = 0;
  87
  88 /* Expand a non-empty list of prompt strings */
  89
  90 if (prompts)
  91   if (!(prompts = expand_cstring(prompts)))
  92     {
  93     auth_defer_msg = expand_string_message;
  94     return DEFER;
  95     }
  96
  97 /* If data was supplied on the AUTH command, decode it, and split it up into
  98 multiple items at binary zeros. The strings are put into $auth1, $auth2, etc,
  99 up to a maximum. To retain backwards compatibility, they are also put int $1,
 100 $2, etc. If the data consists of the string "=" it indicates a single, empty
 101 string. */
 102
 103 if (*data)
 104   if ((rc = auth_read_input(data)) != OK)
 105     return rc;
 106
 107 /* Now go through the list of prompt strings. Skip over any whose data has
 108 already been provided as part of the AUTH command. For the rest, send them
 109 out as prompts, and get a data item back. If the data item is "*", abandon the
 110 authentication attempt. Otherwise, split it into items as above. */
 111
 112 while (  (s = string_nextinlist(&prompts, &sep, big_buffer, big_buffer_size))
 113       && expand_nmax < EXPAND_MAXN)
 114   if (number++ > expand_nmax)
 115     if ((rc = auth_prompt(CUS s)) != OK)
 116       return rc;
 117
 118 /* We now have a number of items of data in $auth1, $auth2, etc (and also, for
 119 compatibility, in $1, $2, etc). Authentication and authorization are handled
 120 together for this authenticator by expanding the server_condition option. Note
 121 that ablock->server_condition is always non-NULL because that's what configures
 122 this authenticator as a server. */
 123
 124 return auth_check_serv_cond(ablock);
 125 }
 126
 127
 128
 129 /*************************************************
 130 *              Client entry point                *
 131 *************************************************/
 132
 133 /* For interface, see auths/README */
 134
 135 int
 136 auth_plaintext_client(
 137   auth_instance *ablock,                 /* authenticator block */
 138   void * sx,                             /* smtp connextion */
 139   int timeout,                           /* command timeout */
 140   uschar *buffer,                        /* buffer for reading response */
 141   int buffsize)                          /* size of buffer */
 142 {
 143 auth_plaintext_options_block *ob =
 144   (auth_plaintext_options_block *)(ablock->options_block);
 145 const uschar * text = ob->client_send;
 146 const uschar * s;
 147 int sep = 0;
 148 int auth_var_idx = 0, rc;
 149 int flags = AUTH_ITEM_FIRST;
 150
 151 if (ob->client_ignore_invalid_base64)
 152   flags |= AUTH_ITEM_IGN64;
 153
 154 /* The text is broken up into a number of different data items, which are
 155 sent one by one. The first one is sent with the AUTH command; the remainder are
 156 sent in response to subsequent prompts. Each is expanded before being sent. */
 157
 158 while ((s = string_nextinlist(&text, &sep, NULL, 0)))
 159   {
 160   if (!text)
 161     flags |= AUTH_ITEM_LAST;
 162
 163   if ((rc = auth_client_item(sx, ablock, &s, flags, timeout, buffer, buffsize))
 164        != DEFER)
 165     return rc;
 166
 167   flags &= ~AUTH_ITEM_FIRST;
 168
 169   if (auth_var_idx < AUTH_VARS)
 170     auth_vars[auth_var_idx++] = string_copy(s);
 171   }
 172
 173 /* Control should never actually get here. */
 174
 175 return FAIL;
 176 }
 177
 178 #endif   /*!MACRO_PREDEF*/
 179 /* End of plaintext.c */