src/src/auths/dovecot.c

   1 /* $Cambridge: exim/src/src/auths/dovecot.c,v 1.6 2007/01/25 16:23:42 ph10 Exp $ */
   2
   3 /*
   4  * Copyright (c) 2004 Andrey Panin <pazke@donpac.ru>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published
   8  * by the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  */
  11
  12 #include "../exim.h"
  13 #include "dovecot.h"
  14
  15 #define VERSION_MAJOR  1
  16 #define VERSION_MINOR  0
  17
  18 /* Options specific to the authentication mechanism. */
  19 optionlist auth_dovecot_options[] = {
  20        {
  21                "server_socket",
  22                opt_stringptr,
  23                (void *)(offsetof(auth_dovecot_options_block, server_socket))
  24        },
  25 };
  26
  27 /* Size of the options list. An extern variable has to be used so that its
  28 address can appear in the tables drtables.c. */
  29 int auth_dovecot_options_count =
  30        sizeof(auth_dovecot_options) / sizeof(optionlist);
  31
  32 /* Default private options block for the authentication method. */
  33 auth_dovecot_options_block auth_dovecot_option_defaults = {
  34        NULL,                           /* server_socket */
  35 };
  36
  37 /*************************************************
  38  *          Initialization entry point           *
  39  *************************************************/
  40
  41 /* Called for each instance, after its options have been read, to
  42 enable consistency checks to be done, or anything else that needs
  43 to be set up. */
  44 void auth_dovecot_init(auth_instance *ablock)
  45 {
  46        auth_dovecot_options_block *ob =
  47                (auth_dovecot_options_block *)(ablock->options_block);
  48
  49        if (ablock->public_name == NULL)
  50                ablock->public_name = ablock->name;
  51        if (ob->server_socket != NULL)
  52                ablock->server = TRUE;
  53        ablock->client = FALSE;
  54 }
  55
  56 static int strcut(char *str, char **ptrs, int nptrs)
  57 {
  58        char *tmp = str;
  59        int n;
  60
  61        for (n = 0; n < nptrs; n++)
  62                ptrs[n] = NULL;
  63        n = 1;
  64
  65        while (*str) {
  66                if (*str == '\t') {
  67                        if (n <= nptrs) {
  68                                *ptrs++ = tmp;
  69                                tmp = str + 1;
  70                                *str = 0;
  71                        }
  72                        n++;
  73                }
  74                str++;
  75        }
  76
  77        if (n < nptrs)
  78                *ptrs = tmp;
  79
  80        return n;
  81 }
  82
  83 #define CHECK_COMMAND(str, arg_min, arg_max) do { \
  84        if (strcasecmp((str), args[0]) != 0) \
  85                goto out; \
  86        if (nargs - 1 < (arg_min)) \
  87                goto out; \
  88        if (nargs - 1 > (arg_max)) \
  89                goto out; \
  90 } while (0)
  91
  92 #define OUT(msg) do { \
  93        auth_defer_msg = (US msg); \
  94        goto out; \
  95 } while(0)
  96
  97
  98
  99 /*************************************************
 100  *             Server entry point                *
 101  *************************************************/
 102
 103 int auth_dovecot_server(auth_instance *ablock, uschar *data)
 104 {
 105        auth_dovecot_options_block *ob =
 106                (auth_dovecot_options_block *)(ablock->options_block);
 107        struct sockaddr_un sa;
 108        char buffer[4096];
 109        char *args[8];
 110        uschar *auth_command;
 111        uschar *auth_extra_data = US"";
 112        int nargs, tmp;
 113        int cuid = 0, cont = 1, found = 0, fd, ret = DEFER;
 114        FILE *f;
 115
 116        HDEBUG(D_auth) debug_printf("dovecot authentication\n");
 117
 118        memset(&sa, 0, sizeof(sa));
 119        sa.sun_family = AF_UNIX;
 120
 121        /* This was the original code here: it is nonsense because strncpy()
 122        does not return an integer. I have converted this to use the function
 123        that formats and checks length. PH */
 124
 125        /*
 126        if (strncpy(sa.sun_path, ob->server_socket, sizeof(sa.sun_path)) < 0) {
 127        */
 128
 129        if (!string_format(US sa.sun_path, sizeof(sa.sun_path), "%s",
 130                           ob->server_socket)) {
 131                auth_defer_msg = US"authentication socket path too long";
 132                return DEFER;
 133        }
 134
 135        auth_defer_msg = US"authentication socket connection error";
 136
 137        fd = socket(PF_UNIX, SOCK_STREAM, 0);
 138        if (fd < 0)
 139                return DEFER;
 140
 141        if (connect(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0)
 142                goto out;
 143
 144        f = fdopen(fd, "a+");
 145        if (f == NULL)
 146                goto out;
 147
 148        auth_defer_msg = US"authentication socket protocol error";
 149
 150        while (cont) {
 151                if (fgets(buffer, sizeof(buffer), f) == NULL)
 152                        OUT("authentication socket read error or premature eof");
 153
 154                buffer[strlen(buffer) - 1] = 0;
 155                HDEBUG(D_auth) debug_printf("received: %s\n", buffer);
 156                nargs = strcut(buffer, args, sizeof(args) / sizeof(args[0]));
 157
 158                switch (toupper(*args[0])) {
 159                case 'C':
 160                        CHECK_COMMAND("CUID", 1, 1);
 161                        cuid = atoi(args[1]);
 162                        break;
 163
 164                case 'D':
 165                        CHECK_COMMAND("DONE", 0, 0);
 166                        cont = 0;
 167                        break;
 168
 169                case 'M':
 170                        CHECK_COMMAND("MECH", 1, INT_MAX);
 171                        if (strcmpic(US args[1], ablock->public_name) == 0)
 172                                found = 1;
 173                        break;
 174
 175                case 'S':
 176                        CHECK_COMMAND("SPID", 1, 1);
 177                        break;
 178
 179                case 'V':
 180                        CHECK_COMMAND("VERSION", 2, 2);
 181                        if (atoi(args[1]) != VERSION_MAJOR)
 182                                OUT("authentication socket protocol version mismatch");
 183                        break;
 184
 185                default:
 186                        goto out;
 187                }
 188        }
 189
 190        if (!found)
 191                goto out;
 192
 193        /* Added by PH: data must not contain tab (as it is
 194        b64 it shouldn't, but check for safety). */
 195
 196        if (Ustrchr(data, '\t') != NULL) {
 197                ret = FAIL;
 198                goto out;
 199        }
 200
 201        /* Added by PH: extra fields when TLS is in use or if the TCP/IP
 202        connection is local. */
 203
 204        if (tls_cipher != NULL)
 205                auth_extra_data = string_sprintf("secured\t%s%s",
 206                    tls_certificate_verified? "valid-client-cert" : "",
 207                    tls_certificate_verified? "\t" : "");
 208        else if (interface_address != NULL &&
 209                 Ustrcmp(sender_host_address, interface_address) == 0)
 210                auth_extra_data = US"secured\t";
 211
 212
 213 /****************************************************************************
 214    The code below was the original code here. It didn't work. A reading of the
 215    file auth-protocol.txt.gz that came with Dovecot 1.0_beta8 indicated that
 216    this was not right. Maybe something changed. I changed it to move the
 217    service indication into the AUTH command, and it seems to be better. PH
 218
 219        fprintf(f, "VERSION\t%d\t%d\r\nSERVICE\tSMTP\r\nCPID\t%d\r\n"
 220                "AUTH\t%d\t%s\trip=%s\tlip=%s\tresp=%s\r\n",
 221                VERSION_MAJOR, VERSION_MINOR, getpid(), cuid,
 222                ablock->public_name, sender_host_address, interface_address,
 223                data ? (char *) data : "");
 224
 225    Subsequently, the command was modified to add "secured" and "valid-client-
 226    cert" when relevant.
 227 ****************************************************************************/
 228
 229        auth_command = string_sprintf("VERSION\t%d\t%d\nCPID\t%d\n"
 230                "AUTH\t%d\t%s\tservice=smtp\t%srip=%s\tlip=%s\tresp=%s\n",
 231                VERSION_MAJOR, VERSION_MINOR, getpid(), cuid,
 232                ablock->public_name, auth_extra_data, sender_host_address,
 233                interface_address, data ? (char *) data : "");
 234
 235        fprintf(f, "%s", auth_command);
 236        HDEBUG(D_auth) debug_printf("sent: %s", auth_command);
 237
 238        while (1) {
 239                if (fgets(buffer, sizeof(buffer), f) == NULL) {
 240                        auth_defer_msg = US"authentication socket read error or premature eof";
 241                        goto out;
 242                }
 243
 244                buffer[strlen(buffer) - 1] = 0;
 245                HDEBUG(D_auth) debug_printf("received: %s\n", buffer);
 246                nargs = strcut(buffer, args, sizeof(args) / sizeof(args[0]));
 247
 248                if (atoi(args[1]) != cuid)
 249                        OUT("authentication socket connection id mismatch");
 250
 251                switch (toupper(*args[0])) {
 252                case 'C':
 253                        CHECK_COMMAND("CONT", 1, 2);
 254
 255                        tmp = auth_get_no64_data(&data, US args[2]);
 256                        if (tmp != OK) {
 257                                ret = tmp;
 258                                goto out;
 259                        }
 260
 261                        /* Added by PH: data must not contain tab (as it is
 262                        b64 it shouldn't, but check for safety). */
 263
 264                        if (Ustrchr(data, '\t') != NULL) {
 265                                ret = FAIL;
 266                                goto out;
 267                        }
 268
 269                        if (fprintf(f, "CONT\t%d\t%s\r\n", cuid, data) < 0)
 270                                OUT("authentication socket write error");
 271
 272                        break;
 273
 274                case 'F':
 275                        CHECK_COMMAND("FAIL", 1, 2);
 276
 277                        /* FIXME: add proper response handling */
 278                        if (args[2]) {
 279                                uschar *p = US strchr(args[2], '=');
 280                                if (p) {
 281                                        ++p;
 282                                        expand_nstring[1] = auth_vars[0] =
 283                                          string_copy(p);  /* PH */
 284                                        expand_nlength[1] = Ustrlen(p);
 285                                        expand_nmax = 1;
 286                                }
 287                        }
 288
 289                        ret = FAIL;
 290                        goto out;
 291
 292                case 'O':
 293                        CHECK_COMMAND("OK", 2, 2);
 294                        {
 295                                /* FIXME: add proper response handling */
 296                                uschar *p = US strchr(args[2], '=');
 297                                if (!p)
 298                                        OUT("authentication socket protocol error, username missing");
 299
 300                                p++;
 301                                expand_nstring[1] = auth_vars[0] =
 302                                  string_copy(p);  /* PH */
 303                                expand_nlength[1] = Ustrlen(p);
 304                                expand_nmax = 1;
 305                        }
 306                        ret = OK;
 307                        /* fallthrough */
 308
 309                default:
 310                        goto out;
 311                }
 312        }
 313
 314 out:   close(fd);
 315
 316        /* Expand server_condition as an authorization check */
 317        return (ret == OK)? auth_check_serv_cond(ablock) : ret;
 318 }