diplodocus.org Git - nmh/blob - uip/popsbr.c

   1 /* popsbr.c -- POP client subroutines
   2  *
   3  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   4  * COPYRIGHT file in the root directory of the nmh distribution for
   5  * complete copyright information.
   6  */
   7
   8 #include <h/mh.h>
   9 #include <h/utils.h>
  10 #include <h/oauth.h>
  11 #include <h/netsec.h>
  12
  13 #include <h/popsbr.h>
  14 #include <h/signals.h>
  15 #include "sbr/base64.h"
  16
  17 #define TRM     "."
  18
  19 static int poprint = 0;
  20
  21 char response[BUFSIZ];
  22 static netsec_context *nsc = NULL;
  23
  24 /*
  25  * static prototypes
  26  */
  27
  28 static int command(const char *, ...) CHECK_PRINTF(1, 2);
  29 static int multiline(void);
  30
  31 static int traverse(int (*)(void *, char *), void *closure,
  32     const char *, ...) CHECK_PRINTF(3, 4);
  33 static int vcommand(const char *, va_list) CHECK_PRINTF(1, 0);
  34 static int pop_getline (char *, int, netsec_context *);
  35 static int pop_sasl_callback(enum sasl_message_type, unsigned const char *,
  36                              unsigned int, unsigned char **, unsigned int *,
  37                              char **);
  38
  39 static int
  40 check_mech(char *server_mechs, size_t server_mechs_size)
  41 {
  42   int status, sasl_capability = 0;
  43
  44     /*
  45      * First off, we're going to send the CAPA command to see if we can
  46      * even support the AUTH command, and if we do, then we'll get a
  47      * list of mechanisms the server supports.  If we don't support
  48      * the CAPA command, then it's unlikely that we will support
  49      * SASL
  50      */
  51
  52     if (command("CAPA") == NOTOK) {
  53         snprintf(response, sizeof(response),
  54                  "The POP CAPA command failed; POP server does not "
  55                  "support SASL");
  56         return NOTOK;
  57     }
  58
  59     while ((status = multiline()) != DONE) {
  60         if (status == NOTOK)
  61             return NOTOK;
  62
  63         if (strncasecmp(response, "SASL ", 5) == 0) {
  64             /* We've seen the SASL capability.  Grab the mech list. */
  65             sasl_capability++;
  66             strncpy(server_mechs, response + 5, server_mechs_size);
  67         }
  68     }
  69
  70     if (!sasl_capability) {
  71         snprintf(response, sizeof(response), "POP server does not support "
  72                  "SASL");
  73         return NOTOK;
  74     }
  75
  76     return OK;
  77 }
  78
  79 /*
  80  * Split string containing proxy command into an array of arguments
  81  * suitable for passing to exec. Returned array must be freed. Shouldn't
  82  * be possible to call this with host set to NULL.
  83  */
  84 char **
  85 parse_proxy(char *proxy, char *host)
  86 {
  87     char **pargv, **p;
  88     int pargc = 2;
  89     int hlen = strlen(host);
  90     int plen = 1;
  91     unsigned char *cur, *pro;
  92     char *c;
  93
  94     /* skip any initial space */
  95     for (pro = (unsigned char *) proxy; isspace(*pro); pro++)
  96         continue;
  97
  98     /* calculate required size for argument array */
  99     for (cur = pro; *cur; cur++) {
 100         if (isspace(*cur) && cur[1] && !isspace(cur[1]))
 101             plen++, pargc++;
 102         else if (*cur == '%' && cur[1] == 'h') {
 103             plen += hlen;
 104             cur++;
 105         } else if (!isspace(*cur))
 106             plen++;
 107     }
 108
 109    /* put together list of arguments */
 110     p = pargv = mh_xmalloc(pargc * sizeof(char *));
 111     c = *pargv = mh_xmalloc(plen * sizeof(char));
 112     for (cur = pro; *cur; cur++) {
 113         if (isspace(*cur) && cur[1] && !isspace(cur[1])) {
 114             *c++ = '\0';
 115             *++p = c;
 116         } else if (*cur == '%' && cur[1] == 'h') {
 117             strcpy (c, host);
 118             c += hlen;
 119             cur++;
 120         } else if (!isspace(*cur))
 121             *c++ = *cur;
 122     }
 123     *c = '\0';
 124     *++p = NULL;
 125     return pargv;
 126 }
 127
 128 int
 129 pop_init (char *host, char *port, char *user, char *proxy, int snoop,
 130           int sasl, char *mech, int tls, const char *oauth_svc)
 131 {
 132     int fd1, fd2;
 133     char buffer[BUFSIZ];
 134     char *errstr;
 135
 136     nsc = netsec_init();
 137
 138     if (user)
 139         netsec_set_userid(nsc, user);
 140
 141     netsec_set_hostname(nsc, host);
 142
 143     if (oauth_svc != NULL) {
 144         if (netsec_set_oauth_service(nsc, oauth_svc) != OK) {
 145             snprintf(response, sizeof(response), "OAuth2 not supported");
 146             return NOTOK;
 147         }
 148     }
 149
 150     if (proxy && *proxy) {
 151        int pid;
 152        int inpipe[2];     /* for reading from the server */
 153        int outpipe[2];    /* for sending to the server */
 154
 155        if (pipe(inpipe) < 0) {
 156            adios ("inpipe", "pipe");
 157        }
 158        if (pipe(outpipe) < 0) {
 159            adios ("outpipe", "pipe");
 160        }
 161
 162        pid=fork();
 163        if (pid==0) {
 164            char **argv;
 165
 166            /* in child */
 167            close(0);
 168            close(1);
 169            dup2(outpipe[0],0);  /* connect read end of connection */
 170            dup2(inpipe[1], 1);  /* connect write end of connection */
 171            if(inpipe[0]>1) close(inpipe[0]);
 172            if(inpipe[1]>1) close(inpipe[1]);
 173            if(outpipe[0]>1) close(outpipe[0]);
 174            if(outpipe[1]>1) close(outpipe[1]);
 175
 176            /* run the proxy command */
 177            argv=parse_proxy(proxy, host);
 178            execvp(argv[0],argv);
 179
 180            perror(argv[0]);
 181            close(0);
 182            close(1);
 183            free(*argv);
 184            free(argv);
 185            exit(10);
 186        }
 187
 188        /* okay in the parent we do some stuff */
 189        close(inpipe[1]);  /* child uses this */
 190        close(outpipe[0]); /* child uses this */
 191
 192        /* we read on fd1 */
 193        fd1=inpipe[0];
 194        /* and write on fd2 */
 195        fd2=outpipe[1];
 196
 197     } else {
 198         if ((fd1 = client (host, port ? port : "pop3", response,
 199                            sizeof(response), snoop)) == NOTOK) {
 200             return NOTOK;
 201         }
 202         fd2 = fd1;
 203     }
 204
 205     SIGNAL (SIGPIPE, SIG_IGN);
 206
 207     netsec_set_fd(nsc, fd1, fd2);
 208     netsec_set_snoop(nsc, snoop);
 209
 210     if (tls & P_INITTLS) {
 211         if (netsec_set_tls(nsc, 1, tls & P_NOVERIFY, &errstr) != OK) {
 212             snprintf(response, sizeof(response), "%s", errstr);
 213             free(errstr);
 214             return NOTOK;
 215         }
 216
 217         if (netsec_negotiate_tls(nsc, &errstr) != OK) {
 218             snprintf(response, sizeof(response), "%s", errstr);
 219             free(errstr);
 220             return NOTOK;
 221         }
 222     }
 223
 224     if (sasl) {
 225         if (netsec_set_sasl_params(nsc, "pop", mech, pop_sasl_callback,
 226                                    &errstr) != OK) {
 227             snprintf(response, sizeof(response), "%s", errstr);
 228             free(errstr);
 229             return NOTOK;
 230         }
 231     }
 232
 233     switch (pop_getline (response, sizeof response, nsc)) {
 234         case OK:
 235             if (poprint)
 236                 fprintf (stderr, "<--- %s\n", response);
 237             if (*response == '+') {
 238                 nmh_creds_t creds;
 239
 240                 if (sasl) {
 241                     char server_mechs[256];
 242                     if (check_mech(server_mechs, sizeof(server_mechs)) != OK)
 243                         return NOTOK;
 244                     if (netsec_negotiate_sasl(nsc, server_mechs,
 245                                               &errstr) != OK) {
 246                         strncpy(response, errstr, sizeof(response));
 247                         response[sizeof(response) - 1] = '\0';
 248                         free(errstr);
 249                         return NOTOK;
 250                     }
 251                     return OK;
 252                 }
 253
 254                 if (!(creds = nmh_get_credentials(host, user)))
 255                     return NOTOK;
 256                 if (command ("USER %s", nmh_cred_get_user(creds))
 257                                                             != NOTOK) {
 258                     if (command("PASS %s", nmh_cred_get_password(creds))
 259                                                             != NOTOK) {
 260                         nmh_credentials_free(creds);
 261                         return OK;
 262                     }
 263                 }
 264                 nmh_credentials_free(creds);
 265             }
 266             strncpy (buffer, response, sizeof(buffer));
 267             command ("QUIT");
 268             strncpy (response, buffer, sizeof(response));
 269             /* FALLTHRU */
 270
 271         case NOTOK:
 272         case DONE:
 273             if (poprint) {
 274                 fputs(response, stderr);
 275                 putc('\n', stderr);
 276             }
 277             netsec_shutdown(nsc);
 278             nsc = NULL;
 279             return NOTOK;
 280     }
 281
 282     return NOTOK;       /* NOTREACHED */
 283 }
 284
 285
 286 /*
 287  * Our SASL callback; we are given SASL tokens and then have to format
 288  * them according to the protocol requirements, and then process incoming
 289  * messages and feed them back into the SASL library.
 290  */
 291
 292 static int
 293 pop_sasl_callback(enum sasl_message_type mtype, unsigned const char *indata,
 294                   unsigned int indatalen, unsigned char **outdata,
 295                   unsigned int *outdatalen, char **errstr)
 296 {
 297     int rc, snoopoffset;
 298     char *mech, *line;
 299     size_t len, b64len;
 300
 301     switch (mtype) {
 302     case NETSEC_SASL_START:
 303         /*
 304          * Generate our AUTH message, but there is a wrinkle.
 305          *
 306          * Technically, according to RFC 5034, if your command INCLUDING
 307          * an initial response exceeds 255 octets (including CRLF), you
 308          * can't issue this all in one go, but have to just issue the
 309          * AUTH command, wait for a blank initial response, and then
 310          * send your data.
 311          */
 312
 313         mech = netsec_get_sasl_mechanism(nsc);
 314
 315         if (indatalen) {
 316             char *b64data;
 317             b64data = mh_xmalloc(BASE64SIZE(indatalen));
 318             writeBase64raw(indata, indatalen, (unsigned char *) b64data);
 319             b64len = strlen(b64data);
 320
 321             /* Formula here is AUTH + SP + mech + SP + out + CR + LF */
 322             len = b64len + 8 + strlen(mech);
 323             if (len > 255) {
 324                 rc = netsec_printf(nsc, errstr, "AUTH %s\r\n", mech);
 325                 if (rc)
 326                     return NOTOK;
 327                 if (netsec_flush(nsc, errstr) != OK)
 328                     return NOTOK;
 329                 line = netsec_readline(nsc, &len, errstr);
 330                 if (! line)
 331                     return NOTOK;
 332                 /*
 333                  * If the protocol is being followed correctly, should just
 334                  * be a "+ ", nothing else.
 335                  */
 336                 if (len != 2 || strcmp(line, "+ ") != 0) {
 337                     netsec_err(errstr, "Did not get expected blank response "
 338                                "for initial challenge response");
 339                     return NOTOK;
 340                 }
 341                 netsec_set_snoop_callback(nsc, netsec_b64_snoop_decoder, NULL);
 342                 rc = netsec_printf(nsc, errstr, "%s\r\n", b64data);
 343                 netsec_set_snoop_callback(nsc, NULL, NULL);
 344                 free(b64data);
 345                 if (rc != OK)
 346                     return NOTOK;
 347                 if (netsec_flush(nsc, errstr) != OK)
 348                     return NOTOK;
 349             } else {
 350                 netsec_set_snoop_callback(nsc, netsec_b64_snoop_decoder,
 351                                           &snoopoffset);
 352                 snoopoffset = 6 + strlen(mech);
 353                 rc = netsec_printf(nsc, errstr, "AUTH %s %s\r\n", mech,
 354                                    b64data);
 355                 free(b64data);
 356                 netsec_set_snoop_callback(nsc, NULL, NULL);
 357                 if (rc != OK)
 358                     return NOTOK;
 359                 if (netsec_flush(nsc, errstr) != OK)
 360                     return NOTOK;
 361             }
 362         } else {
 363             if (netsec_printf(nsc, errstr, "AUTH %s\r\n", mech) != OK)
 364                 return NOTOK;
 365             if (netsec_flush(nsc, errstr) != OK)
 366                 return NOTOK;
 367         }
 368
 369         break;
 370
 371         /*
 372          * We should get one line back, with our base64 data.  Decode that
 373          * and feed it back into the SASL library.
 374          */
 375     case NETSEC_SASL_READ:
 376         netsec_set_snoop_callback(nsc, netsec_b64_snoop_decoder, &snoopoffset);
 377         snoopoffset = 2;
 378         line = netsec_readline(nsc, &len, errstr);
 379         netsec_set_snoop_callback(nsc, NULL, NULL);
 380
 381         if (line == NULL)
 382             return NOTOK;
 383         if (len < 2 || (len == 2 && strcmp(line, "+ ") != 0)) {
 384             netsec_err(errstr, "Invalid format for SASL response");
 385             return NOTOK;
 386         }
 387
 388         if (len == 2) {
 389             *outdata = NULL;
 390             *outdatalen = 0;
 391         } else {
 392             rc = decodeBase64(line + 2, outdata, &len, 0, NULL);
 393             *outdatalen = len;
 394             if (rc != OK) {
 395                 netsec_err(errstr, "Unable to decode base64 response");
 396                 return NOTOK;
 397             }
 398         }
 399         break;
 400
 401     /*
 402      * Our encoding is pretty simple, so this is easy.
 403      */
 404
 405     case NETSEC_SASL_WRITE:
 406         if (indatalen == 0) {
 407             rc = netsec_printf(nsc, errstr, "\r\n");
 408         } else {
 409             unsigned char *b64data;
 410             b64data = mh_xmalloc(BASE64SIZE(indatalen));
 411             writeBase64raw(indata, indatalen, b64data);
 412             netsec_set_snoop_callback(nsc, netsec_b64_snoop_decoder, NULL);
 413             rc = netsec_printf(nsc, errstr, "%s\r\n", b64data);
 414             netsec_set_snoop_callback(nsc, NULL, NULL);
 415             free(b64data);
 416         }
 417
 418         if (rc != OK)
 419             return NOTOK;
 420
 421         if (netsec_flush(nsc, errstr) != OK)
 422             return NOTOK;
 423         break;
 424
 425     /*
 426      * Finish the protocol; we're looking for an +OK
 427      */
 428
 429     case NETSEC_SASL_FINISH:
 430         line = netsec_readline(nsc, &len, errstr);
 431         if (line == NULL)
 432             return NOTOK;
 433
 434         if (!has_prefix(line, "+OK")) {
 435             netsec_err(errstr, "Authentication failed: %s", line);
 436             return NOTOK;
 437         }
 438         break;
 439
 440     /*
 441      * Cancel the SASL exchange in the middle of the commands; for
 442      * POP, that's a single "*".
 443      *
 444      * It's unclear to me if I should be returning errors up; I finally
 445      * decided the answer should be "yes", and if the upper layer wants to
 446      * ignore them that's their choice.
 447      */
 448
 449     case NETSEC_SASL_CANCEL:
 450         rc = netsec_printf(nsc, errstr, "*\r\n");
 451         if (rc == OK)
 452             rc = netsec_flush(nsc, errstr);
 453         if (rc != OK)
 454             return NOTOK;
 455         break;
 456     }
 457
 458     return OK;
 459 }
 460
 461 /*
 462  * Find out number of messages available
 463  * and their total size.
 464  */
 465
 466 int
 467 pop_stat (int *nmsgs, int *nbytes)
 468 {
 469
 470     if (command ("STAT") == NOTOK)
 471         return NOTOK;
 472
 473     *nmsgs = *nbytes = 0;
 474     sscanf (response, "+OK %d %d", nmsgs, nbytes);
 475
 476     return OK;
 477 }
 478
 479
 480 int
 481 pop_retr (int msgno, int (*action)(void *, char *), void *closure)
 482 {
 483     return traverse (action, closure, "RETR %d", msgno);
 484 }
 485
 486
 487 static int
 488 traverse (int (*action)(void *, char *), void *closure, const char *fmt, ...)
 489 {
 490     int result, snoopstate;
 491     va_list ap;
 492     char buffer[sizeof(response)];
 493
 494     va_start(ap, fmt);
 495     result = vcommand (fmt, ap);
 496     va_end(ap);
 497
 498     if (result == NOTOK)
 499         return NOTOK;
 500     strncpy (buffer, response, sizeof(buffer));
 501
 502     if ((snoopstate = netsec_get_snoop(nsc)))
 503         netsec_set_snoop(nsc, 0);
 504
 505     for (;;) {
 506         result = multiline();
 507         if (result == OK) {
 508             result = (*action)(closure, response);
 509             if (result == OK)
 510                 continue;
 511         } else if (result == DONE) {
 512             strncpy(response, buffer, sizeof(response));
 513             result = OK;
 514         }
 515         break;
 516     }
 517
 518     netsec_set_snoop(nsc, snoopstate);
 519     return result;
 520 }
 521
 522
 523 int
 524 pop_dele (int msgno)
 525 {
 526     return command ("DELE %d", msgno);
 527 }
 528
 529
 530 int
 531 pop_quit (void)
 532 {
 533     int i;
 534
 535     i = command ("QUIT");
 536     pop_done ();
 537
 538     return i;
 539 }
 540
 541
 542 int
 543 pop_done (void)
 544 {
 545     if (nsc)
 546         netsec_shutdown(nsc);
 547
 548     return OK;
 549 }
 550
 551
 552 int
 553 command(const char *fmt, ...)
 554 {
 555     va_list ap;
 556     int result;
 557
 558     va_start(ap, fmt);
 559     result = vcommand(fmt, ap);
 560     va_end(ap);
 561
 562     return result;
 563 }
 564
 565
 566 static int
 567 vcommand (const char *fmt, va_list ap)
 568 {
 569     /* char *cp; */
 570     char *errstr;
 571
 572     if (netsec_vprintf(nsc, &errstr, fmt, ap) != OK) {
 573         strncpy(response, errstr, sizeof(response));
 574         response[sizeof(response) - 1] = '\0';
 575         free(errstr);
 576         return NOTOK;
 577     }
 578
 579     if (netsec_printf(nsc, &errstr, "\r\n") != OK) {
 580         strncpy(response, errstr, sizeof(response));
 581         response[sizeof(response) - 1] = '\0';
 582         free(errstr);
 583         return NOTOK;
 584     }
 585
 586     if (netsec_flush(nsc, &errstr) != OK) {
 587         strncpy(response, errstr, sizeof(response));
 588         response[sizeof(response) - 1] = '\0';
 589         free(errstr);
 590         return NOTOK;
 591     }
 592
 593     switch (pop_getline (response, sizeof response, nsc)) {
 594         case OK:
 595             if (poprint)
 596                 fprintf (stderr, "<--- %s\n", response);
 597             return (*response == '+' ? OK : NOTOK);
 598
 599         case NOTOK:
 600         case DONE:
 601             if (poprint) {
 602                 fputs(response, stderr);
 603                 putc('\n', stderr);
 604             }
 605             return NOTOK;
 606     }
 607
 608     return NOTOK;       /* NOTREACHED */
 609 }
 610
 611
 612 int
 613 multiline (void)
 614 {
 615     char buffer[BUFSIZ + LEN(TRM)];
 616
 617     if (pop_getline (buffer, sizeof buffer, nsc) != OK)
 618         return NOTOK;
 619     if (has_prefix(buffer, TRM)) {
 620         if (buffer[LEN(TRM)] == 0)
 621             return DONE;
 622         strncpy (response, buffer + LEN(TRM), sizeof(response));
 623     }
 624     else
 625         strncpy (response, buffer, sizeof(response));
 626
 627     return OK;
 628 }
 629
 630 /*
 631  * This is now just a thin wrapper around netsec_readline().
 632  */
 633
 634 static int
 635 pop_getline (char *s, int n, netsec_context *ns)
 636 {
 637     /* int c = -2; */
 638     char *p;
 639     size_t len, destlen;
 640     /* int rc; */
 641     char *errstr;
 642
 643     p = netsec_readline(ns, &len, &errstr);
 644
 645     if (p == NULL) {
 646         strncpy(response, errstr, sizeof(response));
 647         response[sizeof(response) - 1] = '\0';
 648         free(errstr);
 649         return NOTOK;
 650     }
 651
 652     /*
 653      * If we had an error, it should have been returned already.  Since
 654      * netsec_readline() strips off the CR-LF ending, just copy the existing
 655      * buffer into response now.
 656      *
 657      * We get a length back from netsec_readline, but the rest of the POP
 658      * code doesn't handle it; the assumptions are that everything from
 659      * the network can be represented as C strings.  That should get fixed
 660      * someday.
 661      */
 662
 663     destlen = min(len, (size_t)(n - 1));
 664
 665     memcpy(s, p, destlen);
 666     s[destlen] = '\0';
 667
 668     return OK;
 669 }