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                 fprintf (stderr, "%s\n", response);
 275             netsec_shutdown(nsc);
 276             nsc = NULL;
 277             return NOTOK;
 278     }
 279
 280     return NOTOK;       /* NOTREACHED */
 281 }
 282
 283
 284 /*
 285  * Our SASL callback; we are given SASL tokens and then have to format
 286  * them according to the protocol requirements, and then process incoming
 287  * messages and feed them back into the SASL library.
 288  */
 289
 290 static int
 291 pop_sasl_callback(enum sasl_message_type mtype, unsigned const char *indata,
 292                   unsigned int indatalen, unsigned char **outdata,
 293                   unsigned int *outdatalen, char **errstr)
 294 {
 295     int rc, snoopoffset;
 296     char *mech, *line;
 297     size_t len, b64len;
 298
 299     switch (mtype) {
 300     case NETSEC_SASL_START:
 301         /*
 302          * Generate our AUTH message, but there is a wrinkle.
 303          *
 304          * Technically, according to RFC 5034, if your command INCLUDING
 305          * an initial response exceeds 255 octets (including CRLF), you
 306          * can't issue this all in one go, but have to just issue the
 307          * AUTH command, wait for a blank initial response, and then
 308          * send your data.
 309          */
 310
 311         mech = netsec_get_sasl_mechanism(nsc);
 312
 313         if (indatalen) {
 314             char *b64data;
 315             b64data = mh_xmalloc(BASE64SIZE(indatalen));
 316             writeBase64raw(indata, indatalen, (unsigned char *) b64data);
 317             b64len = strlen(b64data);
 318
 319             /* Formula here is AUTH + SP + mech + SP + out + CR + LF */
 320             len = b64len + 8 + strlen(mech);
 321             if (len > 255) {
 322                 rc = netsec_printf(nsc, errstr, "AUTH %s\r\n", mech);
 323                 if (rc)
 324                     return NOTOK;
 325                 if (netsec_flush(nsc, errstr) != OK)
 326                     return NOTOK;
 327                 line = netsec_readline(nsc, &len, errstr);
 328                 if (! line)
 329                     return NOTOK;
 330                 /*
 331                  * If the protocol is being followed correctly, should just
 332                  * be a "+ ", nothing else.
 333                  */
 334                 if (len != 2 || strcmp(line, "+ ") != 0) {
 335                     netsec_err(errstr, "Did not get expected blank response "
 336                                "for initial challenge response");
 337                     return NOTOK;
 338                 }
 339                 netsec_set_snoop_callback(nsc, netsec_b64_snoop_decoder, NULL);
 340                 rc = netsec_printf(nsc, errstr, "%s\r\n", b64data);
 341                 netsec_set_snoop_callback(nsc, NULL, NULL);
 342                 free(b64data);
 343                 if (rc != OK)
 344                     return NOTOK;
 345                 if (netsec_flush(nsc, errstr) != OK)
 346                     return NOTOK;
 347             } else {
 348                 netsec_set_snoop_callback(nsc, netsec_b64_snoop_decoder,
 349                                           &snoopoffset);
 350                 snoopoffset = 6 + strlen(mech);
 351                 rc = netsec_printf(nsc, errstr, "AUTH %s %s\r\n", mech,
 352                                    b64data);
 353                 free(b64data);
 354                 netsec_set_snoop_callback(nsc, NULL, NULL);
 355                 if (rc != OK)
 356                     return NOTOK;
 357                 if (netsec_flush(nsc, errstr) != OK)
 358                     return NOTOK;
 359             }
 360         } else {
 361             if (netsec_printf(nsc, errstr, "AUTH %s\r\n", mech) != OK)
 362                 return NOTOK;
 363             if (netsec_flush(nsc, errstr) != OK)
 364                 return NOTOK;
 365         }
 366
 367         break;
 368
 369         /*
 370          * We should get one line back, with our base64 data.  Decode that
 371          * and feed it back into the SASL library.
 372          */
 373     case NETSEC_SASL_READ:
 374         netsec_set_snoop_callback(nsc, netsec_b64_snoop_decoder, &snoopoffset);
 375         snoopoffset = 2;
 376         line = netsec_readline(nsc, &len, errstr);
 377         netsec_set_snoop_callback(nsc, NULL, NULL);
 378
 379         if (line == NULL)
 380             return NOTOK;
 381         if (len < 2 || (len == 2 && strcmp(line, "+ ") != 0)) {
 382             netsec_err(errstr, "Invalid format for SASL response");
 383             return NOTOK;
 384         }
 385
 386         if (len == 2) {
 387             *outdata = NULL;
 388             *outdatalen = 0;
 389         } else {
 390             rc = decodeBase64(line + 2, outdata, &len, 0, NULL);
 391             *outdatalen = len;
 392             if (rc != OK) {
 393                 netsec_err(errstr, "Unable to decode base64 response");
 394                 return NOTOK;
 395             }
 396         }
 397         break;
 398
 399     /*
 400      * Our encoding is pretty simple, so this is easy.
 401      */
 402
 403     case NETSEC_SASL_WRITE:
 404         if (indatalen == 0) {
 405             rc = netsec_printf(nsc, errstr, "\r\n");
 406         } else {
 407             unsigned char *b64data;
 408             b64data = mh_xmalloc(BASE64SIZE(indatalen));
 409             writeBase64raw(indata, indatalen, b64data);
 410             netsec_set_snoop_callback(nsc, netsec_b64_snoop_decoder, NULL);
 411             rc = netsec_printf(nsc, errstr, "%s\r\n", b64data);
 412             netsec_set_snoop_callback(nsc, NULL, NULL);
 413             free(b64data);
 414         }
 415
 416         if (rc != OK)
 417             return NOTOK;
 418
 419         if (netsec_flush(nsc, errstr) != OK)
 420             return NOTOK;
 421         break;
 422
 423     /*
 424      * Finish the protocol; we're looking for an +OK
 425      */
 426
 427     case NETSEC_SASL_FINISH:
 428         line = netsec_readline(nsc, &len, errstr);
 429         if (line == NULL)
 430             return NOTOK;
 431
 432         if (!has_prefix(line, "+OK")) {
 433             netsec_err(errstr, "Authentication failed: %s", line);
 434             return NOTOK;
 435         }
 436         break;
 437
 438     /*
 439      * Cancel the SASL exchange in the middle of the commands; for
 440      * POP, that's a single "*".
 441      *
 442      * It's unclear to me if I should be returning errors up; I finally
 443      * decided the answer should be "yes", and if the upper layer wants to
 444      * ignore them that's their choice.
 445      */
 446
 447     case NETSEC_SASL_CANCEL:
 448         rc = netsec_printf(nsc, errstr, "*\r\n");
 449         if (rc == OK)
 450             rc = netsec_flush(nsc, errstr);
 451         if (rc != OK)
 452             return NOTOK;
 453         break;
 454     }
 455
 456     return OK;
 457 }
 458
 459 /*
 460  * Find out number of messages available
 461  * and their total size.
 462  */
 463
 464 int
 465 pop_stat (int *nmsgs, int *nbytes)
 466 {
 467
 468     if (command ("STAT") == NOTOK)
 469         return NOTOK;
 470
 471     *nmsgs = *nbytes = 0;
 472     sscanf (response, "+OK %d %d", nmsgs, nbytes);
 473
 474     return OK;
 475 }
 476
 477
 478 int
 479 pop_retr (int msgno, int (*action)(void *, char *), void *closure)
 480 {
 481     return traverse (action, closure, "RETR %d", msgno);
 482 }
 483
 484
 485 static int
 486 traverse (int (*action)(void *, char *), void *closure, const char *fmt, ...)
 487 {
 488     int result, snoopstate;
 489     va_list ap;
 490     char buffer[sizeof(response)];
 491
 492     va_start(ap, fmt);
 493     result = vcommand (fmt, ap);
 494     va_end(ap);
 495
 496     if (result == NOTOK)
 497         return NOTOK;
 498     strncpy (buffer, response, sizeof(buffer));
 499
 500     if ((snoopstate = netsec_get_snoop(nsc)))
 501         netsec_set_snoop(nsc, 0);
 502
 503     for (;;) {
 504         result = multiline();
 505         if (result == OK) {
 506             result = (*action)(closure, response);
 507             if (result == OK)
 508                 continue;
 509         } else if (result == DONE) {
 510             strncpy(response, buffer, sizeof(response));
 511             result = OK;
 512         }
 513         break;
 514     }
 515
 516     netsec_set_snoop(nsc, snoopstate);
 517     return result;
 518 }
 519
 520
 521 int
 522 pop_dele (int msgno)
 523 {
 524     return command ("DELE %d", msgno);
 525 }
 526
 527
 528 int
 529 pop_quit (void)
 530 {
 531     int i;
 532
 533     i = command ("QUIT");
 534     pop_done ();
 535
 536     return i;
 537 }
 538
 539
 540 int
 541 pop_done (void)
 542 {
 543     if (nsc)
 544         netsec_shutdown(nsc);
 545
 546     return OK;
 547 }
 548
 549
 550 int
 551 command(const char *fmt, ...)
 552 {
 553     va_list ap;
 554     int result;
 555
 556     va_start(ap, fmt);
 557     result = vcommand(fmt, ap);
 558     va_end(ap);
 559
 560     return result;
 561 }
 562
 563
 564 static int
 565 vcommand (const char *fmt, va_list ap)
 566 {
 567     /* char *cp; */
 568     char *errstr;
 569
 570     if (netsec_vprintf(nsc, &errstr, fmt, ap) != OK) {
 571         strncpy(response, errstr, sizeof(response));
 572         response[sizeof(response) - 1] = '\0';
 573         free(errstr);
 574         return NOTOK;
 575     }
 576
 577     if (netsec_printf(nsc, &errstr, "\r\n") != OK) {
 578         strncpy(response, errstr, sizeof(response));
 579         response[sizeof(response) - 1] = '\0';
 580         free(errstr);
 581         return NOTOK;
 582     }
 583
 584     if (netsec_flush(nsc, &errstr) != OK) {
 585         strncpy(response, errstr, sizeof(response));
 586         response[sizeof(response) - 1] = '\0';
 587         free(errstr);
 588         return NOTOK;
 589     }
 590
 591     switch (pop_getline (response, sizeof response, nsc)) {
 592         case OK:
 593             if (poprint)
 594                 fprintf (stderr, "<--- %s\n", response);
 595             return (*response == '+' ? OK : NOTOK);
 596
 597         case NOTOK:
 598         case DONE:
 599             if (poprint)
 600                 fprintf (stderr, "%s\n", response);
 601             return NOTOK;
 602     }
 603
 604     return NOTOK;       /* NOTREACHED */
 605 }
 606
 607
 608 int
 609 multiline (void)
 610 {
 611     char buffer[BUFSIZ + LEN(TRM)];
 612
 613     if (pop_getline (buffer, sizeof buffer, nsc) != OK)
 614         return NOTOK;
 615     if (has_prefix(buffer, TRM)) {
 616         if (buffer[LEN(TRM)] == 0)
 617             return DONE;
 618         strncpy (response, buffer + LEN(TRM), sizeof(response));
 619     }
 620     else
 621         strncpy (response, buffer, sizeof(response));
 622
 623     return OK;
 624 }
 625
 626 /*
 627  * This is now just a thin wrapper around netsec_readline().
 628  */
 629
 630 static int
 631 pop_getline (char *s, int n, netsec_context *ns)
 632 {
 633     /* int c = -2; */
 634     char *p;
 635     size_t len, destlen;
 636     /* int rc; */
 637     char *errstr;
 638
 639     p = netsec_readline(ns, &len, &errstr);
 640
 641     if (p == NULL) {
 642         strncpy(response, errstr, sizeof(response));
 643         response[sizeof(response) - 1] = '\0';
 644         free(errstr);
 645         return NOTOK;
 646     }
 647
 648     /*
 649      * If we had an error, it should have been returned already.  Since
 650      * netsec_readline() strips off the CR-LF ending, just copy the existing
 651      * buffer into response now.
 652      *
 653      * We get a length back from netsec_readline, but the rest of the POP
 654      * code doesn't handle it; the assumptions are that everything from
 655      * the network can be represented as C strings.  That should get fixed
 656      * someday.
 657      */
 658
 659     destlen = min(len, (size_t)(n - 1));
 660
 661     memcpy(s, p, destlen);
 662     s[destlen] = '\0';
 663
 664     return OK;
 665 }