1 /*
2 * Copyright (c) 1998-2003, 2006 Sendmail, Inc. and its suppliers.
3 * All rights reserved.
4 * Copyright (c) 1994, 1996-1997 Eric P. Allman. All rights reserved.
5 * Copyright (c) 1994
6 * The Regents of the University of California. All rights reserved.
7 *
8 * By using this file, you agree to the terms and conditions set
9 * forth in the LICENSE file which can be found at the top level of
10 * the sendmail distribution.
11 *
12 */
13
14 #include <sendmail.h>
15 #include <string.h>
16
17 SM_RCSID("@(#)$Id: mime.c,v 8.147 2007/09/26 23:29:11 ca Exp $")
18
19 /*
20 ** MIME support.
21 **
22 ** I am indebted to John Beck of Hewlett-Packard, who contributed
23 ** his code to me for inclusion. As it turns out, I did not use
24 ** his code since he used a "minimum change" approach that used
25 ** several temp files, and I wanted a "minimum impact" approach
26 ** that would avoid copying. However, looking over his code
27 ** helped me cement my understanding of the problem.
28 **
29 ** I also looked at, but did not directly use, Nathaniel
30 ** Borenstein's "code.c" module. Again, it functioned as
31 ** a file-to-file translator, which did not fit within my
32 ** design bounds, but it was a useful base for understanding
33 ** the problem.
34 */
35
36 /* use "old" mime 7 to 8 algorithm by default */
37 #ifndef MIME7TO8_OLD
38 # define MIME7TO8_OLD 1
39 #endif /* ! MIME7TO8_OLD */
40
41 #if MIME8TO7
42 static int isboundary __P((char *, char **));
43 static int mimeboundary __P((char *, char **));
44 static int mime_getchar __P((SM_FILE_T *, char **, int *));
45 static int mime_getchar_crlf __P((SM_FILE_T *, char **, int *));
46
47 /* character set for hex and base64 encoding */
48 static char Base16Code[] = "0123456789ABCDEF";
49 static char Base64Code[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
50
51 /* types of MIME boundaries */
52 # define MBT_SYNTAX 0 /* syntax error */
53 # define MBT_NOTSEP 1 /* not a boundary */
54 # define MBT_INTERMED 2 /* intermediate boundary (no trailing --) */
55 # define MBT_FINAL 3 /* final boundary (trailing -- included) */
56
57 static char *MimeBoundaryNames[] =
58 {
59 "SYNTAX", "NOTSEP", "INTERMED", "FINAL"
60 };
61
62 static bool MapNLtoCRLF;
63
64 /*
65 ** MIME8TO7 -- output 8 bit body in 7 bit format
66 **
67 ** The header has already been output -- this has to do the
68 ** 8 to 7 bit conversion. It would be easy if we didn't have
69 ** to deal with nested formats (multipart/xxx and message/rfc822).
70 **
71 ** We won't be called if we don't have to do a conversion, and
72 ** appropriate MIME-Version: and Content-Type: fields have been
73 ** output. Any Content-Transfer-Encoding: field has not been
74 ** output, and we can add it here.
75 **
76 ** Parameters:
77 ** mci -- mailer connection information.
78 ** header -- the header for this body part.
79 ** e -- envelope.
80 ** boundaries -- the currently pending message boundaries.
81 ** NULL if we are processing the outer portion.
82 ** flags -- to tweak processing.
83 ** level -- recursion level.
84 **
85 ** Returns:
86 ** An indicator of what terminated the message part:
87 ** MBT_FINAL -- the final boundary
88 ** MBT_INTERMED -- an intermediate boundary
89 ** MBT_NOTSEP -- an end of file
90 ** SM_IO_EOF -- I/O error occurred
91 */
92
93 struct args
94 {
95 char *a_field; /* name of field */
96 char *a_value; /* value of that field */
97 };
98
99 int
mime8to7(mci,header,e,boundaries,flags,level)100 mime8to7(mci, header, e, boundaries, flags, level)
101 register MCI *mci;
102 HDR *header;
103 register ENVELOPE *e;
104 char **boundaries;
105 int flags;
106 int level;
107 {
108 register char *p;
109 int linelen;
110 int bt;
111 off_t offset;
112 size_t sectionsize, sectionhighbits;
113 int i;
114 char *type;
115 char *subtype;
116 char *cte;
117 char **pvp;
118 int argc = 0;
119 char *bp;
120 bool use_qp = false;
121 struct args argv[MAXMIMEARGS];
122 char bbuf[128];
123 char buf[MAXLINE];
124 char pvpbuf[MAXLINE];
125 extern unsigned char MimeTokenTab[256];
126
127 if (level > MAXMIMENESTING)
128 {
129 if (!bitset(EF_TOODEEP, e->e_flags))
130 {
131 if (tTd(43, 4))
132 sm_dprintf("mime8to7: too deep, level=%d\n",
133 level);
134 usrerr("mime8to7: recursion level %d exceeded",
135 level);
136 e->e_flags |= EF_DONT_MIME|EF_TOODEEP;
137 }
138 }
139 if (tTd(43, 1))
140 {
141 sm_dprintf("mime8to7: flags = %x, boundaries =", flags);
142 if (boundaries[0] == NULL)
143 sm_dprintf(" <none>");
144 else
145 {
146 for (i = 0; boundaries[i] != NULL; i++)
147 sm_dprintf(" %s", boundaries[i]);
148 }
149 sm_dprintf("\n");
150 }
151 MapNLtoCRLF = true;
152 p = hvalue("Content-Transfer-Encoding", header);
153 if (p == NULL ||
154 (pvp = prescan(p, '\0', pvpbuf, sizeof(pvpbuf), NULL,
155 MimeTokenTab, false)) == NULL ||
156 pvp[0] == NULL)
157 {
158 cte = NULL;
159 }
160 else
161 {
162 cataddr(pvp, NULL, buf, sizeof(buf), '\0', false);
163 cte = sm_rpool_strdup_x(e->e_rpool, buf);
164 }
165
166 type = subtype = NULL;
167 p = hvalue("Content-Type", header);
168 if (p == NULL)
169 {
170 if (bitset(M87F_DIGEST, flags))
171 p = "message/rfc822";
172 else
173 p = "text/plain";
174 }
175 if (p != NULL &&
176 (pvp = prescan(p, '\0', pvpbuf, sizeof(pvpbuf), NULL,
177 MimeTokenTab, false)) != NULL &&
178 pvp[0] != NULL)
179 {
180 if (tTd(43, 40))
181 {
182 for (i = 0; pvp[i] != NULL; i++)
183 sm_dprintf("pvp[%d] = \"%s\"\n", i, pvp[i]);
184 }
185 type = *pvp++;
186 if (*pvp != NULL && strcmp(*pvp, "/") == 0 &&
187 *++pvp != NULL)
188 {
189 subtype = *pvp++;
190 }
191
192 /* break out parameters */
193 while (*pvp != NULL && argc < MAXMIMEARGS)
194 {
195 /* skip to semicolon separator */
196 while (*pvp != NULL && strcmp(*pvp, ";") != 0)
197 pvp++;
198 if (*pvp++ == NULL || *pvp == NULL)
199 break;
200
201 /* complain about empty values */
202 if (strcmp(*pvp, ";") == 0)
203 {
204 usrerr("mime8to7: Empty parameter in Content-Type header");
205
206 /* avoid bounce loops */
207 e->e_flags |= EF_DONT_MIME;
208 continue;
209 }
210
211 /* extract field name */
212 argv[argc].a_field = *pvp++;
213
214 /* see if there is a value */
215 if (*pvp != NULL && strcmp(*pvp, "=") == 0 &&
216 (*++pvp == NULL || strcmp(*pvp, ";") != 0))
217 {
218 argv[argc].a_value = *pvp;
219 argc++;
220 }
221 }
222 }
223
224 /* check for disaster cases */
225 if (type == NULL)
226 type = "-none-";
227 if (subtype == NULL)
228 subtype = "-none-";
229
230 /* don't propagate some flags more than one level into the message */
231 flags &= ~M87F_DIGEST;
232
233 /*
234 ** Check for cases that can not be encoded.
235 **
236 ** For example, you can't encode certain kinds of types
237 ** or already-encoded messages. If we find this case,
238 ** just copy it through.
239 */
240
241 (void) sm_snprintf(buf, sizeof(buf), "%.100s/%.100s", type, subtype);
242 if (wordinclass(buf, 'n') || (cte != NULL && !wordinclass(cte, 'e')))
243 flags |= M87F_NO8BIT;
244
245 # ifdef USE_B_CLASS
246 if (wordinclass(buf, 'b') || wordinclass(type, 'b'))
247 MapNLtoCRLF = false;
248 # endif /* USE_B_CLASS */
249 if (wordinclass(buf, 'q') || wordinclass(type, 'q'))
250 use_qp = true;
251
252 /*
253 ** Multipart requires special processing.
254 **
255 ** Do a recursive descent into the message.
256 */
257
258 if (sm_strcasecmp(type, "multipart") == 0 &&
259 (!bitset(M87F_NO8BIT, flags) || bitset(M87F_NO8TO7, flags)) &&
260 !bitset(EF_TOODEEP, e->e_flags)
261 )
262 {
263
264 if (sm_strcasecmp(subtype, "digest") == 0)
265 flags |= M87F_DIGEST;
266
267 for (i = 0; i < argc; i++)
268 {
269 if (sm_strcasecmp(argv[i].a_field, "boundary") == 0)
270 break;
271 }
272 if (i >= argc || argv[i].a_value == NULL)
273 {
274 usrerr("mime8to7: Content-Type: \"%s\": %s boundary",
275 i >= argc ? "missing" : "bogus", p);
276 p = "---";
277
278 /* avoid bounce loops */
279 e->e_flags |= EF_DONT_MIME;
280 }
281 else
282 {
283 p = argv[i].a_value;
284 stripquotes(p);
285 }
286 if (sm_strlcpy(bbuf, p, sizeof(bbuf)) >= sizeof(bbuf))
287 {
288 usrerr("mime8to7: multipart boundary \"%s\" too long",
289 p);
290
291 /* avoid bounce loops */
292 e->e_flags |= EF_DONT_MIME;
293 }
294
295 if (tTd(43, 1))
296 sm_dprintf("mime8to7: multipart boundary \"%s\"\n",
297 bbuf);
298 for (i = 0; i < MAXMIMENESTING; i++)
299 {
300 if (boundaries[i] == NULL)
301 break;
302 }
303 if (i >= MAXMIMENESTING)
304 {
305 if (tTd(43, 4))
306 sm_dprintf("mime8to7: too deep, i=%d\n", i);
307 if (!bitset(EF_TOODEEP, e->e_flags))
308 usrerr("mime8to7: multipart nesting boundary too deep");
309
310 /* avoid bounce loops */
311 e->e_flags |= EF_DONT_MIME|EF_TOODEEP;
312 }
313 else
314 {
315 boundaries[i] = bbuf;
316 boundaries[i + 1] = NULL;
317 }
318 mci->mci_flags |= MCIF_INMIME;
319
320 /* skip the early "comment" prologue */
321 if (!putline("", mci))
322 goto writeerr;
323 mci->mci_flags &= ~MCIF_INHEADER;
324 bt = MBT_FINAL;
325 while (sm_io_fgets(e->e_dfp, SM_TIME_DEFAULT, buf, sizeof(buf))
326 != NULL)
327 {
328 bt = mimeboundary(buf, boundaries);
329 if (bt != MBT_NOTSEP)
330 break;
331 if (!putxline(buf, strlen(buf), mci,
332 PXLF_MAPFROM|PXLF_STRIP8BIT))
333 goto writeerr;
334 if (tTd(43, 99))
335 sm_dprintf(" ...%s", buf);
336 }
337 if (sm_io_eof(e->e_dfp))
338 bt = MBT_FINAL;
339 while (bt != MBT_FINAL)
340 {
341 auto HDR *hdr = NULL;
342
343 (void) sm_strlcpyn(buf, sizeof(buf), 2, "--", bbuf);
344 if (!putline(buf, mci))
345 goto writeerr;
346 if (tTd(43, 35))
347 sm_dprintf(" ...%s\n", buf);
348 collect(e->e_dfp, false, &hdr, e, false);
349 if (tTd(43, 101))
350 putline("+++after collect", mci);
351 if (!putheader(mci, hdr, e, flags))
352 goto writeerr;
353 if (tTd(43, 101))
354 putline("+++after putheader", mci);
355 bt = mime8to7(mci, hdr, e, boundaries, flags,
356 level + 1);
357 if (bt == SM_IO_EOF)
358 goto writeerr;
359 }
360 (void) sm_strlcpyn(buf, sizeof(buf), 3, "--", bbuf, "--");
361 if (!putline(buf, mci))
362 goto writeerr;
363 if (tTd(43, 35))
364 sm_dprintf(" ...%s\n", buf);
365 boundaries[i] = NULL;
366 mci->mci_flags &= ~MCIF_INMIME;
367
368 /* skip the late "comment" epilogue */
369 while (sm_io_fgets(e->e_dfp, SM_TIME_DEFAULT, buf, sizeof(buf))
370 != NULL)
371 {
372 bt = mimeboundary(buf, boundaries);
373 if (bt != MBT_NOTSEP)
374 break;
375 if (!putxline(buf, strlen(buf), mci,
376 PXLF_MAPFROM|PXLF_STRIP8BIT))
377 goto writeerr;
378 if (tTd(43, 99))
379 sm_dprintf(" ...%s", buf);
380 }
381 if (sm_io_eof(e->e_dfp))
382 bt = MBT_FINAL;
383 if (tTd(43, 3))
384 sm_dprintf("\t\t\tmime8to7=>%s (multipart)\n",
385 MimeBoundaryNames[bt]);
386 return bt;
387 }
388
389 /*
390 ** Message/xxx types -- recurse exactly once.
391 **
392 ** Class 's' is predefined to have "rfc822" only.
393 */
394
395 if (sm_strcasecmp(type, "message") == 0)
396 {
397 if (!wordinclass(subtype, 's') ||
398 bitset(EF_TOODEEP, e->e_flags))
399 {
400 flags |= M87F_NO8BIT;
401 }
402 else
403 {
404 auto HDR *hdr = NULL;
405
406 if (!putline("", mci))
407 goto writeerr;
408
409 mci->mci_flags |= MCIF_INMIME;
410 collect(e->e_dfp, false, &hdr, e, false);
411 if (tTd(43, 101))
412 putline("+++after collect", mci);
413 if (!putheader(mci, hdr, e, flags))
414 goto writeerr;
415 if (tTd(43, 101))
416 putline("+++after putheader", mci);
417 if (hvalue("MIME-Version", hdr) == NULL &&
418 !bitset(M87F_NO8TO7, flags) &&
419 !putline("MIME-Version: 1.0", mci))
420 goto writeerr;
421 bt = mime8to7(mci, hdr, e, boundaries, flags,
422 level + 1);
423 mci->mci_flags &= ~MCIF_INMIME;
424 return bt;
425 }
426 }
427
428 /*
429 ** Non-compound body type
430 **
431 ** Compute the ratio of seven to eight bit characters;
432 ** use that as a heuristic to decide how to do the
433 ** encoding.
434 */
435
436 sectionsize = sectionhighbits = 0;
437 if (!bitset(M87F_NO8BIT|M87F_NO8TO7, flags))
438 {
439 /* remember where we were */
440 offset = sm_io_tell(e->e_dfp, SM_TIME_DEFAULT);
441 if (offset == -1)
442 syserr("mime8to7: cannot sm_io_tell on %cf%s",
443 DATAFL_LETTER, e->e_id);
444
445 /* do a scan of this body type to count character types */
446 while (sm_io_fgets(e->e_dfp, SM_TIME_DEFAULT, buf, sizeof(buf))
447 != NULL)
448 {
449 if (mimeboundary(buf, boundaries) != MBT_NOTSEP)
450 break;
451 for (p = buf; *p != '\0'; p++)
452 {
453 /* count bytes with the high bit set */
454 sectionsize++;
455 if (bitset(0200, *p))
456 sectionhighbits++;
457 }
458
459 /*
460 ** Heuristic: if 1/4 of the first 4K bytes are 8-bit,
461 ** assume base64. This heuristic avoids double-reading
462 ** large graphics or video files.
463 */
464
465 if (sectionsize >= 4096 &&
466 sectionhighbits > sectionsize / 4)
467 break;
468 }
469
470 /* return to the original offset for processing */
471 /* XXX use relative seeks to handle >31 bit file sizes? */
472 if (sm_io_seek(e->e_dfp, SM_TIME_DEFAULT, offset, SEEK_SET) < 0)
473 syserr("mime8to7: cannot sm_io_fseek on %cf%s",
474 DATAFL_LETTER, e->e_id);
475 else
476 sm_io_clearerr(e->e_dfp);
477 }
478
479 /*
480 ** Heuristically determine encoding method.
481 ** If more than 1/8 of the total characters have the
482 ** eighth bit set, use base64; else use quoted-printable.
483 ** However, only encode binary encoded data as base64,
484 ** since otherwise the NL=>CRLF mapping will be a problem.
485 */
486
487 if (tTd(43, 8))
488 {
489 sm_dprintf("mime8to7: %ld high bit(s) in %ld byte(s), cte=%s, type=%s/%s\n",
490 (long) sectionhighbits, (long) sectionsize,
491 cte == NULL ? "[none]" : cte,
492 type == NULL ? "[none]" : type,
493 subtype == NULL ? "[none]" : subtype);
494 }
495 if (cte != NULL && sm_strcasecmp(cte, "binary") == 0)
496 sectionsize = sectionhighbits;
497 linelen = 0;
498 bp = buf;
499 if (sectionhighbits == 0)
500 {
501 /* no encoding necessary */
502 if (cte != NULL &&
503 bitset(MCIF_CVT8TO7|MCIF_CVT7TO8|MCIF_INMIME,
504 mci->mci_flags) &&
505 !bitset(M87F_NO8TO7, flags))
506 {
507 /*
508 ** Skip _unless_ in MIME mode and potentially
509 ** converting from 8 bit to 7 bit MIME. See
510 ** putheader() for the counterpart where the
511 ** CTE header is skipped in the opposite
512 ** situation.
513 */
514
515 (void) sm_snprintf(buf, sizeof(buf),
516 "Content-Transfer-Encoding: %.200s", cte);
517 if (!putline(buf, mci))
518 goto writeerr;
519 if (tTd(43, 36))
520 sm_dprintf(" ...%s\n", buf);
521 }
522 if (!putline("", mci))
523 goto writeerr;
524 mci->mci_flags &= ~MCIF_INHEADER;
525 while (sm_io_fgets(e->e_dfp, SM_TIME_DEFAULT, buf, sizeof(buf))
526 != NULL)
527 {
528 if (!bitset(MCIF_INLONGLINE, mci->mci_flags))
529 {
530 bt = mimeboundary(buf, boundaries);
531 if (bt != MBT_NOTSEP)
532 break;
533 }
534 if (!putxline(buf, strlen(buf), mci,
535 PXLF_MAPFROM|PXLF_NOADDEOL))
536 goto writeerr;
537 }
538 if (sm_io_eof(e->e_dfp))
539 bt = MBT_FINAL;
540 }
541 else if (!MapNLtoCRLF ||
542 (sectionsize / 8 < sectionhighbits && !use_qp))
543 {
544 /* use base64 encoding */
545 int c1, c2;
546
547 if (tTd(43, 36))
548 sm_dprintf(" ...Content-Transfer-Encoding: base64\n");
549 if (!putline("Content-Transfer-Encoding: base64", mci))
550 goto writeerr;
551 (void) sm_snprintf(buf, sizeof(buf),
552 "X-MIME-Autoconverted: from 8bit to base64 by %s id %s",
553 MyHostName, e->e_id);
554 if (!putline(buf, mci) || !putline("", mci))
555 goto writeerr;
556 mci->mci_flags &= ~MCIF_INHEADER;
557 while ((c1 = mime_getchar_crlf(e->e_dfp, boundaries, &bt)) !=
558 SM_IO_EOF)
559 {
560 if (linelen > 71)
561 {
562 *bp = '\0';
563 if (!putline(buf, mci))
564 goto writeerr;
565 linelen = 0;
566 bp = buf;
567 }
568 linelen += 4;
569 *bp++ = Base64Code[(c1 >> 2)];
570 c1 = (c1 & 0x03) << 4;
571 c2 = mime_getchar_crlf(e->e_dfp, boundaries, &bt);
572 if (c2 == SM_IO_EOF)
573 {
574 *bp++ = Base64Code[c1];
575 *bp++ = '=';
576 *bp++ = '=';
577 break;
578 }
579 c1 |= (c2 >> 4) & 0x0f;
580 *bp++ = Base64Code[c1];
581 c1 = (c2 & 0x0f) << 2;
582 c2 = mime_getchar_crlf(e->e_dfp, boundaries, &bt);
583 if (c2 == SM_IO_EOF)
584 {
585 *bp++ = Base64Code[c1];
586 *bp++ = '=';
587 break;
588 }
589 c1 |= (c2 >> 6) & 0x03;
590 *bp++ = Base64Code[c1];
591 *bp++ = Base64Code[c2 & 0x3f];
592 }
593 *bp = '\0';
594 if (!putline(buf, mci))
595 goto writeerr;
596 }
597 else
598 {
599 /* use quoted-printable encoding */
600 int c1, c2;
601 int fromstate;
602 BITMAP256 badchars;
603
604 /* set up map of characters that must be mapped */
605 clrbitmap(badchars);
606 for (c1 = 0x00; c1 < 0x20; c1++)
607 setbitn(c1, badchars);
608 clrbitn('\t', badchars);
609 for (c1 = 0x7f; c1 < 0x100; c1++)
610 setbitn(c1, badchars);
611 setbitn('=', badchars);
612 if (bitnset(M_EBCDIC, mci->mci_mailer->m_flags))
613 for (p = "!\"#$@[\\]^`{|}~"; *p != '\0'; p++)
614 setbitn(*p, badchars);
615
616 if (tTd(43, 36))
617 sm_dprintf(" ...Content-Transfer-Encoding: quoted-printable\n");
618 if (!putline("Content-Transfer-Encoding: quoted-printable",
619 mci))
620 goto writeerr;
621 (void) sm_snprintf(buf, sizeof(buf),
622 "X-MIME-Autoconverted: from 8bit to quoted-printable by %s id %s",
623 MyHostName, e->e_id);
624 if (!putline(buf, mci) || !putline("", mci))
625 goto writeerr;
626 mci->mci_flags &= ~MCIF_INHEADER;
627 fromstate = 0;
628 c2 = '\n';
629 while ((c1 = mime_getchar(e->e_dfp, boundaries, &bt)) !=
630 SM_IO_EOF)
631 {
632 if (c1 == '\n')
633 {
634 if (c2 == ' ' || c2 == '\t')
635 {
636 *bp++ = '=';
637 *bp++ = Base16Code[(c2 >> 4) & 0x0f];
638 *bp++ = Base16Code[c2 & 0x0f];
639 }
640 if (buf[0] == '.' && bp == &buf[1])
641 {
642 buf[0] = '=';
643 *bp++ = Base16Code[('.' >> 4) & 0x0f];
644 *bp++ = Base16Code['.' & 0x0f];
645 }
646 *bp = '\0';
647 if (!putline(buf, mci))
648 goto writeerr;
649 linelen = fromstate = 0;
650 bp = buf;
651 c2 = c1;
652 continue;
653 }
654 if (c2 == ' ' && linelen == 4 && fromstate == 4 &&
655 bitnset(M_ESCFROM, mci->mci_mailer->m_flags))
656 {
657 *bp++ = '=';
658 *bp++ = '2';
659 *bp++ = '0';
660 linelen += 3;
661 }
662 else if (c2 == ' ' || c2 == '\t')
663 {
664 *bp++ = c2;
665 linelen++;
666 }
667 if (linelen > 72 &&
668 (linelen > 75 || c1 != '.' ||
669 (linelen > 73 && c2 == '.')))
670 {
671 if (linelen > 73 && c2 == '.')
672 bp--;
673 else
674 c2 = '\n';
675 *bp++ = '=';
676 *bp = '\0';
677 if (!putline(buf, mci))
678 goto writeerr;
679 linelen = fromstate = 0;
680 bp = buf;
681 if (c2 == '.')
682 {
683 *bp++ = '.';
684 linelen++;
685 }
686 }
687 if (bitnset(bitidx(c1), badchars))
688 {
689 *bp++ = '=';
690 *bp++ = Base16Code[(c1 >> 4) & 0x0f];
691 *bp++ = Base16Code[c1 & 0x0f];
692 linelen += 3;
693 }
694 else if (c1 != ' ' && c1 != '\t')
695 {
696 if (linelen < 4 && c1 == "From"[linelen])
697 fromstate++;
698 *bp++ = c1;
699 linelen++;
700 }
701 c2 = c1;
702 }
703
704 /* output any saved character */
705 if (c2 == ' ' || c2 == '\t')
706 {
707 *bp++ = '=';
708 *bp++ = Base16Code[(c2 >> 4) & 0x0f];
709 *bp++ = Base16Code[c2 & 0x0f];
710 linelen += 3;
711 }
712
713 if (linelen > 0 || boundaries[0] != NULL)
714 {
715 *bp = '\0';
716 if (!putline(buf, mci))
717 goto writeerr;
718 }
719
720 }
721 if (tTd(43, 3))
722 sm_dprintf("\t\t\tmime8to7=>%s (basic)\n", MimeBoundaryNames[bt]);
723 return bt;
724
725 writeerr:
726 return SM_IO_EOF;
727 }
728 /*
729 ** MIME_GETCHAR -- get a character for MIME processing
730 **
731 ** Treats boundaries as SM_IO_EOF.
732 **
733 ** Parameters:
734 ** fp -- the input file.
735 ** boundaries -- the current MIME boundaries.
736 ** btp -- if the return value is SM_IO_EOF, *btp is set to
737 ** the type of the boundary.
738 **
739 ** Returns:
740 ** The next character in the input stream.
741 */
742
743 static int
mime_getchar(fp,boundaries,btp)744 mime_getchar(fp, boundaries, btp)
745 register SM_FILE_T *fp;
746 char **boundaries;
747 int *btp;
748 {
749 int c;
750 static unsigned char *bp = NULL;
751 static int buflen = 0;
752 static bool atbol = true; /* at beginning of line */
753 static int bt = MBT_SYNTAX; /* boundary type of next SM_IO_EOF */
754 static unsigned char buf[128]; /* need not be a full line */
755 int start = 0; /* indicates position of - in buffer */
756
757 if (buflen == 1 && *bp == '\n')
758 {
759 /* last \n in buffer may be part of next MIME boundary */
760 c = *bp;
761 }
762 else if (buflen > 0)
763 {
764 buflen--;
765 return *bp++;
766 }
767 else
768 c = sm_io_getc(fp, SM_TIME_DEFAULT);
769 bp = buf;
770 buflen = 0;
771 if (c == '\n')
772 {
773 /* might be part of a MIME boundary */
774 *bp++ = c;
775 atbol = true;
776 c = sm_io_getc(fp, SM_TIME_DEFAULT);
777 if (c == '\n')
778 {
779 (void) sm_io_ungetc(fp, SM_TIME_DEFAULT, c);
780 return c;
781 }
782 start = 1;
783 }
784 if (c != SM_IO_EOF)
785 *bp++ = c;
786 else
787 bt = MBT_FINAL;
788 if (atbol && c == '-')
789 {
790 /* check for a message boundary */
791 c = sm_io_getc(fp, SM_TIME_DEFAULT);
792 if (c != '-')
793 {
794 if (c != SM_IO_EOF)
795 *bp++ = c;
796 else
797 bt = MBT_FINAL;
798 buflen = bp - buf - 1;
799 bp = buf;
800 return *bp++;
801 }
802
803 /* got "--", now check for rest of separator */
804 *bp++ = '-';
805 while (bp < &buf[sizeof(buf) - 2] &&
806 (c = sm_io_getc(fp, SM_TIME_DEFAULT)) != SM_IO_EOF &&
807 c != '\n')
808 {
809 *bp++ = c;
810 }
811 *bp = '\0'; /* XXX simply cut off? */
812 bt = mimeboundary((char *) &buf[start], boundaries);
813 switch (bt)
814 {
815 case MBT_FINAL:
816 case MBT_INTERMED:
817 /* we have a message boundary */
818 buflen = 0;
819 *btp = bt;
820 return SM_IO_EOF;
821 }
822
823 if (bp < &buf[sizeof(buf) - 2] && c != SM_IO_EOF)
824 *bp++ = c;
825 }
826
827 atbol = c == '\n';
828 buflen = bp - buf - 1;
829 if (buflen < 0)
830 {
831 *btp = bt;
832 return SM_IO_EOF;
833 }
834 bp = buf;
835 return *bp++;
836 }
837 /*
838 ** MIME_GETCHAR_CRLF -- do mime_getchar, but translate NL => CRLF
839 **
840 ** Parameters:
841 ** fp -- the input file.
842 ** boundaries -- the current MIME boundaries.
843 ** btp -- if the return value is SM_IO_EOF, *btp is set to
844 ** the type of the boundary.
845 **
846 ** Returns:
847 ** The next character in the input stream.
848 */
849
850 static int
mime_getchar_crlf(fp,boundaries,btp)851 mime_getchar_crlf(fp, boundaries, btp)
852 register SM_FILE_T *fp;
853 char **boundaries;
854 int *btp;
855 {
856 static bool sendlf = false;
857 int c;
858
859 if (sendlf)
860 {
861 sendlf = false;
862 return '\n';
863 }
864 c = mime_getchar(fp, boundaries, btp);
865 if (c == '\n' && MapNLtoCRLF)
866 {
867 sendlf = true;
868 return '\r';
869 }
870 return c;
871 }
872 /*
873 ** MIMEBOUNDARY -- determine if this line is a MIME boundary & its type
874 **
875 ** Parameters:
876 ** line -- the input line.
877 ** boundaries -- the set of currently pending boundaries.
878 **
879 ** Returns:
880 ** MBT_NOTSEP -- if this is not a separator line
881 ** MBT_INTERMED -- if this is an intermediate separator
882 ** MBT_FINAL -- if this is a final boundary
883 ** MBT_SYNTAX -- if this is a boundary for the wrong
884 ** enclosure -- i.e., a syntax error.
885 */
886
887 static int
mimeboundary(line,boundaries)888 mimeboundary(line, boundaries)
889 register char *line;
890 char **boundaries;
891 {
892 int type = MBT_NOTSEP;
893 int i;
894 int savec;
895
896 if (line[0] != '-' || line[1] != '-' || boundaries == NULL)
897 return MBT_NOTSEP;
898 i = strlen(line);
899 if (i > 0 && line[i - 1] == '\n')
900 i--;
901
902 /* strip off trailing whitespace */
903 while (i > 0 && (line[i - 1] == ' ' || line[i - 1] == '\t'
904 #if _FFR_MIME_CR_OK
905 || line[i - 1] == '\r'
906 #endif /* _FFR_MIME_CR_OK */
907 ))
908 i--;
909 savec = line[i];
910 line[i] = '\0';
911
912 if (tTd(43, 5))
913 sm_dprintf("mimeboundary: line=\"%s\"... ", line);
914
915 /* check for this as an intermediate boundary */
916 if (isboundary(&line[2], boundaries) >= 0)
917 type = MBT_INTERMED;
918 else if (i > 2 && strncmp(&line[i - 2], "--", 2) == 0)
919 {
920 /* check for a final boundary */
921 line[i - 2] = '\0';
922 if (isboundary(&line[2], boundaries) >= 0)
923 type = MBT_FINAL;
924 line[i - 2] = '-';
925 }
926
927 line[i] = savec;
928 if (tTd(43, 5))
929 sm_dprintf("%s\n", MimeBoundaryNames[type]);
930 return type;
931 }
932 /*
933 ** DEFCHARSET -- return default character set for message
934 **
935 ** The first choice for character set is for the mailer
936 ** corresponding to the envelope sender. If neither that
937 ** nor the global configuration file has a default character
938 ** set defined, return "unknown-8bit" as recommended by
939 ** RFC 1428 section 3.
940 **
941 ** Parameters:
942 ** e -- the envelope for this message.
943 **
944 ** Returns:
945 ** The default character set for that mailer.
946 */
947
948 char *
defcharset(e)949 defcharset(e)
950 register ENVELOPE *e;
951 {
952 if (e != NULL && e->e_from.q_mailer != NULL &&
953 e->e_from.q_mailer->m_defcharset != NULL)
954 return e->e_from.q_mailer->m_defcharset;
955 if (DefaultCharSet != NULL)
956 return DefaultCharSet;
957 return "unknown-8bit";
958 }
959 /*
960 ** ISBOUNDARY -- is a given string a currently valid boundary?
961 **
962 ** Parameters:
963 ** line -- the current input line.
964 ** boundaries -- the list of valid boundaries.
965 **
966 ** Returns:
967 ** The index number in boundaries if the line is found.
968 ** -1 -- otherwise.
969 **
970 */
971
972 static int
isboundary(line,boundaries)973 isboundary(line, boundaries)
974 char *line;
975 char **boundaries;
976 {
977 register int i;
978
979 for (i = 0; i <= MAXMIMENESTING && boundaries[i] != NULL; i++)
980 {
981 if (strcmp(line, boundaries[i]) == 0)
982 return i;
983 }
984 return -1;
985 }
986 #endif /* MIME8TO7 */
987
988 #if MIME7TO8
989 static int mime_fromqp __P((unsigned char *, unsigned char **, int));
990
991 /*
992 ** MIME7TO8 -- output 7 bit encoded MIME body in 8 bit format
993 **
994 ** This is a hack. Supports translating the two 7-bit body-encodings
995 ** (quoted-printable and base64) to 8-bit coded bodies.
996 **
997 ** There is not much point in supporting multipart here, as the UA
998 ** will be able to deal with encoded MIME bodies if it can parse MIME
999 ** multipart messages.
1000 **
1001 ** Note also that we won't be called unless it is a text/plain MIME
1002 ** message, encoded base64 or QP and mailer flag '9' has been defined
1003 ** on mailer.
1004 **
1005 ** Contributed by Marius Olaffson <marius@rhi.hi.is>.
1006 **
1007 ** Parameters:
1008 ** mci -- mailer connection information.
1009 ** header -- the header for this body part.
1010 ** e -- envelope.
1011 **
1012 ** Returns:
1013 ** true iff body was written successfully
1014 */
1015
1016 static char index_64[128] =
1017 {
1018 -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
1019 -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
1020 -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,62, -1,-1,-1,63,
1021 52,53,54,55, 56,57,58,59, 60,61,-1,-1, -1,-1,-1,-1,
1022 -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11,12,13,14,
1023 15,16,17,18, 19,20,21,22, 23,24,25,-1, -1,-1,-1,-1,
1024 -1,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,
1025 41,42,43,44, 45,46,47,48, 49,50,51,-1, -1,-1,-1,-1
1026 };
1027
1028 # define CHAR64(c) (((c) < 0 || (c) > 127) ? -1 : index_64[(c)])
1029
1030 bool
mime7to8(mci,header,e)1031 mime7to8(mci, header, e)
1032 register MCI *mci;
1033 HDR *header;
1034 register ENVELOPE *e;
1035 {
1036 int pxflags;
1037 register char *p;
1038 char *cte;
1039 char **pvp;
1040 unsigned char *fbufp;
1041 char buf[MAXLINE];
1042 unsigned char fbuf[MAXLINE + 1];
1043 char pvpbuf[MAXLINE];
1044 extern unsigned char MimeTokenTab[256];
1045
1046 p = hvalue("Content-Transfer-Encoding", header);
1047 if (p == NULL ||
1048 (pvp = prescan(p, '\0', pvpbuf, sizeof(pvpbuf), NULL,
1049 MimeTokenTab, false)) == NULL ||
1050 pvp[0] == NULL)
1051 {
1052 /* "can't happen" -- upper level should have caught this */
1053 syserr("mime7to8: unparsable CTE %s", p == NULL ? "<NULL>" : p);
1054
1055 /* avoid bounce loops */
1056 e->e_flags |= EF_DONT_MIME;
1057
1058 /* cheap failsafe algorithm -- should work on text/plain */
1059 if (p != NULL)
1060 {
1061 (void) sm_snprintf(buf, sizeof(buf),
1062 "Content-Transfer-Encoding: %s", p);
1063 if (!putline(buf, mci))
1064 goto writeerr;
1065 }
1066 if (!putline("", mci))
1067 goto writeerr;
1068 mci->mci_flags &= ~MCIF_INHEADER;
1069 while (sm_io_fgets(e->e_dfp, SM_TIME_DEFAULT, buf, sizeof(buf))
1070 != NULL)
1071 {
1072 if (!putline(buf, mci))
1073 goto writeerr;
1074 }
1075 return true;
1076 }
1077 cataddr(pvp, NULL, buf, sizeof(buf), '\0', false);
1078 cte = sm_rpool_strdup_x(e->e_rpool, buf);
1079
1080 mci->mci_flags |= MCIF_INHEADER;
1081 if (!putline("Content-Transfer-Encoding: 8bit", mci))
1082 goto writeerr;
1083 (void) sm_snprintf(buf, sizeof(buf),
1084 "X-MIME-Autoconverted: from %.200s to 8bit by %s id %s",
1085 cte, MyHostName, e->e_id);
1086 if (!putline(buf, mci) || !putline("", mci))
1087 goto writeerr;
1088 mci->mci_flags &= ~MCIF_INHEADER;
1089
1090 /*
1091 ** Translate body encoding to 8-bit. Supports two types of
1092 ** encodings; "base64" and "quoted-printable". Assume qp if
1093 ** it is not base64.
1094 */
1095
1096 pxflags = PXLF_MAPFROM;
1097 if (sm_strcasecmp(cte, "base64") == 0)
1098 {
1099 int c1, c2, c3, c4;
1100
1101 fbufp = fbuf;
1102 while ((c1 = sm_io_getc(e->e_dfp, SM_TIME_DEFAULT)) !=
1103 SM_IO_EOF)
1104 {
1105 if (isascii(c1) && isspace(c1))
1106 continue;
1107
1108 do
1109 {
1110 c2 = sm_io_getc(e->e_dfp, SM_TIME_DEFAULT);
1111 } while (isascii(c2) && isspace(c2));
1112 if (c2 == SM_IO_EOF)
1113 break;
1114
1115 do
1116 {
1117 c3 = sm_io_getc(e->e_dfp, SM_TIME_DEFAULT);
1118 } while (isascii(c3) && isspace(c3));
1119 if (c3 == SM_IO_EOF)
1120 break;
1121
1122 do
1123 {
1124 c4 = sm_io_getc(e->e_dfp, SM_TIME_DEFAULT);
1125 } while (isascii(c4) && isspace(c4));
1126 if (c4 == SM_IO_EOF)
1127 break;
1128
1129 if (c1 == '=' || c2 == '=')
1130 continue;
1131 c1 = CHAR64(c1);
1132 c2 = CHAR64(c2);
1133
1134 #if MIME7TO8_OLD
1135 #define CHK_EOL if (*--fbufp != '\n' || (fbufp > fbuf && *--fbufp != '\r')) \
1136 ++fbufp;
1137 #else /* MIME7TO8_OLD */
1138 #define CHK_EOL if (*--fbufp != '\n' || (fbufp > fbuf && *--fbufp != '\r')) \
1139 { \
1140 ++fbufp; \
1141 pxflags |= PXLF_NOADDEOL; \
1142 }
1143 #endif /* MIME7TO8_OLD */
1144
1145 #define PUTLINE64 \
1146 do \
1147 { \
1148 if (*fbufp++ == '\n' || fbufp >= &fbuf[MAXLINE]) \
1149 { \
1150 CHK_EOL; \
1151 if (!putxline((char *) fbuf, fbufp - fbuf, mci, pxflags)) \
1152 goto writeerr; \
1153 pxflags &= ~PXLF_NOADDEOL; \
1154 fbufp = fbuf; \
1155 } \
1156 } while (0)
1157
1158 *fbufp = (c1 << 2) | ((c2 & 0x30) >> 4);
1159 PUTLINE64;
1160 if (c3 == '=')
1161 continue;
1162 c3 = CHAR64(c3);
1163 *fbufp = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2);
1164 PUTLINE64;
1165 if (c4 == '=')
1166 continue;
1167 c4 = CHAR64(c4);
1168 *fbufp = ((c3 & 0x03) << 6) | c4;
1169 PUTLINE64;
1170 }
1171 }
1172 else
1173 {
1174 int off;
1175
1176 /* quoted-printable */
1177 pxflags |= PXLF_NOADDEOL;
1178 fbufp = fbuf;
1179 while (sm_io_fgets(e->e_dfp, SM_TIME_DEFAULT, buf,
1180 sizeof(buf)) != NULL)
1181 {
1182 off = mime_fromqp((unsigned char *) buf, &fbufp,
1183 &fbuf[MAXLINE] - fbufp);
1184 again:
1185 if (off < -1)
1186 continue;
1187
1188 if (fbufp - fbuf > 0)
1189 {
1190 if (!putxline((char *) fbuf, fbufp - fbuf - 1,
1191 mci, pxflags))
1192 goto writeerr;
1193 }
1194 fbufp = fbuf;
1195 if (off >= 0 && buf[off] != '\0')
1196 {
1197 off = mime_fromqp((unsigned char *) (buf + off),
1198 &fbufp,
1199 &fbuf[MAXLINE] - fbufp);
1200 goto again;
1201 }
1202 }
1203 }
1204
1205 /* force out partial last line */
1206 if (fbufp > fbuf)
1207 {
1208 *fbufp = '\0';
1209 if (!putxline((char *) fbuf, fbufp - fbuf, mci, pxflags))
1210 goto writeerr;
1211 }
1212
1213 /*
1214 ** The decoded text may end without an EOL. Since this function
1215 ** is only called for text/plain MIME messages, it is safe to
1216 ** add an extra one at the end just in case. This is a hack,
1217 ** but so is auto-converting MIME in the first place.
1218 */
1219
1220 if (!putline("", mci))
1221 goto writeerr;
1222
1223 if (tTd(43, 3))
1224 sm_dprintf("\t\t\tmime7to8 => %s to 8bit done\n", cte);
1225 return true;
1226
1227 writeerr:
1228 return false;
1229 }
1230 /*
1231 ** The following is based on Borenstein's "codes.c" module, with simplifying
1232 ** changes as we do not deal with multipart, and to do the translation in-core,
1233 ** with an attempt to prevent overrun of output buffers.
1234 **
1235 ** What is needed here are changes to defend this code better against
1236 ** bad encodings. Questionable to always return 0xFF for bad mappings.
1237 */
1238
1239 static char index_hex[128] =
1240 {
1241 -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
1242 -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
1243 -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
1244 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,-1,-1, -1,-1,-1,-1,
1245 -1,10,11,12, 13,14,15,-1, -1,-1,-1,-1, -1,-1,-1,-1,
1246 -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
1247 -1,10,11,12, 13,14,15,-1, -1,-1,-1,-1, -1,-1,-1,-1,
1248 -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1
1249 };
1250
1251 # define HEXCHAR(c) (((c) < 0 || (c) > 127) ? -1 : index_hex[(c)])
1252
1253 /*
1254 ** MIME_FROMQP -- decode quoted printable string
1255 **
1256 ** Parameters:
1257 ** infile -- input (encoded) string
1258 ** outfile -- output string
1259 ** maxlen -- size of output buffer
1260 **
1261 ** Returns:
1262 ** -2 if decoding failure
1263 ** -1 if infile completely decoded into outfile
1264 ** >= 0 is the position in infile decoding
1265 ** reached before maxlen was reached
1266 */
1267
1268 static int
mime_fromqp(infile,outfile,maxlen)1269 mime_fromqp(infile, outfile, maxlen)
1270 unsigned char *infile;
1271 unsigned char **outfile;
1272 int maxlen; /* Max # of chars allowed in outfile */
1273 {
1274 int c1, c2;
1275 int nchar = 0;
1276 unsigned char *b;
1277
1278 /* decrement by one for trailing '\0', at least one other char */
1279 if (--maxlen < 1)
1280 return 0;
1281
1282 b = infile;
1283 while ((c1 = *infile++) != '\0' && nchar < maxlen)
1284 {
1285 if (c1 == '=')
1286 {
1287 if ((c1 = *infile++) == '\0')
1288 break;
1289
1290 if (c1 == '\n' || (c1 = HEXCHAR(c1)) == -1)
1291 {
1292 /* ignore it and the rest of the buffer */
1293 return -2;
1294 }
1295 else
1296 {
1297 do
1298 {
1299 if ((c2 = *infile++) == '\0')
1300 {
1301 c2 = -1;
1302 break;
1303 }
1304 } while ((c2 = HEXCHAR(c2)) == -1);
1305
1306 if (c2 == -1)
1307 break;
1308 nchar++;
1309 *(*outfile)++ = c1 << 4 | c2;
1310 }
1311 }
1312 else
1313 {
1314 nchar++;
1315 *(*outfile)++ = c1;
1316 if (c1 == '\n')
1317 break;
1318 }
1319 }
1320 *(*outfile)++ = '\0';
1321 if (nchar >= maxlen)
1322 return (infile - b - 1);
1323 return -1;
1324 }
1325 #endif /* MIME7TO8 */
1326