crypto/asn1/asn_mime.c

   1 /*
   2  * Copyright 2008-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include "crypto/ctype.h"
  12 #include "internal/cryptlib.h"
  13 #include <openssl/rand.h>
  14 #include <openssl/x509.h>
  15 #include <openssl/asn1.h>
  16 #include <openssl/asn1t.h>
  17 #include "crypto/evp.h"
  18 #include "internal/bio.h"
  19 #include "asn1_local.h"
  20
  21 /*
  22  * Generalised MIME like utilities for streaming ASN1. Although many have a
  23  * PKCS7/CMS like flavour others are more general purpose.
  24  */
  25
  26 /*
  27  * MIME format structures Note that all are translated to lower case apart
  28  * from parameter values. Quotes are stripped off
  29  */
  30
  31 struct mime_param_st {
  32     char *param_name;           /* Param name e.g. "micalg" */
  33     char *param_value;          /* Param value e.g. "sha1" */
  34 };
  35
  36 struct mime_header_st {
  37     char *name;                 /* Name of line e.g. "content-type" */
  38     char *value;                /* Value of line e.g. "text/plain" */
  39     STACK_OF(MIME_PARAM) *params; /* Zero or more parameters */
  40 };
  41
  42 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
  43                             const ASN1_ITEM *it);
  44 static char *strip_ends(char *name);
  45 static char *strip_start(char *name);
  46 static char *strip_end(char *name);
  47 static MIME_HEADER *mime_hdr_new(const char *name, const char *value);
  48 static int mime_hdr_addparam(MIME_HEADER *mhdr, const char *name, const char *value);
  49 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio);
  50 static int mime_hdr_cmp(const MIME_HEADER *const *a,
  51                         const MIME_HEADER *const *b);
  52 static int mime_param_cmp(const MIME_PARAM *const *a,
  53                           const MIME_PARAM *const *b);
  54 static void mime_param_free(MIME_PARAM *param);
  55 static int mime_bound_check(char *line, int linelen, const char *bound, int blen);
  56 static int multi_split(BIO *bio, const char *bound, STACK_OF(BIO) **ret);
  57 static int strip_eol(char *linebuf, int *plen, int flags);
  58 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, const char *name);
  59 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, const char *name);
  60 static void mime_hdr_free(MIME_HEADER *hdr);
  61
  62 #define MAX_SMLEN 1024
  63 #define mime_debug(x)           /* x */
  64
  65 /* Output an ASN1 structure in BER format streaming if necessary */
  66
  67 int i2d_ASN1_bio_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
  68                         const ASN1_ITEM *it)
  69 {
  70     /* If streaming create stream BIO and copy all content through it */
  71     if (flags & SMIME_STREAM) {
  72         BIO *bio, *tbio;
  73         bio = BIO_new_NDEF(out, val, it);
  74         if (!bio) {
  75             ASN1err(ASN1_F_I2D_ASN1_BIO_STREAM, ERR_R_MALLOC_FAILURE);
  76             return 0;
  77         }
  78         SMIME_crlf_copy(in, bio, flags);
  79         (void)BIO_flush(bio);
  80         /* Free up successive BIOs until we hit the old output BIO */
  81         do {
  82             tbio = BIO_pop(bio);
  83             BIO_free(bio);
  84             bio = tbio;
  85         } while (bio != out);
  86     }
  87     /*
  88      * else just write out ASN1 structure which will have all content stored
  89      * internally
  90      */
  91     else
  92         ASN1_item_i2d_bio(it, out, val);
  93     return 1;
  94 }
  95
  96 /* Base 64 read and write of ASN1 structure */
  97
  98 static int B64_write_ASN1(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
  99                           const ASN1_ITEM *it)
 100 {
 101     BIO *b64;
 102     int r;
 103     b64 = BIO_new(BIO_f_base64());
 104     if (b64 == NULL) {
 105         ASN1err(ASN1_F_B64_WRITE_ASN1, ERR_R_MALLOC_FAILURE);
 106         return 0;
 107     }
 108     /*
 109      * prepend the b64 BIO so all data is base64 encoded.
 110      */
 111     out = BIO_push(b64, out);
 112     r = i2d_ASN1_bio_stream(out, val, in, flags, it);
 113     (void)BIO_flush(out);
 114     BIO_pop(out);
 115     BIO_free(b64);
 116     return r;
 117 }
 118
 119 /* Streaming ASN1 PEM write */
 120
 121 int PEM_write_bio_ASN1_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
 122                               const char *hdr, const ASN1_ITEM *it)
 123 {
 124     int r;
 125     BIO_printf(out, "-----BEGIN %s-----\n", hdr);
 126     r = B64_write_ASN1(out, val, in, flags, it);
 127     BIO_printf(out, "-----END %s-----\n", hdr);
 128     return r;
 129 }
 130
 131 static ASN1_VALUE *b64_read_asn1(BIO *bio, const ASN1_ITEM *it)
 132 {
 133     BIO *b64;
 134     ASN1_VALUE *val;
 135
 136     if ((b64 = BIO_new(BIO_f_base64())) == NULL) {
 137         ASN1err(ASN1_F_B64_READ_ASN1, ERR_R_MALLOC_FAILURE);
 138         return 0;
 139     }
 140     bio = BIO_push(b64, bio);
 141     val = ASN1_item_d2i_bio(it, bio, NULL);
 142     if (!val)
 143         ASN1err(ASN1_F_B64_READ_ASN1, ASN1_R_DECODE_ERROR);
 144     (void)BIO_flush(bio);
 145     BIO_pop(bio);
 146     BIO_free(b64);
 147     return val;
 148 }
 149
 150 /* Generate the MIME "micalg" parameter from RFC3851, RFC4490 */
 151
 152 static int asn1_write_micalg(BIO *out, STACK_OF(X509_ALGOR) *mdalgs)
 153 {
 154     const EVP_MD *md;
 155     int i, have_unknown = 0, write_comma, ret = 0, md_nid;
 156     have_unknown = 0;
 157     write_comma = 0;
 158     for (i = 0; i < sk_X509_ALGOR_num(mdalgs); i++) {
 159         if (write_comma)
 160             BIO_write(out, ",", 1);
 161         write_comma = 1;
 162         md_nid = OBJ_obj2nid(sk_X509_ALGOR_value(mdalgs, i)->algorithm);
 163         md = EVP_get_digestbynid(md_nid);
 164         if (md && md->md_ctrl) {
 165             int rv;
 166             char *micstr;
 167             rv = md->md_ctrl(NULL, EVP_MD_CTRL_MICALG, 0, &micstr);
 168             if (rv > 0) {
 169                 BIO_puts(out, micstr);
 170                 OPENSSL_free(micstr);
 171                 continue;
 172             }
 173             if (rv != -2)
 174                 goto err;
 175         }
 176         switch (md_nid) {
 177         case NID_sha1:
 178             BIO_puts(out, "sha1");
 179             break;
 180
 181         case NID_md5:
 182             BIO_puts(out, "md5");
 183             break;
 184
 185         case NID_sha256:
 186             BIO_puts(out, "sha-256");
 187             break;
 188
 189         case NID_sha384:
 190             BIO_puts(out, "sha-384");
 191             break;
 192
 193         case NID_sha512:
 194             BIO_puts(out, "sha-512");
 195             break;
 196
 197         case NID_id_GostR3411_94:
 198             BIO_puts(out, "gostr3411-94");
 199             goto err;
 200
 201         case NID_id_GostR3411_2012_256:
 202             BIO_puts(out, "gostr3411-2012-256");
 203             goto err;
 204
 205         case NID_id_GostR3411_2012_512:
 206             BIO_puts(out, "gostr3411-2012-512");
 207             goto err;
 208
 209         default:
 210             if (have_unknown)
 211                 write_comma = 0;
 212             else {
 213                 BIO_puts(out, "unknown");
 214                 have_unknown = 1;
 215             }
 216             break;
 217
 218         }
 219     }
 220
 221     ret = 1;
 222  err:
 223
 224     return ret;
 225
 226 }
 227
 228 /* SMIME sender */
 229
 230 int SMIME_write_ASN1(BIO *bio, ASN1_VALUE *val, BIO *data, int flags,
 231                      int ctype_nid, int econt_nid,
 232                      STACK_OF(X509_ALGOR) *mdalgs, const ASN1_ITEM *it)
 233 {
 234     char bound[33], c;
 235     int i;
 236     const char *mime_prefix, *mime_eol, *cname = "smime.p7m";
 237     const char *msg_type = NULL;
 238     if (flags & SMIME_OLDMIME)
 239         mime_prefix = "application/x-pkcs7-";
 240     else
 241         mime_prefix = "application/pkcs7-";
 242
 243     if (flags & SMIME_CRLFEOL)
 244         mime_eol = "\r\n";
 245     else
 246         mime_eol = "\n";
 247     if ((flags & SMIME_DETACHED) && data) {
 248         /* We want multipart/signed */
 249         /* Generate a random boundary */
 250         if (RAND_bytes((unsigned char *)bound, 32) <= 0)
 251             return 0;
 252         for (i = 0; i < 32; i++) {
 253             c = bound[i] & 0xf;
 254             if (c < 10)
 255                 c += '0';
 256             else
 257                 c += 'A' - 10;
 258             bound[i] = c;
 259         }
 260         bound[32] = 0;
 261         BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
 262         BIO_printf(bio, "Content-Type: multipart/signed;");
 263         BIO_printf(bio, " protocol=\"%ssignature\";", mime_prefix);
 264         BIO_puts(bio, " micalg=\"");
 265         asn1_write_micalg(bio, mdalgs);
 266         BIO_printf(bio, "\"; boundary=\"----%s\"%s%s",
 267                    bound, mime_eol, mime_eol);
 268         BIO_printf(bio, "This is an S/MIME signed message%s%s",
 269                    mime_eol, mime_eol);
 270         /* Now write out the first part */
 271         BIO_printf(bio, "------%s%s", bound, mime_eol);
 272         if (!asn1_output_data(bio, data, val, flags, it))
 273             return 0;
 274         BIO_printf(bio, "%s------%s%s", mime_eol, bound, mime_eol);
 275
 276         /* Headers for signature */
 277
 278         BIO_printf(bio, "Content-Type: %ssignature;", mime_prefix);
 279         BIO_printf(bio, " name=\"smime.p7s\"%s", mime_eol);
 280         BIO_printf(bio, "Content-Transfer-Encoding: base64%s", mime_eol);
 281         BIO_printf(bio, "Content-Disposition: attachment;");
 282         BIO_printf(bio, " filename=\"smime.p7s\"%s%s", mime_eol, mime_eol);
 283         B64_write_ASN1(bio, val, NULL, 0, it);
 284         BIO_printf(bio, "%s------%s--%s%s", mime_eol, bound,
 285                    mime_eol, mime_eol);
 286         return 1;
 287     }
 288
 289     /* Determine smime-type header */
 290
 291     if (ctype_nid == NID_pkcs7_enveloped)
 292         msg_type = "enveloped-data";
 293     else if (ctype_nid == NID_pkcs7_signed) {
 294         if (econt_nid == NID_id_smime_ct_receipt)
 295             msg_type = "signed-receipt";
 296         else if (sk_X509_ALGOR_num(mdalgs) >= 0)
 297             msg_type = "signed-data";
 298         else
 299             msg_type = "certs-only";
 300     } else if (ctype_nid == NID_id_smime_ct_compressedData) {
 301         msg_type = "compressed-data";
 302         cname = "smime.p7z";
 303     }
 304     /* MIME headers */
 305     BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
 306     BIO_printf(bio, "Content-Disposition: attachment;");
 307     BIO_printf(bio, " filename=\"%s\"%s", cname, mime_eol);
 308     BIO_printf(bio, "Content-Type: %smime;", mime_prefix);
 309     if (msg_type)
 310         BIO_printf(bio, " smime-type=%s;", msg_type);
 311     BIO_printf(bio, " name=\"%s\"%s", cname, mime_eol);
 312     BIO_printf(bio, "Content-Transfer-Encoding: base64%s%s",
 313                mime_eol, mime_eol);
 314     if (!B64_write_ASN1(bio, val, data, flags, it))
 315         return 0;
 316     BIO_printf(bio, "%s", mime_eol);
 317     return 1;
 318 }
 319
 320 /* Handle output of ASN1 data */
 321
 322 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
 323                             const ASN1_ITEM *it)
 324 {
 325     BIO *tmpbio;
 326     const ASN1_AUX *aux = it->funcs;
 327     ASN1_STREAM_ARG sarg;
 328     int rv = 1;
 329
 330     /*
 331      * If data is not detached or resigning then the output BIO is already
 332      * set up to finalise when it is written through.
 333      */
 334     if (!(flags & SMIME_DETACHED) || (flags & PKCS7_REUSE_DIGEST)) {
 335         SMIME_crlf_copy(data, out, flags);
 336         return 1;
 337     }
 338
 339     if (!aux || !aux->asn1_cb) {
 340         ASN1err(ASN1_F_ASN1_OUTPUT_DATA, ASN1_R_STREAMING_NOT_SUPPORTED);
 341         return 0;
 342     }
 343
 344     sarg.out = out;
 345     sarg.ndef_bio = NULL;
 346     sarg.boundary = NULL;
 347
 348     /* Let ASN1 code prepend any needed BIOs */
 349
 350     if (aux->asn1_cb(ASN1_OP_DETACHED_PRE, &val, it, &sarg) <= 0)
 351         return 0;
 352
 353     /* Copy data across, passing through filter BIOs for processing */
 354     SMIME_crlf_copy(data, sarg.ndef_bio, flags);
 355
 356     /* Finalize structure */
 357     if (aux->asn1_cb(ASN1_OP_DETACHED_POST, &val, it, &sarg) <= 0)
 358         rv = 0;
 359
 360     /* Now remove any digests prepended to the BIO */
 361
 362     while (sarg.ndef_bio != out) {
 363         tmpbio = BIO_pop(sarg.ndef_bio);
 364         BIO_free(sarg.ndef_bio);
 365         sarg.ndef_bio = tmpbio;
 366     }
 367
 368     return rv;
 369
 370 }
 371
 372 /*
 373  * SMIME reader: handle multipart/signed and opaque signing. in multipart
 374  * case the content is placed in a memory BIO pointed to by "bcont". In
 375  * opaque this is set to NULL
 376  */
 377
 378 ASN1_VALUE *SMIME_read_ASN1(BIO *bio, BIO **bcont, const ASN1_ITEM *it)
 379 {
 380     BIO *asnin;
 381     STACK_OF(MIME_HEADER) *headers = NULL;
 382     STACK_OF(BIO) *parts = NULL;
 383     MIME_HEADER *hdr;
 384     MIME_PARAM *prm;
 385     ASN1_VALUE *val;
 386     int ret;
 387
 388     if (bcont)
 389         *bcont = NULL;
 390
 391     if ((headers = mime_parse_hdr(bio)) == NULL) {
 392         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_PARSE_ERROR);
 393         return NULL;
 394     }
 395
 396     if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 397         || hdr->value == NULL) {
 398         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 399         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_CONTENT_TYPE);
 400         return NULL;
 401     }
 402
 403     /* Handle multipart/signed */
 404
 405     if (strcmp(hdr->value, "multipart/signed") == 0) {
 406         /* Split into two parts */
 407         prm = mime_param_find(hdr, "boundary");
 408         if (!prm || !prm->param_value) {
 409             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 410             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BOUNDARY);
 411             return NULL;
 412         }
 413         ret = multi_split(bio, prm->param_value, &parts);
 414         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 415         if (!ret || (sk_BIO_num(parts) != 2)) {
 416             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BODY_FAILURE);
 417             sk_BIO_pop_free(parts, BIO_vfree);
 418             return NULL;
 419         }
 420
 421         /* Parse the signature piece */
 422         asnin = sk_BIO_value(parts, 1);
 423
 424         if ((headers = mime_parse_hdr(asnin)) == NULL) {
 425             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_SIG_PARSE_ERROR);
 426             sk_BIO_pop_free(parts, BIO_vfree);
 427             return NULL;
 428         }
 429
 430         /* Get content type */
 431
 432         if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 433             || hdr->value == NULL) {
 434             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 435             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_SIG_CONTENT_TYPE);
 436             sk_BIO_pop_free(parts, BIO_vfree);
 437             return NULL;
 438         }
 439
 440         if (strcmp(hdr->value, "application/x-pkcs7-signature") &&
 441             strcmp(hdr->value, "application/pkcs7-signature")) {
 442             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_SIG_INVALID_MIME_TYPE);
 443             ERR_add_error_data(2, "type: ", hdr->value);
 444             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 445             sk_BIO_pop_free(parts, BIO_vfree);
 446             return NULL;
 447         }
 448         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 449         /* Read in ASN1 */
 450         if ((val = b64_read_asn1(asnin, it)) == NULL) {
 451             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_SIG_PARSE_ERROR);
 452             sk_BIO_pop_free(parts, BIO_vfree);
 453             return NULL;
 454         }
 455
 456         if (bcont) {
 457             *bcont = sk_BIO_value(parts, 0);
 458             BIO_free(asnin);
 459             sk_BIO_free(parts);
 460         } else
 461             sk_BIO_pop_free(parts, BIO_vfree);
 462         return val;
 463     }
 464
 465     /* OK, if not multipart/signed try opaque signature */
 466
 467     if (strcmp(hdr->value, "application/x-pkcs7-mime") &&
 468         strcmp(hdr->value, "application/pkcs7-mime")) {
 469         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_INVALID_MIME_TYPE);
 470         ERR_add_error_data(2, "type: ", hdr->value);
 471         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 472         return NULL;
 473     }
 474
 475     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 476
 477     if ((val = b64_read_asn1(bio, it)) == NULL) {
 478         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_PARSE_ERROR);
 479         return NULL;
 480     }
 481     return val;
 482
 483 }
 484
 485 /* Copy text from one BIO to another making the output CRLF at EOL */
 486 int SMIME_crlf_copy(BIO *in, BIO *out, int flags)
 487 {
 488     BIO *bf;
 489     char eol;
 490     int len;
 491     char linebuf[MAX_SMLEN];
 492     /*
 493      * Buffer output so we don't write one line at a time. This is useful
 494      * when streaming as we don't end up with one OCTET STRING per line.
 495      */
 496     bf = BIO_new(BIO_f_buffer());
 497     if (bf == NULL)
 498         return 0;
 499     out = BIO_push(bf, out);
 500     if (flags & SMIME_BINARY) {
 501         while ((len = BIO_read(in, linebuf, MAX_SMLEN)) > 0)
 502             BIO_write(out, linebuf, len);
 503     } else {
 504         int eolcnt = 0;
 505         if (flags & SMIME_TEXT)
 506             BIO_printf(out, "Content-Type: text/plain\r\n\r\n");
 507         while ((len = BIO_gets(in, linebuf, MAX_SMLEN)) > 0) {
 508             eol = strip_eol(linebuf, &len, flags);
 509             if (len) {
 510                 /* Not EOF: write out all CRLF */
 511                 if (flags & SMIME_ASCIICRLF) {
 512                     int i;
 513                     for (i = 0; i < eolcnt; i++)
 514                         BIO_write(out, "\r\n", 2);
 515                     eolcnt = 0;
 516                 }
 517                 BIO_write(out, linebuf, len);
 518                 if (eol)
 519                     BIO_write(out, "\r\n", 2);
 520             } else if (flags & SMIME_ASCIICRLF)
 521                 eolcnt++;
 522             else if (eol)
 523                 BIO_write(out, "\r\n", 2);
 524         }
 525     }
 526     (void)BIO_flush(out);
 527     BIO_pop(out);
 528     BIO_free(bf);
 529     return 1;
 530 }
 531
 532 /* Strip off headers if they are text/plain */
 533 int SMIME_text(BIO *in, BIO *out)
 534 {
 535     char iobuf[4096];
 536     int len;
 537     STACK_OF(MIME_HEADER) *headers;
 538     MIME_HEADER *hdr;
 539
 540     if ((headers = mime_parse_hdr(in)) == NULL) {
 541         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_PARSE_ERROR);
 542         return 0;
 543     }
 544     if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 545         || hdr->value == NULL) {
 546         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_NO_CONTENT_TYPE);
 547         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 548         return 0;
 549     }
 550     if (strcmp(hdr->value, "text/plain")) {
 551         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_INVALID_MIME_TYPE);
 552         ERR_add_error_data(2, "type: ", hdr->value);
 553         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 554         return 0;
 555     }
 556     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 557     while ((len = BIO_read(in, iobuf, sizeof(iobuf))) > 0)
 558         BIO_write(out, iobuf, len);
 559     if (len < 0)
 560         return 0;
 561     return 1;
 562 }
 563
 564 /*
 565  * Split a multipart/XXX message body into component parts: result is
 566  * canonical parts in a STACK of bios
 567  */
 568
 569 static int multi_split(BIO *bio, const char *bound, STACK_OF(BIO) **ret)
 570 {
 571     char linebuf[MAX_SMLEN];
 572     int len, blen;
 573     int eol = 0, next_eol = 0;
 574     BIO *bpart = NULL;
 575     STACK_OF(BIO) *parts;
 576     char state, part, first;
 577
 578     blen = strlen(bound);
 579     part = 0;
 580     state = 0;
 581     first = 1;
 582     parts = sk_BIO_new_null();
 583     *ret = parts;
 584     if (*ret == NULL)
 585         return 0;
 586     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
 587         state = mime_bound_check(linebuf, len, bound, blen);
 588         if (state == 1) {
 589             first = 1;
 590             part++;
 591         } else if (state == 2) {
 592             if (!sk_BIO_push(parts, bpart)) {
 593                 BIO_free(bpart);
 594                 return 0;
 595             }
 596             return 1;
 597         } else if (part) {
 598             /* Strip CR+LF from linebuf */
 599             next_eol = strip_eol(linebuf, &len, 0);
 600             if (first) {
 601                 first = 0;
 602                 if (bpart)
 603                     if (!sk_BIO_push(parts, bpart)) {
 604                         BIO_free(bpart);
 605                         return 0;
 606                     }
 607                 bpart = BIO_new(BIO_s_mem());
 608                 if (bpart == NULL)
 609                     return 0;
 610                 BIO_set_mem_eof_return(bpart, 0);
 611             } else if (eol)
 612                 BIO_write(bpart, "\r\n", 2);
 613             eol = next_eol;
 614             if (len)
 615                 BIO_write(bpart, linebuf, len);
 616         }
 617     }
 618     BIO_free(bpart);
 619     return 0;
 620 }
 621
 622 /* This is the big one: parse MIME header lines up to message body */
 623
 624 #define MIME_INVALID    0
 625 #define MIME_START      1
 626 #define MIME_TYPE       2
 627 #define MIME_NAME       3
 628 #define MIME_VALUE      4
 629 #define MIME_QUOTE      5
 630 #define MIME_COMMENT    6
 631
 632 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio)
 633 {
 634     char *p, *q, c;
 635     char *ntmp;
 636     char linebuf[MAX_SMLEN];
 637     MIME_HEADER *mhdr = NULL, *new_hdr = NULL;
 638     STACK_OF(MIME_HEADER) *headers;
 639     int len, state, save_state = 0;
 640
 641     headers = sk_MIME_HEADER_new(mime_hdr_cmp);
 642     if (headers == NULL)
 643         return NULL;
 644     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
 645         /* If whitespace at line start then continuation line */
 646         if (mhdr && ossl_isspace(linebuf[0]))
 647             state = MIME_NAME;
 648         else
 649             state = MIME_START;
 650         ntmp = NULL;
 651         /* Go through all characters */
 652         for (p = linebuf, q = linebuf; (c = *p) && (c != '\r') && (c != '\n');
 653              p++) {
 654
 655             /*
 656              * State machine to handle MIME headers if this looks horrible
 657              * that's because it *is*
 658              */
 659
 660             switch (state) {
 661             case MIME_START:
 662                 if (c == ':') {
 663                     state = MIME_TYPE;
 664                     *p = 0;
 665                     ntmp = strip_ends(q);
 666                     q = p + 1;
 667                 }
 668                 break;
 669
 670             case MIME_TYPE:
 671                 if (c == ';') {
 672                     mime_debug("Found End Value\n");
 673                     *p = 0;
 674                     new_hdr = mime_hdr_new(ntmp, strip_ends(q));
 675                     if (new_hdr == NULL)
 676                         goto err;
 677                     if (!sk_MIME_HEADER_push(headers, new_hdr))
 678                         goto err;
 679                     mhdr = new_hdr;
 680                     new_hdr = NULL;
 681                     ntmp = NULL;
 682                     q = p + 1;
 683                     state = MIME_NAME;
 684                 } else if (c == '(') {
 685                     save_state = state;
 686                     state = MIME_COMMENT;
 687                 }
 688                 break;
 689
 690             case MIME_COMMENT:
 691                 if (c == ')') {
 692                     state = save_state;
 693                 }
 694                 break;
 695
 696             case MIME_NAME:
 697                 if (c == '=') {
 698                     state = MIME_VALUE;
 699                     *p = 0;
 700                     ntmp = strip_ends(q);
 701                     q = p + 1;
 702                 }
 703                 break;
 704
 705             case MIME_VALUE:
 706                 if (c == ';') {
 707                     state = MIME_NAME;
 708                     *p = 0;
 709                     mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 710                     ntmp = NULL;
 711                     q = p + 1;
 712                 } else if (c == '"') {
 713                     mime_debug("Found Quote\n");
 714                     state = MIME_QUOTE;
 715                 } else if (c == '(') {
 716                     save_state = state;
 717                     state = MIME_COMMENT;
 718                 }
 719                 break;
 720
 721             case MIME_QUOTE:
 722                 if (c == '"') {
 723                     mime_debug("Found Match Quote\n");
 724                     state = MIME_VALUE;
 725                 }
 726                 break;
 727             }
 728         }
 729
 730         if (state == MIME_TYPE) {
 731             new_hdr = mime_hdr_new(ntmp, strip_ends(q));
 732             if (new_hdr == NULL)
 733                 goto err;
 734             if (!sk_MIME_HEADER_push(headers, new_hdr))
 735                 goto err;
 736             mhdr = new_hdr;
 737             new_hdr = NULL;
 738         } else if (state == MIME_VALUE)
 739             mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 740         if (p == linebuf)
 741             break;              /* Blank line means end of headers */
 742     }
 743
 744     return headers;
 745
 746 err:
 747     mime_hdr_free(new_hdr);
 748     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 749     return NULL;
 750 }
 751
 752 static char *strip_ends(char *name)
 753 {
 754     return strip_end(strip_start(name));
 755 }
 756
 757 /* Strip a parameter of whitespace from start of param */
 758 static char *strip_start(char *name)
 759 {
 760     char *p, c;
 761     /* Look for first non white space or quote */
 762     for (p = name; (c = *p); p++) {
 763         if (c == '"') {
 764             /* Next char is start of string if non null */
 765             if (p[1])
 766                 return p + 1;
 767             /* Else null string */
 768             return NULL;
 769         }
 770         if (!ossl_isspace(c))
 771             return p;
 772     }
 773     return NULL;
 774 }
 775
 776 /* As above but strip from end of string : maybe should handle brackets? */
 777 static char *strip_end(char *name)
 778 {
 779     char *p, c;
 780     if (!name)
 781         return NULL;
 782     /* Look for first non white space or quote */
 783     for (p = name + strlen(name) - 1; p >= name; p--) {
 784         c = *p;
 785         if (c == '"') {
 786             if (p - 1 == name)
 787                 return NULL;
 788             *p = 0;
 789             return name;
 790         }
 791         if (ossl_isspace(c))
 792             *p = 0;
 793         else
 794             return name;
 795     }
 796     return NULL;
 797 }
 798
 799 static MIME_HEADER *mime_hdr_new(const char *name, const char *value)
 800 {
 801     MIME_HEADER *mhdr = NULL;
 802     char *tmpname = NULL, *tmpval = NULL, *p;
 803
 804     if (name) {
 805         if ((tmpname = OPENSSL_strdup(name)) == NULL)
 806             return NULL;
 807         for (p = tmpname; *p; p++)
 808             *p = ossl_tolower(*p);
 809     }
 810     if (value) {
 811         if ((tmpval = OPENSSL_strdup(value)) == NULL)
 812             goto err;
 813         for (p = tmpval; *p; p++)
 814             *p = ossl_tolower(*p);
 815     }
 816     mhdr = OPENSSL_malloc(sizeof(*mhdr));
 817     if (mhdr == NULL)
 818         goto err;
 819     mhdr->name = tmpname;
 820     mhdr->value = tmpval;
 821     if ((mhdr->params = sk_MIME_PARAM_new(mime_param_cmp)) == NULL)
 822         goto err;
 823     return mhdr;
 824
 825  err:
 826     OPENSSL_free(tmpname);
 827     OPENSSL_free(tmpval);
 828     OPENSSL_free(mhdr);
 829     return NULL;
 830 }
 831
 832 static int mime_hdr_addparam(MIME_HEADER *mhdr, const char *name, const char *value)
 833 {
 834     char *tmpname = NULL, *tmpval = NULL, *p;
 835     MIME_PARAM *mparam = NULL;
 836
 837     if (name) {
 838         tmpname = OPENSSL_strdup(name);
 839         if (!tmpname)
 840             goto err;
 841         for (p = tmpname; *p; p++)
 842             *p = ossl_tolower(*p);
 843     }
 844     if (value) {
 845         tmpval = OPENSSL_strdup(value);
 846         if (!tmpval)
 847             goto err;
 848     }
 849     /* Parameter values are case sensitive so leave as is */
 850     mparam = OPENSSL_malloc(sizeof(*mparam));
 851     if (mparam == NULL)
 852         goto err;
 853     mparam->param_name = tmpname;
 854     mparam->param_value = tmpval;
 855     if (!sk_MIME_PARAM_push(mhdr->params, mparam))
 856         goto err;
 857     return 1;
 858  err:
 859     OPENSSL_free(tmpname);
 860     OPENSSL_free(tmpval);
 861     OPENSSL_free(mparam);
 862     return 0;
 863 }
 864
 865 static int mime_hdr_cmp(const MIME_HEADER *const *a,
 866                         const MIME_HEADER *const *b)
 867 {
 868     if (!(*a)->name || !(*b)->name)
 869         return ! !(*a)->name - ! !(*b)->name;
 870
 871     return strcmp((*a)->name, (*b)->name);
 872 }
 873
 874 static int mime_param_cmp(const MIME_PARAM *const *a,
 875                           const MIME_PARAM *const *b)
 876 {
 877     if (!(*a)->param_name || !(*b)->param_name)
 878         return ! !(*a)->param_name - ! !(*b)->param_name;
 879     return strcmp((*a)->param_name, (*b)->param_name);
 880 }
 881
 882 /* Find a header with a given name (if possible) */
 883
 884 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, const char *name)
 885 {
 886     MIME_HEADER htmp;
 887     int idx;
 888
 889     htmp.name = (char *)name;
 890     htmp.value = NULL;
 891     htmp.params = NULL;
 892
 893     idx = sk_MIME_HEADER_find(hdrs, &htmp);
 894     return sk_MIME_HEADER_value(hdrs, idx);
 895 }
 896
 897 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, const char *name)
 898 {
 899     MIME_PARAM param;
 900     int idx;
 901
 902     param.param_name = (char *)name;
 903     param.param_value = NULL;
 904     idx = sk_MIME_PARAM_find(hdr->params, &param);
 905     return sk_MIME_PARAM_value(hdr->params, idx);
 906 }
 907
 908 static void mime_hdr_free(MIME_HEADER *hdr)
 909 {
 910     if (hdr == NULL)
 911         return;
 912     OPENSSL_free(hdr->name);
 913     OPENSSL_free(hdr->value);
 914     if (hdr->params)
 915         sk_MIME_PARAM_pop_free(hdr->params, mime_param_free);
 916     OPENSSL_free(hdr);
 917 }
 918
 919 static void mime_param_free(MIME_PARAM *param)
 920 {
 921     OPENSSL_free(param->param_name);
 922     OPENSSL_free(param->param_value);
 923     OPENSSL_free(param);
 924 }
 925
 926 /*-
 927  * Check for a multipart boundary. Returns:
 928  * 0 : no boundary
 929  * 1 : part boundary
 930  * 2 : final boundary
 931  */
 932 static int mime_bound_check(char *line, int linelen, const char *bound, int blen)
 933 {
 934     if (linelen == -1)
 935         linelen = strlen(line);
 936     if (blen == -1)
 937         blen = strlen(bound);
 938     /* Quickly eliminate if line length too short */
 939     if (blen + 2 > linelen)
 940         return 0;
 941     /* Check for part boundary */
 942     if ((strncmp(line, "--", 2) == 0)
 943         && strncmp(line + 2, bound, blen) == 0) {
 944         if (strncmp(line + blen + 2, "--", 2) == 0)
 945             return 2;
 946         else
 947             return 1;
 948     }
 949     return 0;
 950 }
 951
 952 static int strip_eol(char *linebuf, int *plen, int flags)
 953 {
 954     int len = *plen;
 955     char *p, c;
 956     int is_eol = 0;
 957
 958     for (p = linebuf + len - 1; len > 0; len--, p--) {
 959         c = *p;
 960         if (c == '\n') {
 961             is_eol = 1;
 962         } else if (is_eol && flags & SMIME_ASCIICRLF && c == 32) {
 963             /* Strip trailing space on a line; 32 == ASCII for ' ' */
 964             continue;
 965         } else if (c != '\r') {
 966             break;
 967         }
 968     }
 969     *plen = len;
 970     return is_eol;
 971 }