crypto/asn1/asn_mime.c

   1 /*
   2  * Copyright 2008-2020 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (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 DEFINE_STACK_OF(BIO)
  22 DEFINE_STACK_OF(X509_ALGOR)
  23
  24 /*
  25  * Generalised MIME like utilities for streaming ASN1. Although many have a
  26  * PKCS7/CMS like flavour others are more general purpose.
  27  */
  28
  29 /*
  30  * MIME format structures Note that all are translated to lower case apart
  31  * from parameter values. Quotes are stripped off
  32  */
  33
  34 struct mime_param_st {
  35     char *param_name;           /* Param name e.g. "micalg" */
  36     char *param_value;          /* Param value e.g. "sha1" */
  37 };
  38
  39 struct mime_header_st {
  40     char *name;                 /* Name of line e.g. "content-type" */
  41     char *value;                /* Value of line e.g. "text/plain" */
  42     STACK_OF(MIME_PARAM) *params; /* Zero or more parameters */
  43 };
  44
  45 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
  46                             const ASN1_ITEM *it);
  47 static char *strip_ends(char *name);
  48 static char *strip_start(char *name);
  49 static char *strip_end(char *name);
  50 static MIME_HEADER *mime_hdr_new(const char *name, const char *value);
  51 static int mime_hdr_addparam(MIME_HEADER *mhdr, const char *name, const char *value);
  52 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio);
  53 static int mime_hdr_cmp(const MIME_HEADER *const *a,
  54                         const MIME_HEADER *const *b);
  55 static int mime_param_cmp(const MIME_PARAM *const *a,
  56                           const MIME_PARAM *const *b);
  57 static void mime_param_free(MIME_PARAM *param);
  58 static int mime_bound_check(char *line, int linelen, const char *bound, int blen);
  59 static int multi_split(BIO *bio, const char *bound, STACK_OF(BIO) **ret);
  60 static int strip_eol(char *linebuf, int *plen, int flags);
  61 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, const char *name);
  62 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, const char *name);
  63 static void mime_hdr_free(MIME_HEADER *hdr);
  64
  65 #define MAX_SMLEN 1024
  66 #define mime_debug(x)           /* x */
  67
  68 /* Output an ASN1 structure in BER format streaming if necessary */
  69
  70 /* unfortunately cannot constify this due to CMS_stream() and PKCS7_stream() */
  71 int i2d_ASN1_bio_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
  72                         const ASN1_ITEM *it)
  73 {
  74     /* If streaming create stream BIO and copy all content through it */
  75     if (flags & SMIME_STREAM) {
  76         BIO *bio, *tbio;
  77         bio = BIO_new_NDEF(out, val, it);
  78         if (!bio) {
  79             ASN1err(ASN1_F_I2D_ASN1_BIO_STREAM, ERR_R_MALLOC_FAILURE);
  80             return 0;
  81         }
  82         SMIME_crlf_copy(in, bio, flags);
  83         (void)BIO_flush(bio);
  84         /* Free up successive BIOs until we hit the old output BIO */
  85         do {
  86             tbio = BIO_pop(bio);
  87             BIO_free(bio);
  88             bio = tbio;
  89         } while (bio != out);
  90     }
  91     /*
  92      * else just write out ASN1 structure which will have all content stored
  93      * internally
  94      */
  95     else
  96         ASN1_item_i2d_bio(it, out, val);
  97     return 1;
  98 }
  99
 100 /* Base 64 read and write of ASN1 structure */
 101
 102 static int B64_write_ASN1(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
 103                           const ASN1_ITEM *it)
 104 {
 105     BIO *b64;
 106     int r;
 107     b64 = BIO_new(BIO_f_base64());
 108     if (b64 == NULL) {
 109         ASN1err(ASN1_F_B64_WRITE_ASN1, ERR_R_MALLOC_FAILURE);
 110         return 0;
 111     }
 112     /*
 113      * prepend the b64 BIO so all data is base64 encoded.
 114      */
 115     out = BIO_push(b64, out);
 116     r = i2d_ASN1_bio_stream(out, val, in, flags, it);
 117     (void)BIO_flush(out);
 118     BIO_pop(out);
 119     BIO_free(b64);
 120     return r;
 121 }
 122
 123 /* Streaming ASN1 PEM write */
 124
 125 int PEM_write_bio_ASN1_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
 126                               const char *hdr, const ASN1_ITEM *it)
 127 {
 128     int r;
 129     BIO_printf(out, "-----BEGIN %s-----\n", hdr);
 130     r = B64_write_ASN1(out, val, in, flags, it);
 131     BIO_printf(out, "-----END %s-----\n", hdr);
 132     return r;
 133 }
 134
 135 static ASN1_VALUE *b64_read_asn1(BIO *bio, const ASN1_ITEM *it)
 136 {
 137     BIO *b64;
 138     ASN1_VALUE *val;
 139
 140     if ((b64 = BIO_new(BIO_f_base64())) == NULL) {
 141         ASN1err(ASN1_F_B64_READ_ASN1, ERR_R_MALLOC_FAILURE);
 142         return 0;
 143     }
 144     bio = BIO_push(b64, bio);
 145     val = ASN1_item_d2i_bio(it, bio, NULL);
 146     if (!val)
 147         ASN1err(ASN1_F_B64_READ_ASN1, ASN1_R_DECODE_ERROR);
 148     (void)BIO_flush(bio);
 149     BIO_pop(bio);
 150     BIO_free(b64);
 151     return val;
 152 }
 153
 154 /* Generate the MIME "micalg" parameter from RFC3851, RFC4490 */
 155
 156 static int asn1_write_micalg(BIO *out, STACK_OF(X509_ALGOR) *mdalgs)
 157 {
 158     const EVP_MD *md;
 159     int i, have_unknown = 0, write_comma, ret = 0, md_nid;
 160     have_unknown = 0;
 161     write_comma = 0;
 162     for (i = 0; i < sk_X509_ALGOR_num(mdalgs); i++) {
 163         if (write_comma)
 164             BIO_write(out, ",", 1);
 165         write_comma = 1;
 166         md_nid = OBJ_obj2nid(sk_X509_ALGOR_value(mdalgs, i)->algorithm);
 167         md = EVP_get_digestbynid(md_nid);
 168         if (md && md->md_ctrl) {
 169             int rv;
 170             char *micstr;
 171             rv = md->md_ctrl(NULL, EVP_MD_CTRL_MICALG, 0, &micstr);
 172             if (rv > 0) {
 173                 BIO_puts(out, micstr);
 174                 OPENSSL_free(micstr);
 175                 continue;
 176             }
 177             if (rv != -2)
 178                 goto err;
 179         }
 180         switch (md_nid) {
 181         case NID_sha1:
 182             BIO_puts(out, "sha1");
 183             break;
 184
 185         case NID_md5:
 186             BIO_puts(out, "md5");
 187             break;
 188
 189         case NID_sha256:
 190             BIO_puts(out, "sha-256");
 191             break;
 192
 193         case NID_sha384:
 194             BIO_puts(out, "sha-384");
 195             break;
 196
 197         case NID_sha512:
 198             BIO_puts(out, "sha-512");
 199             break;
 200
 201         case NID_id_GostR3411_94:
 202             BIO_puts(out, "gostr3411-94");
 203             goto err;
 204
 205         case NID_id_GostR3411_2012_256:
 206             BIO_puts(out, "gostr3411-2012-256");
 207             goto err;
 208
 209         case NID_id_GostR3411_2012_512:
 210             BIO_puts(out, "gostr3411-2012-512");
 211             goto err;
 212
 213         default:
 214             if (have_unknown)
 215                 write_comma = 0;
 216             else {
 217                 BIO_puts(out, "unknown");
 218                 have_unknown = 1;
 219             }
 220             break;
 221
 222         }
 223     }
 224
 225     ret = 1;
 226  err:
 227
 228     return ret;
 229
 230 }
 231
 232 /* SMIME sender */
 233
 234 int SMIME_write_ASN1(BIO *bio, ASN1_VALUE *val, BIO *data, int flags,
 235                      int ctype_nid, int econt_nid,
 236                      STACK_OF(X509_ALGOR) *mdalgs, const ASN1_ITEM *it)
 237 {
 238     char bound[33], c;
 239     int i;
 240     const char *mime_prefix, *mime_eol, *cname = "smime.p7m";
 241     const char *msg_type = NULL;
 242     if (flags & SMIME_OLDMIME)
 243         mime_prefix = "application/x-pkcs7-";
 244     else
 245         mime_prefix = "application/pkcs7-";
 246
 247     if (flags & SMIME_CRLFEOL)
 248         mime_eol = "\r\n";
 249     else
 250         mime_eol = "\n";
 251     if ((flags & SMIME_DETACHED) && data) {
 252         /* We want multipart/signed */
 253         /* Generate a random boundary */
 254         if (RAND_bytes((unsigned char *)bound, 32) <= 0)
 255             return 0;
 256         for (i = 0; i < 32; i++) {
 257             c = bound[i] & 0xf;
 258             if (c < 10)
 259                 c += '0';
 260             else
 261                 c += 'A' - 10;
 262             bound[i] = c;
 263         }
 264         bound[32] = 0;
 265         BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
 266         BIO_printf(bio, "Content-Type: multipart/signed;");
 267         BIO_printf(bio, " protocol=\"%ssignature\";", mime_prefix);
 268         BIO_puts(bio, " micalg=\"");
 269         asn1_write_micalg(bio, mdalgs);
 270         BIO_printf(bio, "\"; boundary=\"----%s\"%s%s",
 271                    bound, mime_eol, mime_eol);
 272         BIO_printf(bio, "This is an S/MIME signed message%s%s",
 273                    mime_eol, mime_eol);
 274         /* Now write out the first part */
 275         BIO_printf(bio, "------%s%s", bound, mime_eol);
 276         if (!asn1_output_data(bio, data, val, flags, it))
 277             return 0;
 278         BIO_printf(bio, "%s------%s%s", mime_eol, bound, mime_eol);
 279
 280         /* Headers for signature */
 281
 282         BIO_printf(bio, "Content-Type: %ssignature;", mime_prefix);
 283         BIO_printf(bio, " name=\"smime.p7s\"%s", mime_eol);
 284         BIO_printf(bio, "Content-Transfer-Encoding: base64%s", mime_eol);
 285         BIO_printf(bio, "Content-Disposition: attachment;");
 286         BIO_printf(bio, " filename=\"smime.p7s\"%s%s", mime_eol, mime_eol);
 287         B64_write_ASN1(bio, val, NULL, 0, it);
 288         BIO_printf(bio, "%s------%s--%s%s", mime_eol, bound,
 289                    mime_eol, mime_eol);
 290         return 1;
 291     }
 292
 293     /* Determine smime-type header */
 294
 295     if (ctype_nid == NID_pkcs7_enveloped)
 296         msg_type = "enveloped-data";
 297     else if (ctype_nid == NID_pkcs7_signed) {
 298         if (econt_nid == NID_id_smime_ct_receipt)
 299             msg_type = "signed-receipt";
 300         else if (sk_X509_ALGOR_num(mdalgs) >= 0)
 301             msg_type = "signed-data";
 302         else
 303             msg_type = "certs-only";
 304     } else if (ctype_nid == NID_id_smime_ct_compressedData) {
 305         msg_type = "compressed-data";
 306         cname = "smime.p7z";
 307     }
 308     /* MIME headers */
 309     BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
 310     BIO_printf(bio, "Content-Disposition: attachment;");
 311     BIO_printf(bio, " filename=\"%s\"%s", cname, mime_eol);
 312     BIO_printf(bio, "Content-Type: %smime;", mime_prefix);
 313     if (msg_type)
 314         BIO_printf(bio, " smime-type=%s;", msg_type);
 315     BIO_printf(bio, " name=\"%s\"%s", cname, mime_eol);
 316     BIO_printf(bio, "Content-Transfer-Encoding: base64%s%s",
 317                mime_eol, mime_eol);
 318     if (!B64_write_ASN1(bio, val, data, flags, it))
 319         return 0;
 320     BIO_printf(bio, "%s", mime_eol);
 321     return 1;
 322 }
 323
 324 /* Handle output of ASN1 data */
 325
 326 /* cannot constify val because of CMS_dataFinal() */
 327 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
 328                             const ASN1_ITEM *it)
 329 {
 330     BIO *tmpbio;
 331     const ASN1_AUX *aux = it->funcs;
 332     ASN1_STREAM_ARG sarg;
 333     int rv = 1;
 334
 335     /*
 336      * If data is not detached or resigning then the output BIO is already
 337      * set up to finalise when it is written through.
 338      */
 339     if (!(flags & SMIME_DETACHED) || (flags & PKCS7_REUSE_DIGEST)) {
 340         SMIME_crlf_copy(data, out, flags);
 341         return 1;
 342     }
 343
 344     if (!aux || !aux->asn1_cb) {
 345         ASN1err(ASN1_F_ASN1_OUTPUT_DATA, ASN1_R_STREAMING_NOT_SUPPORTED);
 346         return 0;
 347     }
 348
 349     sarg.out = out;
 350     sarg.ndef_bio = NULL;
 351     sarg.boundary = NULL;
 352
 353     /* Let ASN1 code prepend any needed BIOs */
 354
 355     if (aux->asn1_cb(ASN1_OP_DETACHED_PRE, &val, it, &sarg) <= 0)
 356         return 0;
 357
 358     /* Copy data across, passing through filter BIOs for processing */
 359     SMIME_crlf_copy(data, sarg.ndef_bio, flags);
 360
 361     /* Finalize structure */
 362     if (aux->asn1_cb(ASN1_OP_DETACHED_POST, &val, it, &sarg) <= 0)
 363         rv = 0;
 364
 365     /* Now remove any digests prepended to the BIO */
 366
 367     while (sarg.ndef_bio != out) {
 368         tmpbio = BIO_pop(sarg.ndef_bio);
 369         BIO_free(sarg.ndef_bio);
 370         sarg.ndef_bio = tmpbio;
 371     }
 372
 373     return rv;
 374
 375 }
 376
 377 /*
 378  * SMIME reader: handle multipart/signed and opaque signing. in multipart
 379  * case the content is placed in a memory BIO pointed to by "bcont". In
 380  * opaque this is set to NULL
 381  */
 382
 383 ASN1_VALUE *SMIME_read_ASN1(BIO *bio, BIO **bcont, const ASN1_ITEM *it)
 384 {
 385     BIO *asnin;
 386     STACK_OF(MIME_HEADER) *headers = NULL;
 387     STACK_OF(BIO) *parts = NULL;
 388     MIME_HEADER *hdr;
 389     MIME_PARAM *prm;
 390     ASN1_VALUE *val;
 391     int ret;
 392
 393     if (bcont)
 394         *bcont = NULL;
 395
 396     if ((headers = mime_parse_hdr(bio)) == NULL) {
 397         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_PARSE_ERROR);
 398         return NULL;
 399     }
 400
 401     if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 402         || hdr->value == NULL) {
 403         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 404         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_CONTENT_TYPE);
 405         return NULL;
 406     }
 407
 408     /* Handle multipart/signed */
 409
 410     if (strcmp(hdr->value, "multipart/signed") == 0) {
 411         /* Split into two parts */
 412         prm = mime_param_find(hdr, "boundary");
 413         if (prm == NULL || prm->param_value == NULL) {
 414             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 415             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BOUNDARY);
 416             return NULL;
 417         }
 418         ret = multi_split(bio, prm->param_value, &parts);
 419         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 420         if (!ret || (sk_BIO_num(parts) != 2)) {
 421             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BODY_FAILURE);
 422             sk_BIO_pop_free(parts, BIO_vfree);
 423             return NULL;
 424         }
 425
 426         /* Parse the signature piece */
 427         asnin = sk_BIO_value(parts, 1);
 428
 429         if ((headers = mime_parse_hdr(asnin)) == NULL) {
 430             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_SIG_PARSE_ERROR);
 431             sk_BIO_pop_free(parts, BIO_vfree);
 432             return NULL;
 433         }
 434
 435         /* Get content type */
 436
 437         if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 438             || hdr->value == NULL) {
 439             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 440             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_SIG_CONTENT_TYPE);
 441             sk_BIO_pop_free(parts, BIO_vfree);
 442             return NULL;
 443         }
 444
 445         if (strcmp(hdr->value, "application/x-pkcs7-signature") &&
 446             strcmp(hdr->value, "application/pkcs7-signature")) {
 447             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_SIG_INVALID_MIME_TYPE);
 448             ERR_add_error_data(2, "type: ", hdr->value);
 449             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 450             sk_BIO_pop_free(parts, BIO_vfree);
 451             return NULL;
 452         }
 453         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 454         /* Read in ASN1 */
 455         if ((val = b64_read_asn1(asnin, it)) == NULL) {
 456             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_SIG_PARSE_ERROR);
 457             sk_BIO_pop_free(parts, BIO_vfree);
 458             return NULL;
 459         }
 460
 461         if (bcont) {
 462             *bcont = sk_BIO_value(parts, 0);
 463             BIO_free(asnin);
 464             sk_BIO_free(parts);
 465         } else
 466             sk_BIO_pop_free(parts, BIO_vfree);
 467         return val;
 468     }
 469
 470     /* OK, if not multipart/signed try opaque signature */
 471
 472     if (strcmp(hdr->value, "application/x-pkcs7-mime") &&
 473         strcmp(hdr->value, "application/pkcs7-mime")) {
 474         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_INVALID_MIME_TYPE);
 475         ERR_add_error_data(2, "type: ", hdr->value);
 476         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 477         return NULL;
 478     }
 479
 480     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 481
 482     if ((val = b64_read_asn1(bio, it)) == NULL) {
 483         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_PARSE_ERROR);
 484         return NULL;
 485     }
 486     return val;
 487
 488 }
 489
 490 /* Copy text from one BIO to another making the output CRLF at EOL */
 491 int SMIME_crlf_copy(BIO *in, BIO *out, int flags)
 492 {
 493     BIO *bf;
 494     char eol;
 495     int len;
 496     char linebuf[MAX_SMLEN];
 497     /*
 498      * Buffer output so we don't write one line at a time. This is useful
 499      * when streaming as we don't end up with one OCTET STRING per line.
 500      */
 501     bf = BIO_new(BIO_f_buffer());
 502     if (bf == NULL)
 503         return 0;
 504     out = BIO_push(bf, out);
 505     if (flags & SMIME_BINARY) {
 506         while ((len = BIO_read(in, linebuf, MAX_SMLEN)) > 0)
 507             BIO_write(out, linebuf, len);
 508     } else {
 509         int eolcnt = 0;
 510         if (flags & SMIME_TEXT)
 511             BIO_printf(out, "Content-Type: text/plain\r\n\r\n");
 512         while ((len = BIO_gets(in, linebuf, MAX_SMLEN)) > 0) {
 513             eol = strip_eol(linebuf, &len, flags);
 514             if (len) {
 515                 /* Not EOF: write out all CRLF */
 516                 if (flags & SMIME_ASCIICRLF) {
 517                     int i;
 518                     for (i = 0; i < eolcnt; i++)
 519                         BIO_write(out, "\r\n", 2);
 520                     eolcnt = 0;
 521                 }
 522                 BIO_write(out, linebuf, len);
 523                 if (eol)
 524                     BIO_write(out, "\r\n", 2);
 525             } else if (flags & SMIME_ASCIICRLF)
 526                 eolcnt++;
 527             else if (eol)
 528                 BIO_write(out, "\r\n", 2);
 529         }
 530     }
 531     (void)BIO_flush(out);
 532     BIO_pop(out);
 533     BIO_free(bf);
 534     return 1;
 535 }
 536
 537 /* Strip off headers if they are text/plain */
 538 int SMIME_text(BIO *in, BIO *out)
 539 {
 540     char iobuf[4096];
 541     int len;
 542     STACK_OF(MIME_HEADER) *headers;
 543     MIME_HEADER *hdr;
 544
 545     if ((headers = mime_parse_hdr(in)) == NULL) {
 546         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_PARSE_ERROR);
 547         return 0;
 548     }
 549     if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 550         || hdr->value == NULL) {
 551         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_NO_CONTENT_TYPE);
 552         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 553         return 0;
 554     }
 555     if (strcmp(hdr->value, "text/plain")) {
 556         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_INVALID_MIME_TYPE);
 557         ERR_add_error_data(2, "type: ", hdr->value);
 558         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 559         return 0;
 560     }
 561     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 562     while ((len = BIO_read(in, iobuf, sizeof(iobuf))) > 0)
 563         BIO_write(out, iobuf, len);
 564     if (len < 0)
 565         return 0;
 566     return 1;
 567 }
 568
 569 /*
 570  * Split a multipart/XXX message body into component parts: result is
 571  * canonical parts in a STACK of bios
 572  */
 573
 574 static int multi_split(BIO *bio, const char *bound, STACK_OF(BIO) **ret)
 575 {
 576     char linebuf[MAX_SMLEN];
 577     int len, blen;
 578     int eol = 0, next_eol = 0;
 579     BIO *bpart = NULL;
 580     STACK_OF(BIO) *parts;
 581     char state, part, first;
 582
 583     blen = strlen(bound);
 584     part = 0;
 585     state = 0;
 586     first = 1;
 587     parts = sk_BIO_new_null();
 588     *ret = parts;
 589     if (*ret == NULL)
 590         return 0;
 591     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
 592         state = mime_bound_check(linebuf, len, bound, blen);
 593         if (state == 1) {
 594             first = 1;
 595             part++;
 596         } else if (state == 2) {
 597             if (!sk_BIO_push(parts, bpart)) {
 598                 BIO_free(bpart);
 599                 return 0;
 600             }
 601             return 1;
 602         } else if (part) {
 603             /* Strip CR+LF from linebuf */
 604             next_eol = strip_eol(linebuf, &len, 0);
 605             if (first) {
 606                 first = 0;
 607                 if (bpart)
 608                     if (!sk_BIO_push(parts, bpart)) {
 609                         BIO_free(bpart);
 610                         return 0;
 611                     }
 612                 bpart = BIO_new(BIO_s_mem());
 613                 if (bpart == NULL)
 614                     return 0;
 615                 BIO_set_mem_eof_return(bpart, 0);
 616             } else if (eol)
 617                 BIO_write(bpart, "\r\n", 2);
 618             eol = next_eol;
 619             if (len)
 620                 BIO_write(bpart, linebuf, len);
 621         }
 622     }
 623     BIO_free(bpart);
 624     return 0;
 625 }
 626
 627 /* This is the big one: parse MIME header lines up to message body */
 628
 629 #define MIME_INVALID    0
 630 #define MIME_START      1
 631 #define MIME_TYPE       2
 632 #define MIME_NAME       3
 633 #define MIME_VALUE      4
 634 #define MIME_QUOTE      5
 635 #define MIME_COMMENT    6
 636
 637 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio)
 638 {
 639     char *p, *q, c;
 640     char *ntmp;
 641     char linebuf[MAX_SMLEN];
 642     MIME_HEADER *mhdr = NULL, *new_hdr = NULL;
 643     STACK_OF(MIME_HEADER) *headers;
 644     int len, state, save_state = 0;
 645
 646     headers = sk_MIME_HEADER_new(mime_hdr_cmp);
 647     if (headers == NULL)
 648         return NULL;
 649     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
 650         /* If whitespace at line start then continuation line */
 651         if (mhdr && ossl_isspace(linebuf[0]))
 652             state = MIME_NAME;
 653         else
 654             state = MIME_START;
 655         ntmp = NULL;
 656         /* Go through all characters */
 657         for (p = linebuf, q = linebuf; (c = *p) && (c != '\r') && (c != '\n');
 658              p++) {
 659
 660             /*
 661              * State machine to handle MIME headers if this looks horrible
 662              * that's because it *is*
 663              */
 664
 665             switch (state) {
 666             case MIME_START:
 667                 if (c == ':') {
 668                     state = MIME_TYPE;
 669                     *p = 0;
 670                     ntmp = strip_ends(q);
 671                     q = p + 1;
 672                 }
 673                 break;
 674
 675             case MIME_TYPE:
 676                 if (c == ';') {
 677                     mime_debug("Found End Value\n");
 678                     *p = 0;
 679                     new_hdr = mime_hdr_new(ntmp, strip_ends(q));
 680                     if (new_hdr == NULL)
 681                         goto err;
 682                     if (!sk_MIME_HEADER_push(headers, new_hdr))
 683                         goto err;
 684                     mhdr = new_hdr;
 685                     new_hdr = NULL;
 686                     ntmp = NULL;
 687                     q = p + 1;
 688                     state = MIME_NAME;
 689                 } else if (c == '(') {
 690                     save_state = state;
 691                     state = MIME_COMMENT;
 692                 }
 693                 break;
 694
 695             case MIME_COMMENT:
 696                 if (c == ')') {
 697                     state = save_state;
 698                 }
 699                 break;
 700
 701             case MIME_NAME:
 702                 if (c == '=') {
 703                     state = MIME_VALUE;
 704                     *p = 0;
 705                     ntmp = strip_ends(q);
 706                     q = p + 1;
 707                 }
 708                 break;
 709
 710             case MIME_VALUE:
 711                 if (c == ';') {
 712                     state = MIME_NAME;
 713                     *p = 0;
 714                     mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 715                     ntmp = NULL;
 716                     q = p + 1;
 717                 } else if (c == '"') {
 718                     mime_debug("Found Quote\n");
 719                     state = MIME_QUOTE;
 720                 } else if (c == '(') {
 721                     save_state = state;
 722                     state = MIME_COMMENT;
 723                 }
 724                 break;
 725
 726             case MIME_QUOTE:
 727                 if (c == '"') {
 728                     mime_debug("Found Match Quote\n");
 729                     state = MIME_VALUE;
 730                 }
 731                 break;
 732             }
 733         }
 734
 735         if (state == MIME_TYPE) {
 736             new_hdr = mime_hdr_new(ntmp, strip_ends(q));
 737             if (new_hdr == NULL)
 738                 goto err;
 739             if (!sk_MIME_HEADER_push(headers, new_hdr))
 740                 goto err;
 741             mhdr = new_hdr;
 742             new_hdr = NULL;
 743         } else if (state == MIME_VALUE)
 744             mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 745         if (p == linebuf)
 746             break;              /* Blank line means end of headers */
 747     }
 748
 749     return headers;
 750
 751 err:
 752     mime_hdr_free(new_hdr);
 753     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 754     return NULL;
 755 }
 756
 757 static char *strip_ends(char *name)
 758 {
 759     return strip_end(strip_start(name));
 760 }
 761
 762 /* Strip a parameter of whitespace from start of param */
 763 static char *strip_start(char *name)
 764 {
 765     char *p, c;
 766     /* Look for first non white space or quote */
 767     for (p = name; (c = *p); p++) {
 768         if (c == '"') {
 769             /* Next char is start of string if non null */
 770             if (p[1])
 771                 return p + 1;
 772             /* Else null string */
 773             return NULL;
 774         }
 775         if (!ossl_isspace(c))
 776             return p;
 777     }
 778     return NULL;
 779 }
 780
 781 /* As above but strip from end of string : maybe should handle brackets? */
 782 static char *strip_end(char *name)
 783 {
 784     char *p, c;
 785     if (!name)
 786         return NULL;
 787     /* Look for first non white space or quote */
 788     for (p = name + strlen(name) - 1; p >= name; p--) {
 789         c = *p;
 790         if (c == '"') {
 791             if (p - 1 == name)
 792                 return NULL;
 793             *p = 0;
 794             return name;
 795         }
 796         if (ossl_isspace(c))
 797             *p = 0;
 798         else
 799             return name;
 800     }
 801     return NULL;
 802 }
 803
 804 static MIME_HEADER *mime_hdr_new(const char *name, const char *value)
 805 {
 806     MIME_HEADER *mhdr = NULL;
 807     char *tmpname = NULL, *tmpval = NULL, *p;
 808
 809     if (name) {
 810         if ((tmpname = OPENSSL_strdup(name)) == NULL)
 811             return NULL;
 812         for (p = tmpname; *p; p++)
 813             *p = ossl_tolower(*p);
 814     }
 815     if (value) {
 816         if ((tmpval = OPENSSL_strdup(value)) == NULL)
 817             goto err;
 818         for (p = tmpval; *p; p++)
 819             *p = ossl_tolower(*p);
 820     }
 821     mhdr = OPENSSL_malloc(sizeof(*mhdr));
 822     if (mhdr == NULL)
 823         goto err;
 824     mhdr->name = tmpname;
 825     mhdr->value = tmpval;
 826     if ((mhdr->params = sk_MIME_PARAM_new(mime_param_cmp)) == NULL)
 827         goto err;
 828     return mhdr;
 829
 830  err:
 831     OPENSSL_free(tmpname);
 832     OPENSSL_free(tmpval);
 833     OPENSSL_free(mhdr);
 834     return NULL;
 835 }
 836
 837 static int mime_hdr_addparam(MIME_HEADER *mhdr, const char *name, const char *value)
 838 {
 839     char *tmpname = NULL, *tmpval = NULL, *p;
 840     MIME_PARAM *mparam = NULL;
 841
 842     if (name) {
 843         tmpname = OPENSSL_strdup(name);
 844         if (!tmpname)
 845             goto err;
 846         for (p = tmpname; *p; p++)
 847             *p = ossl_tolower(*p);
 848     }
 849     if (value) {
 850         tmpval = OPENSSL_strdup(value);
 851         if (!tmpval)
 852             goto err;
 853     }
 854     /* Parameter values are case sensitive so leave as is */
 855     mparam = OPENSSL_malloc(sizeof(*mparam));
 856     if (mparam == NULL)
 857         goto err;
 858     mparam->param_name = tmpname;
 859     mparam->param_value = tmpval;
 860     if (!sk_MIME_PARAM_push(mhdr->params, mparam))
 861         goto err;
 862     return 1;
 863  err:
 864     OPENSSL_free(tmpname);
 865     OPENSSL_free(tmpval);
 866     OPENSSL_free(mparam);
 867     return 0;
 868 }
 869
 870 static int mime_hdr_cmp(const MIME_HEADER *const *a,
 871                         const MIME_HEADER *const *b)
 872 {
 873     if (!(*a)->name || !(*b)->name)
 874         return ! !(*a)->name - ! !(*b)->name;
 875
 876     return strcmp((*a)->name, (*b)->name);
 877 }
 878
 879 static int mime_param_cmp(const MIME_PARAM *const *a,
 880                           const MIME_PARAM *const *b)
 881 {
 882     if (!(*a)->param_name || !(*b)->param_name)
 883         return ! !(*a)->param_name - ! !(*b)->param_name;
 884     return strcmp((*a)->param_name, (*b)->param_name);
 885 }
 886
 887 /* Find a header with a given name (if possible) */
 888
 889 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, const char *name)
 890 {
 891     MIME_HEADER htmp;
 892     int idx;
 893
 894     htmp.name = (char *)name;
 895     htmp.value = NULL;
 896     htmp.params = NULL;
 897
 898     idx = sk_MIME_HEADER_find(hdrs, &htmp);
 899     return sk_MIME_HEADER_value(hdrs, idx);
 900 }
 901
 902 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, const char *name)
 903 {
 904     MIME_PARAM param;
 905     int idx;
 906
 907     param.param_name = (char *)name;
 908     param.param_value = NULL;
 909     idx = sk_MIME_PARAM_find(hdr->params, &param);
 910     return sk_MIME_PARAM_value(hdr->params, idx);
 911 }
 912
 913 static void mime_hdr_free(MIME_HEADER *hdr)
 914 {
 915     if (hdr == NULL)
 916         return;
 917     OPENSSL_free(hdr->name);
 918     OPENSSL_free(hdr->value);
 919     if (hdr->params)
 920         sk_MIME_PARAM_pop_free(hdr->params, mime_param_free);
 921     OPENSSL_free(hdr);
 922 }
 923
 924 static void mime_param_free(MIME_PARAM *param)
 925 {
 926     OPENSSL_free(param->param_name);
 927     OPENSSL_free(param->param_value);
 928     OPENSSL_free(param);
 929 }
 930
 931 /*-
 932  * Check for a multipart boundary. Returns:
 933  * 0 : no boundary
 934  * 1 : part boundary
 935  * 2 : final boundary
 936  */
 937 static int mime_bound_check(char *line, int linelen, const char *bound, int blen)
 938 {
 939     if (linelen == -1)
 940         linelen = strlen(line);
 941     if (blen == -1)
 942         blen = strlen(bound);
 943     /* Quickly eliminate if line length too short */
 944     if (blen + 2 > linelen)
 945         return 0;
 946     /* Check for part boundary */
 947     if ((strncmp(line, "--", 2) == 0)
 948         && strncmp(line + 2, bound, blen) == 0) {
 949         if (strncmp(line + blen + 2, "--", 2) == 0)
 950             return 2;
 951         else
 952             return 1;
 953     }
 954     return 0;
 955 }
 956
 957 static int strip_eol(char *linebuf, int *plen, int flags)
 958 {
 959     int len = *plen;
 960     char *p, c;
 961     int is_eol = 0;
 962
 963     for (p = linebuf + len - 1; len > 0; len--, p--) {
 964         c = *p;
 965         if (c == '\n') {
 966             is_eol = 1;
 967         } else if (is_eol && flags & SMIME_ASCIICRLF && c == 32) {
 968             /* Strip trailing space on a line; 32 == ASCII for ' ' */
 969             continue;
 970         } else if (c != '\r') {
 971             break;
 972         }
 973     }
 974     *plen = len;
 975     return is_eol;
 976 }