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 "internal/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 "internal/evp_int.h"
  18 #include "internal/bio.h"
  19 #include "asn1_locl.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         default:
 202             if (have_unknown)
 203                 write_comma = 0;
 204             else {
 205                 BIO_puts(out, "unknown");
 206                 have_unknown = 1;
 207             }
 208             break;
 209
 210         }
 211     }
 212
 213     ret = 1;
 214  err:
 215
 216     return ret;
 217
 218 }
 219
 220 /* SMIME sender */
 221
 222 int SMIME_write_ASN1(BIO *bio, ASN1_VALUE *val, BIO *data, int flags,
 223                      int ctype_nid, int econt_nid,
 224                      STACK_OF(X509_ALGOR) *mdalgs, const ASN1_ITEM *it)
 225 {
 226     char bound[33], c;
 227     int i;
 228     const char *mime_prefix, *mime_eol, *cname = "smime.p7m";
 229     const char *msg_type = NULL;
 230     if (flags & SMIME_OLDMIME)
 231         mime_prefix = "application/x-pkcs7-";
 232     else
 233         mime_prefix = "application/pkcs7-";
 234
 235     if (flags & SMIME_CRLFEOL)
 236         mime_eol = "\r\n";
 237     else
 238         mime_eol = "\n";
 239     if ((flags & SMIME_DETACHED) && data) {
 240         /* We want multipart/signed */
 241         /* Generate a random boundary */
 242         if (RAND_bytes((unsigned char *)bound, 32) <= 0)
 243             return 0;
 244         for (i = 0; i < 32; i++) {
 245             c = bound[i] & 0xf;
 246             if (c < 10)
 247                 c += '0';
 248             else
 249                 c += 'A' - 10;
 250             bound[i] = c;
 251         }
 252         bound[32] = 0;
 253         BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
 254         BIO_printf(bio, "Content-Type: multipart/signed;");
 255         BIO_printf(bio, " protocol=\"%ssignature\";", mime_prefix);
 256         BIO_puts(bio, " micalg=\"");
 257         asn1_write_micalg(bio, mdalgs);
 258         BIO_printf(bio, "\"; boundary=\"----%s\"%s%s",
 259                    bound, mime_eol, mime_eol);
 260         BIO_printf(bio, "This is an S/MIME signed message%s%s",
 261                    mime_eol, mime_eol);
 262         /* Now write out the first part */
 263         BIO_printf(bio, "------%s%s", bound, mime_eol);
 264         if (!asn1_output_data(bio, data, val, flags, it))
 265             return 0;
 266         BIO_printf(bio, "%s------%s%s", mime_eol, bound, mime_eol);
 267
 268         /* Headers for signature */
 269
 270         BIO_printf(bio, "Content-Type: %ssignature;", mime_prefix);
 271         BIO_printf(bio, " name=\"smime.p7s\"%s", mime_eol);
 272         BIO_printf(bio, "Content-Transfer-Encoding: base64%s", mime_eol);
 273         BIO_printf(bio, "Content-Disposition: attachment;");
 274         BIO_printf(bio, " filename=\"smime.p7s\"%s%s", mime_eol, mime_eol);
 275         B64_write_ASN1(bio, val, NULL, 0, it);
 276         BIO_printf(bio, "%s------%s--%s%s", mime_eol, bound,
 277                    mime_eol, mime_eol);
 278         return 1;
 279     }
 280
 281     /* Determine smime-type header */
 282
 283     if (ctype_nid == NID_pkcs7_enveloped)
 284         msg_type = "enveloped-data";
 285     else if (ctype_nid == NID_pkcs7_signed) {
 286         if (econt_nid == NID_id_smime_ct_receipt)
 287             msg_type = "signed-receipt";
 288         else if (sk_X509_ALGOR_num(mdalgs) >= 0)
 289             msg_type = "signed-data";
 290         else
 291             msg_type = "certs-only";
 292     } else if (ctype_nid == NID_id_smime_ct_compressedData) {
 293         msg_type = "compressed-data";
 294         cname = "smime.p7z";
 295     }
 296     /* MIME headers */
 297     BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
 298     BIO_printf(bio, "Content-Disposition: attachment;");
 299     BIO_printf(bio, " filename=\"%s\"%s", cname, mime_eol);
 300     BIO_printf(bio, "Content-Type: %smime;", mime_prefix);
 301     if (msg_type)
 302         BIO_printf(bio, " smime-type=%s;", msg_type);
 303     BIO_printf(bio, " name=\"%s\"%s", cname, mime_eol);
 304     BIO_printf(bio, "Content-Transfer-Encoding: base64%s%s",
 305                mime_eol, mime_eol);
 306     if (!B64_write_ASN1(bio, val, data, flags, it))
 307         return 0;
 308     BIO_printf(bio, "%s", mime_eol);
 309     return 1;
 310 }
 311
 312 /* Handle output of ASN1 data */
 313
 314 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
 315                             const ASN1_ITEM *it)
 316 {
 317     BIO *tmpbio;
 318     const ASN1_AUX *aux = it->funcs;
 319     ASN1_STREAM_ARG sarg;
 320     int rv = 1;
 321
 322     /*
 323      * If data is not detached or resigning then the output BIO is already
 324      * set up to finalise when it is written through.
 325      */
 326     if (!(flags & SMIME_DETACHED) || (flags & PKCS7_REUSE_DIGEST)) {
 327         SMIME_crlf_copy(data, out, flags);
 328         return 1;
 329     }
 330
 331     if (!aux || !aux->asn1_cb) {
 332         ASN1err(ASN1_F_ASN1_OUTPUT_DATA, ASN1_R_STREAMING_NOT_SUPPORTED);
 333         return 0;
 334     }
 335
 336     sarg.out = out;
 337     sarg.ndef_bio = NULL;
 338     sarg.boundary = NULL;
 339
 340     /* Let ASN1 code prepend any needed BIOs */
 341
 342     if (aux->asn1_cb(ASN1_OP_DETACHED_PRE, &val, it, &sarg) <= 0)
 343         return 0;
 344
 345     /* Copy data across, passing through filter BIOs for processing */
 346     SMIME_crlf_copy(data, sarg.ndef_bio, flags);
 347
 348     /* Finalize structure */
 349     if (aux->asn1_cb(ASN1_OP_DETACHED_POST, &val, it, &sarg) <= 0)
 350         rv = 0;
 351
 352     /* Now remove any digests prepended to the BIO */
 353
 354     while (sarg.ndef_bio != out) {
 355         tmpbio = BIO_pop(sarg.ndef_bio);
 356         BIO_free(sarg.ndef_bio);
 357         sarg.ndef_bio = tmpbio;
 358     }
 359
 360     return rv;
 361
 362 }
 363
 364 /*
 365  * SMIME reader: handle multipart/signed and opaque signing. in multipart
 366  * case the content is placed in a memory BIO pointed to by "bcont". In
 367  * opaque this is set to NULL
 368  */
 369
 370 ASN1_VALUE *SMIME_read_ASN1(BIO *bio, BIO **bcont, const ASN1_ITEM *it)
 371 {
 372     BIO *asnin;
 373     STACK_OF(MIME_HEADER) *headers = NULL;
 374     STACK_OF(BIO) *parts = NULL;
 375     MIME_HEADER *hdr;
 376     MIME_PARAM *prm;
 377     ASN1_VALUE *val;
 378     int ret;
 379
 380     if (bcont)
 381         *bcont = NULL;
 382
 383     if ((headers = mime_parse_hdr(bio)) == NULL) {
 384         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_PARSE_ERROR);
 385         return NULL;
 386     }
 387
 388     if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 389         || hdr->value == NULL) {
 390         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 391         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_CONTENT_TYPE);
 392         return NULL;
 393     }
 394
 395     /* Handle multipart/signed */
 396
 397     if (strcmp(hdr->value, "multipart/signed") == 0) {
 398         /* Split into two parts */
 399         prm = mime_param_find(hdr, "boundary");
 400         if (!prm || !prm->param_value) {
 401             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 402             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BOUNDARY);
 403             return NULL;
 404         }
 405         ret = multi_split(bio, prm->param_value, &parts);
 406         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 407         if (!ret || (sk_BIO_num(parts) != 2)) {
 408             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BODY_FAILURE);
 409             sk_BIO_pop_free(parts, BIO_vfree);
 410             return NULL;
 411         }
 412
 413         /* Parse the signature piece */
 414         asnin = sk_BIO_value(parts, 1);
 415
 416         if ((headers = mime_parse_hdr(asnin)) == NULL) {
 417             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_SIG_PARSE_ERROR);
 418             sk_BIO_pop_free(parts, BIO_vfree);
 419             return NULL;
 420         }
 421
 422         /* Get content type */
 423
 424         if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 425             || hdr->value == NULL) {
 426             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 427             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_SIG_CONTENT_TYPE);
 428             sk_BIO_pop_free(parts, BIO_vfree);
 429             return NULL;
 430         }
 431
 432         if (strcmp(hdr->value, "application/x-pkcs7-signature") &&
 433             strcmp(hdr->value, "application/pkcs7-signature")) {
 434             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_SIG_INVALID_MIME_TYPE);
 435             ERR_add_error_data(2, "type: ", hdr->value);
 436             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 437             sk_BIO_pop_free(parts, BIO_vfree);
 438             return NULL;
 439         }
 440         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 441         /* Read in ASN1 */
 442         if ((val = b64_read_asn1(asnin, it)) == NULL) {
 443             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_SIG_PARSE_ERROR);
 444             sk_BIO_pop_free(parts, BIO_vfree);
 445             return NULL;
 446         }
 447
 448         if (bcont) {
 449             *bcont = sk_BIO_value(parts, 0);
 450             BIO_free(asnin);
 451             sk_BIO_free(parts);
 452         } else
 453             sk_BIO_pop_free(parts, BIO_vfree);
 454         return val;
 455     }
 456
 457     /* OK, if not multipart/signed try opaque signature */
 458
 459     if (strcmp(hdr->value, "application/x-pkcs7-mime") &&
 460         strcmp(hdr->value, "application/pkcs7-mime")) {
 461         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_INVALID_MIME_TYPE);
 462         ERR_add_error_data(2, "type: ", hdr->value);
 463         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 464         return NULL;
 465     }
 466
 467     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 468
 469     if ((val = b64_read_asn1(bio, it)) == NULL) {
 470         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_PARSE_ERROR);
 471         return NULL;
 472     }
 473     return val;
 474
 475 }
 476
 477 /* Copy text from one BIO to another making the output CRLF at EOL */
 478 int SMIME_crlf_copy(BIO *in, BIO *out, int flags)
 479 {
 480     BIO *bf;
 481     char eol;
 482     int len;
 483     char linebuf[MAX_SMLEN];
 484     /*
 485      * Buffer output so we don't write one line at a time. This is useful
 486      * when streaming as we don't end up with one OCTET STRING per line.
 487      */
 488     bf = BIO_new(BIO_f_buffer());
 489     if (bf == NULL)
 490         return 0;
 491     out = BIO_push(bf, out);
 492     if (flags & SMIME_BINARY) {
 493         while ((len = BIO_read(in, linebuf, MAX_SMLEN)) > 0)
 494             BIO_write(out, linebuf, len);
 495     } else {
 496         int eolcnt = 0;
 497         if (flags & SMIME_TEXT)
 498             BIO_printf(out, "Content-Type: text/plain\r\n\r\n");
 499         while ((len = BIO_gets(in, linebuf, MAX_SMLEN)) > 0) {
 500             eol = strip_eol(linebuf, &len, flags);
 501             if (len) {
 502                 /* Not EOF: write out all CRLF */
 503                 if (flags & SMIME_ASCIICRLF) {
 504                     int i;
 505                     for (i = 0; i < eolcnt; i++)
 506                         BIO_write(out, "\r\n", 2);
 507                     eolcnt = 0;
 508                 }
 509                 BIO_write(out, linebuf, len);
 510                 if (eol)
 511                     BIO_write(out, "\r\n", 2);
 512             } else if (flags & SMIME_ASCIICRLF)
 513                 eolcnt++;
 514             else if (eol)
 515                 BIO_write(out, "\r\n", 2);
 516         }
 517     }
 518     (void)BIO_flush(out);
 519     BIO_pop(out);
 520     BIO_free(bf);
 521     return 1;
 522 }
 523
 524 /* Strip off headers if they are text/plain */
 525 int SMIME_text(BIO *in, BIO *out)
 526 {
 527     char iobuf[4096];
 528     int len;
 529     STACK_OF(MIME_HEADER) *headers;
 530     MIME_HEADER *hdr;
 531
 532     if ((headers = mime_parse_hdr(in)) == NULL) {
 533         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_PARSE_ERROR);
 534         return 0;
 535     }
 536     if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 537         || hdr->value == NULL) {
 538         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_NO_CONTENT_TYPE);
 539         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 540         return 0;
 541     }
 542     if (strcmp(hdr->value, "text/plain")) {
 543         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_INVALID_MIME_TYPE);
 544         ERR_add_error_data(2, "type: ", hdr->value);
 545         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 546         return 0;
 547     }
 548     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 549     while ((len = BIO_read(in, iobuf, sizeof(iobuf))) > 0)
 550         BIO_write(out, iobuf, len);
 551     if (len < 0)
 552         return 0;
 553     return 1;
 554 }
 555
 556 /*
 557  * Split a multipart/XXX message body into component parts: result is
 558  * canonical parts in a STACK of bios
 559  */
 560
 561 static int multi_split(BIO *bio, const char *bound, STACK_OF(BIO) **ret)
 562 {
 563     char linebuf[MAX_SMLEN];
 564     int len, blen;
 565     int eol = 0, next_eol = 0;
 566     BIO *bpart = NULL;
 567     STACK_OF(BIO) *parts;
 568     char state, part, first;
 569
 570     blen = strlen(bound);
 571     part = 0;
 572     state = 0;
 573     first = 1;
 574     parts = sk_BIO_new_null();
 575     *ret = parts;
 576     if (*ret == NULL)
 577         return 0;
 578     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
 579         state = mime_bound_check(linebuf, len, bound, blen);
 580         if (state == 1) {
 581             first = 1;
 582             part++;
 583         } else if (state == 2) {
 584             if (!sk_BIO_push(parts, bpart)) {
 585                 BIO_free(bpart);
 586                 return 0;
 587             }
 588             return 1;
 589         } else if (part) {
 590             /* Strip CR+LF from linebuf */
 591             next_eol = strip_eol(linebuf, &len, 0);
 592             if (first) {
 593                 first = 0;
 594                 if (bpart)
 595                     if (!sk_BIO_push(parts, bpart)) {
 596                         BIO_free(bpart);
 597                         return 0;
 598                     }
 599                 bpart = BIO_new(BIO_s_mem());
 600                 if (bpart == NULL)
 601                     return 0;
 602                 BIO_set_mem_eof_return(bpart, 0);
 603             } else if (eol)
 604                 BIO_write(bpart, "\r\n", 2);
 605             eol = next_eol;
 606             if (len)
 607                 BIO_write(bpart, linebuf, len);
 608         }
 609     }
 610     BIO_free(bpart);
 611     return 0;
 612 }
 613
 614 /* This is the big one: parse MIME header lines up to message body */
 615
 616 #define MIME_INVALID    0
 617 #define MIME_START      1
 618 #define MIME_TYPE       2
 619 #define MIME_NAME       3
 620 #define MIME_VALUE      4
 621 #define MIME_QUOTE      5
 622 #define MIME_COMMENT    6
 623
 624 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio)
 625 {
 626     char *p, *q, c;
 627     char *ntmp;
 628     char linebuf[MAX_SMLEN];
 629     MIME_HEADER *mhdr = NULL, *new_hdr = NULL;
 630     STACK_OF(MIME_HEADER) *headers;
 631     int len, state, save_state = 0;
 632
 633     headers = sk_MIME_HEADER_new(mime_hdr_cmp);
 634     if (headers == NULL)
 635         return NULL;
 636     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
 637         /* If whitespace at line start then continuation line */
 638         if (mhdr && ossl_isspace(linebuf[0]))
 639             state = MIME_NAME;
 640         else
 641             state = MIME_START;
 642         ntmp = NULL;
 643         /* Go through all characters */
 644         for (p = linebuf, q = linebuf; (c = *p) && (c != '\r') && (c != '\n');
 645              p++) {
 646
 647             /*
 648              * State machine to handle MIME headers if this looks horrible
 649              * that's because it *is*
 650              */
 651
 652             switch (state) {
 653             case MIME_START:
 654                 if (c == ':') {
 655                     state = MIME_TYPE;
 656                     *p = 0;
 657                     ntmp = strip_ends(q);
 658                     q = p + 1;
 659                 }
 660                 break;
 661
 662             case MIME_TYPE:
 663                 if (c == ';') {
 664                     mime_debug("Found End Value\n");
 665                     *p = 0;
 666                     new_hdr = mime_hdr_new(ntmp, strip_ends(q));
 667                     if (new_hdr == NULL)
 668                         goto err;
 669                     if (!sk_MIME_HEADER_push(headers, new_hdr))
 670                         goto err;
 671                     mhdr = new_hdr;
 672                     new_hdr = NULL;
 673                     ntmp = NULL;
 674                     q = p + 1;
 675                     state = MIME_NAME;
 676                 } else if (c == '(') {
 677                     save_state = state;
 678                     state = MIME_COMMENT;
 679                 }
 680                 break;
 681
 682             case MIME_COMMENT:
 683                 if (c == ')') {
 684                     state = save_state;
 685                 }
 686                 break;
 687
 688             case MIME_NAME:
 689                 if (c == '=') {
 690                     state = MIME_VALUE;
 691                     *p = 0;
 692                     ntmp = strip_ends(q);
 693                     q = p + 1;
 694                 }
 695                 break;
 696
 697             case MIME_VALUE:
 698                 if (c == ';') {
 699                     state = MIME_NAME;
 700                     *p = 0;
 701                     mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 702                     ntmp = NULL;
 703                     q = p + 1;
 704                 } else if (c == '"') {
 705                     mime_debug("Found Quote\n");
 706                     state = MIME_QUOTE;
 707                 } else if (c == '(') {
 708                     save_state = state;
 709                     state = MIME_COMMENT;
 710                 }
 711                 break;
 712
 713             case MIME_QUOTE:
 714                 if (c == '"') {
 715                     mime_debug("Found Match Quote\n");
 716                     state = MIME_VALUE;
 717                 }
 718                 break;
 719             }
 720         }
 721
 722         if (state == MIME_TYPE) {
 723             new_hdr = mime_hdr_new(ntmp, strip_ends(q));
 724             if (new_hdr == NULL)
 725                 goto err;
 726             if (!sk_MIME_HEADER_push(headers, new_hdr))
 727                 goto err;
 728             mhdr = new_hdr;
 729             new_hdr = NULL;
 730         } else if (state == MIME_VALUE)
 731             mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 732         if (p == linebuf)
 733             break;              /* Blank line means end of headers */
 734     }
 735
 736     return headers;
 737
 738 err:
 739     mime_hdr_free(new_hdr);
 740     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 741     return NULL;
 742 }
 743
 744 static char *strip_ends(char *name)
 745 {
 746     return strip_end(strip_start(name));
 747 }
 748
 749 /* Strip a parameter of whitespace from start of param */
 750 static char *strip_start(char *name)
 751 {
 752     char *p, c;
 753     /* Look for first non white space or quote */
 754     for (p = name; (c = *p); p++) {
 755         if (c == '"') {
 756             /* Next char is start of string if non null */
 757             if (p[1])
 758                 return p + 1;
 759             /* Else null string */
 760             return NULL;
 761         }
 762         if (!ossl_isspace(c))
 763             return p;
 764     }
 765     return NULL;
 766 }
 767
 768 /* As above but strip from end of string : maybe should handle brackets? */
 769 static char *strip_end(char *name)
 770 {
 771     char *p, c;
 772     if (!name)
 773         return NULL;
 774     /* Look for first non white space or quote */
 775     for (p = name + strlen(name) - 1; p >= name; p--) {
 776         c = *p;
 777         if (c == '"') {
 778             if (p - 1 == name)
 779                 return NULL;
 780             *p = 0;
 781             return name;
 782         }
 783         if (ossl_isspace(c))
 784             *p = 0;
 785         else
 786             return name;
 787     }
 788     return NULL;
 789 }
 790
 791 static MIME_HEADER *mime_hdr_new(const char *name, const char *value)
 792 {
 793     MIME_HEADER *mhdr = NULL;
 794     char *tmpname = NULL, *tmpval = NULL, *p;
 795
 796     if (name) {
 797         if ((tmpname = OPENSSL_strdup(name)) == NULL)
 798             return NULL;
 799         for (p = tmpname; *p; p++)
 800             *p = ossl_tolower(*p);
 801     }
 802     if (value) {
 803         if ((tmpval = OPENSSL_strdup(value)) == NULL)
 804             goto err;
 805         for (p = tmpval; *p; p++)
 806             *p = ossl_tolower(*p);
 807     }
 808     mhdr = OPENSSL_malloc(sizeof(*mhdr));
 809     if (mhdr == NULL)
 810         goto err;
 811     mhdr->name = tmpname;
 812     mhdr->value = tmpval;
 813     if ((mhdr->params = sk_MIME_PARAM_new(mime_param_cmp)) == NULL)
 814         goto err;
 815     return mhdr;
 816
 817  err:
 818     OPENSSL_free(tmpname);
 819     OPENSSL_free(tmpval);
 820     OPENSSL_free(mhdr);
 821     return NULL;
 822 }
 823
 824 static int mime_hdr_addparam(MIME_HEADER *mhdr, const char *name, const char *value)
 825 {
 826     char *tmpname = NULL, *tmpval = NULL, *p;
 827     MIME_PARAM *mparam = NULL;
 828
 829     if (name) {
 830         tmpname = OPENSSL_strdup(name);
 831         if (!tmpname)
 832             goto err;
 833         for (p = tmpname; *p; p++)
 834             *p = ossl_tolower(*p);
 835     }
 836     if (value) {
 837         tmpval = OPENSSL_strdup(value);
 838         if (!tmpval)
 839             goto err;
 840     }
 841     /* Parameter values are case sensitive so leave as is */
 842     mparam = OPENSSL_malloc(sizeof(*mparam));
 843     if (mparam == NULL)
 844         goto err;
 845     mparam->param_name = tmpname;
 846     mparam->param_value = tmpval;
 847     if (!sk_MIME_PARAM_push(mhdr->params, mparam))
 848         goto err;
 849     return 1;
 850  err:
 851     OPENSSL_free(tmpname);
 852     OPENSSL_free(tmpval);
 853     OPENSSL_free(mparam);
 854     return 0;
 855 }
 856
 857 static int mime_hdr_cmp(const MIME_HEADER *const *a,
 858                         const MIME_HEADER *const *b)
 859 {
 860     if (!(*a)->name || !(*b)->name)
 861         return ! !(*a)->name - ! !(*b)->name;
 862
 863     return strcmp((*a)->name, (*b)->name);
 864 }
 865
 866 static int mime_param_cmp(const MIME_PARAM *const *a,
 867                           const MIME_PARAM *const *b)
 868 {
 869     if (!(*a)->param_name || !(*b)->param_name)
 870         return ! !(*a)->param_name - ! !(*b)->param_name;
 871     return strcmp((*a)->param_name, (*b)->param_name);
 872 }
 873
 874 /* Find a header with a given name (if possible) */
 875
 876 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, const char *name)
 877 {
 878     MIME_HEADER htmp;
 879     int idx;
 880
 881     htmp.name = (char *)name;
 882     htmp.value = NULL;
 883     htmp.params = NULL;
 884
 885     idx = sk_MIME_HEADER_find(hdrs, &htmp);
 886     if (idx < 0)
 887         return NULL;
 888     return sk_MIME_HEADER_value(hdrs, idx);
 889 }
 890
 891 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, const char *name)
 892 {
 893     MIME_PARAM param;
 894     int idx;
 895
 896     param.param_name = (char *)name;
 897     param.param_value = NULL;
 898     idx = sk_MIME_PARAM_find(hdr->params, &param);
 899     if (idx < 0)
 900         return NULL;
 901     return sk_MIME_PARAM_value(hdr->params, idx);
 902 }
 903
 904 static void mime_hdr_free(MIME_HEADER *hdr)
 905 {
 906     if (hdr == NULL)
 907         return;
 908     OPENSSL_free(hdr->name);
 909     OPENSSL_free(hdr->value);
 910     if (hdr->params)
 911         sk_MIME_PARAM_pop_free(hdr->params, mime_param_free);
 912     OPENSSL_free(hdr);
 913 }
 914
 915 static void mime_param_free(MIME_PARAM *param)
 916 {
 917     OPENSSL_free(param->param_name);
 918     OPENSSL_free(param->param_value);
 919     OPENSSL_free(param);
 920 }
 921
 922 /*-
 923  * Check for a multipart boundary. Returns:
 924  * 0 : no boundary
 925  * 1 : part boundary
 926  * 2 : final boundary
 927  */
 928 static int mime_bound_check(char *line, int linelen, const char *bound, int blen)
 929 {
 930     if (linelen == -1)
 931         linelen = strlen(line);
 932     if (blen == -1)
 933         blen = strlen(bound);
 934     /* Quickly eliminate if line length too short */
 935     if (blen + 2 > linelen)
 936         return 0;
 937     /* Check for part boundary */
 938     if ((strncmp(line, "--", 2) == 0)
 939         && strncmp(line + 2, bound, blen) == 0) {
 940         if (strncmp(line + blen + 2, "--", 2) == 0)
 941             return 2;
 942         else
 943             return 1;
 944     }
 945     return 0;
 946 }
 947
 948 static int strip_eol(char *linebuf, int *plen, int flags)
 949 {
 950     int len = *plen;
 951     char *p, c;
 952     int is_eol = 0;
 953
 954     for (p = linebuf + len - 1; len > 0; len--, p--) {
 955         c = *p;
 956         if (c == '\n')
 957             is_eol = 1;
 958         else if (is_eol && flags & SMIME_ASCIICRLF && c < 33)
 959             continue;
 960         else if (c != '\r')
 961             break;
 962     }
 963     *plen = len;
 964     return is_eol;
 965 }