crypto/asn1/asn_mime.c

   1 /*
   2  * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   3  * project.
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 1999-2008 The OpenSSL Project.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in
  17  *    the documentation and/or other materials provided with the
  18  *    distribution.
  19  *
  20  * 3. All advertising materials mentioning features or use of this
  21  *    software must display the following acknowledgment:
  22  *    "This product includes software developed by the OpenSSL Project
  23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  24  *
  25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  26  *    endorse or promote products derived from this software without
  27  *    prior written permission. For written permission, please contact
  28  *    licensing@OpenSSL.org.
  29  *
  30  * 5. Products derived from this software may not be called "OpenSSL"
  31  *    nor may "OpenSSL" appear in their names without prior written
  32  *    permission of the OpenSSL Project.
  33  *
  34  * 6. Redistributions of any form whatsoever must retain the following
  35  *    acknowledgment:
  36  *    "This product includes software developed by the OpenSSL Project
  37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  38  *
  39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  50  * OF THE POSSIBILITY OF SUCH DAMAGE.
  51  * ====================================================================
  52  *
  53  */
  54
  55 #include <stdio.h>
  56 #include <ctype.h>
  57 #include "internal/cryptlib.h"
  58 #include <openssl/rand.h>
  59 #include <openssl/x509.h>
  60 #include <openssl/asn1.h>
  61 #include <openssl/asn1t.h>
  62 #include "internal/evp_int.h"
  63 #include "asn1_locl.h"
  64
  65 /*
  66  * Generalised MIME like utilities for streaming ASN1. Although many have a
  67  * PKCS7/CMS like flavour others are more general purpose.
  68  */
  69
  70 /*
  71  * MIME format structures Note that all are translated to lower case apart
  72  * from parameter values. Quotes are stripped off
  73  */
  74
  75 struct mime_param_st {
  76     char *param_name;           /* Param name e.g. "micalg" */
  77     char *param_value;          /* Param value e.g. "sha1" */
  78 };
  79
  80 struct mime_header_st {
  81     char *name;                 /* Name of line e.g. "content-type" */
  82     char *value;                /* Value of line e.g. "text/plain" */
  83     STACK_OF(MIME_PARAM) *params; /* Zero or more parameters */
  84 };
  85
  86 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
  87                             const ASN1_ITEM *it);
  88 static char *strip_ends(char *name);
  89 static char *strip_start(char *name);
  90 static char *strip_end(char *name);
  91 static MIME_HEADER *mime_hdr_new(char *name, char *value);
  92 static int mime_hdr_addparam(MIME_HEADER *mhdr, char *name, char *value);
  93 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio);
  94 static int mime_hdr_cmp(const MIME_HEADER *const *a,
  95                         const MIME_HEADER *const *b);
  96 static int mime_param_cmp(const MIME_PARAM *const *a,
  97                           const MIME_PARAM *const *b);
  98 static void mime_param_free(MIME_PARAM *param);
  99 static int mime_bound_check(char *line, int linelen, char *bound, int blen);
 100 static int multi_split(BIO *bio, char *bound, STACK_OF(BIO) **ret);
 101 static int strip_eol(char *linebuf, int *plen, int flags);
 102 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, char *name);
 103 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, char *name);
 104 static void mime_hdr_free(MIME_HEADER *hdr);
 105
 106 #define MAX_SMLEN 1024
 107 #define mime_debug(x)           /* x */
 108
 109 /* Output an ASN1 structure in BER format streaming if necessary */
 110
 111 int i2d_ASN1_bio_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
 112                         const ASN1_ITEM *it)
 113 {
 114     /* If streaming create stream BIO and copy all content through it */
 115     if (flags & SMIME_STREAM) {
 116         BIO *bio, *tbio;
 117         bio = BIO_new_NDEF(out, val, it);
 118         if (!bio) {
 119             ASN1err(ASN1_F_I2D_ASN1_BIO_STREAM, ERR_R_MALLOC_FAILURE);
 120             return 0;
 121         }
 122         SMIME_crlf_copy(in, bio, flags);
 123         (void)BIO_flush(bio);
 124         /* Free up successive BIOs until we hit the old output BIO */
 125         do {
 126             tbio = BIO_pop(bio);
 127             BIO_free(bio);
 128             bio = tbio;
 129         } while (bio != out);
 130     }
 131     /*
 132      * else just write out ASN1 structure which will have all content stored
 133      * internally
 134      */
 135     else
 136         ASN1_item_i2d_bio(it, out, val);
 137     return 1;
 138 }
 139
 140 /* Base 64 read and write of ASN1 structure */
 141
 142 static int B64_write_ASN1(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
 143                           const ASN1_ITEM *it)
 144 {
 145     BIO *b64;
 146     int r;
 147     b64 = BIO_new(BIO_f_base64());
 148     if (b64 == NULL) {
 149         ASN1err(ASN1_F_B64_WRITE_ASN1, ERR_R_MALLOC_FAILURE);
 150         return 0;
 151     }
 152     /*
 153      * prepend the b64 BIO so all data is base64 encoded.
 154      */
 155     out = BIO_push(b64, out);
 156     r = i2d_ASN1_bio_stream(out, val, in, flags, it);
 157     (void)BIO_flush(out);
 158     BIO_pop(out);
 159     BIO_free(b64);
 160     return r;
 161 }
 162
 163 /* Streaming ASN1 PEM write */
 164
 165 int PEM_write_bio_ASN1_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
 166                               const char *hdr, const ASN1_ITEM *it)
 167 {
 168     int r;
 169     BIO_printf(out, "-----BEGIN %s-----\n", hdr);
 170     r = B64_write_ASN1(out, val, in, flags, it);
 171     BIO_printf(out, "-----END %s-----\n", hdr);
 172     return r;
 173 }
 174
 175 static ASN1_VALUE *b64_read_asn1(BIO *bio, const ASN1_ITEM *it)
 176 {
 177     BIO *b64;
 178     ASN1_VALUE *val;
 179
 180     if ((b64 = BIO_new(BIO_f_base64())) == NULL) {
 181         ASN1err(ASN1_F_B64_READ_ASN1, ERR_R_MALLOC_FAILURE);
 182         return 0;
 183     }
 184     bio = BIO_push(b64, bio);
 185     val = ASN1_item_d2i_bio(it, bio, NULL);
 186     if (!val)
 187         ASN1err(ASN1_F_B64_READ_ASN1, ASN1_R_DECODE_ERROR);
 188     (void)BIO_flush(bio);
 189     bio = BIO_pop(bio);
 190     BIO_free(b64);
 191     return val;
 192 }
 193
 194 /* Generate the MIME "micalg" parameter from RFC3851, RFC4490 */
 195
 196 static int asn1_write_micalg(BIO *out, STACK_OF(X509_ALGOR) *mdalgs)
 197 {
 198     const EVP_MD *md;
 199     int i, have_unknown = 0, write_comma, ret = 0, md_nid;
 200     have_unknown = 0;
 201     write_comma = 0;
 202     for (i = 0; i < sk_X509_ALGOR_num(mdalgs); i++) {
 203         if (write_comma)
 204             BIO_write(out, ",", 1);
 205         write_comma = 1;
 206         md_nid = OBJ_obj2nid(sk_X509_ALGOR_value(mdalgs, i)->algorithm);
 207         md = EVP_get_digestbynid(md_nid);
 208         if (md && md->md_ctrl) {
 209             int rv;
 210             char *micstr;
 211             rv = md->md_ctrl(NULL, EVP_MD_CTRL_MICALG, 0, &micstr);
 212             if (rv > 0) {
 213                 BIO_puts(out, micstr);
 214                 OPENSSL_free(micstr);
 215                 continue;
 216             }
 217             if (rv != -2)
 218                 goto err;
 219         }
 220         switch (md_nid) {
 221         case NID_sha1:
 222             BIO_puts(out, "sha1");
 223             break;
 224
 225         case NID_md5:
 226             BIO_puts(out, "md5");
 227             break;
 228
 229         case NID_sha256:
 230             BIO_puts(out, "sha-256");
 231             break;
 232
 233         case NID_sha384:
 234             BIO_puts(out, "sha-384");
 235             break;
 236
 237         case NID_sha512:
 238             BIO_puts(out, "sha-512");
 239             break;
 240
 241         case NID_id_GostR3411_94:
 242             BIO_puts(out, "gostr3411-94");
 243             goto err;
 244
 245         default:
 246             if (have_unknown)
 247                 write_comma = 0;
 248             else {
 249                 BIO_puts(out, "unknown");
 250                 have_unknown = 1;
 251             }
 252             break;
 253
 254         }
 255     }
 256
 257     ret = 1;
 258  err:
 259
 260     return ret;
 261
 262 }
 263
 264 /* SMIME sender */
 265
 266 int SMIME_write_ASN1(BIO *bio, ASN1_VALUE *val, BIO *data, int flags,
 267                      int ctype_nid, int econt_nid,
 268                      STACK_OF(X509_ALGOR) *mdalgs, const ASN1_ITEM *it)
 269 {
 270     char bound[33], c;
 271     int i;
 272     const char *mime_prefix, *mime_eol, *cname = "smime.p7m";
 273     const char *msg_type = NULL;
 274     if (flags & SMIME_OLDMIME)
 275         mime_prefix = "application/x-pkcs7-";
 276     else
 277         mime_prefix = "application/pkcs7-";
 278
 279     if (flags & SMIME_CRLFEOL)
 280         mime_eol = "\r\n";
 281     else
 282         mime_eol = "\n";
 283     if ((flags & SMIME_DETACHED) && data) {
 284         /* We want multipart/signed */
 285         /* Generate a random boundary */
 286         if (RAND_bytes((unsigned char *)bound, 32) <= 0)
 287             return 0;
 288         for (i = 0; i < 32; i++) {
 289             c = bound[i] & 0xf;
 290             if (c < 10)
 291                 c += '0';
 292             else
 293                 c += 'A' - 10;
 294             bound[i] = c;
 295         }
 296         bound[32] = 0;
 297         BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
 298         BIO_printf(bio, "Content-Type: multipart/signed;");
 299         BIO_printf(bio, " protocol=\"%ssignature\";", mime_prefix);
 300         BIO_puts(bio, " micalg=\"");
 301         asn1_write_micalg(bio, mdalgs);
 302         BIO_printf(bio, "\"; boundary=\"----%s\"%s%s",
 303                    bound, mime_eol, mime_eol);
 304         BIO_printf(bio, "This is an S/MIME signed message%s%s",
 305                    mime_eol, mime_eol);
 306         /* Now write out the first part */
 307         BIO_printf(bio, "------%s%s", bound, mime_eol);
 308         if (!asn1_output_data(bio, data, val, flags, it))
 309             return 0;
 310         BIO_printf(bio, "%s------%s%s", mime_eol, bound, mime_eol);
 311
 312         /* Headers for signature */
 313
 314         BIO_printf(bio, "Content-Type: %ssignature;", mime_prefix);
 315         BIO_printf(bio, " name=\"smime.p7s\"%s", mime_eol);
 316         BIO_printf(bio, "Content-Transfer-Encoding: base64%s", mime_eol);
 317         BIO_printf(bio, "Content-Disposition: attachment;");
 318         BIO_printf(bio, " filename=\"smime.p7s\"%s%s", mime_eol, mime_eol);
 319         B64_write_ASN1(bio, val, NULL, 0, it);
 320         BIO_printf(bio, "%s------%s--%s%s", mime_eol, bound,
 321                    mime_eol, mime_eol);
 322         return 1;
 323     }
 324
 325     /* Determine smime-type header */
 326
 327     if (ctype_nid == NID_pkcs7_enveloped)
 328         msg_type = "enveloped-data";
 329     else if (ctype_nid == NID_pkcs7_signed) {
 330         if (econt_nid == NID_id_smime_ct_receipt)
 331             msg_type = "signed-receipt";
 332         else if (sk_X509_ALGOR_num(mdalgs) >= 0)
 333             msg_type = "signed-data";
 334         else
 335             msg_type = "certs-only";
 336     } else if (ctype_nid == NID_id_smime_ct_compressedData) {
 337         msg_type = "compressed-data";
 338         cname = "smime.p7z";
 339     }
 340     /* MIME headers */
 341     BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
 342     BIO_printf(bio, "Content-Disposition: attachment;");
 343     BIO_printf(bio, " filename=\"%s\"%s", cname, mime_eol);
 344     BIO_printf(bio, "Content-Type: %smime;", mime_prefix);
 345     if (msg_type)
 346         BIO_printf(bio, " smime-type=%s;", msg_type);
 347     BIO_printf(bio, " name=\"%s\"%s", cname, mime_eol);
 348     BIO_printf(bio, "Content-Transfer-Encoding: base64%s%s",
 349                mime_eol, mime_eol);
 350     if (!B64_write_ASN1(bio, val, data, flags, it))
 351         return 0;
 352     BIO_printf(bio, "%s", mime_eol);
 353     return 1;
 354 }
 355
 356 /* Handle output of ASN1 data */
 357
 358 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
 359                             const ASN1_ITEM *it)
 360 {
 361     BIO *tmpbio;
 362     const ASN1_AUX *aux = it->funcs;
 363     ASN1_STREAM_ARG sarg;
 364     int rv = 1;
 365
 366     /*
 367      * If data is not detached or resigning then the output BIO is already
 368      * set up to finalise when it is written through.
 369      */
 370     if (!(flags & SMIME_DETACHED) || (flags & PKCS7_REUSE_DIGEST)) {
 371         SMIME_crlf_copy(data, out, flags);
 372         return 1;
 373     }
 374
 375     if (!aux || !aux->asn1_cb) {
 376         ASN1err(ASN1_F_ASN1_OUTPUT_DATA, ASN1_R_STREAMING_NOT_SUPPORTED);
 377         return 0;
 378     }
 379
 380     sarg.out = out;
 381     sarg.ndef_bio = NULL;
 382     sarg.boundary = NULL;
 383
 384     /* Let ASN1 code prepend any needed BIOs */
 385
 386     if (aux->asn1_cb(ASN1_OP_DETACHED_PRE, &val, it, &sarg) <= 0)
 387         return 0;
 388
 389     /* Copy data across, passing through filter BIOs for processing */
 390     SMIME_crlf_copy(data, sarg.ndef_bio, flags);
 391
 392     /* Finalize structure */
 393     if (aux->asn1_cb(ASN1_OP_DETACHED_POST, &val, it, &sarg) <= 0)
 394         rv = 0;
 395
 396     /* Now remove any digests prepended to the BIO */
 397
 398     while (sarg.ndef_bio != out) {
 399         tmpbio = BIO_pop(sarg.ndef_bio);
 400         BIO_free(sarg.ndef_bio);
 401         sarg.ndef_bio = tmpbio;
 402     }
 403
 404     return rv;
 405
 406 }
 407
 408 /*
 409  * SMIME reader: handle multipart/signed and opaque signing. in multipart
 410  * case the content is placed in a memory BIO pointed to by "bcont". In
 411  * opaque this is set to NULL
 412  */
 413
 414 ASN1_VALUE *SMIME_read_ASN1(BIO *bio, BIO **bcont, const ASN1_ITEM *it)
 415 {
 416     BIO *asnin;
 417     STACK_OF(MIME_HEADER) *headers = NULL;
 418     STACK_OF(BIO) *parts = NULL;
 419     MIME_HEADER *hdr;
 420     MIME_PARAM *prm;
 421     ASN1_VALUE *val;
 422     int ret;
 423
 424     if (bcont)
 425         *bcont = NULL;
 426
 427     if ((headers = mime_parse_hdr(bio)) == NULL) {
 428         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_PARSE_ERROR);
 429         return NULL;
 430     }
 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_CONTENT_TYPE);
 436         return NULL;
 437     }
 438
 439     /* Handle multipart/signed */
 440
 441     if (strcmp(hdr->value, "multipart/signed") == 0) {
 442         /* Split into two parts */
 443         prm = mime_param_find(hdr, "boundary");
 444         if (!prm || !prm->param_value) {
 445             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 446             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BOUNDARY);
 447             return NULL;
 448         }
 449         ret = multi_split(bio, prm->param_value, &parts);
 450         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 451         if (!ret || (sk_BIO_num(parts) != 2)) {
 452             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BODY_FAILURE);
 453             sk_BIO_pop_free(parts, BIO_vfree);
 454             return NULL;
 455         }
 456
 457         /* Parse the signature piece */
 458         asnin = sk_BIO_value(parts, 1);
 459
 460         if ((headers = mime_parse_hdr(asnin)) == NULL) {
 461             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_SIG_PARSE_ERROR);
 462             sk_BIO_pop_free(parts, BIO_vfree);
 463             return NULL;
 464         }
 465
 466         /* Get content type */
 467
 468         if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 469             || hdr->value == NULL) {
 470             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 471             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_SIG_CONTENT_TYPE);
 472             return NULL;
 473         }
 474
 475         if (strcmp(hdr->value, "application/x-pkcs7-signature") &&
 476             strcmp(hdr->value, "application/pkcs7-signature")) {
 477             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_SIG_INVALID_MIME_TYPE);
 478             ERR_add_error_data(2, "type: ", hdr->value);
 479             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 480             sk_BIO_pop_free(parts, BIO_vfree);
 481             return NULL;
 482         }
 483         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 484         /* Read in ASN1 */
 485         if ((val = b64_read_asn1(asnin, it)) == NULL) {
 486             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_SIG_PARSE_ERROR);
 487             sk_BIO_pop_free(parts, BIO_vfree);
 488             return NULL;
 489         }
 490
 491         if (bcont) {
 492             *bcont = sk_BIO_value(parts, 0);
 493             BIO_free(asnin);
 494             sk_BIO_free(parts);
 495         } else
 496             sk_BIO_pop_free(parts, BIO_vfree);
 497         return val;
 498     }
 499
 500     /* OK, if not multipart/signed try opaque signature */
 501
 502     if (strcmp(hdr->value, "application/x-pkcs7-mime") &&
 503         strcmp(hdr->value, "application/pkcs7-mime")) {
 504         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_INVALID_MIME_TYPE);
 505         ERR_add_error_data(2, "type: ", hdr->value);
 506         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 507         return NULL;
 508     }
 509
 510     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 511
 512     if ((val = b64_read_asn1(bio, it)) == NULL) {
 513         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_PARSE_ERROR);
 514         return NULL;
 515     }
 516     return val;
 517
 518 }
 519
 520 /* Copy text from one BIO to another making the output CRLF at EOL */
 521 int SMIME_crlf_copy(BIO *in, BIO *out, int flags)
 522 {
 523     BIO *bf;
 524     char eol;
 525     int len;
 526     char linebuf[MAX_SMLEN];
 527     /*
 528      * Buffer output so we don't write one line at a time. This is useful
 529      * when streaming as we don't end up with one OCTET STRING per line.
 530      */
 531     bf = BIO_new(BIO_f_buffer());
 532     if (bf == NULL)
 533         return 0;
 534     out = BIO_push(bf, out);
 535     if (flags & SMIME_BINARY) {
 536         while ((len = BIO_read(in, linebuf, MAX_SMLEN)) > 0)
 537             BIO_write(out, linebuf, len);
 538     } else {
 539         int eolcnt = 0;
 540         if (flags & SMIME_TEXT)
 541             BIO_printf(out, "Content-Type: text/plain\r\n\r\n");
 542         while ((len = BIO_gets(in, linebuf, MAX_SMLEN)) > 0) {
 543             eol = strip_eol(linebuf, &len, flags);
 544             if (len) {
 545                 /* Not EOF: write out all CRLF */
 546                 if (flags & SMIME_ASCIICRLF) {
 547                     int i;
 548                     for (i = 0; i < eolcnt; i++)
 549                         BIO_write(out, "\r\n", 2);
 550                     eolcnt = 0;
 551                 }
 552                 BIO_write(out, linebuf, len);
 553                 if (eol)
 554                     BIO_write(out, "\r\n", 2);
 555             } else if (flags & SMIME_ASCIICRLF)
 556                 eolcnt++;
 557             else if (eol)
 558                 BIO_write(out, "\r\n", 2);
 559         }
 560     }
 561     (void)BIO_flush(out);
 562     BIO_pop(out);
 563     BIO_free(bf);
 564     return 1;
 565 }
 566
 567 /* Strip off headers if they are text/plain */
 568 int SMIME_text(BIO *in, BIO *out)
 569 {
 570     char iobuf[4096];
 571     int len;
 572     STACK_OF(MIME_HEADER) *headers;
 573     MIME_HEADER *hdr;
 574
 575     if ((headers = mime_parse_hdr(in)) == NULL) {
 576         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_PARSE_ERROR);
 577         return 0;
 578     }
 579     if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 580         || hdr->value == NULL) {
 581         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_NO_CONTENT_TYPE);
 582         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 583         return 0;
 584     }
 585     if (strcmp(hdr->value, "text/plain")) {
 586         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_INVALID_MIME_TYPE);
 587         ERR_add_error_data(2, "type: ", hdr->value);
 588         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 589         return 0;
 590     }
 591     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 592     while ((len = BIO_read(in, iobuf, sizeof(iobuf))) > 0)
 593         BIO_write(out, iobuf, len);
 594     if (len < 0)
 595         return 0;
 596     return 1;
 597 }
 598
 599 /*
 600  * Split a multipart/XXX message body into component parts: result is
 601  * canonical parts in a STACK of bios
 602  */
 603
 604 static int multi_split(BIO *bio, char *bound, STACK_OF(BIO) **ret)
 605 {
 606     char linebuf[MAX_SMLEN];
 607     int len, blen;
 608     int eol = 0, next_eol = 0;
 609     BIO *bpart = NULL;
 610     STACK_OF(BIO) *parts;
 611     char state, part, first;
 612
 613     blen = strlen(bound);
 614     part = 0;
 615     state = 0;
 616     first = 1;
 617     parts = sk_BIO_new_null();
 618     *ret = parts;
 619     if (*ret == NULL)
 620         return 0;
 621     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
 622         state = mime_bound_check(linebuf, len, bound, blen);
 623         if (state == 1) {
 624             first = 1;
 625             part++;
 626         } else if (state == 2) {
 627             if (!sk_BIO_push(parts, bpart)) {
 628                 BIO_free(bpart);
 629                 return 0;
 630             }
 631             return 1;
 632         } else if (part) {
 633             /* Strip CR+LF from linebuf */
 634             next_eol = strip_eol(linebuf, &len, 0);
 635             if (first) {
 636                 first = 0;
 637                 if (bpart)
 638                     if (!sk_BIO_push(parts, bpart)) {
 639                         BIO_free(bpart);
 640                         return 0;
 641                     }
 642                 bpart = BIO_new(BIO_s_mem());
 643                 if (bpart == NULL)
 644                     return 0;
 645                 BIO_set_mem_eof_return(bpart, 0);
 646             } else if (eol)
 647                 BIO_write(bpart, "\r\n", 2);
 648             eol = next_eol;
 649             if (len)
 650                 BIO_write(bpart, linebuf, len);
 651         }
 652     }
 653     BIO_free(bpart);
 654     return 0;
 655 }
 656
 657 /* This is the big one: parse MIME header lines up to message body */
 658
 659 #define MIME_INVALID    0
 660 #define MIME_START      1
 661 #define MIME_TYPE       2
 662 #define MIME_NAME       3
 663 #define MIME_VALUE      4
 664 #define MIME_QUOTE      5
 665 #define MIME_COMMENT    6
 666
 667 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio)
 668 {
 669     char *p, *q, c;
 670     char *ntmp;
 671     char linebuf[MAX_SMLEN];
 672     MIME_HEADER *mhdr = NULL;
 673     STACK_OF(MIME_HEADER) *headers;
 674     int len, state, save_state = 0;
 675
 676     headers = sk_MIME_HEADER_new(mime_hdr_cmp);
 677     if (headers == NULL)
 678         return NULL;
 679     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
 680         /* If whitespace at line start then continuation line */
 681         if (mhdr && isspace((unsigned char)linebuf[0]))
 682             state = MIME_NAME;
 683         else
 684             state = MIME_START;
 685         ntmp = NULL;
 686         /* Go through all characters */
 687         for (p = linebuf, q = linebuf; (c = *p) && (c != '\r') && (c != '\n');
 688              p++) {
 689
 690             /*
 691              * State machine to handle MIME headers if this looks horrible
 692              * that's because it *is*
 693              */
 694
 695             switch (state) {
 696             case MIME_START:
 697                 if (c == ':') {
 698                     state = MIME_TYPE;
 699                     *p = 0;
 700                     ntmp = strip_ends(q);
 701                     q = p + 1;
 702                 }
 703                 break;
 704
 705             case MIME_TYPE:
 706                 if (c == ';') {
 707                     mime_debug("Found End Value\n");
 708                     *p = 0;
 709                     mhdr = mime_hdr_new(ntmp, strip_ends(q));
 710                     sk_MIME_HEADER_push(headers, mhdr);
 711                     ntmp = NULL;
 712                     q = p + 1;
 713                     state = MIME_NAME;
 714                 } else if (c == '(') {
 715                     save_state = state;
 716                     state = MIME_COMMENT;
 717                 }
 718                 break;
 719
 720             case MIME_COMMENT:
 721                 if (c == ')') {
 722                     state = save_state;
 723                 }
 724                 break;
 725
 726             case MIME_NAME:
 727                 if (c == '=') {
 728                     state = MIME_VALUE;
 729                     *p = 0;
 730                     ntmp = strip_ends(q);
 731                     q = p + 1;
 732                 }
 733                 break;
 734
 735             case MIME_VALUE:
 736                 if (c == ';') {
 737                     state = MIME_NAME;
 738                     *p = 0;
 739                     mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 740                     ntmp = NULL;
 741                     q = p + 1;
 742                 } else if (c == '"') {
 743                     mime_debug("Found Quote\n");
 744                     state = MIME_QUOTE;
 745                 } else if (c == '(') {
 746                     save_state = state;
 747                     state = MIME_COMMENT;
 748                 }
 749                 break;
 750
 751             case MIME_QUOTE:
 752                 if (c == '"') {
 753                     mime_debug("Found Match Quote\n");
 754                     state = MIME_VALUE;
 755                 }
 756                 break;
 757             }
 758         }
 759
 760         if (state == MIME_TYPE) {
 761             mhdr = mime_hdr_new(ntmp, strip_ends(q));
 762             sk_MIME_HEADER_push(headers, mhdr);
 763         } else if (state == MIME_VALUE)
 764             mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 765         if (p == linebuf)
 766             break;              /* Blank line means end of headers */
 767     }
 768
 769     return headers;
 770
 771 }
 772
 773 static char *strip_ends(char *name)
 774 {
 775     return strip_end(strip_start(name));
 776 }
 777
 778 /* Strip a parameter of whitespace from start of param */
 779 static char *strip_start(char *name)
 780 {
 781     char *p, c;
 782     /* Look for first non white space or quote */
 783     for (p = name; (c = *p); p++) {
 784         if (c == '"') {
 785             /* Next char is start of string if non null */
 786             if (p[1])
 787                 return p + 1;
 788             /* Else null string */
 789             return NULL;
 790         }
 791         if (!isspace((unsigned char)c))
 792             return p;
 793     }
 794     return NULL;
 795 }
 796
 797 /* As above but strip from end of string : maybe should handle brackets? */
 798 static char *strip_end(char *name)
 799 {
 800     char *p, c;
 801     if (!name)
 802         return NULL;
 803     /* Look for first non white space or quote */
 804     for (p = name + strlen(name) - 1; p >= name; p--) {
 805         c = *p;
 806         if (c == '"') {
 807             if (p - 1 == name)
 808                 return NULL;
 809             *p = 0;
 810             return name;
 811         }
 812         if (isspace((unsigned char)c))
 813             *p = 0;
 814         else
 815             return name;
 816     }
 817     return NULL;
 818 }
 819
 820 static MIME_HEADER *mime_hdr_new(char *name, char *value)
 821 {
 822     MIME_HEADER *mhdr = NULL;
 823     char *tmpname = NULL, *tmpval = NULL, *p;
 824     int c;
 825
 826     if (name) {
 827         if ((tmpname = OPENSSL_strdup(name)) == NULL)
 828             return NULL;
 829         for (p = tmpname; *p; p++) {
 830             c = (unsigned char)*p;
 831             if (isupper(c)) {
 832                 c = tolower(c);
 833                 *p = c;
 834             }
 835         }
 836     }
 837     if (value) {
 838         if ((tmpval = OPENSSL_strdup(value)) == NULL)
 839             goto err;
 840         for (p = tmpval; *p; p++) {
 841             c = (unsigned char)*p;
 842             if (isupper(c)) {
 843                 c = tolower(c);
 844                 *p = c;
 845             }
 846         }
 847     }
 848     mhdr = OPENSSL_malloc(sizeof(*mhdr));
 849     if (mhdr == NULL)
 850         goto err;
 851     mhdr->name = tmpname;
 852     mhdr->value = tmpval;
 853     if ((mhdr->params = sk_MIME_PARAM_new(mime_param_cmp)) == NULL)
 854         goto err;
 855     return mhdr;
 856
 857  err:
 858     OPENSSL_free(tmpname);
 859     OPENSSL_free(tmpval);
 860     OPENSSL_free(mhdr);
 861     return NULL;
 862 }
 863
 864 static int mime_hdr_addparam(MIME_HEADER *mhdr, char *name, char *value)
 865 {
 866     char *tmpname = NULL, *tmpval = NULL, *p;
 867     int c;
 868     MIME_PARAM *mparam = NULL;
 869     if (name) {
 870         tmpname = OPENSSL_strdup(name);
 871         if (!tmpname)
 872             goto err;
 873         for (p = tmpname; *p; p++) {
 874             c = (unsigned char)*p;
 875             if (isupper(c)) {
 876                 c = tolower(c);
 877                 *p = c;
 878             }
 879         }
 880     }
 881     if (value) {
 882         tmpval = OPENSSL_strdup(value);
 883         if (!tmpval)
 884             goto err;
 885     }
 886     /* Parameter values are case sensitive so leave as is */
 887     mparam = OPENSSL_malloc(sizeof(*mparam));
 888     if (mparam == NULL)
 889         goto err;
 890     mparam->param_name = tmpname;
 891     mparam->param_value = tmpval;
 892     if (!sk_MIME_PARAM_push(mhdr->params, mparam))
 893         goto err;
 894     return 1;
 895  err:
 896     OPENSSL_free(tmpname);
 897     OPENSSL_free(tmpval);
 898     OPENSSL_free(mparam);
 899     return 0;
 900 }
 901
 902 static int mime_hdr_cmp(const MIME_HEADER *const *a,
 903                         const MIME_HEADER *const *b)
 904 {
 905     if (!(*a)->name || !(*b)->name)
 906         return ! !(*a)->name - ! !(*b)->name;
 907
 908     return (strcmp((*a)->name, (*b)->name));
 909 }
 910
 911 static int mime_param_cmp(const MIME_PARAM *const *a,
 912                           const MIME_PARAM *const *b)
 913 {
 914     if (!(*a)->param_name || !(*b)->param_name)
 915         return ! !(*a)->param_name - ! !(*b)->param_name;
 916     return (strcmp((*a)->param_name, (*b)->param_name));
 917 }
 918
 919 /* Find a header with a given name (if possible) */
 920
 921 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, char *name)
 922 {
 923     MIME_HEADER htmp;
 924     int idx;
 925     htmp.name = name;
 926     idx = sk_MIME_HEADER_find(hdrs, &htmp);
 927     if (idx < 0)
 928         return NULL;
 929     return sk_MIME_HEADER_value(hdrs, idx);
 930 }
 931
 932 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, char *name)
 933 {
 934     MIME_PARAM param;
 935     int idx;
 936     param.param_name = name;
 937     idx = sk_MIME_PARAM_find(hdr->params, &param);
 938     if (idx < 0)
 939         return NULL;
 940     return sk_MIME_PARAM_value(hdr->params, idx);
 941 }
 942
 943 static void mime_hdr_free(MIME_HEADER *hdr)
 944 {
 945     OPENSSL_free(hdr->name);
 946     OPENSSL_free(hdr->value);
 947     if (hdr->params)
 948         sk_MIME_PARAM_pop_free(hdr->params, mime_param_free);
 949     OPENSSL_free(hdr);
 950 }
 951
 952 static void mime_param_free(MIME_PARAM *param)
 953 {
 954     OPENSSL_free(param->param_name);
 955     OPENSSL_free(param->param_value);
 956     OPENSSL_free(param);
 957 }
 958
 959 /*-
 960  * Check for a multipart boundary. Returns:
 961  * 0 : no boundary
 962  * 1 : part boundary
 963  * 2 : final boundary
 964  */
 965 static int mime_bound_check(char *line, int linelen, char *bound, int blen)
 966 {
 967     if (linelen == -1)
 968         linelen = strlen(line);
 969     if (blen == -1)
 970         blen = strlen(bound);
 971     /* Quickly eliminate if line length too short */
 972     if (blen + 2 > linelen)
 973         return 0;
 974     /* Check for part boundary */
 975     if ((strncmp(line, "--", 2) == 0)
 976         && strncmp(line + 2, bound, blen) == 0) {
 977         if (strncmp(line + blen + 2, "--", 2) == 0)
 978             return 2;
 979         else
 980             return 1;
 981     }
 982     return 0;
 983 }
 984
 985 static int strip_eol(char *linebuf, int *plen, int flags)
 986 {
 987     int len = *plen;
 988     char *p, c;
 989     int is_eol = 0;
 990     p = linebuf + len - 1;
 991     for (p = linebuf + len - 1; len > 0; len--, p--) {
 992         c = *p;
 993         if (c == '\n')
 994             is_eol = 1;
 995         else if (is_eol && flags & SMIME_ASCIICRLF && c < 33)
 996             continue;
 997         else if (c != '\r')
 998             break;
 999     }
1000     *plen = len;
1001     return is_eol;
1002 }