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 <openssl/cms.h>
  18 #include "crypto/evp.h"
  19 #include "internal/bio.h"
  20 #include "asn1_local.h"
  21
  22 /*
  23  * Generalised MIME like utilities for streaming ASN1. Although many have a
  24  * PKCS7/CMS like flavour others are more general purpose.
  25  */
  26
  27 /*
  28  * MIME format structures Note that all are translated to lower case apart
  29  * from parameter values. Quotes are stripped off
  30  */
  31
  32 struct mime_param_st {
  33     char *param_name;           /* Param name e.g. "micalg" */
  34     char *param_value;          /* Param value e.g. "sha1" */
  35 };
  36
  37 struct mime_header_st {
  38     char *name;                 /* Name of line e.g. "content-type" */
  39     char *value;                /* Value of line e.g. "text/plain" */
  40     STACK_OF(MIME_PARAM) *params; /* Zero or more parameters */
  41 };
  42
  43 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
  44                             const ASN1_ITEM *it);
  45 static char *strip_ends(char *name);
  46 static char *strip_start(char *name);
  47 static char *strip_end(char *name);
  48 static MIME_HEADER *mime_hdr_new(const char *name, const char *value);
  49 static int mime_hdr_addparam(MIME_HEADER *mhdr, const char *name, const char *value);
  50 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio);
  51 static int mime_hdr_cmp(const MIME_HEADER *const *a,
  52                         const MIME_HEADER *const *b);
  53 static int mime_param_cmp(const MIME_PARAM *const *a,
  54                           const MIME_PARAM *const *b);
  55 static void mime_param_free(MIME_PARAM *param);
  56 static int mime_bound_check(char *line, int linelen, const char *bound, int blen);
  57 static int multi_split(BIO *bio, const char *bound, STACK_OF(BIO) **ret);
  58 static int strip_eol(char *linebuf, int *plen, int flags);
  59 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, const char *name);
  60 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, const char *name);
  61 static void mime_hdr_free(MIME_HEADER *hdr);
  62
  63 #define MAX_SMLEN 1024
  64 #define mime_debug(x)           /* x */
  65
  66 /* Output an ASN1 structure in BER format streaming if necessary */
  67
  68 /* unfortunately cannot constify this due to CMS_stream() and PKCS7_stream() */
  69 int i2d_ASN1_bio_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
  70                         const ASN1_ITEM *it)
  71 {
  72     /* If streaming create stream BIO and copy all content through it */
  73     if (flags & SMIME_STREAM) {
  74         BIO *bio, *tbio;
  75         bio = BIO_new_NDEF(out, val, it);
  76         if (!bio) {
  77             ASN1err(ASN1_F_I2D_ASN1_BIO_STREAM, ERR_R_MALLOC_FAILURE);
  78             return 0;
  79         }
  80         SMIME_crlf_copy(in, bio, flags);
  81         (void)BIO_flush(bio);
  82         /* Free up successive BIOs until we hit the old output BIO */
  83         do {
  84             tbio = BIO_pop(bio);
  85             BIO_free(bio);
  86             bio = tbio;
  87         } while (bio != out);
  88     }
  89     /*
  90      * else just write out ASN1 structure which will have all content stored
  91      * internally
  92      */
  93     else
  94         ASN1_item_i2d_bio(it, out, val);
  95     return 1;
  96 }
  97
  98 /* Base 64 read and write of ASN1 structure */
  99
 100 static int B64_write_ASN1(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
 101                           const ASN1_ITEM *it)
 102 {
 103     BIO *b64;
 104     int r;
 105     b64 = BIO_new(BIO_f_base64());
 106     if (b64 == NULL) {
 107         ASN1err(ASN1_F_B64_WRITE_ASN1, ERR_R_MALLOC_FAILURE);
 108         return 0;
 109     }
 110     /*
 111      * prepend the b64 BIO so all data is base64 encoded.
 112      */
 113     out = BIO_push(b64, out);
 114     r = i2d_ASN1_bio_stream(out, val, in, flags, it);
 115     (void)BIO_flush(out);
 116     BIO_pop(out);
 117     BIO_free(b64);
 118     return r;
 119 }
 120
 121 /* Streaming ASN1 PEM write */
 122
 123 int PEM_write_bio_ASN1_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
 124                               const char *hdr, const ASN1_ITEM *it)
 125 {
 126     int r;
 127     BIO_printf(out, "-----BEGIN %s-----\n", hdr);
 128     r = B64_write_ASN1(out, val, in, flags, it);
 129     BIO_printf(out, "-----END %s-----\n", hdr);
 130     return r;
 131 }
 132
 133 static ASN1_VALUE *b64_read_asn1(BIO *bio, const ASN1_ITEM *it, ASN1_VALUE **x)
 134 {
 135     BIO *b64;
 136     ASN1_VALUE *val;
 137
 138     if ((b64 = BIO_new(BIO_f_base64())) == NULL) {
 139         ASN1err(ASN1_F_B64_READ_ASN1, ERR_R_MALLOC_FAILURE);
 140         return 0;
 141     }
 142     bio = BIO_push(b64, bio);
 143     val = ASN1_item_d2i_bio(it, bio, x);
 144     if (!val)
 145         ASN1err(ASN1_F_B64_READ_ASN1, ASN1_R_DECODE_ERROR);
 146     (void)BIO_flush(bio);
 147     BIO_pop(bio);
 148     BIO_free(b64);
 149     return val;
 150 }
 151
 152 /* Generate the MIME "micalg" parameter from RFC3851, RFC4490 */
 153
 154 static int asn1_write_micalg(BIO *out, STACK_OF(X509_ALGOR) *mdalgs)
 155 {
 156     const EVP_MD *md;
 157     int i, have_unknown = 0, write_comma, ret = 0, md_nid;
 158     have_unknown = 0;
 159     write_comma = 0;
 160     for (i = 0; i < sk_X509_ALGOR_num(mdalgs); i++) {
 161         if (write_comma)
 162             BIO_write(out, ",", 1);
 163         write_comma = 1;
 164         md_nid = OBJ_obj2nid(sk_X509_ALGOR_value(mdalgs, i)->algorithm);
 165         md = EVP_get_digestbynid(md_nid);
 166         if (md && md->md_ctrl) {
 167             int rv;
 168             char *micstr;
 169             rv = md->md_ctrl(NULL, EVP_MD_CTRL_MICALG, 0, &micstr);
 170             if (rv > 0) {
 171                 BIO_puts(out, micstr);
 172                 OPENSSL_free(micstr);
 173                 continue;
 174             }
 175             if (rv != -2)
 176                 goto err;
 177         }
 178         switch (md_nid) {
 179         case NID_sha1:
 180             BIO_puts(out, "sha1");
 181             break;
 182
 183         case NID_md5:
 184             BIO_puts(out, "md5");
 185             break;
 186
 187         case NID_sha256:
 188             BIO_puts(out, "sha-256");
 189             break;
 190
 191         case NID_sha384:
 192             BIO_puts(out, "sha-384");
 193             break;
 194
 195         case NID_sha512:
 196             BIO_puts(out, "sha-512");
 197             break;
 198
 199         case NID_id_GostR3411_94:
 200             BIO_puts(out, "gostr3411-94");
 201             goto err;
 202
 203         case NID_id_GostR3411_2012_256:
 204             BIO_puts(out, "gostr3411-2012-256");
 205             goto err;
 206
 207         case NID_id_GostR3411_2012_512:
 208             BIO_puts(out, "gostr3411-2012-512");
 209             goto err;
 210
 211         default:
 212             if (have_unknown)
 213                 write_comma = 0;
 214             else {
 215                 BIO_puts(out, "unknown");
 216                 have_unknown = 1;
 217             }
 218             break;
 219
 220         }
 221     }
 222
 223     ret = 1;
 224  err:
 225
 226     return ret;
 227
 228 }
 229
 230 /* SMIME sender */
 231
 232 int SMIME_write_ASN1_ex(BIO *bio, ASN1_VALUE *val, BIO *data, int flags,
 233                         int ctype_nid, int econt_nid,
 234                         STACK_OF(X509_ALGOR) *mdalgs, const ASN1_ITEM *it,
 235                         OPENSSL_CTX *libctx, const char *propq)
 236 {
 237     char bound[33], c;
 238     int i;
 239     const char *mime_prefix, *mime_eol, *cname = "smime.p7m";
 240     const char *msg_type = NULL;
 241
 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_ex(libctx, (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 int SMIME_write_ASN1(BIO *bio, ASN1_VALUE *val, BIO *data, int flags,
 325                      int ctype_nid, int econt_nid,
 326                      STACK_OF(X509_ALGOR) *mdalgs, const ASN1_ITEM *it)
 327 {
 328     return SMIME_write_ASN1_ex(bio, val, data, flags, ctype_nid, econt_nid,
 329                                mdalgs, it, NULL, NULL);
 330 }
 331
 332 /* Handle output of ASN1 data */
 333
 334 /* cannot constify val because of CMS_dataFinal() */
 335 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
 336                             const ASN1_ITEM *it)
 337 {
 338     BIO *tmpbio;
 339     const ASN1_AUX *aux = it->funcs;
 340     ASN1_STREAM_ARG sarg;
 341     int rv = 1;
 342
 343     /*
 344      * If data is not detached or resigning then the output BIO is already
 345      * set up to finalise when it is written through.
 346      */
 347     if (!(flags & SMIME_DETACHED) || (flags & PKCS7_REUSE_DIGEST)) {
 348         SMIME_crlf_copy(data, out, flags);
 349         return 1;
 350     }
 351
 352     if (!aux || !aux->asn1_cb) {
 353         ASN1err(ASN1_F_ASN1_OUTPUT_DATA, ASN1_R_STREAMING_NOT_SUPPORTED);
 354         return 0;
 355     }
 356
 357     sarg.out = out;
 358     sarg.ndef_bio = NULL;
 359     sarg.boundary = NULL;
 360
 361     /* Let ASN1 code prepend any needed BIOs */
 362
 363     if (aux->asn1_cb(ASN1_OP_DETACHED_PRE, &val, it, &sarg) <= 0)
 364         return 0;
 365
 366     /* Copy data across, passing through filter BIOs for processing */
 367     SMIME_crlf_copy(data, sarg.ndef_bio, flags);
 368
 369     /* Finalize structure */
 370     if (aux->asn1_cb(ASN1_OP_DETACHED_POST, &val, it, &sarg) <= 0)
 371         rv = 0;
 372
 373     /* Now remove any digests prepended to the BIO */
 374
 375     while (sarg.ndef_bio != out) {
 376         tmpbio = BIO_pop(sarg.ndef_bio);
 377         BIO_free(sarg.ndef_bio);
 378         sarg.ndef_bio = tmpbio;
 379     }
 380
 381     return rv;
 382
 383 }
 384
 385 /*
 386  * SMIME reader: handle multipart/signed and opaque signing. in multipart
 387  * case the content is placed in a memory BIO pointed to by "bcont". In
 388  * opaque this is set to NULL
 389  */
 390
 391 ASN1_VALUE *SMIME_read_ASN1_ex(BIO *bio, BIO **bcont, const ASN1_ITEM *it,
 392                                ASN1_VALUE **x)
 393 {
 394     BIO *asnin;
 395     STACK_OF(MIME_HEADER) *headers = NULL;
 396     STACK_OF(BIO) *parts = NULL;
 397     MIME_HEADER *hdr;
 398     MIME_PARAM *prm;
 399     ASN1_VALUE *val;
 400     int ret;
 401
 402     if (bcont)
 403         *bcont = NULL;
 404
 405     if ((headers = mime_parse_hdr(bio)) == NULL) {
 406         ASN1err(0, ASN1_R_MIME_PARSE_ERROR);
 407         return NULL;
 408     }
 409
 410     if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 411         || hdr->value == NULL) {
 412         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 413         ASN1err(0, ASN1_R_NO_CONTENT_TYPE);
 414         return NULL;
 415     }
 416
 417     /* Handle multipart/signed */
 418
 419     if (strcmp(hdr->value, "multipart/signed") == 0) {
 420         /* Split into two parts */
 421         prm = mime_param_find(hdr, "boundary");
 422         if (prm == NULL || prm->param_value == NULL) {
 423             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 424             ASN1err(0, ASN1_R_NO_MULTIPART_BOUNDARY);
 425             return NULL;
 426         }
 427         ret = multi_split(bio, prm->param_value, &parts);
 428         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 429         if (!ret || (sk_BIO_num(parts) != 2)) {
 430             ASN1err(0, ASN1_R_NO_MULTIPART_BODY_FAILURE);
 431             sk_BIO_pop_free(parts, BIO_vfree);
 432             return NULL;
 433         }
 434
 435         /* Parse the signature piece */
 436         asnin = sk_BIO_value(parts, 1);
 437
 438         if ((headers = mime_parse_hdr(asnin)) == NULL) {
 439             ASN1err(0, ASN1_R_MIME_SIG_PARSE_ERROR);
 440             sk_BIO_pop_free(parts, BIO_vfree);
 441             return NULL;
 442         }
 443
 444         /* Get content type */
 445
 446         if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 447             || hdr->value == NULL) {
 448             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 449             ASN1err(0, ASN1_R_NO_SIG_CONTENT_TYPE);
 450             sk_BIO_pop_free(parts, BIO_vfree);
 451             return NULL;
 452         }
 453
 454         if (strcmp(hdr->value, "application/x-pkcs7-signature") &&
 455             strcmp(hdr->value, "application/pkcs7-signature")) {
 456             ASN1err(0, ASN1_R_SIG_INVALID_MIME_TYPE);
 457             ERR_add_error_data(2, "type: ", hdr->value);
 458             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 459             sk_BIO_pop_free(parts, BIO_vfree);
 460             return NULL;
 461         }
 462         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 463         /* Read in ASN1 */
 464         if ((val = b64_read_asn1(asnin, it, x)) == NULL) {
 465             ASN1err(0, ASN1_R_ASN1_SIG_PARSE_ERROR);
 466             sk_BIO_pop_free(parts, BIO_vfree);
 467             return NULL;
 468         }
 469
 470         if (bcont) {
 471             *bcont = sk_BIO_value(parts, 0);
 472             BIO_free(asnin);
 473             sk_BIO_free(parts);
 474         } else
 475             sk_BIO_pop_free(parts, BIO_vfree);
 476         return val;
 477     }
 478
 479     /* OK, if not multipart/signed try opaque signature */
 480
 481     if (strcmp(hdr->value, "application/x-pkcs7-mime") &&
 482         strcmp(hdr->value, "application/pkcs7-mime")) {
 483         ASN1err(0, ASN1_R_INVALID_MIME_TYPE);
 484         ERR_add_error_data(2, "type: ", hdr->value);
 485         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 486         return NULL;
 487     }
 488
 489     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 490
 491     if ((val = b64_read_asn1(bio, it, x)) == NULL) {
 492         ASN1err(0, ASN1_R_ASN1_PARSE_ERROR);
 493         return NULL;
 494     }
 495     return val;
 496 }
 497
 498 ASN1_VALUE *SMIME_read_ASN1(BIO *bio, BIO **bcont, const ASN1_ITEM *it)
 499 {
 500     return SMIME_read_ASN1_ex(bio, bcont, it, NULL);
 501 }
 502
 503 /* Copy text from one BIO to another making the output CRLF at EOL */
 504 int SMIME_crlf_copy(BIO *in, BIO *out, int flags)
 505 {
 506     BIO *bf;
 507     char eol;
 508     int len;
 509     char linebuf[MAX_SMLEN];
 510     /*
 511      * Buffer output so we don't write one line at a time. This is useful
 512      * when streaming as we don't end up with one OCTET STRING per line.
 513      */
 514     bf = BIO_new(BIO_f_buffer());
 515     if (bf == NULL)
 516         return 0;
 517     out = BIO_push(bf, out);
 518     if (flags & SMIME_BINARY) {
 519         while ((len = BIO_read(in, linebuf, MAX_SMLEN)) > 0)
 520             BIO_write(out, linebuf, len);
 521     } else {
 522         int eolcnt = 0;
 523         if (flags & SMIME_TEXT)
 524             BIO_printf(out, "Content-Type: text/plain\r\n\r\n");
 525         while ((len = BIO_gets(in, linebuf, MAX_SMLEN)) > 0) {
 526             eol = strip_eol(linebuf, &len, flags);
 527             if (len) {
 528                 /* Not EOF: write out all CRLF */
 529                 if (flags & SMIME_ASCIICRLF) {
 530                     int i;
 531                     for (i = 0; i < eolcnt; i++)
 532                         BIO_write(out, "\r\n", 2);
 533                     eolcnt = 0;
 534                 }
 535                 BIO_write(out, linebuf, len);
 536                 if (eol)
 537                     BIO_write(out, "\r\n", 2);
 538             } else if (flags & SMIME_ASCIICRLF)
 539                 eolcnt++;
 540             else if (eol)
 541                 BIO_write(out, "\r\n", 2);
 542         }
 543     }
 544     (void)BIO_flush(out);
 545     BIO_pop(out);
 546     BIO_free(bf);
 547     return 1;
 548 }
 549
 550 /* Strip off headers if they are text/plain */
 551 int SMIME_text(BIO *in, BIO *out)
 552 {
 553     char iobuf[4096];
 554     int len;
 555     STACK_OF(MIME_HEADER) *headers;
 556     MIME_HEADER *hdr;
 557
 558     if ((headers = mime_parse_hdr(in)) == NULL) {
 559         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_PARSE_ERROR);
 560         return 0;
 561     }
 562     if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 563         || hdr->value == NULL) {
 564         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_NO_CONTENT_TYPE);
 565         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 566         return 0;
 567     }
 568     if (strcmp(hdr->value, "text/plain")) {
 569         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_INVALID_MIME_TYPE);
 570         ERR_add_error_data(2, "type: ", hdr->value);
 571         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 572         return 0;
 573     }
 574     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 575     while ((len = BIO_read(in, iobuf, sizeof(iobuf))) > 0)
 576         BIO_write(out, iobuf, len);
 577     if (len < 0)
 578         return 0;
 579     return 1;
 580 }
 581
 582 /*
 583  * Split a multipart/XXX message body into component parts: result is
 584  * canonical parts in a STACK of bios
 585  */
 586
 587 static int multi_split(BIO *bio, const char *bound, STACK_OF(BIO) **ret)
 588 {
 589     char linebuf[MAX_SMLEN];
 590     int len, blen;
 591     int eol = 0, next_eol = 0;
 592     BIO *bpart = NULL;
 593     STACK_OF(BIO) *parts;
 594     char state, part, first;
 595
 596     blen = strlen(bound);
 597     part = 0;
 598     state = 0;
 599     first = 1;
 600     parts = sk_BIO_new_null();
 601     *ret = parts;
 602     if (*ret == NULL)
 603         return 0;
 604     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
 605         state = mime_bound_check(linebuf, len, bound, blen);
 606         if (state == 1) {
 607             first = 1;
 608             part++;
 609         } else if (state == 2) {
 610             if (!sk_BIO_push(parts, bpart)) {
 611                 BIO_free(bpart);
 612                 return 0;
 613             }
 614             return 1;
 615         } else if (part) {
 616             /* Strip CR+LF from linebuf */
 617             next_eol = strip_eol(linebuf, &len, 0);
 618             if (first) {
 619                 first = 0;
 620                 if (bpart)
 621                     if (!sk_BIO_push(parts, bpart)) {
 622                         BIO_free(bpart);
 623                         return 0;
 624                     }
 625                 bpart = BIO_new(BIO_s_mem());
 626                 if (bpart == NULL)
 627                     return 0;
 628                 BIO_set_mem_eof_return(bpart, 0);
 629             } else if (eol)
 630                 BIO_write(bpart, "\r\n", 2);
 631             eol = next_eol;
 632             if (len)
 633                 BIO_write(bpart, linebuf, len);
 634         }
 635     }
 636     BIO_free(bpart);
 637     return 0;
 638 }
 639
 640 /* This is the big one: parse MIME header lines up to message body */
 641
 642 #define MIME_INVALID    0
 643 #define MIME_START      1
 644 #define MIME_TYPE       2
 645 #define MIME_NAME       3
 646 #define MIME_VALUE      4
 647 #define MIME_QUOTE      5
 648 #define MIME_COMMENT    6
 649
 650 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio)
 651 {
 652     char *p, *q, c;
 653     char *ntmp;
 654     char linebuf[MAX_SMLEN];
 655     MIME_HEADER *mhdr = NULL, *new_hdr = NULL;
 656     STACK_OF(MIME_HEADER) *headers;
 657     int len, state, save_state = 0;
 658
 659     headers = sk_MIME_HEADER_new(mime_hdr_cmp);
 660     if (headers == NULL)
 661         return NULL;
 662     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
 663         /* If whitespace at line start then continuation line */
 664         if (mhdr && ossl_isspace(linebuf[0]))
 665             state = MIME_NAME;
 666         else
 667             state = MIME_START;
 668         ntmp = NULL;
 669         /* Go through all characters */
 670         for (p = linebuf, q = linebuf; (c = *p) && (c != '\r') && (c != '\n');
 671              p++) {
 672
 673             /*
 674              * State machine to handle MIME headers if this looks horrible
 675              * that's because it *is*
 676              */
 677
 678             switch (state) {
 679             case MIME_START:
 680                 if (c == ':') {
 681                     state = MIME_TYPE;
 682                     *p = 0;
 683                     ntmp = strip_ends(q);
 684                     q = p + 1;
 685                 }
 686                 break;
 687
 688             case MIME_TYPE:
 689                 if (c == ';') {
 690                     mime_debug("Found End Value\n");
 691                     *p = 0;
 692                     new_hdr = mime_hdr_new(ntmp, strip_ends(q));
 693                     if (new_hdr == NULL)
 694                         goto err;
 695                     if (!sk_MIME_HEADER_push(headers, new_hdr))
 696                         goto err;
 697                     mhdr = new_hdr;
 698                     new_hdr = NULL;
 699                     ntmp = NULL;
 700                     q = p + 1;
 701                     state = MIME_NAME;
 702                 } else if (c == '(') {
 703                     save_state = state;
 704                     state = MIME_COMMENT;
 705                 }
 706                 break;
 707
 708             case MIME_COMMENT:
 709                 if (c == ')') {
 710                     state = save_state;
 711                 }
 712                 break;
 713
 714             case MIME_NAME:
 715                 if (c == '=') {
 716                     state = MIME_VALUE;
 717                     *p = 0;
 718                     ntmp = strip_ends(q);
 719                     q = p + 1;
 720                 }
 721                 break;
 722
 723             case MIME_VALUE:
 724                 if (c == ';') {
 725                     state = MIME_NAME;
 726                     *p = 0;
 727                     mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 728                     ntmp = NULL;
 729                     q = p + 1;
 730                 } else if (c == '"') {
 731                     mime_debug("Found Quote\n");
 732                     state = MIME_QUOTE;
 733                 } else if (c == '(') {
 734                     save_state = state;
 735                     state = MIME_COMMENT;
 736                 }
 737                 break;
 738
 739             case MIME_QUOTE:
 740                 if (c == '"') {
 741                     mime_debug("Found Match Quote\n");
 742                     state = MIME_VALUE;
 743                 }
 744                 break;
 745             }
 746         }
 747
 748         if (state == MIME_TYPE) {
 749             new_hdr = mime_hdr_new(ntmp, strip_ends(q));
 750             if (new_hdr == NULL)
 751                 goto err;
 752             if (!sk_MIME_HEADER_push(headers, new_hdr))
 753                 goto err;
 754             mhdr = new_hdr;
 755             new_hdr = NULL;
 756         } else if (state == MIME_VALUE)
 757             mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 758         if (p == linebuf)
 759             break;              /* Blank line means end of headers */
 760     }
 761
 762     return headers;
 763
 764 err:
 765     mime_hdr_free(new_hdr);
 766     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 767     return NULL;
 768 }
 769
 770 static char *strip_ends(char *name)
 771 {
 772     return strip_end(strip_start(name));
 773 }
 774
 775 /* Strip a parameter of whitespace from start of param */
 776 static char *strip_start(char *name)
 777 {
 778     char *p, c;
 779     /* Look for first non whitespace or quote */
 780     for (p = name; (c = *p); p++) {
 781         if (c == '"') {
 782             /* Next char is start of string if non null */
 783             if (p[1])
 784                 return p + 1;
 785             /* Else null string */
 786             return NULL;
 787         }
 788         if (!ossl_isspace(c))
 789             return p;
 790     }
 791     return NULL;
 792 }
 793
 794 /* As above but strip from end of string : maybe should handle brackets? */
 795 static char *strip_end(char *name)
 796 {
 797     char *p, c;
 798     if (!name)
 799         return NULL;
 800     /* Look for first non whitespace or quote */
 801     for (p = name + strlen(name) - 1; p >= name; p--) {
 802         c = *p;
 803         if (c == '"') {
 804             if (p - 1 == name)
 805                 return NULL;
 806             *p = 0;
 807             return name;
 808         }
 809         if (ossl_isspace(c))
 810             *p = 0;
 811         else
 812             return name;
 813     }
 814     return NULL;
 815 }
 816
 817 static MIME_HEADER *mime_hdr_new(const char *name, const char *value)
 818 {
 819     MIME_HEADER *mhdr = NULL;
 820     char *tmpname = NULL, *tmpval = NULL, *p;
 821
 822     if (name) {
 823         if ((tmpname = OPENSSL_strdup(name)) == NULL)
 824             return NULL;
 825         for (p = tmpname; *p; p++)
 826             *p = ossl_tolower(*p);
 827     }
 828     if (value) {
 829         if ((tmpval = OPENSSL_strdup(value)) == NULL)
 830             goto err;
 831         for (p = tmpval; *p; p++)
 832             *p = ossl_tolower(*p);
 833     }
 834     mhdr = OPENSSL_malloc(sizeof(*mhdr));
 835     if (mhdr == NULL)
 836         goto err;
 837     mhdr->name = tmpname;
 838     mhdr->value = tmpval;
 839     if ((mhdr->params = sk_MIME_PARAM_new(mime_param_cmp)) == NULL)
 840         goto err;
 841     return mhdr;
 842
 843  err:
 844     OPENSSL_free(tmpname);
 845     OPENSSL_free(tmpval);
 846     OPENSSL_free(mhdr);
 847     return NULL;
 848 }
 849
 850 static int mime_hdr_addparam(MIME_HEADER *mhdr, const char *name, const char *value)
 851 {
 852     char *tmpname = NULL, *tmpval = NULL, *p;
 853     MIME_PARAM *mparam = NULL;
 854
 855     if (name) {
 856         tmpname = OPENSSL_strdup(name);
 857         if (!tmpname)
 858             goto err;
 859         for (p = tmpname; *p; p++)
 860             *p = ossl_tolower(*p);
 861     }
 862     if (value) {
 863         tmpval = OPENSSL_strdup(value);
 864         if (!tmpval)
 865             goto err;
 866     }
 867     /* Parameter values are case sensitive so leave as is */
 868     mparam = OPENSSL_malloc(sizeof(*mparam));
 869     if (mparam == NULL)
 870         goto err;
 871     mparam->param_name = tmpname;
 872     mparam->param_value = tmpval;
 873     if (!sk_MIME_PARAM_push(mhdr->params, mparam))
 874         goto err;
 875     return 1;
 876  err:
 877     OPENSSL_free(tmpname);
 878     OPENSSL_free(tmpval);
 879     OPENSSL_free(mparam);
 880     return 0;
 881 }
 882
 883 static int mime_hdr_cmp(const MIME_HEADER *const *a,
 884                         const MIME_HEADER *const *b)
 885 {
 886     if (!(*a)->name || !(*b)->name)
 887         return ! !(*a)->name - ! !(*b)->name;
 888
 889     return strcmp((*a)->name, (*b)->name);
 890 }
 891
 892 static int mime_param_cmp(const MIME_PARAM *const *a,
 893                           const MIME_PARAM *const *b)
 894 {
 895     if (!(*a)->param_name || !(*b)->param_name)
 896         return ! !(*a)->param_name - ! !(*b)->param_name;
 897     return strcmp((*a)->param_name, (*b)->param_name);
 898 }
 899
 900 /* Find a header with a given name (if possible) */
 901
 902 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, const char *name)
 903 {
 904     MIME_HEADER htmp;
 905     int idx;
 906
 907     htmp.name = (char *)name;
 908     htmp.value = NULL;
 909     htmp.params = NULL;
 910
 911     idx = sk_MIME_HEADER_find(hdrs, &htmp);
 912     return sk_MIME_HEADER_value(hdrs, idx);
 913 }
 914
 915 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, const char *name)
 916 {
 917     MIME_PARAM param;
 918     int idx;
 919
 920     param.param_name = (char *)name;
 921     param.param_value = NULL;
 922     idx = sk_MIME_PARAM_find(hdr->params, &param);
 923     return sk_MIME_PARAM_value(hdr->params, idx);
 924 }
 925
 926 static void mime_hdr_free(MIME_HEADER *hdr)
 927 {
 928     if (hdr == NULL)
 929         return;
 930     OPENSSL_free(hdr->name);
 931     OPENSSL_free(hdr->value);
 932     if (hdr->params)
 933         sk_MIME_PARAM_pop_free(hdr->params, mime_param_free);
 934     OPENSSL_free(hdr);
 935 }
 936
 937 static void mime_param_free(MIME_PARAM *param)
 938 {
 939     OPENSSL_free(param->param_name);
 940     OPENSSL_free(param->param_value);
 941     OPENSSL_free(param);
 942 }
 943
 944 /*-
 945  * Check for a multipart boundary. Returns:
 946  * 0 : no boundary
 947  * 1 : part boundary
 948  * 2 : final boundary
 949  */
 950 static int mime_bound_check(char *line, int linelen, const char *bound, int blen)
 951 {
 952     if (linelen == -1)
 953         linelen = strlen(line);
 954     if (blen == -1)
 955         blen = strlen(bound);
 956     /* Quickly eliminate if line length too short */
 957     if (blen + 2 > linelen)
 958         return 0;
 959     /* Check for part boundary */
 960     if ((strncmp(line, "--", 2) == 0)
 961         && strncmp(line + 2, bound, blen) == 0) {
 962         if (strncmp(line + blen + 2, "--", 2) == 0)
 963             return 2;
 964         else
 965             return 1;
 966     }
 967     return 0;
 968 }
 969
 970 static int strip_eol(char *linebuf, int *plen, int flags)
 971 {
 972     int len = *plen;
 973     char *p, c;
 974     int is_eol = 0;
 975
 976     for (p = linebuf + len - 1; len > 0; len--, p--) {
 977         c = *p;
 978         if (c == '\n') {
 979             is_eol = 1;
 980         } else if (is_eol && flags & SMIME_ASCIICRLF && c == 32) {
 981             /* Strip trailing space on a line; 32 == ASCII for ' ' */
 982             continue;
 983         } else if (c != '\r') {
 984             break;
 985         }
 986     }
 987     *plen = len;
 988     return is_eol;
 989 }