crypto/asn1/asn_mime.c

   1 /*
   2  * Copyright 2008-2021 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, int flags, 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     int rv = 1;
  73
  74     /* If streaming create stream BIO and copy all content through it */
  75     if (flags & SMIME_STREAM) {
  76         BIO *bio, *tbio;
  77         bio = BIO_new_NDEF(out, val, it);
  78         if (!bio) {
  79             ERR_raise(ERR_LIB_ASN1, ERR_R_BUF_LIB);
  80             return 0;
  81         }
  82         if (!SMIME_crlf_copy(in, bio, flags)) {
  83             rv = 0;
  84         }
  85
  86         (void)BIO_flush(bio);
  87         /* Free up successive BIOs until we hit the old output BIO */
  88         do {
  89             tbio = BIO_pop(bio);
  90             BIO_free(bio);
  91             bio = tbio;
  92         } while (bio != out);
  93     }
  94     /*
  95      * else just write out ASN1 structure which will have all content stored
  96      * internally
  97      */
  98     else
  99         ASN1_item_i2d_bio(it, out, val);
 100     return rv;
 101 }
 102
 103 /* Base 64 read and write of ASN1 structure */
 104
 105 static int B64_write_ASN1(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
 106                           const ASN1_ITEM *it)
 107 {
 108     BIO *b64;
 109     int r;
 110     b64 = BIO_new(BIO_f_base64());
 111     if (b64 == NULL) {
 112         ERR_raise(ERR_LIB_ASN1, ERR_R_BIO_LIB);
 113         return 0;
 114     }
 115     /*
 116      * prepend the b64 BIO so all data is base64 encoded.
 117      */
 118     out = BIO_push(b64, out);
 119     r = i2d_ASN1_bio_stream(out, val, in, flags, it);
 120     (void)BIO_flush(out);
 121     BIO_pop(out);
 122     BIO_free(b64);
 123     return r;
 124 }
 125
 126 /* Streaming ASN1 PEM write */
 127
 128 int PEM_write_bio_ASN1_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
 129                               const char *hdr, const ASN1_ITEM *it)
 130 {
 131     int r;
 132     BIO_printf(out, "-----BEGIN %s-----\n", hdr);
 133     r = B64_write_ASN1(out, val, in, flags, it);
 134     BIO_printf(out, "-----END %s-----\n", hdr);
 135     return r;
 136 }
 137
 138 static ASN1_VALUE *b64_read_asn1(BIO *bio, const ASN1_ITEM *it, ASN1_VALUE **x,
 139                                  OSSL_LIB_CTX *libctx, const char *propq)
 140 {
 141     BIO *b64;
 142     ASN1_VALUE *val;
 143
 144     if ((b64 = BIO_new(BIO_f_base64())) == NULL) {
 145         ERR_raise(ERR_LIB_ASN1, ERR_R_BIO_LIB);
 146         return 0;
 147     }
 148     bio = BIO_push(b64, bio);
 149     val = ASN1_item_d2i_bio_ex(it, bio, x, libctx, propq);
 150     if (!val)
 151         ERR_raise(ERR_LIB_ASN1, ASN1_R_DECODE_ERROR);
 152     (void)BIO_flush(bio);
 153     BIO_pop(bio);
 154     BIO_free(b64);
 155     return val;
 156 }
 157
 158 /* Generate the MIME "micalg" parameter from RFC3851, RFC4490 */
 159
 160 static int asn1_write_micalg(BIO *out, STACK_OF(X509_ALGOR) *mdalgs)
 161 {
 162     const EVP_MD *md;
 163     int i, have_unknown = 0, write_comma, ret = 0, md_nid;
 164     have_unknown = 0;
 165     write_comma = 0;
 166     for (i = 0; i < sk_X509_ALGOR_num(mdalgs); i++) {
 167         if (write_comma)
 168             BIO_write(out, ",", 1);
 169         write_comma = 1;
 170         md_nid = OBJ_obj2nid(sk_X509_ALGOR_value(mdalgs, i)->algorithm);
 171         md = EVP_get_digestbynid(md_nid);
 172         if (md && md->md_ctrl) {
 173             int rv;
 174             char *micstr;
 175             rv = md->md_ctrl(NULL, EVP_MD_CTRL_MICALG, 0, &micstr);
 176             if (rv > 0) {
 177                 BIO_puts(out, micstr);
 178                 OPENSSL_free(micstr);
 179                 continue;
 180             }
 181             if (rv != -2)
 182                 goto err;
 183         }
 184         switch (md_nid) {
 185         case NID_sha1:
 186             BIO_puts(out, "sha1");
 187             break;
 188
 189         case NID_md5:
 190             BIO_puts(out, "md5");
 191             break;
 192
 193         case NID_sha256:
 194             BIO_puts(out, "sha-256");
 195             break;
 196
 197         case NID_sha384:
 198             BIO_puts(out, "sha-384");
 199             break;
 200
 201         case NID_sha512:
 202             BIO_puts(out, "sha-512");
 203             break;
 204
 205         case NID_id_GostR3411_94:
 206             BIO_puts(out, "gostr3411-94");
 207             goto err;
 208
 209         case NID_id_GostR3411_2012_256:
 210             BIO_puts(out, "gostr3411-2012-256");
 211             goto err;
 212
 213         case NID_id_GostR3411_2012_512:
 214             BIO_puts(out, "gostr3411-2012-512");
 215             goto err;
 216
 217         default:
 218             if (have_unknown) {
 219                 write_comma = 0;
 220             } else {
 221                 BIO_puts(out, "unknown");
 222                 have_unknown = 1;
 223             }
 224             break;
 225
 226         }
 227     }
 228
 229     ret = 1;
 230  err:
 231
 232     return ret;
 233
 234 }
 235
 236 /* SMIME sender */
 237
 238 int SMIME_write_ASN1_ex(BIO *bio, ASN1_VALUE *val, BIO *data, int flags,
 239                         int ctype_nid, int econt_nid,
 240                         STACK_OF(X509_ALGOR) *mdalgs, const ASN1_ITEM *it,
 241                         OSSL_LIB_CTX *libctx, const char *propq)
 242 {
 243     char bound[33], c;
 244     int i;
 245     const char *mime_prefix, *mime_eol, *cname = "smime.p7m";
 246     const char *msg_type = NULL;
 247
 248     if (flags & SMIME_OLDMIME)
 249         mime_prefix = "application/x-pkcs7-";
 250     else
 251         mime_prefix = "application/pkcs7-";
 252
 253     if (flags & SMIME_CRLFEOL)
 254         mime_eol = "\r\n";
 255     else
 256         mime_eol = "\n";
 257     if ((flags & SMIME_DETACHED) && data) {
 258         /* We want multipart/signed */
 259         /* Generate a random boundary */
 260         if (RAND_bytes_ex(libctx, (unsigned char *)bound, 32, 0) <= 0)
 261             return 0;
 262         for (i = 0; i < 32; i++) {
 263             c = bound[i] & 0xf;
 264             if (c < 10)
 265                 c += '0';
 266             else
 267                 c += 'A' - 10;
 268             bound[i] = c;
 269         }
 270         bound[32] = 0;
 271         BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
 272         BIO_printf(bio, "Content-Type: multipart/signed;");
 273         BIO_printf(bio, " protocol=\"%ssignature\";", mime_prefix);
 274         BIO_puts(bio, " micalg=\"");
 275         asn1_write_micalg(bio, mdalgs);
 276         BIO_printf(bio, "\"; boundary=\"----%s\"%s%s",
 277                    bound, mime_eol, mime_eol);
 278         BIO_printf(bio, "This is an S/MIME signed message%s%s",
 279                    mime_eol, mime_eol);
 280         /* Now write out the first part */
 281         BIO_printf(bio, "------%s%s", bound, mime_eol);
 282         if (!asn1_output_data(bio, data, val, flags, it))
 283             return 0;
 284         BIO_printf(bio, "%s------%s%s", mime_eol, bound, mime_eol);
 285
 286         /* Headers for signature */
 287
 288         BIO_printf(bio, "Content-Type: %ssignature;", mime_prefix);
 289         BIO_printf(bio, " name=\"smime.p7s\"%s", mime_eol);
 290         BIO_printf(bio, "Content-Transfer-Encoding: base64%s", mime_eol);
 291         BIO_printf(bio, "Content-Disposition: attachment;");
 292         BIO_printf(bio, " filename=\"smime.p7s\"%s%s", mime_eol, mime_eol);
 293         B64_write_ASN1(bio, val, NULL, 0, it);
 294         BIO_printf(bio, "%s------%s--%s%s", mime_eol, bound,
 295                    mime_eol, mime_eol);
 296         return 1;
 297     }
 298
 299     /* Determine smime-type header */
 300
 301     if (ctype_nid == NID_pkcs7_enveloped) {
 302         msg_type = "enveloped-data";
 303     } else if (ctype_nid == NID_pkcs7_signed) {
 304         if (econt_nid == NID_id_smime_ct_receipt)
 305             msg_type = "signed-receipt";
 306         else if (sk_X509_ALGOR_num(mdalgs) >= 0)
 307             msg_type = "signed-data";
 308         else
 309             msg_type = "certs-only";
 310     } else if (ctype_nid == NID_id_smime_ct_compressedData) {
 311         msg_type = "compressed-data";
 312         cname = "smime.p7z";
 313     }
 314     /* MIME headers */
 315     BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
 316     BIO_printf(bio, "Content-Disposition: attachment;");
 317     BIO_printf(bio, " filename=\"%s\"%s", cname, mime_eol);
 318     BIO_printf(bio, "Content-Type: %smime;", mime_prefix);
 319     if (msg_type)
 320         BIO_printf(bio, " smime-type=%s;", msg_type);
 321     BIO_printf(bio, " name=\"%s\"%s", cname, mime_eol);
 322     BIO_printf(bio, "Content-Transfer-Encoding: base64%s%s",
 323                mime_eol, mime_eol);
 324     if (!B64_write_ASN1(bio, val, data, flags, it))
 325         return 0;
 326     BIO_printf(bio, "%s", mime_eol);
 327     return 1;
 328 }
 329
 330 int SMIME_write_ASN1(BIO *bio, ASN1_VALUE *val, BIO *data, int flags,
 331                      int ctype_nid, int econt_nid,
 332                      STACK_OF(X509_ALGOR) *mdalgs, const ASN1_ITEM *it)
 333 {
 334     return SMIME_write_ASN1_ex(bio, val, data, flags, ctype_nid, econt_nid,
 335                                mdalgs, it, NULL, NULL);
 336 }
 337
 338 /* Handle output of ASN1 data */
 339
 340 /* cannot constify val because of CMS_dataFinal() */
 341 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
 342                             const ASN1_ITEM *it)
 343 {
 344     BIO *tmpbio;
 345     const ASN1_AUX *aux = it->funcs;
 346     ASN1_STREAM_ARG sarg;
 347     int rv = 1;
 348
 349     /*
 350      * If data is not detached or resigning then the output BIO is already
 351      * set up to finalise when it is written through.
 352      */
 353     if (!(flags & SMIME_DETACHED) || (flags & PKCS7_REUSE_DIGEST)) {
 354         return SMIME_crlf_copy(data, out, flags);
 355     }
 356
 357     if (!aux || !aux->asn1_cb) {
 358         ERR_raise(ERR_LIB_ASN1, ASN1_R_STREAMING_NOT_SUPPORTED);
 359         return 0;
 360     }
 361
 362     sarg.out = out;
 363     sarg.ndef_bio = NULL;
 364     sarg.boundary = NULL;
 365
 366     /* Let ASN1 code prepend any needed BIOs */
 367
 368     if (aux->asn1_cb(ASN1_OP_DETACHED_PRE, &val, it, &sarg) <= 0)
 369         return 0;
 370
 371     /* Copy data across, passing through filter BIOs for processing */
 372     if (!SMIME_crlf_copy(data, sarg.ndef_bio, flags))
 373         rv = 0;
 374
 375     /* Finalize structure */
 376     if (aux->asn1_cb(ASN1_OP_DETACHED_POST, &val, it, &sarg) <= 0)
 377         rv = 0;
 378
 379     /* Now remove any digests prepended to the BIO */
 380
 381     while (sarg.ndef_bio != out) {
 382         tmpbio = BIO_pop(sarg.ndef_bio);
 383         BIO_free(sarg.ndef_bio);
 384         sarg.ndef_bio = tmpbio;
 385     }
 386
 387     return rv;
 388
 389 }
 390
 391 /*
 392  * SMIME reader: handle multipart/signed and opaque signing. in multipart
 393  * case the content is placed in a memory BIO pointed to by "bcont". In
 394  * opaque this is set to NULL
 395  */
 396
 397 ASN1_VALUE *SMIME_read_ASN1_ex(BIO *bio, int flags, BIO **bcont,
 398                                const ASN1_ITEM *it, ASN1_VALUE **x,
 399                                OSSL_LIB_CTX *libctx, const char *propq)
 400 {
 401     BIO *asnin;
 402     STACK_OF(MIME_HEADER) *headers = NULL;
 403     STACK_OF(BIO) *parts = NULL;
 404     MIME_HEADER *hdr;
 405     MIME_PARAM *prm;
 406     ASN1_VALUE *val;
 407     int ret;
 408
 409     if (bcont)
 410         *bcont = NULL;
 411
 412     if ((headers = mime_parse_hdr(bio)) == NULL) {
 413         ERR_raise(ERR_LIB_ASN1, ASN1_R_MIME_PARSE_ERROR);
 414         return NULL;
 415     }
 416
 417     if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 418         || hdr->value == NULL) {
 419         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 420         ERR_raise(ERR_LIB_ASN1, ASN1_R_NO_CONTENT_TYPE);
 421         return NULL;
 422     }
 423
 424     /* Handle multipart/signed */
 425
 426     if (strcmp(hdr->value, "multipart/signed") == 0) {
 427         /* Split into two parts */
 428         prm = mime_param_find(hdr, "boundary");
 429         if (prm == NULL || prm->param_value == NULL) {
 430             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 431             ERR_raise(ERR_LIB_ASN1, ASN1_R_NO_MULTIPART_BOUNDARY);
 432             return NULL;
 433         }
 434         ret = multi_split(bio, flags, prm->param_value, &parts);
 435         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 436         if (!ret || (sk_BIO_num(parts) != 2)) {
 437             ERR_raise(ERR_LIB_ASN1, ASN1_R_NO_MULTIPART_BODY_FAILURE);
 438             sk_BIO_pop_free(parts, BIO_vfree);
 439             return NULL;
 440         }
 441
 442         /* Parse the signature piece */
 443         asnin = sk_BIO_value(parts, 1);
 444
 445         if ((headers = mime_parse_hdr(asnin)) == NULL) {
 446             ERR_raise(ERR_LIB_ASN1, ASN1_R_MIME_SIG_PARSE_ERROR);
 447             sk_BIO_pop_free(parts, BIO_vfree);
 448             return NULL;
 449         }
 450
 451         /* Get content type */
 452
 453         if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 454             || hdr->value == NULL) {
 455             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 456             ERR_raise(ERR_LIB_ASN1, ASN1_R_NO_SIG_CONTENT_TYPE);
 457             sk_BIO_pop_free(parts, BIO_vfree);
 458             return NULL;
 459         }
 460
 461         if (strcmp(hdr->value, "application/x-pkcs7-signature") &&
 462             strcmp(hdr->value, "application/pkcs7-signature")) {
 463             ERR_raise_data(ERR_LIB_ASN1, ASN1_R_SIG_INVALID_MIME_TYPE,
 464                            "type: %s", hdr->value);
 465             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 466             sk_BIO_pop_free(parts, BIO_vfree);
 467             return NULL;
 468         }
 469         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 470         /* Read in ASN1 */
 471         if ((val = b64_read_asn1(asnin, it, x, libctx, propq)) == NULL) {
 472             ERR_raise(ERR_LIB_ASN1, ASN1_R_ASN1_SIG_PARSE_ERROR);
 473             sk_BIO_pop_free(parts, BIO_vfree);
 474             return NULL;
 475         }
 476
 477         if (bcont) {
 478             *bcont = sk_BIO_value(parts, 0);
 479             BIO_free(asnin);
 480             sk_BIO_free(parts);
 481         } else {
 482             sk_BIO_pop_free(parts, BIO_vfree);
 483         }
 484         return val;
 485     }
 486
 487     /* OK, if not multipart/signed try opaque signature */
 488
 489     if (strcmp(hdr->value, "application/x-pkcs7-mime") &&
 490         strcmp(hdr->value, "application/pkcs7-mime")) {
 491         ERR_raise_data(ERR_LIB_ASN1, ASN1_R_INVALID_MIME_TYPE,
 492                        "type: %s", hdr->value);
 493         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 494         return NULL;
 495     }
 496
 497     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 498
 499     if ((val = b64_read_asn1(bio, it, x, libctx, propq)) == NULL) {
 500         ERR_raise(ERR_LIB_ASN1, ASN1_R_ASN1_PARSE_ERROR);
 501         return NULL;
 502     }
 503     return val;
 504 }
 505
 506 ASN1_VALUE *SMIME_read_ASN1(BIO *bio, BIO **bcont, const ASN1_ITEM *it)
 507 {
 508     return SMIME_read_ASN1_ex(bio, 0, bcont, it, NULL, NULL, NULL);
 509 }
 510
 511 /* Copy text from one BIO to another making the output CRLF at EOL */
 512 int SMIME_crlf_copy(BIO *in, BIO *out, int flags)
 513 {
 514     BIO *bf;
 515     char eol;
 516     int len;
 517     char linebuf[MAX_SMLEN];
 518     /*
 519      * Buffer output so we don't write one line at a time. This is useful
 520      * when streaming as we don't end up with one OCTET STRING per line.
 521      */
 522     bf = BIO_new(BIO_f_buffer());
 523     if (bf == NULL) {
 524         ERR_raise(ERR_LIB_ASN1, ERR_R_BIO_LIB);
 525         return 0;
 526     }
 527     out = BIO_push(bf, out);
 528     if (flags & SMIME_BINARY) {
 529         while ((len = BIO_read(in, linebuf, MAX_SMLEN)) > 0)
 530             BIO_write(out, linebuf, len);
 531     } else {
 532         int eolcnt = 0;
 533         if (flags & SMIME_TEXT)
 534             BIO_printf(out, "Content-Type: text/plain\r\n\r\n");
 535         while ((len = BIO_gets(in, linebuf, MAX_SMLEN)) > 0) {
 536             eol = strip_eol(linebuf, &len, flags);
 537             if (len > 0) {
 538                 /* Not EOF: write out all CRLF */
 539                 if (flags & SMIME_ASCIICRLF) {
 540                     int i;
 541                     for (i = 0; i < eolcnt; i++)
 542                         BIO_write(out, "\r\n", 2);
 543                     eolcnt = 0;
 544                 }
 545                 BIO_write(out, linebuf, len);
 546                 if (eol)
 547                     BIO_write(out, "\r\n", 2);
 548             } else if (flags & SMIME_ASCIICRLF) {
 549                 eolcnt++;
 550             } else if (eol) {
 551                 BIO_write(out, "\r\n", 2);
 552             }
 553         }
 554     }
 555     (void)BIO_flush(out);
 556     BIO_pop(out);
 557     BIO_free(bf);
 558     return 1;
 559 }
 560
 561 /* Strip off headers if they are text/plain */
 562 int SMIME_text(BIO *in, BIO *out)
 563 {
 564     char iobuf[4096];
 565     int len;
 566     STACK_OF(MIME_HEADER) *headers;
 567     MIME_HEADER *hdr;
 568
 569     if ((headers = mime_parse_hdr(in)) == NULL) {
 570         ERR_raise(ERR_LIB_ASN1, ASN1_R_MIME_PARSE_ERROR);
 571         return 0;
 572     }
 573     if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 574         || hdr->value == NULL) {
 575         ERR_raise(ERR_LIB_ASN1, ASN1_R_MIME_NO_CONTENT_TYPE);
 576         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 577         return 0;
 578     }
 579     if (strcmp(hdr->value, "text/plain")) {
 580         ERR_raise_data(ERR_LIB_ASN1, ASN1_R_INVALID_MIME_TYPE,
 581                        "type: %s", hdr->value);
 582         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 583         return 0;
 584     }
 585     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 586     while ((len = BIO_read(in, iobuf, sizeof(iobuf))) > 0)
 587         BIO_write(out, iobuf, len);
 588     if (len < 0)
 589         return 0;
 590     return 1;
 591 }
 592
 593 /*
 594  * Split a multipart/XXX message body into component parts: result is
 595  * canonical parts in a STACK of bios
 596  */
 597
 598 static int multi_split(BIO *bio, int flags, const char *bound, STACK_OF(BIO) **ret)
 599 {
 600     char linebuf[MAX_SMLEN];
 601     int len, blen;
 602     int eol = 0, next_eol = 0;
 603     BIO *bpart = NULL;
 604     STACK_OF(BIO) *parts;
 605     char state, part, first;
 606
 607     blen = strlen(bound);
 608     part = 0;
 609     state = 0;
 610     first = 1;
 611     parts = sk_BIO_new_null();
 612     *ret = parts;
 613     if (*ret == NULL)
 614         return 0;
 615     while ((len = BIO_get_line(bio, linebuf, MAX_SMLEN)) > 0) {
 616         state = mime_bound_check(linebuf, len, bound, blen);
 617         if (state == 1) {
 618             first = 1;
 619             part++;
 620         } else if (state == 2) {
 621             if (!sk_BIO_push(parts, bpart)) {
 622                 BIO_free(bpart);
 623                 return 0;
 624             }
 625             return 1;
 626         } else if (part != 0) {
 627             /* Strip (possibly CR +) LF from linebuf */
 628             next_eol = strip_eol(linebuf, &len, flags);
 629             if (first) {
 630                 first = 0;
 631                 if (bpart)
 632                     if (!sk_BIO_push(parts, bpart)) {
 633                         BIO_free(bpart);
 634                         return 0;
 635                     }
 636                 bpart = BIO_new(BIO_s_mem());
 637                 if (bpart == NULL)
 638                     return 0;
 639                 BIO_set_mem_eof_return(bpart, 0);
 640             } else if (eol) {
 641                 if (
 642 #ifndef OPENSSL_NO_CMS
 643                     (flags & CMS_BINARY) == 0
 644 #else
 645                     1
 646 #endif
 647                         || (flags & SMIME_CRLFEOL) != 0)
 648                     BIO_write(bpart, "\r\n", 2);
 649                 else
 650                     BIO_write(bpart, "\n", 1);
 651             }
 652             eol = next_eol;
 653             if (len > 0)
 654                 BIO_write(bpart, linebuf, len);
 655         }
 656     }
 657     BIO_free(bpart);
 658     return 0;
 659 }
 660
 661 /* This is the big one: parse MIME header lines up to message body */
 662
 663 #define MIME_INVALID    0
 664 #define MIME_START      1
 665 #define MIME_TYPE       2
 666 #define MIME_NAME       3
 667 #define MIME_VALUE      4
 668 #define MIME_QUOTE      5
 669 #define MIME_COMMENT    6
 670
 671 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio)
 672 {
 673     char *p, *q, c;
 674     char *ntmp;
 675     char linebuf[MAX_SMLEN];
 676     MIME_HEADER *mhdr = NULL, *new_hdr = NULL;
 677     STACK_OF(MIME_HEADER) *headers;
 678     int len, state, save_state = 0;
 679
 680     headers = sk_MIME_HEADER_new(mime_hdr_cmp);
 681     if (headers == NULL)
 682         return NULL;
 683     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
 684         /* If whitespace at line start then continuation line */
 685         if (mhdr && ossl_isspace(linebuf[0]))
 686             state = MIME_NAME;
 687         else
 688             state = MIME_START;
 689         ntmp = NULL;
 690         /* Go through all characters */
 691         for (p = linebuf, q = linebuf; (c = *p) && (c != '\r') && (c != '\n');
 692              p++) {
 693
 694             /*
 695              * State machine to handle MIME headers if this looks horrible
 696              * that's because it *is*
 697              */
 698
 699             switch (state) {
 700             case MIME_START:
 701                 if (c == ':') {
 702                     state = MIME_TYPE;
 703                     *p = 0;
 704                     ntmp = strip_ends(q);
 705                     q = p + 1;
 706                 }
 707                 break;
 708
 709             case MIME_TYPE:
 710                 if (c == ';') {
 711                     mime_debug("Found End Value\n");
 712                     *p = 0;
 713                     new_hdr = mime_hdr_new(ntmp, strip_ends(q));
 714                     if (new_hdr == NULL)
 715                         goto err;
 716                     if (!sk_MIME_HEADER_push(headers, new_hdr))
 717                         goto err;
 718                     mhdr = new_hdr;
 719                     new_hdr = NULL;
 720                     ntmp = NULL;
 721                     q = p + 1;
 722                     state = MIME_NAME;
 723                 } else if (c == '(') {
 724                     save_state = state;
 725                     state = MIME_COMMENT;
 726                 }
 727                 break;
 728
 729             case MIME_COMMENT:
 730                 if (c == ')') {
 731                     state = save_state;
 732                 }
 733                 break;
 734
 735             case MIME_NAME:
 736                 if (c == '=') {
 737                     state = MIME_VALUE;
 738                     *p = 0;
 739                     ntmp = strip_ends(q);
 740                     q = p + 1;
 741                 }
 742                 break;
 743
 744             case MIME_VALUE:
 745                 if (c == ';') {
 746                     state = MIME_NAME;
 747                     *p = 0;
 748                     mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 749                     ntmp = NULL;
 750                     q = p + 1;
 751                 } else if (c == '"') {
 752                     mime_debug("Found Quote\n");
 753                     state = MIME_QUOTE;
 754                 } else if (c == '(') {
 755                     save_state = state;
 756                     state = MIME_COMMENT;
 757                 }
 758                 break;
 759
 760             case MIME_QUOTE:
 761                 if (c == '"') {
 762                     mime_debug("Found Match Quote\n");
 763                     state = MIME_VALUE;
 764                 }
 765                 break;
 766             }
 767         }
 768
 769         if (state == MIME_TYPE) {
 770             new_hdr = mime_hdr_new(ntmp, strip_ends(q));
 771             if (new_hdr == NULL)
 772                 goto err;
 773             if (!sk_MIME_HEADER_push(headers, new_hdr))
 774                 goto err;
 775             mhdr = new_hdr;
 776             new_hdr = NULL;
 777         } else if (state == MIME_VALUE) {
 778             mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 779         }
 780         if (p == linebuf)
 781             break;              /* Blank line means end of headers */
 782     }
 783
 784     return headers;
 785
 786  err:
 787     mime_hdr_free(new_hdr);
 788     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 789     return NULL;
 790 }
 791
 792 static char *strip_ends(char *name)
 793 {
 794     return strip_end(strip_start(name));
 795 }
 796
 797 /* Strip a parameter of whitespace from start of param */
 798 static char *strip_start(char *name)
 799 {
 800     char *p, c;
 801     /* Look for first non whitespace or quote */
 802     for (p = name; (c = *p); p++) {
 803         if (c == '"') {
 804             /* Next char is start of string if non null */
 805             if (p[1])
 806                 return p + 1;
 807             /* Else null string */
 808             return NULL;
 809         }
 810         if (!ossl_isspace(c))
 811             return p;
 812     }
 813     return NULL;
 814 }
 815
 816 /* As above but strip from end of string : maybe should handle brackets? */
 817 static char *strip_end(char *name)
 818 {
 819     char *p, c;
 820     if (!name)
 821         return NULL;
 822     /* Look for first non whitespace or quote */
 823     for (p = name + strlen(name) - 1; p >= name; p--) {
 824         c = *p;
 825         if (c == '"') {
 826             if (p - 1 == name)
 827                 return NULL;
 828             *p = 0;
 829             return name;
 830         }
 831         if (ossl_isspace(c))
 832             *p = 0;
 833         else
 834             return name;
 835     }
 836     return NULL;
 837 }
 838
 839 static MIME_HEADER *mime_hdr_new(const char *name, const char *value)
 840 {
 841     MIME_HEADER *mhdr = NULL;
 842     char *tmpname = NULL, *tmpval = NULL, *p;
 843
 844     if (name) {
 845         if ((tmpname = OPENSSL_strdup(name)) == NULL)
 846             return NULL;
 847         for (p = tmpname; *p; p++)
 848             *p = ossl_tolower(*p);
 849     }
 850     if (value) {
 851         if ((tmpval = OPENSSL_strdup(value)) == NULL)
 852             goto err;
 853         for (p = tmpval; *p; p++)
 854             *p = ossl_tolower(*p);
 855     }
 856     mhdr = OPENSSL_malloc(sizeof(*mhdr));
 857     if (mhdr == NULL)
 858         goto err;
 859     mhdr->name = tmpname;
 860     mhdr->value = tmpval;
 861     if ((mhdr->params = sk_MIME_PARAM_new(mime_param_cmp)) == NULL)
 862         goto err;
 863     return mhdr;
 864
 865  err:
 866     OPENSSL_free(tmpname);
 867     OPENSSL_free(tmpval);
 868     OPENSSL_free(mhdr);
 869     return NULL;
 870 }
 871
 872 static int mime_hdr_addparam(MIME_HEADER *mhdr, const char *name, const char *value)
 873 {
 874     char *tmpname = NULL, *tmpval = NULL, *p;
 875     MIME_PARAM *mparam = NULL;
 876
 877     if (name) {
 878         tmpname = OPENSSL_strdup(name);
 879         if (!tmpname)
 880             goto err;
 881         for (p = tmpname; *p; p++)
 882             *p = ossl_tolower(*p);
 883     }
 884     if (value) {
 885         tmpval = OPENSSL_strdup(value);
 886         if (!tmpval)
 887             goto err;
 888     }
 889     /* Parameter values are case sensitive so leave as is */
 890     mparam = OPENSSL_malloc(sizeof(*mparam));
 891     if (mparam == NULL)
 892         goto err;
 893     mparam->param_name = tmpname;
 894     mparam->param_value = tmpval;
 895     if (!sk_MIME_PARAM_push(mhdr->params, mparam))
 896         goto err;
 897     return 1;
 898  err:
 899     OPENSSL_free(tmpname);
 900     OPENSSL_free(tmpval);
 901     OPENSSL_free(mparam);
 902     return 0;
 903 }
 904
 905 static int mime_hdr_cmp(const MIME_HEADER *const *a,
 906                         const MIME_HEADER *const *b)
 907 {
 908     if ((*a)->name == NULL || (*b)->name == NULL)
 909         return ((*a)->name != NULL) - ((*b)->name != NULL);
 910
 911     return strcmp((*a)->name, (*b)->name);
 912 }
 913
 914 static int mime_param_cmp(const MIME_PARAM *const *a,
 915                           const MIME_PARAM *const *b)
 916 {
 917     if ((*a)->param_name == NULL || (*b)->param_name == NULL)
 918         return ((*a)->param_name != NULL) - ((*b)->param_name != NULL);
 919     return strcmp((*a)->param_name, (*b)->param_name);
 920 }
 921
 922 /* Find a header with a given name (if possible) */
 923
 924 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, const char *name)
 925 {
 926     MIME_HEADER htmp;
 927     int idx;
 928
 929     htmp.name = (char *)name;
 930     htmp.value = NULL;
 931     htmp.params = NULL;
 932
 933     idx = sk_MIME_HEADER_find(hdrs, &htmp);
 934     return sk_MIME_HEADER_value(hdrs, idx);
 935 }
 936
 937 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, const char *name)
 938 {
 939     MIME_PARAM param;
 940     int idx;
 941
 942     param.param_name = (char *)name;
 943     param.param_value = NULL;
 944     idx = sk_MIME_PARAM_find(hdr->params, &param);
 945     return sk_MIME_PARAM_value(hdr->params, idx);
 946 }
 947
 948 static void mime_hdr_free(MIME_HEADER *hdr)
 949 {
 950     if (hdr == NULL)
 951         return;
 952     OPENSSL_free(hdr->name);
 953     OPENSSL_free(hdr->value);
 954     if (hdr->params)
 955         sk_MIME_PARAM_pop_free(hdr->params, mime_param_free);
 956     OPENSSL_free(hdr);
 957 }
 958
 959 static void mime_param_free(MIME_PARAM *param)
 960 {
 961     OPENSSL_free(param->param_name);
 962     OPENSSL_free(param->param_value);
 963     OPENSSL_free(param);
 964 }
 965
 966 /*-
 967  * Check for a multipart boundary. Returns:
 968  * 0 : no boundary
 969  * 1 : part boundary
 970  * 2 : final boundary
 971  */
 972 static int mime_bound_check(char *line, int linelen, const char *bound, int blen)
 973 {
 974     if (linelen == -1)
 975         linelen = strlen(line);
 976     if (blen == -1)
 977         blen = strlen(bound);
 978     /* Quickly eliminate if line length too short */
 979     if (blen + 2 > linelen)
 980         return 0;
 981     /* Check for part boundary */
 982     if ((CHECK_AND_SKIP_PREFIX(line, "--")) && strncmp(line, bound, blen) == 0)
 983         return HAS_PREFIX(line + blen, "--") ? 2 : 1;
 984     return 0;
 985 }
 986
 987 static int strip_eol(char *linebuf, int *plen, int flags)
 988 {
 989     int len = *plen;
 990     char *p, c;
 991     int is_eol = 0;
 992
 993 #ifndef OPENSSL_NO_CMS
 994     if ((flags & CMS_BINARY) != 0) {
 995         if (len <= 0 || linebuf[len - 1] != '\n')
 996             return 0;
 997         if ((flags & SMIME_CRLFEOL) != 0) {
 998             if (len <= 1 || linebuf[len - 2] != '\r')
 999                 return 0;
1000             len--;
1001         }
1002         len--;
1003         *plen = len;
1004         return 1;
1005     }
1006 #endif
1007
1008     for (p = linebuf + len - 1; len > 0; len--, p--) {
1009         c = *p;
1010         if (c == '\n') {
1011             is_eol = 1;
1012         } else if (is_eol && (flags & SMIME_ASCIICRLF) != 0 && c == 32) {
1013             /* Strip trailing space on a line; 32 == ASCII for ' ' */
1014             continue;
1015         } else if (c != '\r') {
1016             break;
1017         }
1018     }
1019     *plen = len;
1020     return is_eol;
1021 }