crypto/asn1/asn_mime.c

   1 /*
   2  * Copyright 2008-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include "crypto/ctype.h"
  12 #include "internal/cryptlib.h"
  13 #include <openssl/rand.h>
  14 #include <openssl/x509.h>
  15 #include <openssl/asn1.h>
  16 #include <openssl/asn1t.h>
  17 #include "crypto/evp.h"
  18 #include "internal/bio.h"
  19 #include "asn1_local.h"
  20
  21 /*
  22  * Generalised MIME like utilities for streaming ASN1. Although many have a
  23  * PKCS7/CMS like flavour others are more general purpose.
  24  */
  25
  26 /*
  27  * MIME format structures Note that all are translated to lower case apart
  28  * from parameter values. Quotes are stripped off
  29  */
  30
  31 struct mime_param_st {
  32     char *param_name;           /* Param name e.g. "micalg" */
  33     char *param_value;          /* Param value e.g. "sha1" */
  34 };
  35
  36 struct mime_header_st {
  37     char *name;                 /* Name of line e.g. "content-type" */
  38     char *value;                /* Value of line e.g. "text/plain" */
  39     STACK_OF(MIME_PARAM) *params; /* Zero or more parameters */
  40 };
  41
  42 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
  43                             const ASN1_ITEM *it);
  44 static char *strip_ends(char *name);
  45 static char *strip_start(char *name);
  46 static char *strip_end(char *name);
  47 static MIME_HEADER *mime_hdr_new(const char *name, const char *value);
  48 static int mime_hdr_addparam(MIME_HEADER *mhdr, const char *name, const char *value);
  49 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio);
  50 static int mime_hdr_cmp(const MIME_HEADER *const *a,
  51                         const MIME_HEADER *const *b);
  52 static int mime_param_cmp(const MIME_PARAM *const *a,
  53                           const MIME_PARAM *const *b);
  54 static void mime_param_free(MIME_PARAM *param);
  55 static int mime_bound_check(char *line, int linelen, const char *bound, int blen);
  56 static int multi_split(BIO *bio, const char *bound, STACK_OF(BIO) **ret);
  57 static int strip_eol(char *linebuf, int *plen, int flags);
  58 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, const char *name);
  59 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, const char *name);
  60 static void mime_hdr_free(MIME_HEADER *hdr);
  61
  62 #define MAX_SMLEN 1024
  63 #define mime_debug(x)           /* x */
  64
  65 /* Output an ASN1 structure in BER format streaming if necessary */
  66
  67 /* unfortunately cannot constify this due to CMS_stream() and PKCS7_stream() */
  68 int i2d_ASN1_bio_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
  69                         const ASN1_ITEM *it)
  70 {
  71     /* If streaming create stream BIO and copy all content through it */
  72     if (flags & SMIME_STREAM) {
  73         BIO *bio, *tbio;
  74         bio = BIO_new_NDEF(out, val, it);
  75         if (!bio) {
  76             ASN1err(ASN1_F_I2D_ASN1_BIO_STREAM, ERR_R_MALLOC_FAILURE);
  77             return 0;
  78         }
  79         SMIME_crlf_copy(in, bio, flags);
  80         (void)BIO_flush(bio);
  81         /* Free up successive BIOs until we hit the old output BIO */
  82         do {
  83             tbio = BIO_pop(bio);
  84             BIO_free(bio);
  85             bio = tbio;
  86         } while (bio != out);
  87     }
  88     /*
  89      * else just write out ASN1 structure which will have all content stored
  90      * internally
  91      */
  92     else
  93         ASN1_item_i2d_bio(it, out, val);
  94     return 1;
  95 }
  96
  97 /* Base 64 read and write of ASN1 structure */
  98
  99 static int B64_write_ASN1(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
 100                           const ASN1_ITEM *it)
 101 {
 102     BIO *b64;
 103     int r;
 104     b64 = BIO_new(BIO_f_base64());
 105     if (b64 == NULL) {
 106         ASN1err(ASN1_F_B64_WRITE_ASN1, ERR_R_MALLOC_FAILURE);
 107         return 0;
 108     }
 109     /*
 110      * prepend the b64 BIO so all data is base64 encoded.
 111      */
 112     out = BIO_push(b64, out);
 113     r = i2d_ASN1_bio_stream(out, val, in, flags, it);
 114     (void)BIO_flush(out);
 115     BIO_pop(out);
 116     BIO_free(b64);
 117     return r;
 118 }
 119
 120 /* Streaming ASN1 PEM write */
 121
 122 int PEM_write_bio_ASN1_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
 123                               const char *hdr, const ASN1_ITEM *it)
 124 {
 125     int r;
 126     BIO_printf(out, "-----BEGIN %s-----\n", hdr);
 127     r = B64_write_ASN1(out, val, in, flags, it);
 128     BIO_printf(out, "-----END %s-----\n", hdr);
 129     return r;
 130 }
 131
 132 static ASN1_VALUE *b64_read_asn1(BIO *bio, const ASN1_ITEM *it)
 133 {
 134     BIO *b64;
 135     ASN1_VALUE *val;
 136
 137     if ((b64 = BIO_new(BIO_f_base64())) == NULL) {
 138         ASN1err(ASN1_F_B64_READ_ASN1, ERR_R_MALLOC_FAILURE);
 139         return 0;
 140     }
 141     bio = BIO_push(b64, bio);
 142     val = ASN1_item_d2i_bio(it, bio, NULL);
 143     if (!val)
 144         ASN1err(ASN1_F_B64_READ_ASN1, ASN1_R_DECODE_ERROR);
 145     (void)BIO_flush(bio);
 146     BIO_pop(bio);
 147     BIO_free(b64);
 148     return val;
 149 }
 150
 151 /* Generate the MIME "micalg" parameter from RFC3851, RFC4490 */
 152
 153 static int asn1_write_micalg(BIO *out, STACK_OF(X509_ALGOR) *mdalgs)
 154 {
 155     const EVP_MD *md;
 156     int i, have_unknown = 0, write_comma, ret = 0, md_nid;
 157     have_unknown = 0;
 158     write_comma = 0;
 159     for (i = 0; i < sk_X509_ALGOR_num(mdalgs); i++) {
 160         if (write_comma)
 161             BIO_write(out, ",", 1);
 162         write_comma = 1;
 163         md_nid = OBJ_obj2nid(sk_X509_ALGOR_value(mdalgs, i)->algorithm);
 164         md = EVP_get_digestbynid(md_nid);
 165         if (md && md->md_ctrl) {
 166             int rv;
 167             char *micstr;
 168             rv = md->md_ctrl(NULL, EVP_MD_CTRL_MICALG, 0, &micstr);
 169             if (rv > 0) {
 170                 BIO_puts(out, micstr);
 171                 OPENSSL_free(micstr);
 172                 continue;
 173             }
 174             if (rv != -2)
 175                 goto err;
 176         }
 177         switch (md_nid) {
 178         case NID_sha1:
 179             BIO_puts(out, "sha1");
 180             break;
 181
 182         case NID_md5:
 183             BIO_puts(out, "md5");
 184             break;
 185
 186         case NID_sha256:
 187             BIO_puts(out, "sha-256");
 188             break;
 189
 190         case NID_sha384:
 191             BIO_puts(out, "sha-384");
 192             break;
 193
 194         case NID_sha512:
 195             BIO_puts(out, "sha-512");
 196             break;
 197
 198         case NID_id_GostR3411_94:
 199             BIO_puts(out, "gostr3411-94");
 200             goto err;
 201
 202         case NID_id_GostR3411_2012_256:
 203             BIO_puts(out, "gostr3411-2012-256");
 204             goto err;
 205
 206         case NID_id_GostR3411_2012_512:
 207             BIO_puts(out, "gostr3411-2012-512");
 208             goto err;
 209
 210         default:
 211             if (have_unknown)
 212                 write_comma = 0;
 213             else {
 214                 BIO_puts(out, "unknown");
 215                 have_unknown = 1;
 216             }
 217             break;
 218
 219         }
 220     }
 221
 222     ret = 1;
 223  err:
 224
 225     return ret;
 226
 227 }
 228
 229 /* SMIME sender */
 230
 231 int SMIME_write_ASN1(BIO *bio, ASN1_VALUE *val, BIO *data, int flags,
 232                      int ctype_nid, int econt_nid,
 233                      STACK_OF(X509_ALGOR) *mdalgs, const ASN1_ITEM *it)
 234 {
 235     char bound[33], c;
 236     int i;
 237     const char *mime_prefix, *mime_eol, *cname = "smime.p7m";
 238     const char *msg_type = NULL;
 239     if (flags & SMIME_OLDMIME)
 240         mime_prefix = "application/x-pkcs7-";
 241     else
 242         mime_prefix = "application/pkcs7-";
 243
 244     if (flags & SMIME_CRLFEOL)
 245         mime_eol = "\r\n";
 246     else
 247         mime_eol = "\n";
 248     if ((flags & SMIME_DETACHED) && data) {
 249         /* We want multipart/signed */
 250         /* Generate a random boundary */
 251         if (RAND_bytes((unsigned char *)bound, 32) <= 0)
 252             return 0;
 253         for (i = 0; i < 32; i++) {
 254             c = bound[i] & 0xf;
 255             if (c < 10)
 256                 c += '0';
 257             else
 258                 c += 'A' - 10;
 259             bound[i] = c;
 260         }
 261         bound[32] = 0;
 262         BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
 263         BIO_printf(bio, "Content-Type: multipart/signed;");
 264         BIO_printf(bio, " protocol=\"%ssignature\";", mime_prefix);
 265         BIO_puts(bio, " micalg=\"");
 266         asn1_write_micalg(bio, mdalgs);
 267         BIO_printf(bio, "\"; boundary=\"----%s\"%s%s",
 268                    bound, mime_eol, mime_eol);
 269         BIO_printf(bio, "This is an S/MIME signed message%s%s",
 270                    mime_eol, mime_eol);
 271         /* Now write out the first part */
 272         BIO_printf(bio, "------%s%s", bound, mime_eol);
 273         if (!asn1_output_data(bio, data, val, flags, it))
 274             return 0;
 275         BIO_printf(bio, "%s------%s%s", mime_eol, bound, mime_eol);
 276
 277         /* Headers for signature */
 278
 279         BIO_printf(bio, "Content-Type: %ssignature;", mime_prefix);
 280         BIO_printf(bio, " name=\"smime.p7s\"%s", mime_eol);
 281         BIO_printf(bio, "Content-Transfer-Encoding: base64%s", mime_eol);
 282         BIO_printf(bio, "Content-Disposition: attachment;");
 283         BIO_printf(bio, " filename=\"smime.p7s\"%s%s", mime_eol, mime_eol);
 284         B64_write_ASN1(bio, val, NULL, 0, it);
 285         BIO_printf(bio, "%s------%s--%s%s", mime_eol, bound,
 286                    mime_eol, mime_eol);
 287         return 1;
 288     }
 289
 290     /* Determine smime-type header */
 291
 292     if (ctype_nid == NID_pkcs7_enveloped)
 293         msg_type = "enveloped-data";
 294     else if (ctype_nid == NID_pkcs7_signed) {
 295         if (econt_nid == NID_id_smime_ct_receipt)
 296             msg_type = "signed-receipt";
 297         else if (sk_X509_ALGOR_num(mdalgs) >= 0)
 298             msg_type = "signed-data";
 299         else
 300             msg_type = "certs-only";
 301     } else if (ctype_nid == NID_id_smime_ct_compressedData) {
 302         msg_type = "compressed-data";
 303         cname = "smime.p7z";
 304     }
 305     /* MIME headers */
 306     BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
 307     BIO_printf(bio, "Content-Disposition: attachment;");
 308     BIO_printf(bio, " filename=\"%s\"%s", cname, mime_eol);
 309     BIO_printf(bio, "Content-Type: %smime;", mime_prefix);
 310     if (msg_type)
 311         BIO_printf(bio, " smime-type=%s;", msg_type);
 312     BIO_printf(bio, " name=\"%s\"%s", cname, mime_eol);
 313     BIO_printf(bio, "Content-Transfer-Encoding: base64%s%s",
 314                mime_eol, mime_eol);
 315     if (!B64_write_ASN1(bio, val, data, flags, it))
 316         return 0;
 317     BIO_printf(bio, "%s", mime_eol);
 318     return 1;
 319 }
 320
 321 /* Handle output of ASN1 data */
 322
 323 /* cannot constify val because of CMS_dataFinal() */
 324 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
 325                             const ASN1_ITEM *it)
 326 {
 327     BIO *tmpbio;
 328     const ASN1_AUX *aux = it->funcs;
 329     ASN1_STREAM_ARG sarg;
 330     int rv = 1;
 331
 332     /*
 333      * If data is not detached or resigning then the output BIO is already
 334      * set up to finalise when it is written through.
 335      */
 336     if (!(flags & SMIME_DETACHED) || (flags & PKCS7_REUSE_DIGEST)) {
 337         SMIME_crlf_copy(data, out, flags);
 338         return 1;
 339     }
 340
 341     if (!aux || !aux->asn1_cb) {
 342         ASN1err(ASN1_F_ASN1_OUTPUT_DATA, ASN1_R_STREAMING_NOT_SUPPORTED);
 343         return 0;
 344     }
 345
 346     sarg.out = out;
 347     sarg.ndef_bio = NULL;
 348     sarg.boundary = NULL;
 349
 350     /* Let ASN1 code prepend any needed BIOs */
 351
 352     if (aux->asn1_cb(ASN1_OP_DETACHED_PRE, &val, it, &sarg) <= 0)
 353         return 0;
 354
 355     /* Copy data across, passing through filter BIOs for processing */
 356     SMIME_crlf_copy(data, sarg.ndef_bio, flags);
 357
 358     /* Finalize structure */
 359     if (aux->asn1_cb(ASN1_OP_DETACHED_POST, &val, it, &sarg) <= 0)
 360         rv = 0;
 361
 362     /* Now remove any digests prepended to the BIO */
 363
 364     while (sarg.ndef_bio != out) {
 365         tmpbio = BIO_pop(sarg.ndef_bio);
 366         BIO_free(sarg.ndef_bio);
 367         sarg.ndef_bio = tmpbio;
 368     }
 369
 370     return rv;
 371
 372 }
 373
 374 /*
 375  * SMIME reader: handle multipart/signed and opaque signing. in multipart
 376  * case the content is placed in a memory BIO pointed to by "bcont". In
 377  * opaque this is set to NULL
 378  */
 379
 380 ASN1_VALUE *SMIME_read_ASN1(BIO *bio, BIO **bcont, const ASN1_ITEM *it)
 381 {
 382     BIO *asnin;
 383     STACK_OF(MIME_HEADER) *headers = NULL;
 384     STACK_OF(BIO) *parts = NULL;
 385     MIME_HEADER *hdr;
 386     MIME_PARAM *prm;
 387     ASN1_VALUE *val;
 388     int ret;
 389
 390     if (bcont)
 391         *bcont = NULL;
 392
 393     if ((headers = mime_parse_hdr(bio)) == NULL) {
 394         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_PARSE_ERROR);
 395         return NULL;
 396     }
 397
 398     if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 399         || hdr->value == NULL) {
 400         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 401         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_CONTENT_TYPE);
 402         return NULL;
 403     }
 404
 405     /* Handle multipart/signed */
 406
 407     if (strcmp(hdr->value, "multipart/signed") == 0) {
 408         /* Split into two parts */
 409         prm = mime_param_find(hdr, "boundary");
 410         if (prm == NULL || prm->param_value == NULL) {
 411             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 412             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BOUNDARY);
 413             return NULL;
 414         }
 415         ret = multi_split(bio, prm->param_value, &parts);
 416         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 417         if (!ret || (sk_BIO_num(parts) != 2)) {
 418             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BODY_FAILURE);
 419             sk_BIO_pop_free(parts, BIO_vfree);
 420             return NULL;
 421         }
 422
 423         /* Parse the signature piece */
 424         asnin = sk_BIO_value(parts, 1);
 425
 426         if ((headers = mime_parse_hdr(asnin)) == NULL) {
 427             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_SIG_PARSE_ERROR);
 428             sk_BIO_pop_free(parts, BIO_vfree);
 429             return NULL;
 430         }
 431
 432         /* Get content type */
 433
 434         if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 435             || hdr->value == NULL) {
 436             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 437             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_SIG_CONTENT_TYPE);
 438             sk_BIO_pop_free(parts, BIO_vfree);
 439             return NULL;
 440         }
 441
 442         if (strcmp(hdr->value, "application/x-pkcs7-signature") &&
 443             strcmp(hdr->value, "application/pkcs7-signature")) {
 444             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_SIG_INVALID_MIME_TYPE);
 445             ERR_add_error_data(2, "type: ", hdr->value);
 446             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 447             sk_BIO_pop_free(parts, BIO_vfree);
 448             return NULL;
 449         }
 450         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 451         /* Read in ASN1 */
 452         if ((val = b64_read_asn1(asnin, it)) == NULL) {
 453             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_SIG_PARSE_ERROR);
 454             sk_BIO_pop_free(parts, BIO_vfree);
 455             return NULL;
 456         }
 457
 458         if (bcont) {
 459             *bcont = sk_BIO_value(parts, 0);
 460             BIO_free(asnin);
 461             sk_BIO_free(parts);
 462         } else
 463             sk_BIO_pop_free(parts, BIO_vfree);
 464         return val;
 465     }
 466
 467     /* OK, if not multipart/signed try opaque signature */
 468
 469     if (strcmp(hdr->value, "application/x-pkcs7-mime") &&
 470         strcmp(hdr->value, "application/pkcs7-mime")) {
 471         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_INVALID_MIME_TYPE);
 472         ERR_add_error_data(2, "type: ", hdr->value);
 473         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 474         return NULL;
 475     }
 476
 477     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 478
 479     if ((val = b64_read_asn1(bio, it)) == NULL) {
 480         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_PARSE_ERROR);
 481         return NULL;
 482     }
 483     return val;
 484
 485 }
 486
 487 /* Copy text from one BIO to another making the output CRLF at EOL */
 488 int SMIME_crlf_copy(BIO *in, BIO *out, int flags)
 489 {
 490     BIO *bf;
 491     char eol;
 492     int len;
 493     char linebuf[MAX_SMLEN];
 494     /*
 495      * Buffer output so we don't write one line at a time. This is useful
 496      * when streaming as we don't end up with one OCTET STRING per line.
 497      */
 498     bf = BIO_new(BIO_f_buffer());
 499     if (bf == NULL)
 500         return 0;
 501     out = BIO_push(bf, out);
 502     if (flags & SMIME_BINARY) {
 503         while ((len = BIO_read(in, linebuf, MAX_SMLEN)) > 0)
 504             BIO_write(out, linebuf, len);
 505     } else {
 506         int eolcnt = 0;
 507         if (flags & SMIME_TEXT)
 508             BIO_printf(out, "Content-Type: text/plain\r\n\r\n");
 509         while ((len = BIO_gets(in, linebuf, MAX_SMLEN)) > 0) {
 510             eol = strip_eol(linebuf, &len, flags);
 511             if (len) {
 512                 /* Not EOF: write out all CRLF */
 513                 if (flags & SMIME_ASCIICRLF) {
 514                     int i;
 515                     for (i = 0; i < eolcnt; i++)
 516                         BIO_write(out, "\r\n", 2);
 517                     eolcnt = 0;
 518                 }
 519                 BIO_write(out, linebuf, len);
 520                 if (eol)
 521                     BIO_write(out, "\r\n", 2);
 522             } else if (flags & SMIME_ASCIICRLF)
 523                 eolcnt++;
 524             else if (eol)
 525                 BIO_write(out, "\r\n", 2);
 526         }
 527     }
 528     (void)BIO_flush(out);
 529     BIO_pop(out);
 530     BIO_free(bf);
 531     return 1;
 532 }
 533
 534 /* Strip off headers if they are text/plain */
 535 int SMIME_text(BIO *in, BIO *out)
 536 {
 537     char iobuf[4096];
 538     int len;
 539     STACK_OF(MIME_HEADER) *headers;
 540     MIME_HEADER *hdr;
 541
 542     if ((headers = mime_parse_hdr(in)) == NULL) {
 543         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_PARSE_ERROR);
 544         return 0;
 545     }
 546     if ((hdr = mime_hdr_find(headers, "content-type")) == NULL
 547         || hdr->value == NULL) {
 548         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_NO_CONTENT_TYPE);
 549         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 550         return 0;
 551     }
 552     if (strcmp(hdr->value, "text/plain")) {
 553         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_INVALID_MIME_TYPE);
 554         ERR_add_error_data(2, "type: ", hdr->value);
 555         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 556         return 0;
 557     }
 558     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 559     while ((len = BIO_read(in, iobuf, sizeof(iobuf))) > 0)
 560         BIO_write(out, iobuf, len);
 561     if (len < 0)
 562         return 0;
 563     return 1;
 564 }
 565
 566 /*
 567  * Split a multipart/XXX message body into component parts: result is
 568  * canonical parts in a STACK of bios
 569  */
 570
 571 static int multi_split(BIO *bio, const char *bound, STACK_OF(BIO) **ret)
 572 {
 573     char linebuf[MAX_SMLEN];
 574     int len, blen;
 575     int eol = 0, next_eol = 0;
 576     BIO *bpart = NULL;
 577     STACK_OF(BIO) *parts;
 578     char state, part, first;
 579
 580     blen = strlen(bound);
 581     part = 0;
 582     state = 0;
 583     first = 1;
 584     parts = sk_BIO_new_null();
 585     *ret = parts;
 586     if (*ret == NULL)
 587         return 0;
 588     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
 589         state = mime_bound_check(linebuf, len, bound, blen);
 590         if (state == 1) {
 591             first = 1;
 592             part++;
 593         } else if (state == 2) {
 594             if (!sk_BIO_push(parts, bpart)) {
 595                 BIO_free(bpart);
 596                 return 0;
 597             }
 598             return 1;
 599         } else if (part) {
 600             /* Strip CR+LF from linebuf */
 601             next_eol = strip_eol(linebuf, &len, 0);
 602             if (first) {
 603                 first = 0;
 604                 if (bpart)
 605                     if (!sk_BIO_push(parts, bpart)) {
 606                         BIO_free(bpart);
 607                         return 0;
 608                     }
 609                 bpart = BIO_new(BIO_s_mem());
 610                 if (bpart == NULL)
 611                     return 0;
 612                 BIO_set_mem_eof_return(bpart, 0);
 613             } else if (eol)
 614                 BIO_write(bpart, "\r\n", 2);
 615             eol = next_eol;
 616             if (len)
 617                 BIO_write(bpart, linebuf, len);
 618         }
 619     }
 620     BIO_free(bpart);
 621     return 0;
 622 }
 623
 624 /* This is the big one: parse MIME header lines up to message body */
 625
 626 #define MIME_INVALID    0
 627 #define MIME_START      1
 628 #define MIME_TYPE       2
 629 #define MIME_NAME       3
 630 #define MIME_VALUE      4
 631 #define MIME_QUOTE      5
 632 #define MIME_COMMENT    6
 633
 634 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio)
 635 {
 636     char *p, *q, c;
 637     char *ntmp;
 638     char linebuf[MAX_SMLEN];
 639     MIME_HEADER *mhdr = NULL, *new_hdr = NULL;
 640     STACK_OF(MIME_HEADER) *headers;
 641     int len, state, save_state = 0;
 642
 643     headers = sk_MIME_HEADER_new(mime_hdr_cmp);
 644     if (headers == NULL)
 645         return NULL;
 646     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
 647         /* If whitespace at line start then continuation line */
 648         if (mhdr && ossl_isspace(linebuf[0]))
 649             state = MIME_NAME;
 650         else
 651             state = MIME_START;
 652         ntmp = NULL;
 653         /* Go through all characters */
 654         for (p = linebuf, q = linebuf; (c = *p) && (c != '\r') && (c != '\n');
 655              p++) {
 656
 657             /*
 658              * State machine to handle MIME headers if this looks horrible
 659              * that's because it *is*
 660              */
 661
 662             switch (state) {
 663             case MIME_START:
 664                 if (c == ':') {
 665                     state = MIME_TYPE;
 666                     *p = 0;
 667                     ntmp = strip_ends(q);
 668                     q = p + 1;
 669                 }
 670                 break;
 671
 672             case MIME_TYPE:
 673                 if (c == ';') {
 674                     mime_debug("Found End Value\n");
 675                     *p = 0;
 676                     new_hdr = mime_hdr_new(ntmp, strip_ends(q));
 677                     if (new_hdr == NULL)
 678                         goto err;
 679                     if (!sk_MIME_HEADER_push(headers, new_hdr))
 680                         goto err;
 681                     mhdr = new_hdr;
 682                     new_hdr = NULL;
 683                     ntmp = NULL;
 684                     q = p + 1;
 685                     state = MIME_NAME;
 686                 } else if (c == '(') {
 687                     save_state = state;
 688                     state = MIME_COMMENT;
 689                 }
 690                 break;
 691
 692             case MIME_COMMENT:
 693                 if (c == ')') {
 694                     state = save_state;
 695                 }
 696                 break;
 697
 698             case MIME_NAME:
 699                 if (c == '=') {
 700                     state = MIME_VALUE;
 701                     *p = 0;
 702                     ntmp = strip_ends(q);
 703                     q = p + 1;
 704                 }
 705                 break;
 706
 707             case MIME_VALUE:
 708                 if (c == ';') {
 709                     state = MIME_NAME;
 710                     *p = 0;
 711                     mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 712                     ntmp = NULL;
 713                     q = p + 1;
 714                 } else if (c == '"') {
 715                     mime_debug("Found Quote\n");
 716                     state = MIME_QUOTE;
 717                 } else if (c == '(') {
 718                     save_state = state;
 719                     state = MIME_COMMENT;
 720                 }
 721                 break;
 722
 723             case MIME_QUOTE:
 724                 if (c == '"') {
 725                     mime_debug("Found Match Quote\n");
 726                     state = MIME_VALUE;
 727                 }
 728                 break;
 729             }
 730         }
 731
 732         if (state == MIME_TYPE) {
 733             new_hdr = mime_hdr_new(ntmp, strip_ends(q));
 734             if (new_hdr == NULL)
 735                 goto err;
 736             if (!sk_MIME_HEADER_push(headers, new_hdr))
 737                 goto err;
 738             mhdr = new_hdr;
 739             new_hdr = NULL;
 740         } else if (state == MIME_VALUE)
 741             mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
 742         if (p == linebuf)
 743             break;              /* Blank line means end of headers */
 744     }
 745
 746     return headers;
 747
 748 err:
 749     mime_hdr_free(new_hdr);
 750     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
 751     return NULL;
 752 }
 753
 754 static char *strip_ends(char *name)
 755 {
 756     return strip_end(strip_start(name));
 757 }
 758
 759 /* Strip a parameter of whitespace from start of param */
 760 static char *strip_start(char *name)
 761 {
 762     char *p, c;
 763     /* Look for first non white space or quote */
 764     for (p = name; (c = *p); p++) {
 765         if (c == '"') {
 766             /* Next char is start of string if non null */
 767             if (p[1])
 768                 return p + 1;
 769             /* Else null string */
 770             return NULL;
 771         }
 772         if (!ossl_isspace(c))
 773             return p;
 774     }
 775     return NULL;
 776 }
 777
 778 /* As above but strip from end of string : maybe should handle brackets? */
 779 static char *strip_end(char *name)
 780 {
 781     char *p, c;
 782     if (!name)
 783         return NULL;
 784     /* Look for first non white space or quote */
 785     for (p = name + strlen(name) - 1; p >= name; p--) {
 786         c = *p;
 787         if (c == '"') {
 788             if (p - 1 == name)
 789                 return NULL;
 790             *p = 0;
 791             return name;
 792         }
 793         if (ossl_isspace(c))
 794             *p = 0;
 795         else
 796             return name;
 797     }
 798     return NULL;
 799 }
 800
 801 static MIME_HEADER *mime_hdr_new(const char *name, const char *value)
 802 {
 803     MIME_HEADER *mhdr = NULL;
 804     char *tmpname = NULL, *tmpval = NULL, *p;
 805
 806     if (name) {
 807         if ((tmpname = OPENSSL_strdup(name)) == NULL)
 808             return NULL;
 809         for (p = tmpname; *p; p++)
 810             *p = ossl_tolower(*p);
 811     }
 812     if (value) {
 813         if ((tmpval = OPENSSL_strdup(value)) == NULL)
 814             goto err;
 815         for (p = tmpval; *p; p++)
 816             *p = ossl_tolower(*p);
 817     }
 818     mhdr = OPENSSL_malloc(sizeof(*mhdr));
 819     if (mhdr == NULL)
 820         goto err;
 821     mhdr->name = tmpname;
 822     mhdr->value = tmpval;
 823     if ((mhdr->params = sk_MIME_PARAM_new(mime_param_cmp)) == NULL)
 824         goto err;
 825     return mhdr;
 826
 827  err:
 828     OPENSSL_free(tmpname);
 829     OPENSSL_free(tmpval);
 830     OPENSSL_free(mhdr);
 831     return NULL;
 832 }
 833
 834 static int mime_hdr_addparam(MIME_HEADER *mhdr, const char *name, const char *value)
 835 {
 836     char *tmpname = NULL, *tmpval = NULL, *p;
 837     MIME_PARAM *mparam = NULL;
 838
 839     if (name) {
 840         tmpname = OPENSSL_strdup(name);
 841         if (!tmpname)
 842             goto err;
 843         for (p = tmpname; *p; p++)
 844             *p = ossl_tolower(*p);
 845     }
 846     if (value) {
 847         tmpval = OPENSSL_strdup(value);
 848         if (!tmpval)
 849             goto err;
 850     }
 851     /* Parameter values are case sensitive so leave as is */
 852     mparam = OPENSSL_malloc(sizeof(*mparam));
 853     if (mparam == NULL)
 854         goto err;
 855     mparam->param_name = tmpname;
 856     mparam->param_value = tmpval;
 857     if (!sk_MIME_PARAM_push(mhdr->params, mparam))
 858         goto err;
 859     return 1;
 860  err:
 861     OPENSSL_free(tmpname);
 862     OPENSSL_free(tmpval);
 863     OPENSSL_free(mparam);
 864     return 0;
 865 }
 866
 867 static int mime_hdr_cmp(const MIME_HEADER *const *a,
 868                         const MIME_HEADER *const *b)
 869 {
 870     if (!(*a)->name || !(*b)->name)
 871         return ! !(*a)->name - ! !(*b)->name;
 872
 873     return strcmp((*a)->name, (*b)->name);
 874 }
 875
 876 static int mime_param_cmp(const MIME_PARAM *const *a,
 877                           const MIME_PARAM *const *b)
 878 {
 879     if (!(*a)->param_name || !(*b)->param_name)
 880         return ! !(*a)->param_name - ! !(*b)->param_name;
 881     return strcmp((*a)->param_name, (*b)->param_name);
 882 }
 883
 884 /* Find a header with a given name (if possible) */
 885
 886 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, const char *name)
 887 {
 888     MIME_HEADER htmp;
 889     int idx;
 890
 891     htmp.name = (char *)name;
 892     htmp.value = NULL;
 893     htmp.params = NULL;
 894
 895     idx = sk_MIME_HEADER_find(hdrs, &htmp);
 896     return sk_MIME_HEADER_value(hdrs, idx);
 897 }
 898
 899 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, const char *name)
 900 {
 901     MIME_PARAM param;
 902     int idx;
 903
 904     param.param_name = (char *)name;
 905     param.param_value = NULL;
 906     idx = sk_MIME_PARAM_find(hdr->params, &param);
 907     return sk_MIME_PARAM_value(hdr->params, idx);
 908 }
 909
 910 static void mime_hdr_free(MIME_HEADER *hdr)
 911 {
 912     if (hdr == NULL)
 913         return;
 914     OPENSSL_free(hdr->name);
 915     OPENSSL_free(hdr->value);
 916     if (hdr->params)
 917         sk_MIME_PARAM_pop_free(hdr->params, mime_param_free);
 918     OPENSSL_free(hdr);
 919 }
 920
 921 static void mime_param_free(MIME_PARAM *param)
 922 {
 923     OPENSSL_free(param->param_name);
 924     OPENSSL_free(param->param_value);
 925     OPENSSL_free(param);
 926 }
 927
 928 /*-
 929  * Check for a multipart boundary. Returns:
 930  * 0 : no boundary
 931  * 1 : part boundary
 932  * 2 : final boundary
 933  */
 934 static int mime_bound_check(char *line, int linelen, const char *bound, int blen)
 935 {
 936     if (linelen == -1)
 937         linelen = strlen(line);
 938     if (blen == -1)
 939         blen = strlen(bound);
 940     /* Quickly eliminate if line length too short */
 941     if (blen + 2 > linelen)
 942         return 0;
 943     /* Check for part boundary */
 944     if ((strncmp(line, "--", 2) == 0)
 945         && strncmp(line + 2, bound, blen) == 0) {
 946         if (strncmp(line + blen + 2, "--", 2) == 0)
 947             return 2;
 948         else
 949             return 1;
 950     }
 951     return 0;
 952 }
 953
 954 static int strip_eol(char *linebuf, int *plen, int flags)
 955 {
 956     int len = *plen;
 957     char *p, c;
 958     int is_eol = 0;
 959
 960     for (p = linebuf + len - 1; len > 0; len--, p--) {
 961         c = *p;
 962         if (c == '\n') {
 963             is_eol = 1;
 964         } else if (is_eol && flags & SMIME_ASCIICRLF && c == 32) {
 965             /* Strip trailing space on a line; 32 == ASCII for ' ' */
 966             continue;
 967         } else if (c != '\r') {
 968             break;
 969         }
 970     }
 971     *plen = len;
 972     return is_eol;
 973 }