1 /* asn_mime.c */
2 /*
3  * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
4  * project.
5  */
6 /* ====================================================================
7  * Copyright (c) 1999-2008 The OpenSSL Project.  All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  *
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in
18  *    the documentation and/or other materials provided with the
19  *    distribution.
20  *
21  * 3. All advertising materials mentioning features or use of this
22  *    software must display the following acknowledgment:
23  *    "This product includes software developed by the OpenSSL Project
24  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
25  *
26  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
27  *    endorse or promote products derived from this software without
28  *    prior written permission. For written permission, please contact
29  *    licensing@OpenSSL.org.
30  *
31  * 5. Products derived from this software may not be called "OpenSSL"
32  *    nor may "OpenSSL" appear in their names without prior written
33  *    permission of the OpenSSL Project.
34  *
35  * 6. Redistributions of any form whatsoever must retain the following
36  *    acknowledgment:
37  *    "This product includes software developed by the OpenSSL Project
38  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
39  *
40  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
41  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
43  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
44  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
47  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
49  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
50  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
51  * OF THE POSSIBILITY OF SUCH DAMAGE.
52  * ====================================================================
53  *
54  */
55 
56 #include <stdio.h>
57 #include <ctype.h>
58 #include "cryptlib.h"
59 #include <openssl/rand.h>
60 #include <openssl/x509.h>
61 #include <openssl/asn1.h>
62 #include <openssl/asn1t.h>
63 #include "asn1_locl.h"
64 
65 /*
66  * Generalised MIME like utilities for streaming ASN1. Although many have a
67  * PKCS7/CMS like flavour others are more general purpose.
68  */
69 
70 /*
71  * MIME format structures Note that all are translated to lower case apart
72  * from parameter values. Quotes are stripped off
73  */
74 
75 typedef struct {
76     char *param_name;           /* Param name e.g. "micalg" */
77     char *param_value;          /* Param value e.g. "sha1" */
78 } MIME_PARAM;
79 
80 DECLARE_STACK_OF(MIME_PARAM)
81 IMPLEMENT_STACK_OF(MIME_PARAM)
82 
83 typedef struct {
84     char *name;                 /* Name of line e.g. "content-type" */
85     char *value;                /* Value of line e.g. "text/plain" */
86     STACK_OF(MIME_PARAM) *params; /* Zero or more parameters */
87 } MIME_HEADER;
88 
89 DECLARE_STACK_OF(MIME_HEADER)
90 IMPLEMENT_STACK_OF(MIME_HEADER)
91 
92 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
93                             const ASN1_ITEM *it);
94 static char *strip_ends(char *name);
95 static char *strip_start(char *name);
96 static char *strip_end(char *name);
97 static MIME_HEADER *mime_hdr_new(char *name, char *value);
98 static int mime_hdr_addparam(MIME_HEADER *mhdr, char *name, char *value);
99 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio);
100 static int mime_hdr_cmp(const MIME_HEADER *const *a,
101                         const MIME_HEADER *const *b);
102 static int mime_param_cmp(const MIME_PARAM *const *a,
103                           const MIME_PARAM *const *b);
104 static void mime_param_free(MIME_PARAM *param);
105 static int mime_bound_check(char *line, int linelen, char *bound, int blen);
106 static int multi_split(BIO *bio, char *bound, STACK_OF(BIO) **ret);
107 static int strip_eol(char *linebuf, int *plen);
108 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, char *name);
109 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, char *name);
110 static void mime_hdr_free(MIME_HEADER *hdr);
111 
112 #define MAX_SMLEN 1024
113 #define mime_debug(x)           /* x */
114 
115 /* Output an ASN1 structure in BER format streaming if necessary */
116 
i2d_ASN1_bio_stream(BIO * out,ASN1_VALUE * val,BIO * in,int flags,const ASN1_ITEM * it)117 int i2d_ASN1_bio_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
118                         const ASN1_ITEM *it)
119 {
120     /* If streaming create stream BIO and copy all content through it */
121     if (flags & SMIME_STREAM) {
122         BIO *bio, *tbio;
123         bio = BIO_new_NDEF(out, val, it);
124         if (!bio) {
125             ASN1err(ASN1_F_I2D_ASN1_BIO_STREAM, ERR_R_MALLOC_FAILURE);
126             return 0;
127         }
128         SMIME_crlf_copy(in, bio, flags);
129         (void)BIO_flush(bio);
130         /* Free up successive BIOs until we hit the old output BIO */
131         do {
132             tbio = BIO_pop(bio);
133             BIO_free(bio);
134             bio = tbio;
135         } while (bio != out);
136     }
137     /*
138      * else just write out ASN1 structure which will have all content stored
139      * internally
140      */
141     else
142         ASN1_item_i2d_bio(it, out, val);
143     return 1;
144 }
145 
146 /* Base 64 read and write of ASN1 structure */
147 
B64_write_ASN1(BIO * out,ASN1_VALUE * val,BIO * in,int flags,const ASN1_ITEM * it)148 static int B64_write_ASN1(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
149                           const ASN1_ITEM *it)
150 {
151     BIO *b64;
152     int r;
153     b64 = BIO_new(BIO_f_base64());
154     if (!b64) {
155         ASN1err(ASN1_F_B64_WRITE_ASN1, ERR_R_MALLOC_FAILURE);
156         return 0;
157     }
158     /*
159      * prepend the b64 BIO so all data is base64 encoded.
160      */
161     out = BIO_push(b64, out);
162     r = i2d_ASN1_bio_stream(out, val, in, flags, it);
163     (void)BIO_flush(out);
164     BIO_pop(out);
165     BIO_free(b64);
166     return r;
167 }
168 
169 /* Streaming ASN1 PEM write */
170 
PEM_write_bio_ASN1_stream(BIO * out,ASN1_VALUE * val,BIO * in,int flags,const char * hdr,const ASN1_ITEM * it)171 int PEM_write_bio_ASN1_stream(BIO *out, ASN1_VALUE *val, BIO *in, int flags,
172                               const char *hdr, const ASN1_ITEM *it)
173 {
174     int r;
175     BIO_printf(out, "-----BEGIN %s-----\n", hdr);
176     r = B64_write_ASN1(out, val, in, flags, it);
177     BIO_printf(out, "-----END %s-----\n", hdr);
178     return r;
179 }
180 
b64_read_asn1(BIO * bio,const ASN1_ITEM * it)181 static ASN1_VALUE *b64_read_asn1(BIO *bio, const ASN1_ITEM *it)
182 {
183     BIO *b64;
184     ASN1_VALUE *val;
185     if (!(b64 = BIO_new(BIO_f_base64()))) {
186         ASN1err(ASN1_F_B64_READ_ASN1, ERR_R_MALLOC_FAILURE);
187         return 0;
188     }
189     bio = BIO_push(b64, bio);
190     val = ASN1_item_d2i_bio(it, bio, NULL);
191     if (!val)
192         ASN1err(ASN1_F_B64_READ_ASN1, ASN1_R_DECODE_ERROR);
193     (void)BIO_flush(bio);
194     bio = BIO_pop(bio);
195     BIO_free(b64);
196     return val;
197 }
198 
199 /* Generate the MIME "micalg" parameter from RFC3851, RFC4490 */
200 
asn1_write_micalg(BIO * out,STACK_OF (X509_ALGOR)* mdalgs)201 static int asn1_write_micalg(BIO *out, STACK_OF(X509_ALGOR) *mdalgs)
202 {
203     const EVP_MD *md;
204     int i, have_unknown = 0, write_comma, ret = 0, md_nid;
205     have_unknown = 0;
206     write_comma = 0;
207     for (i = 0; i < sk_X509_ALGOR_num(mdalgs); i++) {
208         if (write_comma)
209             BIO_write(out, ",", 1);
210         write_comma = 1;
211         md_nid = OBJ_obj2nid(sk_X509_ALGOR_value(mdalgs, i)->algorithm);
212         md = EVP_get_digestbynid(md_nid);
213         if (md && md->md_ctrl) {
214             int rv;
215             char *micstr;
216             rv = md->md_ctrl(NULL, EVP_MD_CTRL_MICALG, 0, &micstr);
217             if (rv > 0) {
218                 BIO_puts(out, micstr);
219                 OPENSSL_free(micstr);
220                 continue;
221             }
222             if (rv != -2)
223                 goto err;
224         }
225         switch (md_nid) {
226         case NID_sha1:
227             BIO_puts(out, "sha1");
228             break;
229 
230         case NID_md5:
231             BIO_puts(out, "md5");
232             break;
233 
234         case NID_sha256:
235             BIO_puts(out, "sha-256");
236             break;
237 
238         case NID_sha384:
239             BIO_puts(out, "sha-384");
240             break;
241 
242         case NID_sha512:
243             BIO_puts(out, "sha-512");
244             break;
245 
246         case NID_id_GostR3411_94:
247             BIO_puts(out, "gostr3411-94");
248             goto err;
249             break;
250 
251         default:
252             if (have_unknown)
253                 write_comma = 0;
254             else {
255                 BIO_puts(out, "unknown");
256                 have_unknown = 1;
257             }
258             break;
259 
260         }
261     }
262 
263     ret = 1;
264  err:
265 
266     return ret;
267 
268 }
269 
270 /* SMIME sender */
271 
SMIME_write_ASN1(BIO * bio,ASN1_VALUE * val,BIO * data,int flags,int ctype_nid,int econt_nid,STACK_OF (X509_ALGOR)* mdalgs,const ASN1_ITEM * it)272 int SMIME_write_ASN1(BIO *bio, ASN1_VALUE *val, BIO *data, int flags,
273                      int ctype_nid, int econt_nid,
274                      STACK_OF(X509_ALGOR) *mdalgs, const ASN1_ITEM *it)
275 {
276     char bound[33], c;
277     int i;
278     const char *mime_prefix, *mime_eol, *cname = "smime.p7m";
279     const char *msg_type = NULL;
280     if (flags & SMIME_OLDMIME)
281         mime_prefix = "application/x-pkcs7-";
282     else
283         mime_prefix = "application/pkcs7-";
284 
285     if (flags & SMIME_CRLFEOL)
286         mime_eol = "\r\n";
287     else
288         mime_eol = "\n";
289     if ((flags & SMIME_DETACHED) && data) {
290         /* We want multipart/signed */
291         /* Generate a random boundary */
292         if (RAND_pseudo_bytes((unsigned char *)bound, 32) < 0)
293             return 0;
294         for (i = 0; i < 32; i++) {
295             c = bound[i] & 0xf;
296             if (c < 10)
297                 c += '0';
298             else
299                 c += 'A' - 10;
300             bound[i] = c;
301         }
302         bound[32] = 0;
303         BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
304         BIO_printf(bio, "Content-Type: multipart/signed;");
305         BIO_printf(bio, " protocol=\"%ssignature\";", mime_prefix);
306         BIO_puts(bio, " micalg=\"");
307         asn1_write_micalg(bio, mdalgs);
308         BIO_printf(bio, "\"; boundary=\"----%s\"%s%s",
309                    bound, mime_eol, mime_eol);
310         BIO_printf(bio, "This is an S/MIME signed message%s%s",
311                    mime_eol, mime_eol);
312         /* Now write out the first part */
313         BIO_printf(bio, "------%s%s", bound, mime_eol);
314         if (!asn1_output_data(bio, data, val, flags, it))
315             return 0;
316         BIO_printf(bio, "%s------%s%s", mime_eol, bound, mime_eol);
317 
318         /* Headers for signature */
319 
320         BIO_printf(bio, "Content-Type: %ssignature;", mime_prefix);
321         BIO_printf(bio, " name=\"smime.p7s\"%s", mime_eol);
322         BIO_printf(bio, "Content-Transfer-Encoding: base64%s", mime_eol);
323         BIO_printf(bio, "Content-Disposition: attachment;");
324         BIO_printf(bio, " filename=\"smime.p7s\"%s%s", mime_eol, mime_eol);
325         B64_write_ASN1(bio, val, NULL, 0, it);
326         BIO_printf(bio, "%s------%s--%s%s", mime_eol, bound,
327                    mime_eol, mime_eol);
328         return 1;
329     }
330 
331     /* Determine smime-type header */
332 
333     if (ctype_nid == NID_pkcs7_enveloped)
334         msg_type = "enveloped-data";
335     else if (ctype_nid == NID_pkcs7_signed) {
336         if (econt_nid == NID_id_smime_ct_receipt)
337             msg_type = "signed-receipt";
338         else if (sk_X509_ALGOR_num(mdalgs) >= 0)
339             msg_type = "signed-data";
340         else
341             msg_type = "certs-only";
342     } else if (ctype_nid == NID_id_smime_ct_compressedData) {
343         msg_type = "compressed-data";
344         cname = "smime.p7z";
345     }
346     /* MIME headers */
347     BIO_printf(bio, "MIME-Version: 1.0%s", mime_eol);
348     BIO_printf(bio, "Content-Disposition: attachment;");
349     BIO_printf(bio, " filename=\"%s\"%s", cname, mime_eol);
350     BIO_printf(bio, "Content-Type: %smime;", mime_prefix);
351     if (msg_type)
352         BIO_printf(bio, " smime-type=%s;", msg_type);
353     BIO_printf(bio, " name=\"%s\"%s", cname, mime_eol);
354     BIO_printf(bio, "Content-Transfer-Encoding: base64%s%s",
355                mime_eol, mime_eol);
356     if (!B64_write_ASN1(bio, val, data, flags, it))
357         return 0;
358     BIO_printf(bio, "%s", mime_eol);
359     return 1;
360 }
361 
362 /* Handle output of ASN1 data */
363 
asn1_output_data(BIO * out,BIO * data,ASN1_VALUE * val,int flags,const ASN1_ITEM * it)364 static int asn1_output_data(BIO *out, BIO *data, ASN1_VALUE *val, int flags,
365                             const ASN1_ITEM *it)
366 {
367     BIO *tmpbio;
368     const ASN1_AUX *aux = it->funcs;
369     ASN1_STREAM_ARG sarg;
370     int rv = 1;
371 
372     /*
373      * If data is not deteched or resigning then the output BIO is already
374      * set up to finalise when it is written through.
375      */
376     if (!(flags & SMIME_DETACHED) || (flags & PKCS7_REUSE_DIGEST)) {
377         SMIME_crlf_copy(data, out, flags);
378         return 1;
379     }
380 
381     if (!aux || !aux->asn1_cb) {
382         ASN1err(ASN1_F_ASN1_OUTPUT_DATA, ASN1_R_STREAMING_NOT_SUPPORTED);
383         return 0;
384     }
385 
386     sarg.out = out;
387     sarg.ndef_bio = NULL;
388     sarg.boundary = NULL;
389 
390     /* Let ASN1 code prepend any needed BIOs */
391 
392     if (aux->asn1_cb(ASN1_OP_DETACHED_PRE, &val, it, &sarg) <= 0)
393         return 0;
394 
395     /* Copy data across, passing through filter BIOs for processing */
396     SMIME_crlf_copy(data, sarg.ndef_bio, flags);
397 
398     /* Finalize structure */
399     if (aux->asn1_cb(ASN1_OP_DETACHED_POST, &val, it, &sarg) <= 0)
400         rv = 0;
401 
402     /* Now remove any digests prepended to the BIO */
403 
404     while (sarg.ndef_bio != out) {
405         tmpbio = BIO_pop(sarg.ndef_bio);
406         BIO_free(sarg.ndef_bio);
407         sarg.ndef_bio = tmpbio;
408     }
409 
410     return rv;
411 
412 }
413 
414 /*
415  * SMIME reader: handle multipart/signed and opaque signing. in multipart
416  * case the content is placed in a memory BIO pointed to by "bcont". In
417  * opaque this is set to NULL
418  */
419 
SMIME_read_ASN1(BIO * bio,BIO ** bcont,const ASN1_ITEM * it)420 ASN1_VALUE *SMIME_read_ASN1(BIO *bio, BIO **bcont, const ASN1_ITEM *it)
421 {
422     BIO *asnin;
423     STACK_OF(MIME_HEADER) *headers = NULL;
424     STACK_OF(BIO) *parts = NULL;
425     MIME_HEADER *hdr;
426     MIME_PARAM *prm;
427     ASN1_VALUE *val;
428     int ret;
429 
430     if (bcont)
431         *bcont = NULL;
432 
433     if (!(headers = mime_parse_hdr(bio))) {
434         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_PARSE_ERROR);
435         return NULL;
436     }
437 
438     if (!(hdr = mime_hdr_find(headers, "content-type")) || !hdr->value) {
439         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
440         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_CONTENT_TYPE);
441         return NULL;
442     }
443 
444     /* Handle multipart/signed */
445 
446     if (!strcmp(hdr->value, "multipart/signed")) {
447         /* Split into two parts */
448         prm = mime_param_find(hdr, "boundary");
449         if (!prm || !prm->param_value) {
450             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
451             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BOUNDARY);
452             return NULL;
453         }
454         ret = multi_split(bio, prm->param_value, &parts);
455         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
456         if (!ret || (sk_BIO_num(parts) != 2)) {
457             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_MULTIPART_BODY_FAILURE);
458             sk_BIO_pop_free(parts, BIO_vfree);
459             return NULL;
460         }
461 
462         /* Parse the signature piece */
463         asnin = sk_BIO_value(parts, 1);
464 
465         if (!(headers = mime_parse_hdr(asnin))) {
466             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_MIME_SIG_PARSE_ERROR);
467             sk_BIO_pop_free(parts, BIO_vfree);
468             return NULL;
469         }
470 
471         /* Get content type */
472 
473         if (!(hdr = mime_hdr_find(headers, "content-type")) || !hdr->value) {
474             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
475             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_NO_SIG_CONTENT_TYPE);
476             return NULL;
477         }
478 
479         if (strcmp(hdr->value, "application/x-pkcs7-signature") &&
480             strcmp(hdr->value, "application/pkcs7-signature")) {
481             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_SIG_INVALID_MIME_TYPE);
482             ERR_add_error_data(2, "type: ", hdr->value);
483             sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
484             sk_BIO_pop_free(parts, BIO_vfree);
485             return NULL;
486         }
487         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
488         /* Read in ASN1 */
489         if (!(val = b64_read_asn1(asnin, it))) {
490             ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_SIG_PARSE_ERROR);
491             sk_BIO_pop_free(parts, BIO_vfree);
492             return NULL;
493         }
494 
495         if (bcont) {
496             *bcont = sk_BIO_value(parts, 0);
497             BIO_free(asnin);
498             sk_BIO_free(parts);
499         } else
500             sk_BIO_pop_free(parts, BIO_vfree);
501         return val;
502     }
503 
504     /* OK, if not multipart/signed try opaque signature */
505 
506     if (strcmp(hdr->value, "application/x-pkcs7-mime") &&
507         strcmp(hdr->value, "application/pkcs7-mime")) {
508         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_INVALID_MIME_TYPE);
509         ERR_add_error_data(2, "type: ", hdr->value);
510         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
511         return NULL;
512     }
513 
514     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
515 
516     if (!(val = b64_read_asn1(bio, it))) {
517         ASN1err(ASN1_F_SMIME_READ_ASN1, ASN1_R_ASN1_PARSE_ERROR);
518         return NULL;
519     }
520     return val;
521 
522 }
523 
524 /* Copy text from one BIO to another making the output CRLF at EOL */
SMIME_crlf_copy(BIO * in,BIO * out,int flags)525 int SMIME_crlf_copy(BIO *in, BIO *out, int flags)
526 {
527     BIO *bf;
528     char eol;
529     int len;
530     char linebuf[MAX_SMLEN];
531     /*
532      * Buffer output so we don't write one line at a time. This is useful
533      * when streaming as we don't end up with one OCTET STRING per line.
534      */
535     bf = BIO_new(BIO_f_buffer());
536     if (!bf)
537         return 0;
538     out = BIO_push(bf, out);
539     if (flags & SMIME_BINARY) {
540         while ((len = BIO_read(in, linebuf, MAX_SMLEN)) > 0)
541             BIO_write(out, linebuf, len);
542     } else {
543         if (flags & SMIME_TEXT)
544             BIO_printf(out, "Content-Type: text/plain\r\n\r\n");
545         while ((len = BIO_gets(in, linebuf, MAX_SMLEN)) > 0) {
546             eol = strip_eol(linebuf, &len);
547             if (len)
548                 BIO_write(out, linebuf, len);
549             if (eol)
550                 BIO_write(out, "\r\n", 2);
551         }
552     }
553     (void)BIO_flush(out);
554     BIO_pop(out);
555     BIO_free(bf);
556     return 1;
557 }
558 
559 /* Strip off headers if they are text/plain */
SMIME_text(BIO * in,BIO * out)560 int SMIME_text(BIO *in, BIO *out)
561 {
562     char iobuf[4096];
563     int len;
564     STACK_OF(MIME_HEADER) *headers;
565     MIME_HEADER *hdr;
566 
567     if (!(headers = mime_parse_hdr(in))) {
568         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_PARSE_ERROR);
569         return 0;
570     }
571     if (!(hdr = mime_hdr_find(headers, "content-type")) || !hdr->value) {
572         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_MIME_NO_CONTENT_TYPE);
573         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
574         return 0;
575     }
576     if (strcmp(hdr->value, "text/plain")) {
577         ASN1err(ASN1_F_SMIME_TEXT, ASN1_R_INVALID_MIME_TYPE);
578         ERR_add_error_data(2, "type: ", hdr->value);
579         sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
580         return 0;
581     }
582     sk_MIME_HEADER_pop_free(headers, mime_hdr_free);
583     while ((len = BIO_read(in, iobuf, sizeof(iobuf))) > 0)
584         BIO_write(out, iobuf, len);
585     if (len < 0)
586         return 0;
587     return 1;
588 }
589 
590 /*
591  * Split a multipart/XXX message body into component parts: result is
592  * canonical parts in a STACK of bios
593  */
594 
multi_split(BIO * bio,char * bound,STACK_OF (BIO)** ret)595 static int multi_split(BIO *bio, char *bound, STACK_OF(BIO) **ret)
596 {
597     char linebuf[MAX_SMLEN];
598     int len, blen;
599     int eol = 0, next_eol = 0;
600     BIO *bpart = NULL;
601     STACK_OF(BIO) *parts;
602     char state, part, first;
603 
604     blen = strlen(bound);
605     part = 0;
606     state = 0;
607     first = 1;
608     parts = sk_BIO_new_null();
609     *ret = parts;
610     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
611         state = mime_bound_check(linebuf, len, bound, blen);
612         if (state == 1) {
613             first = 1;
614             part++;
615         } else if (state == 2) {
616             sk_BIO_push(parts, bpart);
617             return 1;
618         } else if (part) {
619             /* Strip CR+LF from linebuf */
620             next_eol = strip_eol(linebuf, &len);
621             if (first) {
622                 first = 0;
623                 if (bpart)
624                     sk_BIO_push(parts, bpart);
625                 bpart = BIO_new(BIO_s_mem());
626                 BIO_set_mem_eof_return(bpart, 0);
627             } else if (eol)
628                 BIO_write(bpart, "\r\n", 2);
629             eol = next_eol;
630             if (len)
631                 BIO_write(bpart, linebuf, len);
632         }
633     }
634     return 0;
635 }
636 
637 /* This is the big one: parse MIME header lines up to message body */
638 
639 #define MIME_INVALID    0
640 #define MIME_START      1
641 #define MIME_TYPE       2
642 #define MIME_NAME       3
643 #define MIME_VALUE      4
644 #define MIME_QUOTE      5
645 #define MIME_COMMENT    6
646 
STACK_OF(MIME_HEADER)647 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio)
648 {
649     char *p, *q, c;
650     char *ntmp;
651     char linebuf[MAX_SMLEN];
652     MIME_HEADER *mhdr = NULL;
653     STACK_OF(MIME_HEADER) *headers;
654     int len, state, save_state = 0;
655 
656     headers = sk_MIME_HEADER_new(mime_hdr_cmp);
657     if (!headers)
658         return NULL;
659     while ((len = BIO_gets(bio, linebuf, MAX_SMLEN)) > 0) {
660         /* If whitespace at line start then continuation line */
661         if (mhdr && isspace((unsigned char)linebuf[0]))
662             state = MIME_NAME;
663         else
664             state = MIME_START;
665         ntmp = NULL;
666         /* Go through all characters */
667         for (p = linebuf, q = linebuf; (c = *p) && (c != '\r') && (c != '\n');
668              p++) {
669 
670             /*
671              * State machine to handle MIME headers if this looks horrible
672              * that's because it *is*
673              */
674 
675             switch (state) {
676             case MIME_START:
677                 if (c == ':') {
678                     state = MIME_TYPE;
679                     *p = 0;
680                     ntmp = strip_ends(q);
681                     q = p + 1;
682                 }
683                 break;
684 
685             case MIME_TYPE:
686                 if (c == ';') {
687                     mime_debug("Found End Value\n");
688                     *p = 0;
689                     mhdr = mime_hdr_new(ntmp, strip_ends(q));
690                     sk_MIME_HEADER_push(headers, mhdr);
691                     ntmp = NULL;
692                     q = p + 1;
693                     state = MIME_NAME;
694                 } else if (c == '(') {
695                     save_state = state;
696                     state = MIME_COMMENT;
697                 }
698                 break;
699 
700             case MIME_COMMENT:
701                 if (c == ')') {
702                     state = save_state;
703                 }
704                 break;
705 
706             case MIME_NAME:
707                 if (c == '=') {
708                     state = MIME_VALUE;
709                     *p = 0;
710                     ntmp = strip_ends(q);
711                     q = p + 1;
712                 }
713                 break;
714 
715             case MIME_VALUE:
716                 if (c == ';') {
717                     state = MIME_NAME;
718                     *p = 0;
719                     mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
720                     ntmp = NULL;
721                     q = p + 1;
722                 } else if (c == '"') {
723                     mime_debug("Found Quote\n");
724                     state = MIME_QUOTE;
725                 } else if (c == '(') {
726                     save_state = state;
727                     state = MIME_COMMENT;
728                 }
729                 break;
730 
731             case MIME_QUOTE:
732                 if (c == '"') {
733                     mime_debug("Found Match Quote\n");
734                     state = MIME_VALUE;
735                 }
736                 break;
737             }
738         }
739 
740         if (state == MIME_TYPE) {
741             mhdr = mime_hdr_new(ntmp, strip_ends(q));
742             sk_MIME_HEADER_push(headers, mhdr);
743         } else if (state == MIME_VALUE)
744             mime_hdr_addparam(mhdr, ntmp, strip_ends(q));
745         if (p == linebuf)
746             break;              /* Blank line means end of headers */
747     }
748 
749     return headers;
750 
751 }
752 
strip_ends(char * name)753 static char *strip_ends(char *name)
754 {
755     return strip_end(strip_start(name));
756 }
757 
758 /* Strip a parameter of whitespace from start of param */
strip_start(char * name)759 static char *strip_start(char *name)
760 {
761     char *p, c;
762     /* Look for first non white space or quote */
763     for (p = name; (c = *p); p++) {
764         if (c == '"') {
765             /* Next char is start of string if non null */
766             if (p[1])
767                 return p + 1;
768             /* Else null string */
769             return NULL;
770         }
771         if (!isspace((unsigned char)c))
772             return p;
773     }
774     return NULL;
775 }
776 
777 /* As above but strip from end of string : maybe should handle brackets? */
strip_end(char * name)778 static char *strip_end(char *name)
779 {
780     char *p, c;
781     if (!name)
782         return NULL;
783     /* Look for first non white space or quote */
784     for (p = name + strlen(name) - 1; p >= name; p--) {
785         c = *p;
786         if (c == '"') {
787             if (p - 1 == name)
788                 return NULL;
789             *p = 0;
790             return name;
791         }
792         if (isspace((unsigned char)c))
793             *p = 0;
794         else
795             return name;
796     }
797     return NULL;
798 }
799 
mime_hdr_new(char * name,char * value)800 static MIME_HEADER *mime_hdr_new(char *name, char *value)
801 {
802     MIME_HEADER *mhdr;
803     char *tmpname, *tmpval, *p;
804     int c;
805     if (name) {
806         if (!(tmpname = BUF_strdup(name)))
807             return NULL;
808         for (p = tmpname; *p; p++) {
809             c = (unsigned char)*p;
810             if (isupper(c)) {
811                 c = tolower(c);
812                 *p = c;
813             }
814         }
815     } else
816         tmpname = NULL;
817     if (value) {
818         if (!(tmpval = BUF_strdup(value)))
819             return NULL;
820         for (p = tmpval; *p; p++) {
821             c = (unsigned char)*p;
822             if (isupper(c)) {
823                 c = tolower(c);
824                 *p = c;
825             }
826         }
827     } else
828         tmpval = NULL;
829     mhdr = (MIME_HEADER *)OPENSSL_malloc(sizeof(MIME_HEADER));
830     if (!mhdr)
831         return NULL;
832     mhdr->name = tmpname;
833     mhdr->value = tmpval;
834     if (!(mhdr->params = sk_MIME_PARAM_new(mime_param_cmp)))
835         return NULL;
836     return mhdr;
837 }
838 
mime_hdr_addparam(MIME_HEADER * mhdr,char * name,char * value)839 static int mime_hdr_addparam(MIME_HEADER *mhdr, char *name, char *value)
840 {
841     char *tmpname, *tmpval, *p;
842     int c;
843     MIME_PARAM *mparam;
844     if (name) {
845         tmpname = BUF_strdup(name);
846         if (!tmpname)
847             return 0;
848         for (p = tmpname; *p; p++) {
849             c = (unsigned char)*p;
850             if (isupper(c)) {
851                 c = tolower(c);
852                 *p = c;
853             }
854         }
855     } else
856         tmpname = NULL;
857     if (value) {
858         tmpval = BUF_strdup(value);
859         if (!tmpval)
860             return 0;
861     } else
862         tmpval = NULL;
863     /* Parameter values are case sensitive so leave as is */
864     mparam = (MIME_PARAM *)OPENSSL_malloc(sizeof(MIME_PARAM));
865     if (!mparam)
866         return 0;
867     mparam->param_name = tmpname;
868     mparam->param_value = tmpval;
869     sk_MIME_PARAM_push(mhdr->params, mparam);
870     return 1;
871 }
872 
mime_hdr_cmp(const MIME_HEADER * const * a,const MIME_HEADER * const * b)873 static int mime_hdr_cmp(const MIME_HEADER *const *a,
874                         const MIME_HEADER *const *b)
875 {
876     if (!(*a)->name || !(*b)->name)
877         return ! !(*a)->name - ! !(*b)->name;
878 
879     return (strcmp((*a)->name, (*b)->name));
880 }
881 
mime_param_cmp(const MIME_PARAM * const * a,const MIME_PARAM * const * b)882 static int mime_param_cmp(const MIME_PARAM *const *a,
883                           const MIME_PARAM *const *b)
884 {
885     if (!(*a)->param_name || !(*b)->param_name)
886         return ! !(*a)->param_name - ! !(*b)->param_name;
887     return (strcmp((*a)->param_name, (*b)->param_name));
888 }
889 
890 /* Find a header with a given name (if possible) */
891 
mime_hdr_find(STACK_OF (MIME_HEADER)* hdrs,char * name)892 static MIME_HEADER *mime_hdr_find(STACK_OF(MIME_HEADER) *hdrs, char *name)
893 {
894     MIME_HEADER htmp;
895     int idx;
896     htmp.name = name;
897     idx = sk_MIME_HEADER_find(hdrs, &htmp);
898     if (idx < 0)
899         return NULL;
900     return sk_MIME_HEADER_value(hdrs, idx);
901 }
902 
mime_param_find(MIME_HEADER * hdr,char * name)903 static MIME_PARAM *mime_param_find(MIME_HEADER *hdr, char *name)
904 {
905     MIME_PARAM param;
906     int idx;
907     param.param_name = name;
908     idx = sk_MIME_PARAM_find(hdr->params, &param);
909     if (idx < 0)
910         return NULL;
911     return sk_MIME_PARAM_value(hdr->params, idx);
912 }
913 
mime_hdr_free(MIME_HEADER * hdr)914 static void mime_hdr_free(MIME_HEADER *hdr)
915 {
916     if (hdr->name)
917         OPENSSL_free(hdr->name);
918     if (hdr->value)
919         OPENSSL_free(hdr->value);
920     if (hdr->params)
921         sk_MIME_PARAM_pop_free(hdr->params, mime_param_free);
922     OPENSSL_free(hdr);
923 }
924 
mime_param_free(MIME_PARAM * param)925 static void mime_param_free(MIME_PARAM *param)
926 {
927     if (param->param_name)
928         OPENSSL_free(param->param_name);
929     if (param->param_value)
930         OPENSSL_free(param->param_value);
931     OPENSSL_free(param);
932 }
933 
934 /*-
935  * Check for a multipart boundary. Returns:
936  * 0 : no boundary
937  * 1 : part boundary
938  * 2 : final boundary
939  */
mime_bound_check(char * line,int linelen,char * bound,int blen)940 static int mime_bound_check(char *line, int linelen, char *bound, int blen)
941 {
942     if (linelen == -1)
943         linelen = strlen(line);
944     if (blen == -1)
945         blen = strlen(bound);
946     /* Quickly eliminate if line length too short */
947     if (blen + 2 > linelen)
948         return 0;
949     /* Check for part boundary */
950     if (!strncmp(line, "--", 2) && !strncmp(line + 2, bound, blen)) {
951         if (!strncmp(line + blen + 2, "--", 2))
952             return 2;
953         else
954             return 1;
955     }
956     return 0;
957 }
958 
strip_eol(char * linebuf,int * plen)959 static int strip_eol(char *linebuf, int *plen)
960 {
961     int len = *plen;
962     char *p, c;
963     int is_eol = 0;
964     p = linebuf + len - 1;
965     for (p = linebuf + len - 1; len > 0; len--, p--) {
966         c = *p;
967         if (c == '\n')
968             is_eol = 1;
969         else if (c != '\r')
970             break;
971     }
972     *plen = len;
973     return is_eol;
974 }
975