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