1/* crypto/engine/e_gmp.c */
2/* Written by Geoff Thorpe (geoff@geoffthorpe.net) for the OpenSSL
3 * project 2003.
4 */
5/* ====================================================================
6 * Copyright (c) 1999-2001 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 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com).  This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
56 *
57 */
58
59/* This engine is not (currently) compiled in by default. Do enable it,
60 * reconfigure OpenSSL with "enable-gmp -lgmp". The GMP libraries and
61 * headers must reside in one of the paths searched by the compiler/linker,
62 * otherwise paths must be specified - eg. try configuring with
63 * "enable-gmp -I<includepath> -L<libpath> -lgmp". YMMV. */
64
65/* As for what this does - it's a largely unoptimised implementation of an
66 * ENGINE that uses the GMP library to perform RSA private key operations. To
67 * obtain more information about what "unoptimised" means, see my original mail
68 * on the subject (though ignore the build instructions which have since
69 * changed);
70 *
71 *    http://www.mail-archive.com/openssl-dev@openssl.org/msg12227.html
72 *
73 * On my athlon system at least, it appears the builtin OpenSSL code is now
74 * slightly faster, which is to say that the RSA-related MPI performance
75 * between OpenSSL's BIGNUM and GMP's mpz implementations is probably pretty
76 * balanced for this chip, and so the performance degradation in this ENGINE by
77 * having to convert to/from GMP formats (and not being able to cache
78 * montgomery forms) is probably the difference. However, if some unconfirmed
79 * reports from users is anything to go by, the situation on some other
80 * chipsets might be a good deal more favourable to the GMP version (eg. PPC).
81 * Feedback welcome. */
82
83#include <stdio.h>
84#include <string.h>
85#include <openssl/crypto.h>
86#include <openssl/buffer.h>
87#include <openssl/engine.h>
88#ifndef OPENSSL_NO_RSA
89#include <openssl/rsa.h>
90#endif
91#include <openssl/bn.h>
92
93#ifndef OPENSSL_NO_HW
94#ifndef OPENSSL_NO_GMP
95
96#include <gmp.h>
97
98#define E_GMP_LIB_NAME "gmp engine"
99#include "e_gmp_err.c"
100
101static int e_gmp_destroy(ENGINE *e);
102static int e_gmp_init(ENGINE *e);
103static int e_gmp_finish(ENGINE *e);
104static int e_gmp_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)(void));
105
106#ifndef OPENSSL_NO_RSA
107/* RSA stuff */
108static int e_gmp_rsa_mod_exp(BIGNUM *r, const BIGNUM *I, RSA *rsa, BN_CTX *ctx);
109static int e_gmp_rsa_finish(RSA *r);
110#endif
111
112/* The definitions for control commands specific to this engine */
113/* #define E_GMP_CMD_SO_PATH		ENGINE_CMD_BASE */
114static const ENGINE_CMD_DEFN e_gmp_cmd_defns[] = {
115#if 0
116	{E_GMP_CMD_SO_PATH,
117		"SO_PATH",
118		"Specifies the path to the 'e_gmp' shared library",
119		ENGINE_CMD_FLAG_STRING},
120#endif
121	{0, NULL, NULL, 0}
122	};
123
124#ifndef OPENSSL_NO_RSA
125/* Our internal RSA_METHOD that we provide pointers to */
126static RSA_METHOD e_gmp_rsa =
127	{
128	"GMP RSA method",
129	NULL,
130	NULL,
131	NULL,
132	NULL,
133	e_gmp_rsa_mod_exp,
134	NULL,
135	NULL,
136	e_gmp_rsa_finish,
137	/* These flags initialise montgomery crud that GMP ignores, however it
138	 * makes sure the public key ops (which are done in openssl) don't seem
139	 * *slower* than usual :-) */
140	RSA_FLAG_CACHE_PUBLIC|RSA_FLAG_CACHE_PRIVATE,
141	NULL,
142	NULL,
143	NULL
144	};
145#endif
146
147/* Constants used when creating the ENGINE */
148static const char *engine_e_gmp_id = "gmp";
149static const char *engine_e_gmp_name = "GMP engine support";
150
151/* This internal function is used by ENGINE_gmp() and possibly by the
152 * "dynamic" ENGINE support too */
153static int bind_helper(ENGINE *e)
154	{
155#ifndef OPENSSL_NO_RSA
156	const RSA_METHOD *meth1;
157#endif
158	if(!ENGINE_set_id(e, engine_e_gmp_id) ||
159			!ENGINE_set_name(e, engine_e_gmp_name) ||
160#ifndef OPENSSL_NO_RSA
161			!ENGINE_set_RSA(e, &e_gmp_rsa) ||
162#endif
163			!ENGINE_set_destroy_function(e, e_gmp_destroy) ||
164			!ENGINE_set_init_function(e, e_gmp_init) ||
165			!ENGINE_set_finish_function(e, e_gmp_finish) ||
166			!ENGINE_set_ctrl_function(e, e_gmp_ctrl) ||
167			!ENGINE_set_cmd_defns(e, e_gmp_cmd_defns))
168		return 0;
169
170#ifndef OPENSSL_NO_RSA
171	meth1 = RSA_PKCS1_SSLeay();
172	e_gmp_rsa.rsa_pub_enc = meth1->rsa_pub_enc;
173	e_gmp_rsa.rsa_pub_dec = meth1->rsa_pub_dec;
174	e_gmp_rsa.rsa_priv_enc = meth1->rsa_priv_enc;
175	e_gmp_rsa.rsa_priv_dec = meth1->rsa_priv_dec;
176	e_gmp_rsa.bn_mod_exp = meth1->bn_mod_exp;
177#endif
178
179	/* Ensure the e_gmp error handling is set up */
180	ERR_load_GMP_strings();
181	return 1;
182	}
183
184static ENGINE *engine_gmp(void)
185	{
186	ENGINE *ret = ENGINE_new();
187	if(!ret)
188		return NULL;
189	if(!bind_helper(ret))
190		{
191		ENGINE_free(ret);
192		return NULL;
193		}
194	return ret;
195	}
196
197void ENGINE_load_gmp(void)
198	{
199	/* Copied from eng_[openssl|dyn].c */
200	ENGINE *toadd = engine_gmp();
201	if(!toadd) return;
202	ENGINE_add(toadd);
203	ENGINE_free(toadd);
204	ERR_clear_error();
205	}
206
207#ifndef OPENSSL_NO_RSA
208/* Used to attach our own key-data to an RSA structure */
209static int hndidx_rsa = -1;
210#endif
211
212static int e_gmp_destroy(ENGINE *e)
213	{
214	ERR_unload_GMP_strings();
215	return 1;
216	}
217
218/* (de)initialisation functions. */
219static int e_gmp_init(ENGINE *e)
220	{
221#ifndef OPENSSL_NO_RSA
222	if (hndidx_rsa == -1)
223		hndidx_rsa = RSA_get_ex_new_index(0,
224			"GMP-based RSA key handle",
225			NULL, NULL, NULL);
226#endif
227	if (hndidx_rsa == -1)
228		return 0;
229	return 1;
230	}
231
232static int e_gmp_finish(ENGINE *e)
233	{
234	return 1;
235	}
236
237static int e_gmp_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)(void))
238	{
239	int to_return = 1;
240
241	switch(cmd)
242		{
243#if 0
244	case E_GMP_CMD_SO_PATH:
245		/* ... */
246#endif
247	/* The command isn't understood by this engine */
248	default:
249		GMPerr(GMP_F_E_GMP_CTRL,
250			GMP_R_CTRL_COMMAND_NOT_IMPLEMENTED);
251		to_return = 0;
252		break;
253		}
254
255	return to_return;
256	}
257
258
259/* Most often limb sizes will be the same. If not, we use hex conversion
260 * which is neat, but extremely inefficient. */
261static int bn2gmp(const BIGNUM *bn, mpz_t g)
262	{
263	bn_check_top(bn);
264	if(((sizeof(bn->d[0]) * 8) == GMP_NUMB_BITS) &&
265			(BN_BITS2 == GMP_NUMB_BITS))
266		{
267		/* The common case */
268		if(!_mpz_realloc (g, bn->top))
269			return 0;
270		memcpy(&g->_mp_d[0], &bn->d[0], bn->top * sizeof(bn->d[0]));
271		g->_mp_size = bn->top;
272		if(bn->neg)
273			g->_mp_size = -g->_mp_size;
274		return 1;
275		}
276	else
277		{
278		int toret;
279		char *tmpchar = BN_bn2hex(bn);
280		if(!tmpchar) return 0;
281		toret = (mpz_set_str(g, tmpchar, 16) == 0 ? 1 : 0);
282		OPENSSL_free(tmpchar);
283		return toret;
284		}
285	}
286
287static int gmp2bn(mpz_t g, BIGNUM *bn)
288	{
289	if(((sizeof(bn->d[0]) * 8) == GMP_NUMB_BITS) &&
290			(BN_BITS2 == GMP_NUMB_BITS))
291		{
292		/* The common case */
293		int s = (g->_mp_size >= 0) ? g->_mp_size : -g->_mp_size;
294		BN_zero(bn);
295		if(bn_expand2 (bn, s) == NULL)
296			return 0;
297		bn->top = s;
298		memcpy(&bn->d[0], &g->_mp_d[0], s * sizeof(bn->d[0]));
299		bn_correct_top(bn);
300		bn->neg = g->_mp_size >= 0 ? 0 : 1;
301		return 1;
302		}
303	else
304		{
305		int toret;
306		char *tmpchar = OPENSSL_malloc(mpz_sizeinbase(g, 16) + 10);
307		if(!tmpchar) return 0;
308		mpz_get_str(tmpchar, 16, g);
309		toret = BN_hex2bn(&bn, tmpchar);
310		OPENSSL_free(tmpchar);
311		return toret;
312		}
313	}
314
315#ifndef OPENSSL_NO_RSA
316typedef struct st_e_gmp_rsa_ctx
317	{
318	int public_only;
319	mpz_t n;
320	mpz_t d;
321	mpz_t e;
322	mpz_t p;
323	mpz_t q;
324	mpz_t dmp1;
325	mpz_t dmq1;
326	mpz_t iqmp;
327	mpz_t r0, r1, I0, m1;
328	} E_GMP_RSA_CTX;
329
330static E_GMP_RSA_CTX *e_gmp_get_rsa(RSA *rsa)
331	{
332	E_GMP_RSA_CTX *hptr = RSA_get_ex_data(rsa, hndidx_rsa);
333	if(hptr) return hptr;
334	hptr = OPENSSL_malloc(sizeof(E_GMP_RSA_CTX));
335	if(!hptr) return NULL;
336	/* These inits could probably be replaced by more intelligent
337	 * mpz_init2() versions, to reduce malloc-thrashing. */
338	mpz_init(hptr->n);
339	mpz_init(hptr->d);
340	mpz_init(hptr->e);
341	mpz_init(hptr->p);
342	mpz_init(hptr->q);
343	mpz_init(hptr->dmp1);
344	mpz_init(hptr->dmq1);
345	mpz_init(hptr->iqmp);
346	mpz_init(hptr->r0);
347	mpz_init(hptr->r1);
348	mpz_init(hptr->I0);
349	mpz_init(hptr->m1);
350	if(!bn2gmp(rsa->n, hptr->n) || !bn2gmp(rsa->e, hptr->e))
351		goto err;
352	if(!rsa->p || !rsa->q || !rsa->d || !rsa->dmp1 || !rsa->dmq1 || !rsa->iqmp)
353		{
354		hptr->public_only = 1;
355		return hptr;
356		}
357	if(!bn2gmp(rsa->d, hptr->d) || !bn2gmp(rsa->p, hptr->p) ||
358			!bn2gmp(rsa->q, hptr->q) || !bn2gmp(rsa->dmp1, hptr->dmp1) ||
359			!bn2gmp(rsa->dmq1, hptr->dmq1) || !bn2gmp(rsa->iqmp, hptr->iqmp))
360		goto err;
361	hptr->public_only = 0;
362	RSA_set_ex_data(rsa, hndidx_rsa, hptr);
363	return hptr;
364err:
365	mpz_clear(hptr->n);
366	mpz_clear(hptr->d);
367	mpz_clear(hptr->e);
368	mpz_clear(hptr->p);
369	mpz_clear(hptr->q);
370	mpz_clear(hptr->dmp1);
371	mpz_clear(hptr->dmq1);
372	mpz_clear(hptr->iqmp);
373	mpz_clear(hptr->r0);
374	mpz_clear(hptr->r1);
375	mpz_clear(hptr->I0);
376	mpz_clear(hptr->m1);
377	OPENSSL_free(hptr);
378	return NULL;
379	}
380
381static int e_gmp_rsa_finish(RSA *rsa)
382	{
383	E_GMP_RSA_CTX *hptr = RSA_get_ex_data(rsa, hndidx_rsa);
384	if(!hptr) return 0;
385	mpz_clear(hptr->n);
386	mpz_clear(hptr->d);
387	mpz_clear(hptr->e);
388	mpz_clear(hptr->p);
389	mpz_clear(hptr->q);
390	mpz_clear(hptr->dmp1);
391	mpz_clear(hptr->dmq1);
392	mpz_clear(hptr->iqmp);
393	mpz_clear(hptr->r0);
394	mpz_clear(hptr->r1);
395	mpz_clear(hptr->I0);
396	mpz_clear(hptr->m1);
397	OPENSSL_free(hptr);
398	RSA_set_ex_data(rsa, hndidx_rsa, NULL);
399	return 1;
400	}
401
402static int e_gmp_rsa_mod_exp(BIGNUM *r, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
403	{
404	E_GMP_RSA_CTX *hptr;
405	int to_return = 0;
406
407	hptr = e_gmp_get_rsa(rsa);
408	if(!hptr)
409		{
410		GMPerr(GMP_F_E_GMP_RSA_MOD_EXP,
411				GMP_R_KEY_CONTEXT_ERROR);
412		return 0;
413		}
414	if(hptr->public_only)
415		{
416		GMPerr(GMP_F_E_GMP_RSA_MOD_EXP,
417				GMP_R_MISSING_KEY_COMPONENTS);
418		return 0;
419		}
420
421	/* ugh!!! */
422	if(!bn2gmp(I, hptr->I0))
423		return 0;
424
425	/* This is basically the CRT logic in crypto/rsa/rsa_eay.c reworded into
426	 * GMP-speak. It may be that GMP's API facilitates cleaner formulations
427	 * of this stuff, eg. better handling of negatives, or functions that
428	 * combine operations. */
429
430	mpz_mod(hptr->r1, hptr->I0, hptr->q);
431	mpz_powm(hptr->m1, hptr->r1, hptr->dmq1, hptr->q);
432
433	mpz_mod(hptr->r1, hptr->I0, hptr->p);
434	mpz_powm(hptr->r0, hptr->r1, hptr->dmp1, hptr->p);
435
436	mpz_sub(hptr->r0, hptr->r0, hptr->m1);
437
438	if(mpz_sgn(hptr->r0) < 0)
439		mpz_add(hptr->r0, hptr->r0, hptr->p);
440	mpz_mul(hptr->r1, hptr->r0, hptr->iqmp);
441	mpz_mod(hptr->r0, hptr->r1, hptr->p);
442
443	if(mpz_sgn(hptr->r0) < 0)
444		mpz_add(hptr->r0, hptr->r0, hptr->p);
445	mpz_mul(hptr->r1, hptr->r0, hptr->q);
446	mpz_add(hptr->r0, hptr->r1, hptr->m1);
447
448	/* ugh!!! */
449	if(gmp2bn(hptr->r0, r))
450		to_return = 1;
451
452	return 1;
453	}
454#endif
455
456#endif /* !OPENSSL_NO_GMP */
457
458/* This stuff is needed if this ENGINE is being compiled into a self-contained
459 * shared-library. */
460#ifndef OPENSSL_NO_DYNAMIC_ENGINE
461IMPLEMENT_DYNAMIC_CHECK_FN()
462#ifndef OPENSSL_NO_GMP
463static int bind_fn(ENGINE *e, const char *id)
464	{
465	if(id && (strcmp(id, engine_e_gmp_id) != 0))
466		return 0;
467	if(!bind_helper(e))
468		return 0;
469	return 1;
470	}
471IMPLEMENT_DYNAMIC_BIND_FN(bind_fn)
472#else
473OPENSSL_EXPORT
474int bind_engine(ENGINE *e, const char *id, const dynamic_fns *fns);
475OPENSSL_EXPORT
476int bind_engine(ENGINE *e, const char *id, const dynamic_fns *fns) { return 0; }
477#endif
478#endif /* !OPENSSL_NO_DYNAMIC_ENGINE */
479
480#endif /* !OPENSSL_NO_HW */
481