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Date:: Sun Jan 21 12:33:33 2024 UTC
Message:: convert crypto.c to the new imsg API
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1 /*
2  * Copyright (c) 2023 Omar Polo <op@omarpolo.com>
3  * Copyright (c) 2014 Reyk Floeter <reyk@openbsd.org>
4  * Copyright (c) 2012 Gilles Chehade <gilles@poolp.org>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include "gmid.h"
20 
21 #include <string.h>
22 
23 #include <openssl/err.h>
24 #include <openssl/pem.h>
25 
26 #include "log.h"
27 #include "proc.h"
28 
29 #ifndef nitems
30 #define nitems(_a) (sizeof((_a)) / sizeof((_a)[0]))
31 #endif
32 
33 static void crypto_init(struct privsep *, struct privsep_proc *, void *);
34 static int crypto_dispatch_parent(int, struct privsep_proc *, struct imsg *);
35 static int crypto_dispatch_server(int, struct privsep_proc *, struct imsg *);
36 
37 static struct privsep_proc procs[] = {
38 	{ "parent",	PROC_PARENT,	crypto_dispatch_parent },
39 	{ "server",	PROC_SERVER,	crypto_dispatch_server },
40 };
41 
42 struct imsg_crypto_req {
43 	uint64_t	 id;
44 	char		 hash[TLS_CERT_HASH_SIZE];
45 	size_t		 flen;
46 	size_t		 tlen;
47 	int		 padding;
48 	/* followed by flen bytes of `from'. */
49 };
50 
51 struct imsg_crypto_res {
52 	uint64_t	 id;
53 	int		 ret;
54 	size_t		 len;
55 	/* followed by len bytes of reply */
56 };
57 
58 static uint64_t		 reqid;
59 static struct conf	*conf;
60 
61 void
62 crypto(struct privsep *ps, struct privsep_proc *p)
63 {
64 	proc_run(ps, p, procs, nitems(procs), crypto_init, NULL);
65 }
66 
67 static void
68 crypto_init(struct privsep *ps, struct privsep_proc *p, void *arg)
69 {
70 #if 0
71 	static volatile int attached;
72 	while (!attached) sleep(1);
73 #endif
74 
75 	conf = ps->ps_env;
76 
77 	sandbox_crypto_process();
78 }
79 
80 static int
81 crypto_dispatch_parent(int fd, struct privsep_proc *p, struct imsg *imsg)
82 {
83 	switch (imsg->hdr.type) {
84 	case IMSG_RECONF_START:
85 	case IMSG_RECONF_CERT:
86 	case IMSG_RECONF_KEY:
87 	case IMSG_RECONF_END:
88 		if (config_recv(conf, imsg) == -1)
89 			return -1;
90 		break;
91 	default:
92 		return -1;
93 	}
94 
95 	return 0;
96 }
97 
98 static EVP_PKEY *
99 get_pkey(const char *hash)
100 {
101 	struct pki *pki;
102 
103 	TAILQ_FOREACH(pki, &conf->pkis, pkis) {
104 		if (!strcmp(pki->hash, hash))
105 			return pki->pkey;
106 	}
107 
108 	return NULL;
109 }
110 
111 static int
112 crypto_dispatch_server(int fd, struct privsep_proc *p, struct imsg *imsg)
113 {
114 	struct privsep		*ps = p->p_ps;
115 	RSA			*rsa = NULL;
116 	EC_KEY			*ecdsa = NULL;
117 	EVP_PKEY		*pkey;
118 	struct imsg_crypto_req	 req;
119 	struct imsg_crypto_res	 res;
120 	struct iovec		 iov[2];
121 	const void		*from;
122 	unsigned char		*data, *to;
123 	size_t			 datalen;
124 	int			 n, ret;
125 	unsigned int		 len;
126 
127 	data = imsg->data;
128 	datalen = IMSG_DATA_SIZE(imsg);
129 
130 	switch (imsg->hdr.type) {
131 	case IMSG_CRYPTO_RSA_PRIVENC:
132 	case IMSG_CRYPTO_RSA_PRIVDEC:
133 		if (datalen < sizeof(req))
134 			fatalx("size mismatch for imsg %d", imsg->hdr.type);
135 		memcpy(&req, data, sizeof(req));
136 		if (datalen != sizeof(req) + req.flen)
137 			fatalx("size mismatch for imsg %d", imsg->hdr.type);
138 		from = data + sizeof(req);
139 
140 		if ((pkey = get_pkey(req.hash)) == NULL ||
141 		    (rsa = EVP_PKEY_get1_RSA(pkey)) == NULL)
142 			fatalx("invalid pkey hash");
143 
144 		if ((to = calloc(1, req.tlen)) == NULL)
145 			fatal("calloc");
146 
147 		if (imsg->hdr.type == IMSG_CRYPTO_RSA_PRIVENC)
148 			ret = RSA_private_encrypt(req.flen, from,
149 			    to, rsa, req.padding);
150 		else
151 			ret = RSA_private_decrypt(req.flen, from,
152 			    to, rsa, req.padding);
153 
154 		memset(&res, 0, sizeof(res));
155 		res.id = req.id;
156 		res.ret = ret;
157 
158 		memset(&iov, 0, sizeof(iov));
159 		n = 0;
160 		iov[n].iov_base = &res;
161 		iov[n].iov_len = sizeof(res);
162 		n++;
163 
164 		if (ret > 0) {
165 			res.len = ret;
166 			iov[n].iov_base = to;
167 			iov[n].iov_len = ret;
168 			n++;
169 		}
170 
171 		log_debug("replying to server #%d", imsg->hdr.pid);
172 		if (proc_composev_imsg(ps, PROC_SERVER, imsg->hdr.pid - 1,
173 		    imsg->hdr.type, 0, -1, iov, n) == -1)
174 			fatal("proc_composev_imsg");
175 
176 		if (proc_flush_imsg(ps, PROC_SERVER, imsg->hdr.pid - 1) == -1)
177 			fatal("proc_flush_imsg");
178 
179 		free(to);
180 		RSA_free(rsa);
181 		break;
182 
183 	case IMSG_CRYPTO_ECDSA_SIGN:
184 		if (datalen < sizeof(req))
185 			fatalx("size mismatch for imsg %d", imsg->hdr.type);
186 		memcpy(&req, data, sizeof(req));
187 		if (datalen != sizeof(req) + req.flen)
188 			fatalx("size mismatch for imsg %d", imsg->hdr.type);
189 		from = data + sizeof(req);
190 
191 		if ((pkey = get_pkey(req.hash)) == NULL ||
192 		    (ecdsa = EVP_PKEY_get1_EC_KEY(pkey)) == NULL)
193 			fatalx("invalid pkey hash");
194 
195 		len = ECDSA_size(ecdsa);
196 		if ((to = calloc(1, len)) == NULL)
197 			fatal("calloc");
198 		ret = ECDSA_sign(0, from, req.flen, to, &len, ecdsa);
199 
200 		memset(&res, 0, sizeof(res));
201 		res.id = req.id;
202 		res.ret = ret;
203 
204 		memset(&iov, 0, sizeof(iov));
205 		n = 0;
206 		iov[0].iov_base = &res;
207 		iov[0].iov_len = sizeof(res);
208 		n++;
209 
210 		if (ret > 0) {
211 			res.len = len;
212 			iov[n].iov_base = to;
213 			iov[n].iov_len = len;
214 			n++;
215 		}
216 
217 		log_debug("replying to server #%d", imsg->hdr.pid);
218 		if (proc_composev_imsg(ps, PROC_SERVER, imsg->hdr.pid - 1,
219 		    imsg->hdr.type, 0, -1, iov, n) == -1)
220 			fatal("proc_composev_imsg");
221 
222 		if (proc_flush_imsg(ps, PROC_SERVER, imsg->hdr.pid - 1) == -1)
223 			fatal("proc_flush_imsg");
224 
225 		free(to);
226 		EC_KEY_free(ecdsa);
227 		break;
228 
229 	default:
230 		return -1;
231 	}
232 
233 	return 0;
234 }
235 
236 
237 /*
238  * RSA privsep engine (called from unprivileged processes)
239  */
240 
241 static const RSA_METHOD	*rsa_default;
242 static RSA_METHOD	*rsae_method;
243 
244 static int
245 rsae_send_imsg(int flen, const unsigned char *from, unsigned char *to,
246     RSA *rsa, int padding, unsigned int cmd)
247 {
248 	struct imsg_crypto_req	 req;
249 	struct iovec		 iov[2];
250 	struct imsg_crypto_res	 res;
251 	struct imsgev		*iev;
252 	struct privsep_proc	*p;
253 	struct privsep		*ps = conf->ps;
254 	struct imsgbuf		*imsgbuf;
255 	struct imsg		 imsg;
256 	struct ibuf		 ibuf;
257 	int			 ret = 0;
258 	int			 n, done = 0;
259 	const void		*toptr;
260 	char			*hash;
261 
262 	if ((hash = RSA_get_ex_data(rsa, 0)) == NULL)
263 		return (0);
264 
265 	/*
266 	 * Send a synchronous imsg because we cannot defer the RSA
267 	 * operation in OpenSSL's engine layer.
268 	 */
269 	memset(&req, 0, sizeof(req));
270 	req.id = ++reqid;
271 	if (strlcpy(req.hash, hash, sizeof(req.hash)) >= sizeof(req.hash))
272 		fatalx("%s: hash too long (%zu)", __func__, strlen(hash));
273 	req.flen = flen;
274 	req.tlen = RSA_size(rsa);
275 	req.padding = padding;
276 
277 	memset(&iov, 0, sizeof(iov));
278 	iov[0].iov_base = &req;
279 	iov[0].iov_len = sizeof(req);
280 	iov[1].iov_base = (void *)from;
281 	iov[1].iov_len = flen;
282 
283 	if (proc_composev(ps, PROC_CRYPTO, cmd, iov, 2) == -1)
284 		fatal("proc_composev");
285 
286 	if (proc_flush_imsg(ps, PROC_CRYPTO, -1) == -1)
287 		fatal("proc_flush_imsg");
288 
289 	iev = ps->ps_ievs[PROC_CRYPTO];
290 	p = iev->proc;
291 	imsgbuf = &iev->ibuf;
292 
293 	while (!done) {
294 		if ((n = imsg_read(imsgbuf)) == -1 && errno != EAGAIN)
295 			fatalx("imsg_read");
296 		if (n == 0)
297 			fatalx("pipe closed");
298 
299 		while (!done) {
300 			if ((n = imsg_get(imsgbuf, &imsg)) == -1)
301 				fatalx("imsg_get error");
302 			if (n == 0)
303 				break;
304 
305 #if DEBUG > 1
306 			log_debug(
307 			    "%s: %s %d got imsg %d id %d from %s %d",
308 			    __func__, title, 1, imsg_get_type(&imsg),
309 			    imsg_get_id(&imsg), "crypto", imsg_get_pid(&imsg));
310 #endif
311 
312 			if ((p->p_cb)(imsgbuf->fd, p, &imsg) == 0) {
313 				/* Message was handled by the callback */
314 				imsg_free(&imsg);
315 				continue;
316 			}
317 
318 			switch (imsg_get_type(&imsg)) {
319 			case IMSG_CRYPTO_RSA_PRIVENC:
320 			case IMSG_CRYPTO_RSA_PRIVDEC:
321 				break;
322 			default:
323 				fatalx("%s: %s %d got invalid imsg %d"
324 				    " id %d from %s %d",
325 				    __func__, "server", ps->ps_instance + 1,
326 				    imsg_get_type(&imsg), imsg_get_id(&imsg),
327 				    "crypto", imsg_get_pid(&imsg));
328 			}
329 
330 			if (imsg_get_ibuf(&imsg, &ibuf) == -1 ||
331 			    ibuf_get(&ibuf, &res, sizeof(res)) == -1 ||
332 			    (int)ibuf_size(&ibuf) != res.ret)
333 				fatalx("size mismatch for imsg %d",
334 				    imsg.hdr.type);
335 			ret = res.ret;
336 			toptr = ibuf_data(&ibuf);
337 
338 			if (res.id != reqid)
339 				fatalx("invalid id; got %llu, want %llu",
340 				    (unsigned long long)res.id,
341 				    (unsigned long long)reqid);
342 			if (res.ret > 0)
343 				memcpy(to, toptr, res.len);
344 
345 			done = 1;
346 
347 			imsg_free(&imsg);
348 		}
349 	}
350 	imsg_event_add(iev);
351 
352 	return (ret);
353 }
354 
355 static int
356 rsae_priv_enc(int flen, const unsigned char *from, unsigned char *to, RSA *rsa,
357     int padding)
358 {
359 	log_debug("debug: %s", __func__);
360 	if (RSA_get_ex_data(rsa, 0) != NULL)
361 		return (rsae_send_imsg(flen, from, to, rsa, padding,
362 		    IMSG_CRYPTO_RSA_PRIVENC));
363 	return (RSA_meth_get_priv_enc(rsa_default)(flen, from, to, rsa, padding));
364 }
365 
366 static int
367 rsae_priv_dec(int flen, const unsigned char *from, unsigned char *to, RSA *rsa,
368     int padding)
369 {
370 	log_debug("debug: %s", __func__);
371 	if (RSA_get_ex_data(rsa, 0) != NULL)
372 		return (rsae_send_imsg(flen, from, to, rsa, padding,
373 		    IMSG_CRYPTO_RSA_PRIVDEC));
374 
375 	return (RSA_meth_get_priv_dec(rsa_default)(flen, from, to, rsa, padding));
376 }
377 
378 
379 /*
380  * ECDSA privsep engine (called from unprivileged processes)
381  */
382 
383 static const EC_KEY_METHOD	*ecdsa_default;
384 static EC_KEY_METHOD		*ecdsae_method;
385 
386 static ECDSA_SIG *
387 ecdsae_send_enc_imsg(const unsigned char *dgst, int dgst_len,
388     const BIGNUM *inv, const BIGNUM *rp, EC_KEY *eckey)
389 {
390 	ECDSA_SIG		*sig = NULL;
391 	struct imsg_crypto_req	 req;
392 	struct iovec		 iov[2];
393 	struct imsg_crypto_res	 res;
394 	struct imsgev		*iev;
395 	struct privsep_proc	*p;
396 	struct privsep		*ps = conf->ps;
397 	struct imsgbuf		*imsgbuf;
398 	struct imsg		 imsg;
399 	struct ibuf		 ibuf;
400 	int			 n, done = 0;
401 	const void		*toptr;
402 	char			*hash;
403 
404 	if ((hash = EC_KEY_get_ex_data(eckey, 0)) == NULL)
405 		return (0);
406 
407 	/*
408 	 * Send a synchronous imsg because we cannot defer the RSA
409 	 * operation in OpenSSL's engine layer.
410 	 */
411 	memset(&req, 0, sizeof(req));
412 	req.id = ++reqid;
413 	if (strlcpy(req.hash, hash, sizeof(req.hash)) >= sizeof(req.hash))
414 		fatalx("%s: hash too long (%zu)", __func__, strlen(hash));
415 	req.flen = dgst_len;
416 
417 	memset(&iov, 0, sizeof(iov));
418 	iov[0].iov_base = &req;
419 	iov[0].iov_len = sizeof(req);
420 	iov[1].iov_base = (void *)dgst;
421 	iov[1].iov_len = dgst_len;
422 
423 	if (proc_composev(ps, PROC_CRYPTO, IMSG_CRYPTO_ECDSA_SIGN, iov, 2) == -1)
424 		fatal("proc_composev");
425 
426 	if (proc_flush_imsg(ps, PROC_CRYPTO, -1) == -1)
427 		fatal("proc_flush_imsg");
428 
429 	iev = ps->ps_ievs[PROC_CRYPTO];
430 	p = iev->proc;
431 	imsgbuf = &iev->ibuf;
432 
433 	while (!done) {
434 		if ((n = imsg_read(imsgbuf)) == -1 && errno != EAGAIN)
435 			fatalx("imsg_read");
436 		if (n == 0)
437 			fatalx("pipe closed");
438 
439 		while (!done) {
440 			if ((n = imsg_get(imsgbuf, &imsg)) == -1)
441 				fatalx("imsg_get error");
442 			if (n == 0)
443 				break;
444 
445 #if DEBUG > 1
446 			log_debug(
447 			    "%s: %s %d got imsg %d peerid %d from %s %d",
448 			    __func__, title, 1, imsg.hdr.type,
449 			    imsg.hdr.peerid, "crypto", imsg.hdr.pid);
450 #endif
451 
452 			if (imsg.hdr.type != IMSG_CRYPTO_ECDSA_SIGN &&
453 			    crypto_dispatch_server(imsgbuf->fd, p, &imsg)
454 			    == 0) {
455 				/* Message was handled by the callback */
456 				imsg_free(&imsg);
457 				continue;
458 			}
459 
460 			if (imsg.hdr.type != IMSG_CRYPTO_ECDSA_SIGN)
461 				fatalx("%s: %s %d got invalid imsg %d"
462 				    " peerid %d from %s %d",
463 				    __func__, "server", ps->ps_instance + 1,
464 				    imsg.hdr.type, imsg.hdr.peerid,
465 				    "crypto", imsg.hdr.pid);
466 
467 			if (imsg_get_ibuf(&imsg, &ibuf) == -1 ||
468 			    ibuf_get(&ibuf, &res, sizeof(res)) == -1 ||
469 			    ibuf_size(&ibuf) != res.len)
470 				fatalx("size mismatch for imsg %d",
471 				    imsg.hdr.type);
472 
473 			toptr = ibuf_data(&ibuf);
474 
475 			if (res.id != reqid)
476 				fatalx("invalid response id");
477 			if (res.ret > 0) {
478 				d2i_ECDSA_SIG(&sig,
479 				    (const unsigned char **)&toptr, res.len);
480 			}
481 
482 			done = 1;
483 
484 			imsg_free(&imsg);
485 		}
486 	}
487 	imsg_event_add(iev);
488 
489 	return (sig);
490 }
491 
492 static ECDSA_SIG *
493 ecdsae_do_sign(const unsigned char *dgst, int dgst_len, const BIGNUM *inv,
494     const BIGNUM *rp, EC_KEY *eckey)
495 {
496 	ECDSA_SIG *(*psign_sig)(const unsigned char *, int, const BIGNUM *,
497 	    const BIGNUM *, EC_KEY *);
498 
499 	log_debug("debug: %s", __func__);
500 	if (EC_KEY_get_ex_data(eckey, 0) != NULL)
501 		return (ecdsae_send_enc_imsg(dgst, dgst_len, inv, rp, eckey));
502 	EC_KEY_METHOD_get_sign(ecdsa_default, NULL, NULL, &psign_sig);
503 	return (psign_sig(dgst, dgst_len, inv, rp, eckey));
504 }
505 
506 
507 /*
508  * Initialize the two engines.
509  */
510 
511 static void
512 rsa_engine_init(void)
513 {
514 	const char	*errstr;
515 
516 	if ((rsa_default = RSA_get_default_method()) == NULL) {
517 		errstr = "RSA_get_default_method";
518 		goto fail;
519 	}
520 
521 	if ((rsae_method = RSA_meth_dup(rsa_default)) == NULL) {
522 		errstr = "RSA_meth_dup";
523 		goto fail;
524 	}
525 
526 	RSA_meth_set_priv_enc(rsae_method, rsae_priv_enc);
527 	RSA_meth_set_priv_dec(rsae_method, rsae_priv_dec);
528 
529 	RSA_meth_set_flags(rsae_method,
530 	    RSA_meth_get_flags(rsa_default) | RSA_METHOD_FLAG_NO_CHECK);
531 	RSA_meth_set0_app_data(rsae_method,
532 	    RSA_meth_get0_app_data(rsa_default));
533 
534 	RSA_set_default_method(rsae_method);
535 
536 	return;
537 
538  fail:
539 	ssl_error(errstr);
540 	fatalx("%s", errstr);
541 }
542 
543 static void
544 ecdsa_engine_init(void)
545 {
546 	int (*sign)(int, const unsigned char *, int, unsigned char *,
547 	    unsigned int *, const BIGNUM *, const BIGNUM *, EC_KEY *);
548 	int (*sign_setup)(EC_KEY *, BN_CTX *, BIGNUM **, BIGNUM **);
549 	const char *errstr;
550 
551 	if ((ecdsa_default = EC_KEY_get_default_method()) == NULL) {
552 		errstr = "EC_KEY_get_default_method";
553 		goto fail;
554 	}
555 
556 	if ((ecdsae_method = EC_KEY_METHOD_new(ecdsa_default)) == NULL) {
557 		errstr = "EC_KEY_METHOD_new";
558 		goto fail;
559 	}
560 
561 	EC_KEY_METHOD_get_sign(ecdsa_default, &sign, &sign_setup, NULL);
562 	EC_KEY_METHOD_set_sign(ecdsae_method, sign, sign_setup,
563 	    ecdsae_do_sign);
564 
565 	EC_KEY_set_default_method(ecdsae_method);
566 
567 	return;
568 
569  fail:
570 	ssl_error(errstr);
571 	fatalx("%s", errstr);
572 }
573 
574 void
575 crypto_engine_init(struct conf *c)
576 {
577 	conf = c;
578 
579 	rsa_engine_init();
580 	ecdsa_engine_init();
581 }
582