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Date:: Sun Jan 21 19:40:06 2024 UTC
Message:: convert remaining code to the imsg getters Now gmid doesn't touch anymore the internals of the imsg structs.
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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_get_type(imsg)) {
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 ibuf		 ibuf;
121 	struct iovec		 iov[2];
122 	const void		*from;
123 	unsigned char		*to;
124 	int			 n, ret, type;
125 	unsigned int		 len;
126 	pid_t			 pid;
127 
128 	if (imsg_get_ibuf(imsg, &ibuf) == -1)
129 		fatalx("%s: couldn't get an ibuf", __func__);
130 
131 	pid = imsg_get_pid(imsg);
132 	switch (type = imsg_get_type(imsg)) {
133 	case IMSG_CRYPTO_RSA_PRIVENC:
134 	case IMSG_CRYPTO_RSA_PRIVDEC:
135 		if (ibuf_get(&ibuf, &req, sizeof(req)) == -1 ||
136 		    ibuf_size(&ibuf) != req.flen)
137 			fatalx("size mismatch for imsg %d", type);
138 		from = ibuf_data(&ibuf);
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 (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", pid);
172 		if (proc_composev_imsg(ps, PROC_SERVER, pid - 1,
173 		    type, 0, -1, iov, n) == -1)
174 			fatal("proc_composev_imsg");
175 
176 		if (proc_flush_imsg(ps, PROC_SERVER, 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 (ibuf_get(&ibuf, &req, sizeof(req)) == -1 ||
185 		    ibuf_size(&ibuf) != req.flen)
186 			fatalx("size mismatch for imsg %d", type);
187 		from = ibuf_data(&ibuf);
188 
189 		if ((pkey = get_pkey(req.hash)) == NULL ||
190 		    (ecdsa = EVP_PKEY_get1_EC_KEY(pkey)) == NULL)
191 			fatalx("invalid pkey hash");
192 
193 		len = ECDSA_size(ecdsa);
194 		if ((to = calloc(1, len)) == NULL)
195 			fatal("calloc");
196 		ret = ECDSA_sign(0, from, req.flen, to, &len, ecdsa);
197 
198 		memset(&res, 0, sizeof(res));
199 		res.id = req.id;
200 		res.ret = ret;
201 
202 		memset(&iov, 0, sizeof(iov));
203 		n = 0;
204 		iov[0].iov_base = &res;
205 		iov[0].iov_len = sizeof(res);
206 		n++;
207 
208 		if (ret > 0) {
209 			res.len = len;
210 			iov[n].iov_base = to;
211 			iov[n].iov_len = len;
212 			n++;
213 		}
214 
215 		log_debug("replying to server #%d", pid);
216 		if (proc_composev_imsg(ps, PROC_SERVER, pid - 1,
217 		    type, 0, -1, iov, n) == -1)
218 			fatal("proc_composev_imsg");
219 
220 		if (proc_flush_imsg(ps, PROC_SERVER, pid - 1) == -1)
221 			fatal("proc_flush_imsg");
222 
223 		free(to);
224 		EC_KEY_free(ecdsa);
225 		break;
226 
227 	default:
228 		return -1;
229 	}
230 
231 	return 0;
232 }
233 
234 
235 /*
236  * RSA privsep engine (called from unprivileged processes)
237  */
238 
239 static const RSA_METHOD	*rsa_default;
240 static RSA_METHOD	*rsae_method;
241 
242 static int
243 rsae_send_imsg(int flen, const unsigned char *from, unsigned char *to,
244     RSA *rsa, int padding, unsigned int cmd)
245 {
246 	struct imsg_crypto_req	 req;
247 	struct iovec		 iov[2];
248 	struct imsg_crypto_res	 res;
249 	struct imsgev		*iev;
250 	struct privsep_proc	*p;
251 	struct privsep		*ps = conf->ps;
252 	struct imsgbuf		*imsgbuf;
253 	struct imsg		 imsg;
254 	struct ibuf		 ibuf;
255 	int			 ret = 0;
256 	int			 n, done = 0;
257 	const void		*toptr;
258 	char			*hash;
259 
260 	if ((hash = RSA_get_ex_data(rsa, 0)) == NULL)
261 		return (0);
262 
263 	/*
264 	 * Send a synchronous imsg because we cannot defer the RSA
265 	 * operation in OpenSSL's engine layer.
266 	 */
267 	memset(&req, 0, sizeof(req));
268 	req.id = ++reqid;
269 	if (strlcpy(req.hash, hash, sizeof(req.hash)) >= sizeof(req.hash))
270 		fatalx("%s: hash too long (%zu)", __func__, strlen(hash));
271 	req.flen = flen;
272 	req.tlen = RSA_size(rsa);
273 	req.padding = padding;
274 
275 	memset(&iov, 0, sizeof(iov));
276 	iov[0].iov_base = &req;
277 	iov[0].iov_len = sizeof(req);
278 	iov[1].iov_base = (void *)from;
279 	iov[1].iov_len = flen;
280 
281 	if (proc_composev(ps, PROC_CRYPTO, cmd, iov, 2) == -1)
282 		fatal("proc_composev");
283 
284 	if (proc_flush_imsg(ps, PROC_CRYPTO, -1) == -1)
285 		fatal("proc_flush_imsg");
286 
287 	iev = ps->ps_ievs[PROC_CRYPTO];
288 	p = iev->proc;
289 	imsgbuf = &iev->ibuf;
290 
291 	while (!done) {
292 		if ((n = imsg_read(imsgbuf)) == -1 && errno != EAGAIN)
293 			fatalx("imsg_read");
294 		if (n == 0)
295 			fatalx("pipe closed");
296 
297 		while (!done) {
298 			if ((n = imsg_get(imsgbuf, &imsg)) == -1)
299 				fatalx("imsg_get error");
300 			if (n == 0)
301 				break;
302 
303 #if DEBUG > 1
304 			log_debug(
305 			    "%s: %s %d got imsg %d id %d from %s %d",
306 			    __func__, title, 1, imsg_get_type(&imsg),
307 			    imsg_get_id(&imsg), "crypto", imsg_get_pid(&imsg));
308 #endif
309 
310 			if ((p->p_cb)(imsgbuf->fd, p, &imsg) == 0) {
311 				/* Message was handled by the callback */
312 				imsg_free(&imsg);
313 				continue;
314 			}
315 
316 			switch (imsg_get_type(&imsg)) {
317 			case IMSG_CRYPTO_RSA_PRIVENC:
318 			case IMSG_CRYPTO_RSA_PRIVDEC:
319 				break;
320 			default:
321 				fatalx("%s: %s %d got invalid imsg %d"
322 				    " id %d from %s %d",
323 				    __func__, "server", ps->ps_instance + 1,
324 				    imsg_get_type(&imsg), imsg_get_id(&imsg),
325 				    "crypto", imsg_get_pid(&imsg));
326 			}
327 
328 			if (imsg_get_ibuf(&imsg, &ibuf) == -1 ||
329 			    ibuf_get(&ibuf, &res, sizeof(res)) == -1 ||
330 			    (int)ibuf_size(&ibuf) != res.ret)
331 				fatalx("size mismatch for imsg %d",
332 				    imsg.hdr.type);
333 			ret = res.ret;
334 			toptr = ibuf_data(&ibuf);
335 
336 			if (res.id != reqid)
337 				fatalx("invalid id; got %llu, want %llu",
338 				    (unsigned long long)res.id,
339 				    (unsigned long long)reqid);
340 			if (res.ret > 0)
341 				memcpy(to, toptr, res.len);
342 
343 			done = 1;
344 
345 			imsg_free(&imsg);
346 		}
347 	}
348 	imsg_event_add(iev);
349 
350 	return (ret);
351 }
352 
353 static int
354 rsae_priv_enc(int flen, const unsigned char *from, unsigned char *to, RSA *rsa,
355     int padding)
356 {
357 	log_debug("debug: %s", __func__);
358 	if (RSA_get_ex_data(rsa, 0) != NULL)
359 		return (rsae_send_imsg(flen, from, to, rsa, padding,
360 		    IMSG_CRYPTO_RSA_PRIVENC));
361 	return (RSA_meth_get_priv_enc(rsa_default)(flen, from, to, rsa, padding));
362 }
363 
364 static int
365 rsae_priv_dec(int flen, const unsigned char *from, unsigned char *to, RSA *rsa,
366     int padding)
367 {
368 	log_debug("debug: %s", __func__);
369 	if (RSA_get_ex_data(rsa, 0) != NULL)
370 		return (rsae_send_imsg(flen, from, to, rsa, padding,
371 		    IMSG_CRYPTO_RSA_PRIVDEC));
372 
373 	return (RSA_meth_get_priv_dec(rsa_default)(flen, from, to, rsa, padding));
374 }
375 
376 
377 /*
378  * ECDSA privsep engine (called from unprivileged processes)
379  */
380 
381 static const EC_KEY_METHOD	*ecdsa_default;
382 static EC_KEY_METHOD		*ecdsae_method;
383 
384 static ECDSA_SIG *
385 ecdsae_send_enc_imsg(const unsigned char *dgst, int dgst_len,
386     const BIGNUM *inv, const BIGNUM *rp, EC_KEY *eckey)
387 {
388 	ECDSA_SIG		*sig = NULL;
389 	struct imsg_crypto_req	 req;
390 	struct iovec		 iov[2];
391 	struct imsg_crypto_res	 res;
392 	struct imsgev		*iev;
393 	struct privsep_proc	*p;
394 	struct privsep		*ps = conf->ps;
395 	struct imsgbuf		*imsgbuf;
396 	struct imsg		 imsg;
397 	struct ibuf		 ibuf;
398 	int			 n, done = 0;
399 	const void		*toptr;
400 	char			*hash;
401 
402 	if ((hash = EC_KEY_get_ex_data(eckey, 0)) == NULL)
403 		return (0);
404 
405 	/*
406 	 * Send a synchronous imsg because we cannot defer the RSA
407 	 * operation in OpenSSL's engine layer.
408 	 */
409 	memset(&req, 0, sizeof(req));
410 	req.id = ++reqid;
411 	if (strlcpy(req.hash, hash, sizeof(req.hash)) >= sizeof(req.hash))
412 		fatalx("%s: hash too long (%zu)", __func__, strlen(hash));
413 	req.flen = dgst_len;
414 
415 	memset(&iov, 0, sizeof(iov));
416 	iov[0].iov_base = &req;
417 	iov[0].iov_len = sizeof(req);
418 	iov[1].iov_base = (void *)dgst;
419 	iov[1].iov_len = dgst_len;
420 
421 	if (proc_composev(ps, PROC_CRYPTO, IMSG_CRYPTO_ECDSA_SIGN, iov, 2) == -1)
422 		fatal("proc_composev");
423 
424 	if (proc_flush_imsg(ps, PROC_CRYPTO, -1) == -1)
425 		fatal("proc_flush_imsg");
426 
427 	iev = ps->ps_ievs[PROC_CRYPTO];
428 	p = iev->proc;
429 	imsgbuf = &iev->ibuf;
430 
431 	while (!done) {
432 		if ((n = imsg_read(imsgbuf)) == -1 && errno != EAGAIN)
433 			fatalx("imsg_read");
434 		if (n == 0)
435 			fatalx("pipe closed");
436 
437 		while (!done) {
438 			if ((n = imsg_get(imsgbuf, &imsg)) == -1)
439 				fatalx("imsg_get error");
440 			if (n == 0)
441 				break;
442 
443 #if DEBUG > 1
444 			log_debug(
445 			    "%s: %s %d got imsg %d peerid %d from %s %d",
446 			    __func__, title, 1, imsg.hdr.type,
447 			    imsg.hdr.peerid, "crypto", imsg.hdr.pid);
448 #endif
449 
450 			if (imsg.hdr.type != IMSG_CRYPTO_ECDSA_SIGN &&
451 			    crypto_dispatch_server(imsgbuf->fd, p, &imsg)
452 			    == 0) {
453 				/* Message was handled by the callback */
454 				imsg_free(&imsg);
455 				continue;
456 			}
457 
458 			if (imsg.hdr.type != IMSG_CRYPTO_ECDSA_SIGN)
459 				fatalx("%s: %s %d got invalid imsg %d"
460 				    " peerid %d from %s %d",
461 				    __func__, "server", ps->ps_instance + 1,
462 				    imsg.hdr.type, imsg.hdr.peerid,
463 				    "crypto", imsg.hdr.pid);
464 
465 			if (imsg_get_ibuf(&imsg, &ibuf) == -1 ||
466 			    ibuf_get(&ibuf, &res, sizeof(res)) == -1 ||
467 			    ibuf_size(&ibuf) != res.len)
468 				fatalx("size mismatch for imsg %d",
469 				    imsg.hdr.type);
470 
471 			toptr = ibuf_data(&ibuf);
472 
473 			if (res.id != reqid)
474 				fatalx("invalid response id");
475 			if (res.ret > 0) {
476 				d2i_ECDSA_SIG(&sig,
477 				    (const unsigned char **)&toptr, res.len);
478 			}
479 
480 			done = 1;
481 
482 			imsg_free(&imsg);
483 		}
484 	}
485 	imsg_event_add(iev);
486 
487 	return (sig);
488 }
489 
490 static ECDSA_SIG *
491 ecdsae_do_sign(const unsigned char *dgst, int dgst_len, const BIGNUM *inv,
492     const BIGNUM *rp, EC_KEY *eckey)
493 {
494 	ECDSA_SIG *(*psign_sig)(const unsigned char *, int, const BIGNUM *,
495 	    const BIGNUM *, EC_KEY *);
496 
497 	log_debug("debug: %s", __func__);
498 	if (EC_KEY_get_ex_data(eckey, 0) != NULL)
499 		return (ecdsae_send_enc_imsg(dgst, dgst_len, inv, rp, eckey));
500 	EC_KEY_METHOD_get_sign(ecdsa_default, NULL, NULL, &psign_sig);
501 	return (psign_sig(dgst, dgst_len, inv, rp, eckey));
502 }
503 
504 
505 /*
506  * Initialize the two engines.
507  */
508 
509 static void
510 rsa_engine_init(void)
511 {
512 	const char	*errstr;
513 
514 	if ((rsa_default = RSA_get_default_method()) == NULL) {
515 		errstr = "RSA_get_default_method";
516 		goto fail;
517 	}
518 
519 	if ((rsae_method = RSA_meth_dup(rsa_default)) == NULL) {
520 		errstr = "RSA_meth_dup";
521 		goto fail;
522 	}
523 
524 	RSA_meth_set_priv_enc(rsae_method, rsae_priv_enc);
525 	RSA_meth_set_priv_dec(rsae_method, rsae_priv_dec);
526 
527 	RSA_meth_set_flags(rsae_method,
528 	    RSA_meth_get_flags(rsa_default) | RSA_METHOD_FLAG_NO_CHECK);
529 	RSA_meth_set0_app_data(rsae_method,
530 	    RSA_meth_get0_app_data(rsa_default));
531 
532 	RSA_set_default_method(rsae_method);
533 
534 	return;
535 
536  fail:
537 	ssl_error(errstr);
538 	fatalx("%s", errstr);
539 }
540 
541 static void
542 ecdsa_engine_init(void)
543 {
544 	int (*sign)(int, const unsigned char *, int, unsigned char *,
545 	    unsigned int *, const BIGNUM *, const BIGNUM *, EC_KEY *);
546 	int (*sign_setup)(EC_KEY *, BN_CTX *, BIGNUM **, BIGNUM **);
547 	const char *errstr;
548 
549 	if ((ecdsa_default = EC_KEY_get_default_method()) == NULL) {
550 		errstr = "EC_KEY_get_default_method";
551 		goto fail;
552 	}
553 
554 	if ((ecdsae_method = EC_KEY_METHOD_new(ecdsa_default)) == NULL) {
555 		errstr = "EC_KEY_METHOD_new";
556 		goto fail;
557 	}
558 
559 	EC_KEY_METHOD_get_sign(ecdsa_default, &sign, &sign_setup, NULL);
560 	EC_KEY_METHOD_set_sign(ecdsae_method, sign, sign_setup,
561 	    ecdsae_do_sign);
562 
563 	EC_KEY_set_default_method(ecdsae_method);
564 
565 	return;
566 
567  fail:
568 	ssl_error(errstr);
569 	fatalx("%s", errstr);
570 }
571 
572 void
573 crypto_engine_init(struct conf *c)
574 {
575 	conf = c;
576 
577 	rsa_engine_init();
578 	ecdsa_engine_init();
579 }
580