xref: /freebsd/usr.sbin/rpc.tlsservd/rpc.tlscommon.c (revision ba3c1f5972d7b90feb6e6da47905ff2757e0fe57)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2021 Rick Macklem
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/queue.h>
33 #include <sys/syslog.h>
34 #include <sys/select.h>
35 #include <sys/time.h>
36 
37 #include <netdb.h>
38 #include <signal.h>
39 #include <stdarg.h>
40 #include <stdbool.h>
41 #include <string.h>
42 
43 #include <rpc/rpc.h>
44 
45 #include <openssl/opensslconf.h>
46 #include <openssl/bio.h>
47 #include <openssl/ssl.h>
48 #include <openssl/err.h>
49 #include <openssl/x509v3.h>
50 
51 #include "rpc.tlscommon.h"
52 
53 /*
54  * How long to delay a reload of the CRL when there are RPC request(s)
55  * to process, in usec.  Must be less than 1second.
56  */
57 #define	RELOADDELAY	250000
58 
59 void
60 rpctls_svc_run(void)
61 {
62 	int ret;
63 	struct timeval tv;
64 	fd_set readfds;
65 	uint64_t curtime, nexttime;
66 	struct timespec tp;
67 	sigset_t sighup_mask;
68 
69 	/* Expand svc_run() here so that we can call rpctls_loadcrlfile(). */
70 	curtime = nexttime = 0;
71 	sigemptyset(&sighup_mask);
72 	sigaddset(&sighup_mask, SIGHUP);
73 	for (;;) {
74 		clock_gettime(CLOCK_MONOTONIC, &tp);
75 		curtime = tp.tv_sec;
76 		curtime = curtime * 1000000 + tp.tv_nsec / 1000;
77 		sigprocmask(SIG_BLOCK, &sighup_mask, NULL);
78 		if (rpctls_gothup && curtime >= nexttime) {
79 			rpctls_gothup = false;
80 			sigprocmask(SIG_UNBLOCK, &sighup_mask, NULL);
81 			ret = rpctls_loadcrlfile(rpctls_ctx);
82 			if (ret != 0)
83 				rpctls_checkcrl();
84 			else
85 				rpctls_verbose_out("rpc.tlsservd: Can't "
86 				    "reload CRLfile\n");
87 			clock_gettime(CLOCK_MONOTONIC, &tp);
88 			nexttime = tp.tv_sec;
89 			nexttime = nexttime * 1000000 + tp.tv_nsec / 1000 +
90 			    RELOADDELAY;
91 		} else
92 			sigprocmask(SIG_UNBLOCK, &sighup_mask, NULL);
93 
94 		/*
95 		 * If a reload is pending, poll for received request(s),
96 		 * otherwise set a RELOADDELAY timeout, since a SIGHUP
97 		 * could be processed between the got_sighup test and
98 		 * the select() system call.
99 		 */
100 		tv.tv_sec = 0;
101 		if (rpctls_gothup)
102 			tv.tv_usec = 0;
103 		else
104 			tv.tv_usec = RELOADDELAY;
105 		readfds = svc_fdset;
106 		switch (select(svc_maxfd + 1, &readfds, NULL, NULL, &tv)) {
107 		case -1:
108 			if (errno == EINTR) {
109 				/* Allow a reload now. */
110 				nexttime = 0;
111 				continue;
112 			}
113 			syslog(LOG_ERR, "rpc.tls daemon died: select: %m");
114 			exit(1);
115 		case 0:
116 			/* Allow a reload now. */
117 			nexttime = 0;
118 			continue;
119 		default:
120 			svc_getreqset(&readfds);
121 		}
122 	}
123 }
124 
125 /*
126  * (re)load the CRLfile into the certificate verification store.
127  */
128 int
129 rpctls_loadcrlfile(SSL_CTX *ctx)
130 {
131 	X509_STORE *certstore;
132 	X509_LOOKUP *certlookup;
133 	int ret;
134 
135 	if ((rpctls_verify_cafile != NULL ||
136 	    rpctls_verify_capath != NULL) &&
137 	    rpctls_crlfile != NULL) {
138 		certstore = SSL_CTX_get_cert_store(ctx);
139 		certlookup = X509_STORE_add_lookup(
140 		    certstore, X509_LOOKUP_file());
141 		ret = 0;
142 		if (certlookup != NULL)
143 			ret = X509_load_crl_file(certlookup,
144 			    rpctls_crlfile, X509_FILETYPE_PEM);
145 		if (ret != 0)
146 			ret = X509_STORE_set_flags(certstore,
147 			    X509_V_FLAG_CRL_CHECK |
148 			    X509_V_FLAG_CRL_CHECK_ALL);
149 		if (ret == 0) {
150 			rpctls_verbose_out(
151 			    "rpctls_loadcrlfile: Can't"
152 			    " load CRLfile=%s\n",
153 			    rpctls_crlfile);
154 			return (ret);
155 		}
156 	}
157 	return (1);
158 }
159 
160 /*
161  * Read the CRL file and check for any extant connections
162  * that might now be revoked.
163  */
164 void
165 rpctls_checkcrl(void)
166 {
167 	struct ssl_entry *slp;
168 	BIO *infile;
169 	X509_CRL *crl;
170 	X509_REVOKED *revoked;
171 	char *cp, *cp2, nullstr[1];
172 	int ret;
173 
174 	if (rpctls_crlfile == NULL || (rpctls_verify_cafile == NULL &&
175 	    rpctls_verify_capath == NULL))
176 		return;
177 	infile = BIO_new(BIO_s_file());
178 	if (infile == NULL) {
179 		rpctls_verbose_out("rpctls_checkcrl: Cannot BIO_new\n");
180 		return;
181 	}
182 	ret = BIO_read_filename(infile, rpctls_crlfile);
183 	if (ret != 1) {
184 		rpctls_verbose_out("rpctls_checkcrl: Cannot read CRL file\n");
185 		BIO_free(infile);
186 		return;
187 	}
188 
189 	nullstr[0] = '\0';
190 	for (crl = PEM_read_bio_X509_CRL(infile, NULL, NULL, nullstr);
191 	    crl != NULL; crl = PEM_read_bio_X509_CRL(infile, NULL, NULL,
192 	    nullstr)) {
193 		LIST_FOREACH(slp, &rpctls_ssllist, next) {
194 			if (slp->cert != NULL) {
195 				ret = X509_CRL_get0_by_cert(crl, &revoked,
196 				    slp->cert);
197 				/*
198 				 * Do a shutdown on the socket, so that it
199 				 * can no longer be used.  The kernel RPC
200 				 * code will notice the socket is disabled
201 				 * and will do a disconnect upcall, which will
202 				 * close the socket.
203 				 */
204 				if (ret == 1) {
205 					cp2 = X509_NAME_oneline(
206 					    X509_get_subject_name(slp->cert),
207 					    NULL, 0);
208 					cp = X509_NAME_oneline(
209 					    X509_get_issuer_name(slp->cert),
210 					    NULL, 0);
211 					if (rpctls_debug_level == 0)
212 						syslog(LOG_INFO | LOG_DAEMON,
213 						    "rpctls_daemon: Certificate"
214 						    " Revoked "
215 						    "issuerName=%s "
216 						    "subjectName=%s: "
217 						    "TCP connection closed",
218 						    cp, cp2);
219 					else
220 						fprintf(stderr,
221 						    "rpctls_daemon: Certificate"
222 						    " Revoked "
223 						    "issuerName=%s "
224 						    "subjectName=%s: "
225 						    "TCP connection closed",
226 						    cp, cp2);
227 					shutdown(slp->s, SHUT_WR);
228 					slp->shutoff = true;
229 				}
230 			}
231 		}
232 		X509_CRL_free(crl);
233 	}
234 	BIO_free(infile);
235 }
236 
237 void
238 rpctls_verbose_out(const char *fmt, ...)
239 {
240 	va_list ap;
241 
242 	if (rpctls_verbose) {
243 		va_start(ap, fmt);
244 		if (rpctls_debug_level == 0)
245 			vsyslog(LOG_INFO | LOG_DAEMON, fmt, ap);
246 		else
247 			vfprintf(stderr, fmt, ap);
248 		va_end(ap);
249 	}
250 }
251 
252 /*
253  * Check a IP address against any host address in the
254  * certificate.  Basically getnameinfo(3) and
255  * X509_check_host().
256  */
257 int
258 rpctls_checkhost(struct sockaddr *sad, X509 *cert, unsigned int wildcard)
259 {
260 	char hostnam[NI_MAXHOST];
261 	int ret;
262 
263 	if (getnameinfo((const struct sockaddr *)sad,
264 	    sad->sa_len, hostnam, sizeof(hostnam),
265 	    NULL, 0, NI_NAMEREQD) != 0)
266 		return (0);
267 	rpctls_verbose_out("rpctls_checkhost: DNS %s\n",
268 	    hostnam);
269 	ret = X509_check_host(cert, hostnam, strlen(hostnam),
270 	    wildcard, NULL);
271 	return (ret);
272 }
273 
274 /*
275  * Get the peer's IP address.
276  */
277 int
278 rpctls_gethost(int s, struct sockaddr *sad, char *hostip, size_t hostlen)
279 {
280 	socklen_t slen;
281 	int ret;
282 
283 	slen = sizeof(struct sockaddr_storage);
284 	if (getpeername(s, sad, &slen) < 0)
285 		return (0);
286 	ret = 0;
287 	if (getnameinfo((const struct sockaddr *)sad,
288 	    sad->sa_len, hostip, hostlen,
289 	    NULL, 0, NI_NUMERICHOST) == 0) {
290 		rpctls_verbose_out("rpctls_gethost: %s\n",
291 		    hostip);
292 		ret = 1;
293 	}
294 	return (ret);
295 }
296