1 /*
2  * Copyright (c) 2021, 2023 Omar Polo <op@omarpolo.com>
3  * Copyright (c) 2008 Pierre-Yves Ritschard <pyr@openbsd.org>
4  * Copyright (c) 2008 Reyk Floeter <reyk@openbsd.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 <errno.h>
22 #include <string.h>
23 
24 #include <openssl/bn.h>
25 #include <openssl/err.h>
26 #include <openssl/pem.h>
27 #include <openssl/x509_vfy.h>
28 #include <openssl/x509v3.h>
29 
30 #include "log.h"
31 
32 const char *
33 strip_path(const char *path, int strip)
34 {
35 	char *t;
36 
37 	while (strip > 0) {
38 		if ((t = strchr(path, '/')) == NULL) {
39 			path = strchr(path, '\0');
40 			break;
41 		}
42 		path = t;
43 		strip--;
44 	}
45 
46 	return path;
47 }
48 
49 int
50 starts_with(const char *str, const char *prefix)
51 {
52 	size_t i;
53 
54 	if (prefix == NULL)
55 		return 0;
56 
57 	for (i = 0; prefix[i] != '\0'; ++i)
58 		if (str[i] != prefix[i])
59 			return 0;
60 	return 1;
61 }
62 
63 int
64 ends_with(const char *str, const char *sufx)
65 {
66 	size_t i, j;
67 
68 	i = strlen(str);
69 	j = strlen(sufx);
70 
71 	if (j > i)
72 		return 0;
73 
74 	i -= j;
75 	for (j = 0; str[i] != '\0'; i++, j++)
76 		if (str[i] != sufx[j])
77 			return 0;
78 	return 1;
79 }
80 
81 char *
82 absolutify_path(const char *path)
83 {
84 	char *wd, *r;
85 
86 	if (*path == '/') {
87 		if ((r = strdup(path)) == NULL)
88 			fatal("strdup");
89 		return r;
90 	}
91 
92 	wd = getcwd(NULL, 0);
93 	if (asprintf(&r, "%s/%s", wd, path) == -1)
94 		fatal("asprintf");
95 	free(wd);
96 	return r;
97 }
98 
99 char *
100 xstrdup(const char *s)
101 {
102 	char *d;
103 
104 	if ((d = strdup(s)) == NULL)
105 		fatal("strdup");
106 	return d;
107 }
108 
109 void *
110 xcalloc(size_t nmemb, size_t size)
111 {
112 	void *d;
113 
114 	if ((d = calloc(nmemb, size)) == NULL)
115 		fatal("calloc");
116 	return d;
117 }
118 
119 void
120 gen_certificate(const char *hostname, const char *certpath, const char *keypath)
121 {
122 	BIGNUM		*e;
123 	EVP_PKEY	*pkey;
124 	RSA		*rsa;
125 	X509		*x509;
126 	X509_NAME	*name;
127 	FILE		*f;
128 	const unsigned char *host = (const unsigned char*)hostname;
129 
130 	log_info("generating new certificate for %s (it could take a while)",
131 	    host);
132 
133 	if ((pkey = EVP_PKEY_new()) == NULL)
134 		fatalx("couldn't create a new private key");
135 
136 	if ((rsa = RSA_new()) == NULL)
137 		fatalx("couldn't generate rsa");
138 
139 	if ((e = BN_new()) == NULL)
140 		fatalx("couldn't allocate a bignum");
141 
142 	BN_set_word(e, RSA_F4);
143 	if (!RSA_generate_key_ex(rsa, 4096, e, NULL))
144 		fatalx("couldn't generate a rsa key");
145 
146 	if (!EVP_PKEY_assign_RSA(pkey, rsa))
147 		fatalx("couldn't assign the key");
148 
149 	if ((x509 = X509_new()) == NULL)
150 		fatalx("couldn't generate the X509 certificate");
151 
152 	ASN1_INTEGER_set(X509_get_serialNumber(x509), 0);
153 	X509_gmtime_adj(X509_get_notBefore(x509), 0);
154 	X509_gmtime_adj(X509_get_notAfter(x509), 315360000L); /* 10 years */
155 	X509_set_version(x509, 3);
156 
157 	if (!X509_set_pubkey(x509, pkey))
158 		fatalx("couldn't set the public key");
159 
160 	name = X509_get_subject_name(x509);
161 	if (!X509_NAME_add_entry_by_txt(name, "CN", MBSTRING_ASC, host, -1, -1, 0))
162 		fatalx("couldn't add CN to cert");
163 	X509_set_issuer_name(x509, name);
164 
165 	if (!X509_sign(x509, pkey, EVP_sha256()))
166 		fatalx("couldn't sign the certificate");
167 
168 	if ((f = fopen(keypath, "w")) == NULL)
169 		fatal("can't open %s", keypath);
170 	if (!PEM_write_PrivateKey(f, pkey, NULL, NULL, 0, NULL, NULL))
171 		fatalx("couldn't write private key");
172 	fclose(f);
173 
174 	if ((f = fopen(certpath, "w")) == NULL)
175 		fatal("can't open %s", certpath);
176 	if (!PEM_write_X509(f, x509))
177 		fatalx("couldn't write cert");
178 	fclose(f);
179 
180 	BN_free(e);
181 	X509_free(x509);
182 	RSA_free(rsa);
183 
184 	log_info("certificate successfully generated");
185 }
186 
187 X509_STORE *
188 load_ca(uint8_t *d, size_t len)
189 {
190 	BIO		*in;
191 	X509		*x = NULL;
192 	X509_STORE	*store;
193 
194 	if ((store = X509_STORE_new()) == NULL) {
195 		log_warnx("%s: X509_STORE_new failed", __func__);
196 		return NULL;
197 	}
198 
199 	if ((in = BIO_new_mem_buf(d, len)) == NULL) {
200 		log_warnx("%s: BIO_new_mem_buf failed", __func__);
201 		goto err;
202 	}
203 
204 	if ((x = PEM_read_bio_X509(in, NULL, NULL, NULL)) == NULL) {
205 		log_warnx("%s: PEM_read_bio_X509 failed", __func__);
206 		ssl_error("PEM_read_bio_X509");
207 		goto err;
208 	}
209 
210 	if (X509_check_ca(x) == 0) {
211 		ssl_error("X509_check_ca");
212 		goto err;
213 	}
214 
215 	if (!X509_STORE_add_cert(store, x)) {
216 		ssl_error("X509_STORE_add_cert");
217 		goto err;
218 	}
219 
220 	X509_free(x);
221 	BIO_free(in);
222 	return store;
223 
224 err:
225 	X509_STORE_free(store);
226 	if (x != NULL)
227 		X509_free(x);
228 	if (in != NULL)
229 		BIO_free(in);
230 	return NULL;
231 }
232 
233 int
234 validate_against_ca(X509_STORE *ca, const uint8_t *chain, size_t len)
235 {
236 	X509		*client;
237 	BIO		*m;
238 	X509_STORE_CTX	*ctx = NULL;
239 	int		 ret = 0;
240 
241 	if ((m = BIO_new_mem_buf(chain, len)) == NULL)
242 		return 0;
243 
244 	if ((client = PEM_read_bio_X509(m, NULL, NULL, NULL)) == NULL)
245 		goto end;
246 
247 	if ((ctx = X509_STORE_CTX_new()) == NULL)
248 		goto end;
249 
250 	if (!X509_STORE_CTX_init(ctx, ca, client, NULL))
251 		goto end;
252 
253 	ret = X509_verify_cert(ctx);
254 
255 end:
256 	BIO_free(m);
257 	if (client != NULL)
258 		X509_free(client);
259 	if (ctx != NULL)
260 		X509_STORE_CTX_free(ctx);
261 	return ret;
262 }
263 
264 void
265 ssl_error(const char *where)
266 {
267 	unsigned long	 code;
268 	char		 errbuf[128];
269 
270 	while ((code = ERR_get_error()) != 0) {
271 		ERR_error_string_n(code, errbuf, sizeof(errbuf));
272 		log_debug("debug: SSL library error: %s: %s", where, errbuf);
273 	}
274 }
275 
276 char *
277 ssl_pubkey_hash(const uint8_t *buf, size_t len)
278 {
279 	static const char hex[] = "0123456789abcdef";
280 	BIO		*in;
281 	X509		*x509 = NULL;
282 	char		*hash = NULL;
283 	size_t		 off;
284 	unsigned char	 digest[EVP_MAX_MD_SIZE];
285 	unsigned int	 dlen, i;
286 
287 	if ((in = BIO_new_mem_buf(buf, len)) == NULL) {
288 		log_warnx("%s: BIO_new_mem_buf failed", __func__);
289 		return NULL;
290 	}
291 
292 	if ((x509 = PEM_read_bio_X509(in, NULL, NULL, NULL)) == NULL) {
293 		log_warnx("%s: PEM_read_bio_X509 failed", __func__);
294 		ssl_error("PEM_read_bio_X509");
295 		goto fail;
296 	}
297 
298 	if ((hash = malloc(TLS_CERT_HASH_SIZE)) == NULL) {
299 		log_warn("%s: malloc", __func__);
300 		goto fail;
301 	}
302 
303 	if (X509_pubkey_digest(x509, EVP_sha256(), digest, &dlen) != 1) {
304 		log_warnx("%s: X509_pubkey_digest failed", __func__);
305 		ssl_error("X509_pubkey_digest");
306 		free(hash);
307 		hash = NULL;
308 		goto fail;
309 	}
310 
311 	if (TLS_CERT_HASH_SIZE < 2 * dlen + sizeof("SHA256:"))
312 		fatalx("%s: hash buffer too small", __func__);
313 
314 	off = strlcpy(hash, "SHA256:", TLS_CERT_HASH_SIZE);
315 	for (i = 0; i < dlen; ++i) {
316 		hash[off++] = hex[(digest[i] >> 4) & 0xf];
317 		hash[off++] = hex[digest[i] & 0xf];
318 	}
319 	hash[off] = '\0';
320 
321  fail:
322 	BIO_free(in);
323 	if (x509)
324 		X509_free(x509);
325 	return hash;
326 }
327 
328 EVP_PKEY *
329 ssl_load_pkey(const uint8_t *buf, size_t len)
330 {
331 	BIO		*in;
332 	EVP_PKEY	*pkey;
333 
334 	if ((in = BIO_new_mem_buf(buf, len)) == NULL) {
335 		log_warnx("%s: BIO_new_mem_buf failed", __func__);
336 		return NULL;
337 	}
338 
339 	if ((pkey = PEM_read_bio_PrivateKey(in, NULL, NULL, NULL)) == NULL) {
340 		log_warnx("%s: PEM_read_bio_PrivateKey failed", __func__);
341 		ssl_error("PEM_read_bio_PrivateKey");
342 	}
343 
344 	BIO_free(in);
345 	return pkey;
346 }
347 
348 struct vhost *
349 new_vhost(void)
350 {
351 	struct vhost *h;
352 
353 	h = xcalloc(1, sizeof(*h));
354 	TAILQ_INIT(&h->addrs);
355 	TAILQ_INIT(&h->locations);
356 	TAILQ_INIT(&h->aliases);
357 	TAILQ_INIT(&h->proxies);
358 	return h;
359 }
360 
361 struct location *
362 new_location(void)
363 {
364 	struct location *l;
365 
366 	l = xcalloc(1, sizeof(*l));
367 	l->dirfd = -1;
368 	l->fcgi = -1;
369 	TAILQ_INIT(&l->params);
370 	return l;
371 }
372 
373 struct proxy *
374 new_proxy(void)
375 {
376 	struct proxy *p;
377 
378 	p = xcalloc(1, sizeof(*p));
379 	p->protocols = TLS_PROTOCOLS_DEFAULT;
380 	return p;
381 }