1 /*
2  * Copyright (c) 2018, 2019 Ori Bernstein <ori@openbsd.org>
3  * Copyright (c) 2021 Stefan Sperling <stsp@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <sys/queue.h>
19 #include <sys/types.h>
20 #include <sys/socket.h>
21 #include <netdb.h>
22 
23 #include <assert.h>
24 #include <err.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <unistd.h>
29 
30 #include "got_error.h"
31 #include "got_path.h"
32 
33 #include "got_lib_dial.h"
34 #include "got_dial.h"
35 
36 #ifndef nitems
37 #define nitems(_a) (sizeof((_a)) / sizeof((_a)[0]))
38 #endif
39 
40 #ifndef ssizeof
41 #define ssizeof(_x) ((ssize_t)(sizeof(_x)))
42 #endif
43 
44 #ifndef MIN
45 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
46 #endif
47 
48 #ifndef GOT_DIAL_PATH_SSH
49 #define GOT_DIAL_PATH_SSH	"/usr/bin/ssh"
50 #endif
51 
52 /* IANA assigned */
53 #define GOT_DEFAULT_GIT_PORT		9418
54 #define GOT_DEFAULT_GIT_PORT_STR	"9418"
55 
56 const struct got_error *
57 got_dial_apply_unveil(const char *proto)
58 {
59 	if (strcmp(proto, "git+ssh") == 0 || strcmp(proto, "ssh") == 0) {
60 		if (unveil(GOT_DIAL_PATH_SSH, "x") != 0) {
61 			return got_error_from_errno2("unveil",
62 			    GOT_DIAL_PATH_SSH);
63 		}
64 	}
65 
66 	return NULL;
67 }
68 
69 static int
70 hassuffix(const char *base, const char *suf)
71 {
72 	int nb, ns;
73 
74 	nb = strlen(base);
75 	ns = strlen(suf);
76 	if (ns <= nb && strcmp(base + (nb - ns), suf) == 0)
77 		return 1;
78 	return 0;
79 }
80 
81 const struct got_error *
82 got_dial_parse_uri(char **proto, char **host, char **port,
83     char **server_path, char **repo_name, const char *uri)
84 {
85 	const struct got_error *err = NULL;
86 	char *s, *p, *q;
87 
88 	*proto = *host = *port = *server_path = *repo_name = NULL;
89 
90 	p = strstr(uri, "://");
91 	if (!p) {
92 		/* Try parsing Git's "scp" style URL syntax. */
93 		*proto = strdup("ssh");
94 		if (*proto == NULL) {
95 			err = got_error_from_errno("strdup");
96 			goto done;
97 		}
98 		s = (char *)uri;
99 		q = strchr(s, ':');
100 		if (q == NULL) {
101 			err = got_error(GOT_ERR_PARSE_URI);
102 			goto done;
103 		}
104 		/* No slashes allowed before first colon. */
105 		p = strchr(s, '/');
106 		if (p && q > p) {
107 			err = got_error(GOT_ERR_PARSE_URI);
108 			goto done;
109 		}
110 		*host = strndup(s, q - s);
111 		if (*host == NULL) {
112 			err = got_error_from_errno("strndup");
113 			goto done;
114 		}
115 		if ((*host)[0] == '\0') {
116 			err = got_error(GOT_ERR_PARSE_URI);
117 			goto done;
118 		}
119 		p = q + 1;
120 	} else {
121 		*proto = strndup(uri, p - uri);
122 		if (*proto == NULL) {
123 			err = got_error_from_errno("strndup");
124 			goto done;
125 		}
126 		s = p + 3;
127 
128 		p = strstr(s, "/");
129 		if (p == NULL || strlen(p) == 1) {
130 			err = got_error(GOT_ERR_PARSE_URI);
131 			goto done;
132 		}
133 
134 		q = memchr(s, ':', p - s);
135 		if (q) {
136 			*host = strndup(s, q - s);
137 			if (*host == NULL) {
138 				err = got_error_from_errno("strndup");
139 				goto done;
140 			}
141 			if ((*host)[0] == '\0') {
142 				err = got_error(GOT_ERR_PARSE_URI);
143 				goto done;
144 			}
145 			*port = strndup(q + 1, p - (q + 1));
146 			if (*port == NULL) {
147 				err = got_error_from_errno("strndup");
148 				goto done;
149 			}
150 			if ((*port)[0] == '\0') {
151 				err = got_error(GOT_ERR_PARSE_URI);
152 				goto done;
153 			}
154 		} else {
155 			*host = strndup(s, p - s);
156 			if (*host == NULL) {
157 				err = got_error_from_errno("strndup");
158 				goto done;
159 			}
160 			if ((*host)[0] == '\0') {
161 				err = got_error(GOT_ERR_PARSE_URI);
162 				goto done;
163 			}
164 		}
165 	}
166 
167 	while (p[0] == '/' && p[1] == '/')
168 		p++;
169 	*server_path = strdup(p);
170 	if (*server_path == NULL) {
171 		err = got_error_from_errno("strdup");
172 		goto done;
173 	}
174 	got_path_strip_trailing_slashes(*server_path);
175 	if ((*server_path)[0] == '\0') {
176 		err = got_error(GOT_ERR_PARSE_URI);
177 		goto done;
178 	}
179 
180 	err = got_path_basename(repo_name, *server_path);
181 	if (err)
182 		goto done;
183 	if (hassuffix(*repo_name, ".git"))
184 		(*repo_name)[strlen(*repo_name) - 4] = '\0';
185 	if ((*repo_name)[0] == '\0')
186 		err = got_error(GOT_ERR_PARSE_URI);
187 done:
188 	if (err) {
189 		free(*proto);
190 		*proto = NULL;
191 		free(*host);
192 		*host = NULL;
193 		free(*port);
194 		*port = NULL;
195 		free(*server_path);
196 		*server_path = NULL;
197 		free(*repo_name);
198 		*repo_name = NULL;
199 	}
200 	return err;
201 }
202 
203 const struct got_error *
204 got_dial_ssh(pid_t *newpid, int *newfd, const char *host,
205     const char *port, const char *path, const char *direction, int verbosity)
206 {
207 	const struct got_error *error = NULL;
208 	int pid, pfd[2];
209 	char cmd[64];
210 	const char *argv[11];
211 	int i = 0, j;
212 
213 	*newpid = -1;
214 	*newfd = -1;
215 
216 	argv[i++] = GOT_DIAL_PATH_SSH;
217 	if (port != NULL) {
218 		argv[i++] = "-p";
219 		argv[i++] = (char *)port;
220 	}
221 	if (verbosity == -1) {
222 		argv[i++] = "-q";
223 	} else {
224 		/* ssh(1) allows up to 3 "-v" options. */
225 		for (j = 0; j < MIN(3, verbosity); j++)
226 			argv[i++] = "-v";
227 	}
228 	argv[i++] = "--";
229 	argv[i++] = (char *)host;
230 	argv[i++] = (char *)cmd;
231 	argv[i++] = (char *)path;
232 	argv[i++] = NULL;
233 	assert(i <= nitems(argv));
234 
235 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pfd) == -1)
236 		return got_error_from_errno("socketpair");
237 
238 	pid = fork();
239 	if (pid == -1) {
240 		error = got_error_from_errno("fork");
241 		close(pfd[0]);
242 		close(pfd[1]);
243 		return error;
244 	} else if (pid == 0) {
245 		int n;
246 		if (close(pfd[1]) == -1)
247 			err(1, "close");
248 		if (dup2(pfd[0], 0) == -1)
249 			err(1, "dup2");
250 		if (dup2(pfd[0], 1) == -1)
251 			err(1, "dup2");
252 		n = snprintf(cmd, sizeof(cmd), "git-%s-pack", direction);
253 		if (n < 0 || n >= ssizeof(cmd))
254 			err(1, "snprintf");
255 		if (execv(GOT_DIAL_PATH_SSH, (char *const *)argv) == -1)
256 			err(1, "execv");
257 		abort(); /* not reached */
258 	} else {
259 		if (close(pfd[0]) == -1)
260 			return got_error_from_errno("close");
261 		*newpid = pid;
262 		*newfd = pfd[1];
263 		return NULL;
264 	}
265 }
266 
267 const struct got_error *
268 got_dial_git(int *newfd, const char *host, const char *port,
269     const char *path, const char *direction)
270 {
271 	const struct got_error *err = NULL;
272 	struct addrinfo hints, *servinfo, *p;
273 	char *cmd = NULL;
274 	int fd = -1, len, r, eaicode;
275 
276 	*newfd = -1;
277 
278 	if (port == NULL)
279 		port = GOT_DEFAULT_GIT_PORT_STR;
280 
281 	memset(&hints, 0, sizeof hints);
282 	hints.ai_family = AF_UNSPEC;
283 	hints.ai_socktype = SOCK_STREAM;
284 	eaicode = getaddrinfo(host, port, &hints, &servinfo);
285 	if (eaicode) {
286 		char msg[512];
287 		snprintf(msg, sizeof(msg), "%s: %s", host,
288 		    gai_strerror(eaicode));
289 		return got_error_msg(GOT_ERR_ADDRINFO, msg);
290 	}
291 
292 	for (p = servinfo; p != NULL; p = p->ai_next) {
293 		if ((fd = socket(p->ai_family, p->ai_socktype,
294 		    p->ai_protocol)) == -1)
295 			continue;
296 		if (connect(fd, p->ai_addr, p->ai_addrlen) == 0) {
297 			err = NULL;
298 			break;
299 		}
300 		err = got_error_from_errno("connect");
301 		close(fd);
302 	}
303 	freeaddrinfo(servinfo);
304 	if (p == NULL)
305 		goto done;
306 
307 	if (asprintf(&cmd, "git-%s-pack %s", direction, path) == -1) {
308 		err = got_error_from_errno("asprintf");
309 		goto done;
310 	}
311 	len = 4 + strlen(cmd) + 1 + strlen("host=") + strlen(host) + 1;
312 	r = dprintf(fd, "%04x%s%chost=%s%c", len, cmd, '\0', host, '\0');
313 	if (r < 0)
314 		err = got_error_from_errno("dprintf");
315 done:
316 	free(cmd);
317 	if (err) {
318 		if (fd != -1)
319 			close(fd);
320 	} else
321 		*newfd = fd;
322 	return err;
323 }