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 "got_compat.h"
19 
20 #include <sys/queue.h>
21 #include <sys/types.h>
22 #include <sys/socket.h>
23 #include <netdb.h>
24 
25 #include <assert.h>
26 #include <err.h>
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <unistd.h>
31 
32 #include "got_error.h"
33 #include "got_path.h"
34 
35 #include "got_compat.h"
36 
37 #include "got_lib_dial.h"
38 #include "got_dial.h"
39 
40 #ifndef nitems
41 #define nitems(_a) (sizeof((_a)) / sizeof((_a)[0]))
42 #endif
43 
44 #ifndef ssizeof
45 #define ssizeof(_x) ((ssize_t)(sizeof(_x)))
46 #endif
47 
48 #ifndef MIN
49 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
50 #endif
51 
52 #ifndef GOT_DIAL_PATH_SSH
53 #define GOT_DIAL_PATH_SSH	"/usr/bin/ssh"
54 #endif
55 
56 /* IANA assigned */
57 #define GOT_DEFAULT_GIT_PORT		9418
58 #define GOT_DEFAULT_GIT_PORT_STR	"9418"
59 
60 const struct got_error *
61 got_dial_apply_unveil(const char *proto)
62 {
63 	if (strcmp(proto, "git+ssh") == 0 || strcmp(proto, "ssh") == 0) {
64 		if (unveil(GOT_DIAL_PATH_SSH, "x") != 0) {
65 			return got_error_from_errno2("unveil",
66 			    GOT_DIAL_PATH_SSH);
67 		}
68 	}
69 
70 	return NULL;
71 }
72 
73 static int
74 hassuffix(const char *base, const char *suf)
75 {
76 	int nb, ns;
77 
78 	nb = strlen(base);
79 	ns = strlen(suf);
80 	if (ns <= nb && strcmp(base + (nb - ns), suf) == 0)
81 		return 1;
82 	return 0;
83 }
84 
85 const struct got_error *
86 got_dial_parse_uri(char **proto, char **host, char **port,
87     char **server_path, char **repo_name, const char *uri)
88 {
89 	const struct got_error *err = NULL;
90 	char *s, *p, *q;
91 
92 	*proto = *host = *port = *server_path = *repo_name = NULL;
93 
94 	p = strstr(uri, "://");
95 	if (!p) {
96 		/* Try parsing Git's "scp" style URL syntax. */
97 		*proto = strdup("ssh");
98 		if (*proto == NULL) {
99 			err = got_error_from_errno("strdup");
100 			goto done;
101 		}
102 		s = (char *)uri;
103 		q = strchr(s, ':');
104 		if (q == NULL) {
105 			err = got_error(GOT_ERR_PARSE_URI);
106 			goto done;
107 		}
108 		/* No slashes allowed before first colon. */
109 		p = strchr(s, '/');
110 		if (p && q > p) {
111 			err = got_error(GOT_ERR_PARSE_URI);
112 			goto done;
113 		}
114 		*host = strndup(s, q - s);
115 		if (*host == NULL) {
116 			err = got_error_from_errno("strndup");
117 			goto done;
118 		}
119 		if ((*host)[0] == '\0') {
120 			err = got_error(GOT_ERR_PARSE_URI);
121 			goto done;
122 		}
123 		p = q + 1;
124 	} else {
125 		*proto = strndup(uri, p - uri);
126 		if (*proto == NULL) {
127 			err = got_error_from_errno("strndup");
128 			goto done;
129 		}
130 		s = p + 3;
131 
132 		p = strstr(s, "/");
133 		if (p == NULL || strlen(p) == 1) {
134 			err = got_error(GOT_ERR_PARSE_URI);
135 			goto done;
136 		}
137 
138 		q = memchr(s, ':', p - s);
139 		if (q) {
140 			*host = strndup(s, q - s);
141 			if (*host == NULL) {
142 				err = got_error_from_errno("strndup");
143 				goto done;
144 			}
145 			if ((*host)[0] == '\0') {
146 				err = got_error(GOT_ERR_PARSE_URI);
147 				goto done;
148 			}
149 			*port = strndup(q + 1, p - (q + 1));
150 			if (*port == NULL) {
151 				err = got_error_from_errno("strndup");
152 				goto done;
153 			}
154 			if ((*port)[0] == '\0') {
155 				err = got_error(GOT_ERR_PARSE_URI);
156 				goto done;
157 			}
158 		} else {
159 			*host = strndup(s, p - s);
160 			if (*host == NULL) {
161 				err = got_error_from_errno("strndup");
162 				goto done;
163 			}
164 			if ((*host)[0] == '\0') {
165 				err = got_error(GOT_ERR_PARSE_URI);
166 				goto done;
167 			}
168 		}
169 	}
170 
171 	while (p[0] == '/' && p[1] == '/')
172 		p++;
173 	*server_path = strdup(p);
174 	if (*server_path == NULL) {
175 		err = got_error_from_errno("strdup");
176 		goto done;
177 	}
178 	got_path_strip_trailing_slashes(*server_path);
179 	if ((*server_path)[0] == '\0') {
180 		err = got_error(GOT_ERR_PARSE_URI);
181 		goto done;
182 	}
183 
184 	err = got_path_basename(repo_name, *server_path);
185 	if (err)
186 		goto done;
187 	if (hassuffix(*repo_name, ".git"))
188 		(*repo_name)[strlen(*repo_name) - 4] = '\0';
189 	if ((*repo_name)[0] == '\0')
190 		err = got_error(GOT_ERR_PARSE_URI);
191 done:
192 	if (err) {
193 		free(*proto);
194 		*proto = NULL;
195 		free(*host);
196 		*host = NULL;
197 		free(*port);
198 		*port = NULL;
199 		free(*server_path);
200 		*server_path = NULL;
201 		free(*repo_name);
202 		*repo_name = NULL;
203 	}
204 	return err;
205 }
206 
207 const struct got_error *
208 got_dial_ssh(pid_t *newpid, int *newfd, const char *host,
209     const char *port, const char *path, const char *direction, int verbosity)
210 {
211 	const struct got_error *error = NULL;
212 	int pid, pfd[2];
213 	char cmd[64];
214 	const char *argv[11];
215 	int i = 0, j;
216 
217 	*newpid = -1;
218 	*newfd = -1;
219 
220 	argv[i++] = GOT_DIAL_PATH_SSH;
221 	if (port != NULL) {
222 		argv[i++] = "-p";
223 		argv[i++] = (char *)port;
224 	}
225 	if (verbosity == -1) {
226 		argv[i++] = "-q";
227 	} else {
228 		/* ssh(1) allows up to 3 "-v" options. */
229 		for (j = 0; j < MIN(3, verbosity); j++)
230 			argv[i++] = "-v";
231 	}
232 	argv[i++] = "--";
233 	argv[i++] = (char *)host;
234 	argv[i++] = (char *)cmd;
235 	argv[i++] = (char *)path;
236 	argv[i++] = NULL;
237 	assert(i <= nitems(argv));
238 
239 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pfd) == -1)
240 		return got_error_from_errno("socketpair");
241 
242 	pid = fork();
243 	if (pid == -1) {
244 		error = got_error_from_errno("fork");
245 		close(pfd[0]);
246 		close(pfd[1]);
247 		return error;
248 	} else if (pid == 0) {
249 		int n;
250 		if (close(pfd[1]) == -1)
251 			err(1, "close");
252 		if (dup2(pfd[0], 0) == -1)
253 			err(1, "dup2");
254 		if (dup2(pfd[0], 1) == -1)
255 			err(1, "dup2");
256 		n = snprintf(cmd, sizeof(cmd), "git-%s-pack", direction);
257 		if (n < 0 || n >= ssizeof(cmd))
258 			err(1, "snprintf");
259 		if (execv(GOT_DIAL_PATH_SSH, (char *const *)argv) == -1)
260 			err(1, "execv");
261 		abort(); /* not reached */
262 	} else {
263 		if (close(pfd[0]) == -1)
264 			return got_error_from_errno("close");
265 		*newpid = pid;
266 		*newfd = pfd[1];
267 		return NULL;
268 	}
269 }
270 
271 const struct got_error *
272 got_dial_git(int *newfd, const char *host, const char *port,
273     const char *path, const char *direction)
274 {
275 	const struct got_error *err = NULL;
276 	struct addrinfo hints, *servinfo, *p;
277 	char *cmd = NULL;
278 	int fd = -1, len, r, eaicode;
279 
280 	*newfd = -1;
281 
282 	if (port == NULL)
283 		port = GOT_DEFAULT_GIT_PORT_STR;
284 
285 	memset(&hints, 0, sizeof hints);
286 	hints.ai_family = AF_UNSPEC;
287 	hints.ai_socktype = SOCK_STREAM;
288 	eaicode = getaddrinfo(host, port, &hints, &servinfo);
289 	if (eaicode) {
290 		char msg[512];
291 		snprintf(msg, sizeof(msg), "%s: %s", host,
292 		    gai_strerror(eaicode));
293 		return got_error_msg(GOT_ERR_ADDRINFO, msg);
294 	}
295 
296 	for (p = servinfo; p != NULL; p = p->ai_next) {
297 		if ((fd = socket(p->ai_family, p->ai_socktype,
298 		    p->ai_protocol)) == -1)
299 			continue;
300 		if (connect(fd, p->ai_addr, p->ai_addrlen) == 0) {
301 			err = NULL;
302 			break;
303 		}
304 		err = got_error_from_errno("connect");
305 		close(fd);
306 	}
307 	freeaddrinfo(servinfo);
308 	if (p == NULL)
309 		goto done;
310 
311 	if (asprintf(&cmd, "git-%s-pack %s", direction, path) == -1) {
312 		err = got_error_from_errno("asprintf");
313 		goto done;
314 	}
315 	len = 4 + strlen(cmd) + 1 + strlen("host=") + strlen(host) + 1;
316 	r = dprintf(fd, "%04x%s%chost=%s%c", len, cmd, '\0', host, '\0');
317 	if (r < 0)
318 		err = got_error_from_errno("dprintf");
319 done:
320 	free(cmd);
321 	if (err) {
322 		if (fd != -1)
323 			close(fd);
324 	} else
325 		*newfd = fd;
326 	return err;
327 }