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