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