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