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 	int n;
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 		p = q + 1;
116 	} else {
117 		*proto = strndup(uri, p - uri);
118 		if (proto == NULL) {
119 			err = got_error_from_errno("strndup");
120 			goto done;
121 		}
122 		s = p + 3;
123 
124 		p = strstr(s, "/");
125 		if (p == NULL || strlen(p) == 1) {
126 			err = got_error(GOT_ERR_PARSE_URI);
127 			goto done;
128 		}
129 
130 		q = memchr(s, ':', p - s);
131 		if (q) {
132 			*host = strndup(s, q - s);
133 			if (*host == NULL) {
134 				err = got_error_from_errno("strndup");
135 				goto done;
136 			}
137 			*port = strndup(q + 1, p - (q + 1));
138 			if (*port == NULL) {
139 				err = got_error_from_errno("strndup");
140 				goto done;
141 			}
142 		} else {
143 			*host = strndup(s, p - s);
144 			if (*host == NULL) {
145 				err = got_error_from_errno("strndup");
146 				goto done;
147 			}
148 		}
149 	}
150 
151 	while (p[0] == '/' && p[1] == '/')
152 		p++;
153 	*server_path = strdup(p);
154 	if (*server_path == NULL) {
155 		err = got_error_from_errno("strdup");
156 		goto done;
157 	}
158 	got_path_strip_trailing_slashes(*server_path);
159 
160 	p = strrchr(p, '/');
161 	if (!p || strlen(p) <= 1) {
162 		err = got_error(GOT_ERR_PARSE_URI);
163 		goto done;
164 	}
165 	p++;
166 	n = strlen(p);
167 	if (n == 0) {
168 		err = got_error(GOT_ERR_PARSE_URI);
169 		goto done;
170 	}
171 	if (hassuffix(p, ".git"))
172 		n -= 4;
173 	*repo_name = strndup(p, (p + n) - p);
174 	if (*repo_name == NULL) {
175 		err = got_error_from_errno("strndup");
176 		goto done;
177 	}
178 done:
179 	if (err) {
180 		free(*proto);
181 		*proto = NULL;
182 		free(*host);
183 		*host = NULL;
184 		free(*port);
185 		*port = NULL;
186 		free(*server_path);
187 		*server_path = NULL;
188 		free(*repo_name);
189 		*repo_name = NULL;
190 	}
191 	return err;
192 }
193 
194 const struct got_error *
195 got_dial_ssh(pid_t *newpid, int *newfd, const char *host,
196     const char *port, const char *path, const char *direction, int verbosity)
197 {
198 	const struct got_error *error = NULL;
199 	int pid, pfd[2];
200 	char cmd[64];
201 	char *argv[11];
202 	int i = 0, j;
203 
204 	*newpid = -1;
205 	*newfd = -1;
206 
207 	argv[i++] = GOT_DIAL_PATH_SSH;
208 	if (port != NULL) {
209 		argv[i++] = "-p";
210 		argv[i++] = (char *)port;
211 	}
212 	if (verbosity == -1) {
213 		argv[i++] = "-q";
214 	} else {
215 		/* ssh(1) allows up to 3 "-v" options. */
216 		for (j = 0; j < MIN(3, verbosity); j++)
217 			argv[i++] = "-v";
218 	}
219 	argv[i++] = "--";
220 	argv[i++] = (char *)host;
221 	argv[i++] = (char *)cmd;
222 	argv[i++] = (char *)path;
223 	argv[i++] = NULL;
224 	assert(i <= nitems(argv));
225 
226 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pfd) == -1)
227 		return got_error_from_errno("socketpair");
228 
229 	pid = fork();
230 	if (pid == -1) {
231 		error = got_error_from_errno("fork");
232 		close(pfd[0]);
233 		close(pfd[1]);
234 		return error;
235 	} else if (pid == 0) {
236 		int n;
237 		if (close(pfd[1]) == -1)
238 			err(1, "close");
239 		if (dup2(pfd[0], 0) == -1)
240 			err(1, "dup2");
241 		if (dup2(pfd[0], 1) == -1)
242 			err(1, "dup2");
243 		n = snprintf(cmd, sizeof(cmd), "git-%s-pack", direction);
244 		if (n < 0 || n >= ssizeof(cmd))
245 			err(1, "snprintf");
246 		if (execv(GOT_DIAL_PATH_SSH, argv) == -1)
247 			err(1, "execv");
248 		abort(); /* not reached */
249 	} else {
250 		if (close(pfd[0]) == -1)
251 			return got_error_from_errno("close");
252 		*newpid = pid;
253 		*newfd = pfd[1];
254 		return NULL;
255 	}
256 }
257 
258 const struct got_error *
259 got_dial_git(int *newfd, const char *host, const char *port,
260     const char *path, const char *direction)
261 {
262 	const struct got_error *err = NULL;
263 	struct addrinfo hints, *servinfo, *p;
264 	char *cmd = NULL;
265 	int fd = -1, len, r, eaicode;
266 
267 	*newfd = -1;
268 
269 	if (port == NULL)
270 		port = GOT_DEFAULT_GIT_PORT_STR;
271 
272 	memset(&hints, 0, sizeof hints);
273 	hints.ai_family = AF_UNSPEC;
274 	hints.ai_socktype = SOCK_STREAM;
275 	eaicode = getaddrinfo(host, port, &hints, &servinfo);
276 	if (eaicode) {
277 		char msg[512];
278 		snprintf(msg, sizeof(msg), "%s: %s", host,
279 		    gai_strerror(eaicode));
280 		return got_error_msg(GOT_ERR_ADDRINFO, msg);
281 	}
282 
283 	for (p = servinfo; p != NULL; p = p->ai_next) {
284 		if ((fd = socket(p->ai_family, p->ai_socktype,
285 		    p->ai_protocol)) == -1)
286 			continue;
287 		if (connect(fd, p->ai_addr, p->ai_addrlen) == 0) {
288 			err = NULL;
289 			break;
290 		}
291 		err = got_error_from_errno("connect");
292 		close(fd);
293 	}
294 	if (p == NULL)
295 		goto done;
296 
297 	if (asprintf(&cmd, "git-%s-pack %s", direction, path) == -1) {
298 		err = got_error_from_errno("asprintf");
299 		goto done;
300 	}
301 	len = 4 + strlen(cmd) + 1 + strlen("host=") + strlen(host) + 1;
302 	r = dprintf(fd, "%04x%s%chost=%s%c", len, cmd, '\0', host, '\0');
303 	if (r < 0)
304 		err = got_error_from_errno("dprintf");
305 done:
306 	free(cmd);
307 	if (err) {
308 		if (fd != -1)
309 			close(fd);
310 	} else
311 		*newfd = fd;
312 	return err;
313 }