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 
36 #ifndef nitems
37 #define nitems(_a) (sizeof((_a)) / sizeof((_a)[0]))
38 #endif
39 
40 #ifndef ssizeof
41 #define ssizeof(_x) ((ssize_t)(sizeof(_x)))
42 #endif
43 
44 #ifndef MIN
45 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
46 #endif
47 
48 #ifndef GOT_DIAL_PATH_SSH
49 #define GOT_DIAL_PATH_SSH	"/usr/bin/ssh"
50 #endif
51 
52 /* IANA assigned */
53 #define GOT_DEFAULT_GIT_PORT		9418
54 #define GOT_DEFAULT_GIT_PORT_STR	"9418"
55 
56 const struct got_error *
57 got_dial_apply_unveil(const char *proto)
58 {
59 	if (strcmp(proto, "git+ssh") == 0 || strcmp(proto, "ssh") == 0) {
60 		if (unveil(GOT_DIAL_PATH_SSH, "x") != 0) {
61 			return got_error_from_errno2("unveil",
62 			    GOT_DIAL_PATH_SSH);
63 		}
64 	}
65 
66 	return NULL;
67 }
68 
69 static int
70 hassuffix(char *base, char *suf)
71 {
72 	int nb, ns;
73 
74 	nb = strlen(base);
75 	ns = strlen(suf);
76 	if (ns <= nb && strcmp(base + (nb - ns), suf) == 0)
77 		return 1;
78 	return 0;
79 }
80 
81 const struct got_error *
82 got_dial_parse_uri(char **proto, char **host, char **port,
83     char **server_path, char **repo_name, const char *uri)
84 {
85 	const struct got_error *err = NULL;
86 	char *s, *p, *q;
87 	int n;
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 		p = q + 1;
117 	} else {
118 		*proto = strndup(uri, p - uri);
119 		if (proto == NULL) {
120 			err = got_error_from_errno("strndup");
121 			goto done;
122 		}
123 		s = p + 3;
124 
125 		p = strstr(s, "/");
126 		if (p == NULL || strlen(p) == 1) {
127 			err = got_error(GOT_ERR_PARSE_URI);
128 			goto done;
129 		}
130 
131 		q = memchr(s, ':', p - s);
132 		if (q) {
133 			*host = strndup(s, q - s);
134 			if (*host == NULL) {
135 				err = got_error_from_errno("strndup");
136 				goto done;
137 			}
138 			*port = strndup(q + 1, p - (q + 1));
139 			if (*port == NULL) {
140 				err = got_error_from_errno("strndup");
141 				goto done;
142 			}
143 		} else {
144 			*host = strndup(s, p - s);
145 			if (*host == NULL) {
146 				err = got_error_from_errno("strndup");
147 				goto done;
148 			}
149 		}
150 	}
151 
152 	while (p[0] == '/' && p[1] == '/')
153 		p++;
154 	*server_path = strdup(p);
155 	if (*server_path == NULL) {
156 		err = got_error_from_errno("strdup");
157 		goto done;
158 	}
159 	got_path_strip_trailing_slashes(*server_path);
160 
161 	p = strrchr(p, '/');
162 	if (!p || strlen(p) <= 1) {
163 		err = got_error(GOT_ERR_PARSE_URI);
164 		goto done;
165 	}
166 	p++;
167 	n = strlen(p);
168 	if (n == 0) {
169 		err = got_error(GOT_ERR_PARSE_URI);
170 		goto done;
171 	}
172 	if (hassuffix(p, ".git"))
173 		n -= 4;
174 	*repo_name = strndup(p, (p + n) - p);
175 	if (*repo_name == NULL) {
176 		err = got_error_from_errno("strndup");
177 		goto done;
178 	}
179 done:
180 	if (err) {
181 		free(*proto);
182 		*proto = NULL;
183 		free(*host);
184 		*host = NULL;
185 		free(*port);
186 		*port = NULL;
187 		free(*server_path);
188 		*server_path = NULL;
189 		free(*repo_name);
190 		*repo_name = NULL;
191 	}
192 	return err;
193 }
194 
195 const struct got_error *
196 got_dial_ssh(pid_t *newpid, int *newfd, const char *host,
197     const char *port, const char *path, const char *direction, int verbosity)
198 {
199 	const struct got_error *error = NULL;
200 	int pid, pfd[2];
201 	char cmd[64];
202 	char *argv[11];
203 	int i = 0, j;
204 
205 	*newpid = -1;
206 	*newfd = -1;
207 
208 	argv[i++] = GOT_DIAL_PATH_SSH;
209 	if (port != NULL) {
210 		argv[i++] = "-p";
211 		argv[i++] = (char *)port;
212 	}
213 	if (verbosity == -1) {
214 		argv[i++] = "-q";
215 	} else {
216 		/* ssh(1) allows up to 3 "-v" options. */
217 		for (j = 0; j < MIN(3, verbosity); j++)
218 			argv[i++] = "-v";
219 	}
220 	argv[i++] = "--";
221 	argv[i++] = (char *)host;
222 	argv[i++] = (char *)cmd;
223 	argv[i++] = (char *)path;
224 	argv[i++] = NULL;
225 	assert(i <= nitems(argv));
226 
227 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pfd) == -1)
228 		return got_error_from_errno("socketpair");
229 
230 	pid = fork();
231 	if (pid == -1) {
232 		error = got_error_from_errno("fork");
233 		close(pfd[0]);
234 		close(pfd[1]);
235 		return error;
236 	} else if (pid == 0) {
237 		int n;
238 		if (close(pfd[1]) == -1)
239 			err(1, "close");
240 		if (dup2(pfd[0], 0) == -1)
241 			err(1, "dup2");
242 		if (dup2(pfd[0], 1) == -1)
243 			err(1, "dup2");
244 		n = snprintf(cmd, sizeof(cmd), "git-%s-pack", direction);
245 		if (n < 0 || n >= ssizeof(cmd))
246 			err(1, "snprintf");
247 		if (execv(GOT_DIAL_PATH_SSH, argv) == -1)
248 			err(1, "execv");
249 		abort(); /* not reached */
250 	} else {
251 		if (close(pfd[0]) == -1)
252 			return got_error_from_errno("close");
253 		*newpid = pid;
254 		*newfd = pfd[1];
255 		return NULL;
256 	}
257 }
258 
259 const struct got_error *
260 got_dial_git(int *newfd, const char *host, const char *port,
261     const char *path, const char *direction)
262 {
263 	const struct got_error *err = NULL;
264 	struct addrinfo hints, *servinfo, *p;
265 	char *cmd = NULL;
266 	int fd = -1, len, r, eaicode;
267 
268 	*newfd = -1;
269 
270 	if (port == NULL)
271 		port = GOT_DEFAULT_GIT_PORT_STR;
272 
273 	memset(&hints, 0, sizeof hints);
274 	hints.ai_family = AF_UNSPEC;
275 	hints.ai_socktype = SOCK_STREAM;
276 	eaicode = getaddrinfo(host, port, &hints, &servinfo);
277 	if (eaicode) {
278 		char msg[512];
279 		snprintf(msg, sizeof(msg), "%s: %s", host,
280 		    gai_strerror(eaicode));
281 		return got_error_msg(GOT_ERR_ADDRINFO, msg);
282 	}
283 
284 	for (p = servinfo; p != NULL; p = p->ai_next) {
285 		if ((fd = socket(p->ai_family, p->ai_socktype,
286 		    p->ai_protocol)) == -1)
287 			continue;
288 		if (connect(fd, p->ai_addr, p->ai_addrlen) == 0) {
289 			err = NULL;
290 			break;
291 		}
292 		err = got_error_from_errno("connect");
293 		close(fd);
294 	}
295 	if (p == NULL)
296 		goto done;
297 
298 	if (asprintf(&cmd, "git-%s-pack %s", direction, path) == -1) {
299 		err = got_error_from_errno("asprintf");
300 		goto done;
301 	}
302 	len = 4 + strlen(cmd) + 1 + strlen("host=") + strlen(host) + 1;
303 	r = dprintf(fd, "%04x%s%chost=%s%c", len, cmd, '\0', host, '\0');
304 	if (r < 0)
305 		err = got_error_from_errno("dprintf");
306 done:
307 	free(cmd);
308 	if (err) {
309 		if (fd != -1)
310 			close(fd);
311 	} else
312 		*newfd = fd;
313 	return err;
314 }