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 <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_lib_dial.h"
33 
34 #ifndef ssizeof
35 #define ssizeof(_x) ((ssize_t)(sizeof(_x)))
36 #endif
37 
38 #ifndef MIN
39 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
40 #endif
41 
42 #ifndef GOT_DIAL_PATH_SSH
43 #define GOT_DIAL_PATH_SSH	"/usr/bin/ssh"
44 #endif
45 
46 /* IANA assigned */
47 #define GOT_DEFAULT_GIT_PORT		9418
48 #define GOT_DEFAULT_GIT_PORT_STR	"9418"
49 
50 const struct got_error *
51 got_dial_apply_unveil(const char *proto)
52 {
53 	if (strcmp(proto, "git+ssh") == 0 || strcmp(proto, "ssh") == 0) {
54 		if (unveil(GOT_DIAL_PATH_SSH, "x") != 0) {
55 			return got_error_from_errno2("unveil",
56 			    GOT_DIAL_PATH_SSH);
57 		}
58 	}
59 
60 	return NULL;
61 }
62 
63 static int
64 hassuffix(char *base, char *suf)
65 {
66 	int nb, ns;
67 
68 	nb = strlen(base);
69 	ns = strlen(suf);
70 	if (ns <= nb && strcmp(base + (nb - ns), suf) == 0)
71 		return 1;
72 	return 0;
73 }
74 
75 const struct got_error *
76 got_dial_parse_uri(char **proto, char **host, char **port,
77     char **server_path, char **repo_name, const char *uri)
78 {
79 	const struct got_error *err = NULL;
80 	char *s, *p, *q;
81 	int n;
82 
83 	*proto = *host = *port = *server_path = *repo_name = NULL;
84 
85 	p = strstr(uri, "://");
86 	if (!p) {
87 		/* Try parsing Git's "scp" style URL syntax. */
88 		*proto = strdup("ssh");
89 		if (proto == NULL) {
90 			err = got_error_from_errno("strdup");
91 			goto done;
92 		}
93 		s = (char *)uri;
94 		q = strchr(s, ':');
95 		if (q == NULL) {
96 			err = got_error(GOT_ERR_PARSE_URI);
97 			goto done;
98 		}
99 		/* No slashes allowed before first colon. */
100 		p = strchr(s, '/');
101 		if (p && q > p) {
102 			err = got_error(GOT_ERR_PARSE_URI);
103 			goto done;
104 		}
105 		*host = strndup(s, q - s);
106 		if (*host == NULL) {
107 			err = got_error_from_errno("strndup");
108 			goto done;
109 		}
110 		p = q + 1;
111 	} else {
112 		*proto = strndup(uri, p - uri);
113 		if (proto == NULL) {
114 			err = got_error_from_errno("strndup");
115 			goto done;
116 		}
117 		s = p + 3;
118 
119 		p = strstr(s, "/");
120 		if (p == NULL || strlen(p) == 1) {
121 			err = got_error(GOT_ERR_PARSE_URI);
122 			goto done;
123 		}
124 
125 		q = memchr(s, ':', p - s);
126 		if (q) {
127 			*host = strndup(s, q - s);
128 			if (*host == NULL) {
129 				err = got_error_from_errno("strndup");
130 				goto done;
131 			}
132 			*port = strndup(q + 1, p - (q + 1));
133 			if (*port == NULL) {
134 				err = got_error_from_errno("strndup");
135 				goto done;
136 			}
137 		} else {
138 			*host = strndup(s, p - s);
139 			if (*host == NULL) {
140 				err = got_error_from_errno("strndup");
141 				goto done;
142 			}
143 		}
144 	}
145 
146 	while (p[0] == '/' && p[1] == '/')
147 		p++;
148 	*server_path = strdup(p);
149 	if (*server_path == NULL) {
150 		err = got_error_from_errno("strdup");
151 		goto done;
152 	}
153 	got_path_strip_trailing_slashes(*server_path);
154 
155 	p = strrchr(p, '/');
156 	if (!p || strlen(p) <= 1) {
157 		err = got_error(GOT_ERR_PARSE_URI);
158 		goto done;
159 	}
160 	p++;
161 	n = strlen(p);
162 	if (n == 0) {
163 		err = got_error(GOT_ERR_PARSE_URI);
164 		goto done;
165 	}
166 	if (hassuffix(p, ".git"))
167 		n -= 4;
168 	*repo_name = strndup(p, (p + n) - p);
169 	if (*repo_name == NULL) {
170 		err = got_error_from_errno("strndup");
171 		goto done;
172 	}
173 done:
174 	if (err) {
175 		free(*proto);
176 		*proto = NULL;
177 		free(*host);
178 		*host = NULL;
179 		free(*port);
180 		*port = NULL;
181 		free(*server_path);
182 		*server_path = NULL;
183 		free(*repo_name);
184 		*repo_name = NULL;
185 	}
186 	return err;
187 }
188 
189 const struct got_error *
190 got_dial_ssh(pid_t *newpid, int *newfd, const char *host,
191     const char *port, const char *path, const char *direction, int verbosity)
192 {
193 	const struct got_error *error = NULL;
194 	int pid, pfd[2];
195 	char cmd[64];
196 	char *argv[11];
197 	int i = 0, j;
198 
199 	*newpid = -1;
200 	*newfd = -1;
201 
202 	argv[i++] = GOT_DIAL_PATH_SSH;
203 	if (port != NULL) {
204 		argv[i++] = "-p";
205 		argv[i++] = (char *)port;
206 	}
207 	if (verbosity == -1) {
208 		argv[i++] = "-q";
209 	} else {
210 		/* ssh(1) allows up to 3 "-v" options. */
211 		for (j = 0; j < MIN(3, verbosity); j++)
212 			argv[i++] = "-v";
213 	}
214 	argv[i++] = "--";
215 	argv[i++] = (char *)host;
216 	argv[i++] = (char *)cmd;
217 	argv[i++] = (char *)path;
218 	argv[i++] = NULL;
219 
220 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pfd) == -1)
221 		return got_error_from_errno("socketpair");
222 
223 	pid = fork();
224 	if (pid == -1) {
225 		error = got_error_from_errno("fork");
226 		close(pfd[0]);
227 		close(pfd[1]);
228 		return error;
229 	} else if (pid == 0) {
230 		int n;
231 		if (close(pfd[1]) == -1)
232 			err(1, "close");
233 		if (dup2(pfd[0], 0) == -1)
234 			err(1, "dup2");
235 		if (dup2(pfd[0], 1) == -1)
236 			err(1, "dup2");
237 		n = snprintf(cmd, sizeof(cmd), "git-%s-pack", direction);
238 		if (n < 0 || n >= ssizeof(cmd))
239 			err(1, "snprintf");
240 		if (execv(GOT_DIAL_PATH_SSH, argv) == -1)
241 			err(1, "execv");
242 		abort(); /* not reached */
243 	} else {
244 		if (close(pfd[0]) == -1)
245 			return got_error_from_errno("close");
246 		*newpid = pid;
247 		*newfd = pfd[1];
248 		return NULL;
249 	}
250 }
251 
252 const struct got_error *
253 got_dial_git(int *newfd, const char *host, const char *port,
254     const char *path, const char *direction)
255 {
256 	const struct got_error *err = NULL;
257 	struct addrinfo hints, *servinfo, *p;
258 	char *cmd = NULL;
259 	int fd = -1, len, r, eaicode;
260 
261 	*newfd = -1;
262 
263 	if (port == NULL)
264 		port = GOT_DEFAULT_GIT_PORT_STR;
265 
266 	memset(&hints, 0, sizeof hints);
267 	hints.ai_family = AF_UNSPEC;
268 	hints.ai_socktype = SOCK_STREAM;
269 	eaicode = getaddrinfo(host, port, &hints, &servinfo);
270 	if (eaicode) {
271 		char msg[512];
272 		snprintf(msg, sizeof(msg), "%s: %s", host,
273 		    gai_strerror(eaicode));
274 		return got_error_msg(GOT_ERR_ADDRINFO, msg);
275 	}
276 
277 	for (p = servinfo; p != NULL; p = p->ai_next) {
278 		if ((fd = socket(p->ai_family, p->ai_socktype,
279 		    p->ai_protocol)) == -1)
280 			continue;
281 		if (connect(fd, p->ai_addr, p->ai_addrlen) == 0) {
282 			err = NULL;
283 			break;
284 		}
285 		err = got_error_from_errno("connect");
286 		close(fd);
287 	}
288 	if (p == NULL)
289 		goto done;
290 
291 	if (asprintf(&cmd, "git-%s-pack %s", direction, path) == -1) {
292 		err = got_error_from_errno("asprintf");
293 		goto done;
294 	}
295 	len = 4 + strlen(cmd) + 1 + strlen("host=") + strlen(host) + 1;
296 	r = dprintf(fd, "%04x%s%chost=%s%c", len, cmd, '\0', host, '\0');
297 	if (r < 0)
298 		err = got_error_from_errno("dprintf");
299 done:
300 	free(cmd);
301 	if (err) {
302 		if (fd != -1)
303 			close(fd);
304 	} else
305 		*newfd = fd;
306 	return err;
307 }