1 5dcb3a43 2023-04-01 thomas /*
  2 5dcb3a43 2023-04-01 thomas  * Copyright (c) 2023 Stefan Sperling <stsp@openbsd.org>
  3 5dcb3a43 2023-04-01 thomas  *
  4 5dcb3a43 2023-04-01 thomas  * Permission to use, copy, modify, and distribute this software for any
  5 5dcb3a43 2023-04-01 thomas  * purpose with or without fee is hereby granted, provided that the above
  6 5dcb3a43 2023-04-01 thomas  * copyright notice and this permission notice appear in all copies.
  7 5dcb3a43 2023-04-01 thomas  *
  8 5dcb3a43 2023-04-01 thomas  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  9 5dcb3a43 2023-04-01 thomas  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 10 5dcb3a43 2023-04-01 thomas  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 11 5dcb3a43 2023-04-01 thomas  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 12 5dcb3a43 2023-04-01 thomas  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 13 5dcb3a43 2023-04-01 thomas  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 14 5dcb3a43 2023-04-01 thomas  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 15 5dcb3a43 2023-04-01 thomas  */
 16 5dcb3a43 2023-04-01 thomas 
 17 5dcb3a43 2023-04-01 thomas /*
 18 5dcb3a43 2023-04-01 thomas  * Resolve path namespace conflicts for git-upload-pack and git-receive-pack.
 19 5dcb3a43 2023-04-01 thomas  */
 20 5dcb3a43 2023-04-01 thomas 
 21 5dcb3a43 2023-04-01 thomas #include <sys/queue.h>
 22 5dcb3a43 2023-04-01 thomas #include <sys/types.h>
 23 5dcb3a43 2023-04-01 thomas #include <sys/uio.h>
 24 5dcb3a43 2023-04-01 thomas #include <sys/wait.h>
 25 5dcb3a43 2023-04-01 thomas 
 26 5dcb3a43 2023-04-01 thomas #include <err.h>
 27 5dcb3a43 2023-04-01 thomas #include <errno.h>
 28 5dcb3a43 2023-04-01 thomas #include <event.h>
 29 5dcb3a43 2023-04-01 thomas #include <imsg.h>
 30 5dcb3a43 2023-04-01 thomas #include <limits.h>
 31 5dcb3a43 2023-04-01 thomas #include <stdio.h>
 32 5dcb3a43 2023-04-01 thomas #include <stdlib.h>
 33 5dcb3a43 2023-04-01 thomas #include <string.h>
 34 5dcb3a43 2023-04-01 thomas #include <sha1.h>
 35 5dcb3a43 2023-04-01 thomas #include <sha2.h>
 36 5dcb3a43 2023-04-01 thomas #include <syslog.h>
 37 5dcb3a43 2023-04-01 thomas #include <util.h>
 38 5dcb3a43 2023-04-01 thomas #include <unistd.h>
 39 5dcb3a43 2023-04-01 thomas 
 40 5dcb3a43 2023-04-01 thomas #include "got_error.h"
 41 5dcb3a43 2023-04-01 thomas #include "got_path.h"
 42 5dcb3a43 2023-04-01 thomas #include "got_serve.h"
 43 5dcb3a43 2023-04-01 thomas 
 44 5dcb3a43 2023-04-01 thomas #include "gotd.h"
 45 5dcb3a43 2023-04-01 thomas #include "log.h"
 46 5dcb3a43 2023-04-01 thomas 
 47 5dcb3a43 2023-04-01 thomas #ifndef GITWRAPPER_GIT_LIBEXEC_DIR
 48 5dcb3a43 2023-04-01 thomas #define GITWRAPPER_GIT_LIBEXEC_DIR "/usr/local/libexec/git"
 49 5dcb3a43 2023-04-01 thomas #endif
 50 5dcb3a43 2023-04-01 thomas 
 51 5dcb3a43 2023-04-01 thomas #ifndef GITWRAPPER_MY_SERVER_PROG
 52 5dcb3a43 2023-04-01 thomas #define GITWRAPPER_MY_SERVER_PROG "gotsh"
 53 5dcb3a43 2023-04-01 thomas #endif
 54 5dcb3a43 2023-04-01 thomas 
 55 5dcb3a43 2023-04-01 thomas 
 56 5dcb3a43 2023-04-01 thomas __dead static void
 57 5dcb3a43 2023-04-01 thomas usage(void)
 58 5dcb3a43 2023-04-01 thomas {
 59 5dcb3a43 2023-04-01 thomas 	fprintf(stderr, "usage: %s -c '%s|%s repository-path'\n",
 60 5dcb3a43 2023-04-01 thomas 	    getprogname(), GOT_SERVE_CMD_SEND, GOT_SERVE_CMD_FETCH);
 61 5dcb3a43 2023-04-01 thomas 	exit(1);
 62 5dcb3a43 2023-04-01 thomas }
 63 5dcb3a43 2023-04-01 thomas 
 64 5dcb3a43 2023-04-01 thomas /*
 65 5dcb3a43 2023-04-01 thomas  * Unveil the specific programs we want to start and hide everything else.
 66 5dcb3a43 2023-04-01 thomas  * This is important to limit the impact of our "exec" pledge.
 67 5dcb3a43 2023-04-01 thomas  */
 68 5dcb3a43 2023-04-01 thomas static const struct got_error *
 69 5dcb3a43 2023-04-01 thomas apply_unveil(const char *myserver)
 70 5dcb3a43 2023-04-01 thomas {
 71 5dcb3a43 2023-04-01 thomas 	const char *fetchcmd = GITWRAPPER_GIT_LIBEXEC_DIR "/" \
 72 5dcb3a43 2023-04-01 thomas 		GOT_SERVE_CMD_FETCH;
 73 5dcb3a43 2023-04-01 thomas 	const char *sendcmd = GITWRAPPER_GIT_LIBEXEC_DIR "/" \
 74 5dcb3a43 2023-04-01 thomas 		GOT_SERVE_CMD_SEND;
 75 5dcb3a43 2023-04-01 thomas 
 76 5dcb3a43 2023-04-01 thomas #ifdef PROFILE
 77 5dcb3a43 2023-04-01 thomas 	if (unveil("gmon.out", "rwc") != 0)
 78 5dcb3a43 2023-04-01 thomas 		return got_error_from_errno2("unveil", "gmon.out");
 79 5dcb3a43 2023-04-01 thomas #endif
 80 5dcb3a43 2023-04-01 thomas 	if (unveil(fetchcmd, "x") != 0)
 81 5dcb3a43 2023-04-01 thomas 		return got_error_from_errno2("unveil", fetchcmd);
 82 5dcb3a43 2023-04-01 thomas 
 83 5dcb3a43 2023-04-01 thomas 	if (unveil(sendcmd, "x") != 0)
 84 5dcb3a43 2023-04-01 thomas 		return got_error_from_errno2("unveil", sendcmd);
 85 5dcb3a43 2023-04-01 thomas 
 86 5dcb3a43 2023-04-01 thomas 	if (myserver && unveil(myserver, "x") != 0)
 87 5dcb3a43 2023-04-01 thomas 		return got_error_from_errno2("unveil", myserver);
 88 5dcb3a43 2023-04-01 thomas 
 89 5dcb3a43 2023-04-01 thomas 	if (unveil(NULL, NULL) != 0)
 90 5dcb3a43 2023-04-01 thomas 		return got_error_from_errno("unveil");
 91 5dcb3a43 2023-04-01 thomas 
 92 5dcb3a43 2023-04-01 thomas 	return NULL;
 93 5dcb3a43 2023-04-01 thomas }
 94 5dcb3a43 2023-04-01 thomas 
 95 5dcb3a43 2023-04-01 thomas int
 96 5dcb3a43 2023-04-01 thomas main(int argc, char *argv[])
 97 5dcb3a43 2023-04-01 thomas {
 98 5dcb3a43 2023-04-01 thomas 	const struct got_error *error;
 99 5dcb3a43 2023-04-01 thomas 	const char *confpath = NULL;
100 5dcb3a43 2023-04-01 thomas 	char *command = NULL, *repo_name = NULL; /* for matching gotd.conf */
101 5dcb3a43 2023-04-01 thomas 	char *myserver = NULL;
102 5dcb3a43 2023-04-01 thomas 	const char *repo_path = NULL; /* as passed on the command line */
103 5dcb3a43 2023-04-01 thomas 	const char *relpath;
104 5dcb3a43 2023-04-01 thomas 	char *gitcommand = NULL;
105 5dcb3a43 2023-04-01 thomas 	struct gotd gotd;
106 5dcb3a43 2023-04-01 thomas 	struct gotd_repo *repo = NULL;
107 5dcb3a43 2023-04-01 thomas 	pid_t pid;
108 5dcb3a43 2023-04-01 thomas 	int st = -1;
109 5dcb3a43 2023-04-01 thomas 
110 5dcb3a43 2023-04-01 thomas 	log_init(1, LOG_USER); /* Log to stderr. */
111 5dcb3a43 2023-04-01 thomas 
112 5dcb3a43 2023-04-01 thomas #ifndef PROFILE
113 5dcb3a43 2023-04-01 thomas 	if (pledge("stdio rpath proc exec unveil", NULL) == -1)
114 5dcb3a43 2023-04-01 thomas 		err(1, "pledge");
115 5dcb3a43 2023-04-01 thomas #endif
116 5dcb3a43 2023-04-01 thomas 
117 5dcb3a43 2023-04-01 thomas 	/*
118 5dcb3a43 2023-04-01 thomas 	 * Look up our own server program in PATH so we can unveil(2) it.
119 5dcb3a43 2023-04-01 thomas 	 * This call only errors out upon memory allocation failure.
120 5dcb3a43 2023-04-01 thomas 	 * If the program cannot be found then myserver will be set to NULL.
121 5dcb3a43 2023-04-01 thomas 	 */
122 5dcb3a43 2023-04-01 thomas 	error = got_path_find_prog(&myserver, GITWRAPPER_MY_SERVER_PROG);
123 5dcb3a43 2023-04-01 thomas 	if (error)
124 5dcb3a43 2023-04-01 thomas 		goto done;
125 5dcb3a43 2023-04-01 thomas 
126 5dcb3a43 2023-04-01 thomas 	/*
127 5dcb3a43 2023-04-01 thomas 	 * Run parse_config() before unveil(2) because parse_config()
128 5dcb3a43 2023-04-01 thomas 	 * checks whether repository paths exist on disk.
129 5dcb3a43 2023-04-01 thomas 	 * Parsing errors and warnings will be logged to stderr.
130 5dcb3a43 2023-04-01 thomas 	 * Upon failure we will run Git's native tooling so do not
131 5dcb3a43 2023-04-01 thomas 	 * bother checking for errors here.
132 5dcb3a43 2023-04-01 thomas 	 */
133 5dcb3a43 2023-04-01 thomas 	confpath = getenv("GOTD_CONF_PATH");
134 5dcb3a43 2023-04-01 thomas 	if (confpath == NULL)
135 5dcb3a43 2023-04-01 thomas 		confpath = GOTD_CONF_PATH;
136 5dcb3a43 2023-04-01 thomas 	parse_config(confpath, PROC_GOTD, &gotd);
137 5dcb3a43 2023-04-01 thomas 
138 5dcb3a43 2023-04-01 thomas 	error = apply_unveil(myserver);
139 5dcb3a43 2023-04-01 thomas 	if (error)
140 5dcb3a43 2023-04-01 thomas 		goto done;
141 5dcb3a43 2023-04-01 thomas 
142 5dcb3a43 2023-04-01 thomas #ifndef PROFILE
143 5dcb3a43 2023-04-01 thomas 	if (pledge("stdio proc exec", NULL) == -1)
144 5dcb3a43 2023-04-01 thomas 		err(1, "pledge");
145 5dcb3a43 2023-04-01 thomas #endif
146 5dcb3a43 2023-04-01 thomas 
147 5dcb3a43 2023-04-01 thomas 	if (strcmp(getprogname(), GOT_SERVE_CMD_SEND) == 0 ||
148 5dcb3a43 2023-04-01 thomas 	    strcmp(getprogname(), GOT_SERVE_CMD_FETCH) == 0) {
149 5dcb3a43 2023-04-01 thomas 		if (argc != 2)
150 5dcb3a43 2023-04-01 thomas 			usage();
151 5dcb3a43 2023-04-01 thomas 		command = strdup(getprogname());
152 5dcb3a43 2023-04-01 thomas 		if (command == NULL) {
153 5dcb3a43 2023-04-01 thomas 			error = got_error_from_errno("strdup");
154 5dcb3a43 2023-04-01 thomas 			goto done;
155 5dcb3a43 2023-04-01 thomas 		}
156 5dcb3a43 2023-04-01 thomas 		repo_path = argv[1];
157 5dcb3a43 2023-04-01 thomas 		relpath = argv[1];
158 5dcb3a43 2023-04-01 thomas 		while (relpath[0] == '/')
159 5dcb3a43 2023-04-01 thomas 			relpath++;
160 5dcb3a43 2023-04-01 thomas 		repo_name = strdup(relpath);
161 5dcb3a43 2023-04-01 thomas 		if (repo_name == NULL) {
162 5dcb3a43 2023-04-01 thomas 			error = got_error_from_errno("strdup");
163 5dcb3a43 2023-04-01 thomas 			goto done;
164 5dcb3a43 2023-04-01 thomas 		}
165 5dcb3a43 2023-04-01 thomas 	} else {
166 5dcb3a43 2023-04-01 thomas 		if (argc != 3 || strcmp(argv[1], "-c") != 0)
167 5dcb3a43 2023-04-01 thomas 			usage();
168 5dcb3a43 2023-04-01 thomas 		repo_path = argv[2];
169 5dcb3a43 2023-04-01 thomas 		error = got_serve_parse_command(&command, &repo_name,
170 5dcb3a43 2023-04-01 thomas 		    repo_path);
171 5dcb3a43 2023-04-01 thomas 		if (error && error->code == GOT_ERR_BAD_PACKET)
172 5dcb3a43 2023-04-01 thomas 			usage();
173 5dcb3a43 2023-04-01 thomas 		if (error)
174 5dcb3a43 2023-04-01 thomas 			goto done;
175 5dcb3a43 2023-04-01 thomas 	}
176 5dcb3a43 2023-04-01 thomas 
177 5dcb3a43 2023-04-01 thomas 	repo = gotd_find_repo_by_name(repo_name, &gotd);
178 5dcb3a43 2023-04-01 thomas 
179 5dcb3a43 2023-04-01 thomas 	/*
180 5dcb3a43 2023-04-01 thomas 	 * Invoke our custom Git server if it was found in PATH and
181 5dcb3a43 2023-04-01 thomas 	 * if the repository was found in gotd.conf.
182 5dcb3a43 2023-04-01 thomas 	 * Otherwise invoke native git(1) tooling.
183 5dcb3a43 2023-04-01 thomas 	 */
184 5dcb3a43 2023-04-01 thomas 	switch (pid = fork()) {
185 5dcb3a43 2023-04-01 thomas 	case -1:
186 5dcb3a43 2023-04-01 thomas 		goto done;
187 5dcb3a43 2023-04-01 thomas 	case 0:
188 5dcb3a43 2023-04-01 thomas 		if (repo && myserver) {
189 5dcb3a43 2023-04-01 thomas 			if (execl(myserver, command, repo_name,
190 5dcb3a43 2023-04-01 thomas 			    (char *)NULL) ==  -1) {
191 5dcb3a43 2023-04-01 thomas 				error = got_error_from_errno2("execl",
192 5dcb3a43 2023-04-01 thomas 				    myserver);
193 5dcb3a43 2023-04-01 thomas 				goto done;
194 5dcb3a43 2023-04-01 thomas 			 }
195 5dcb3a43 2023-04-01 thomas 		} else {
196 5dcb3a43 2023-04-01 thomas 			if (asprintf(&gitcommand, "%s/%s",
197 5dcb3a43 2023-04-01 thomas 			    GITWRAPPER_GIT_LIBEXEC_DIR, command) == -1) {
198 5dcb3a43 2023-04-01 thomas 				error = got_error_from_errno("asprintf");
199 5dcb3a43 2023-04-01 thomas 				goto done;
200 5dcb3a43 2023-04-01 thomas 			}
201 5dcb3a43 2023-04-01 thomas 			if (execl(gitcommand, gitcommand, repo_path,
202 5dcb3a43 2023-04-01 thomas 			    (char *)NULL) == -1) {
203 5dcb3a43 2023-04-01 thomas 				error = got_error_from_errno2("execl",
204 5dcb3a43 2023-04-01 thomas 				    gitcommand);
205 5dcb3a43 2023-04-01 thomas 				goto done;
206 5dcb3a43 2023-04-01 thomas 			 }
207 5dcb3a43 2023-04-01 thomas 		}
208 5dcb3a43 2023-04-01 thomas 		_exit(127);
209 5dcb3a43 2023-04-01 thomas 	}
210 5dcb3a43 2023-04-01 thomas 
211 5dcb3a43 2023-04-01 thomas 	while (waitpid(pid, &st, 0) == -1) {
212 5dcb3a43 2023-04-01 thomas 		if (errno != EINTR)
213 5dcb3a43 2023-04-01 thomas 			break;
214 5dcb3a43 2023-04-01 thomas 	}
215 5dcb3a43 2023-04-01 thomas done:
216 5dcb3a43 2023-04-01 thomas 	free(command);
217 5dcb3a43 2023-04-01 thomas 	free(repo_name);
218 5dcb3a43 2023-04-01 thomas 	free(myserver);
219 5dcb3a43 2023-04-01 thomas 	free(gitcommand);
220 5dcb3a43 2023-04-01 thomas 	if (error) {
221 5dcb3a43 2023-04-01 thomas 		fprintf(stderr, "%s: %s\n", getprogname(), error->msg);
222 5dcb3a43 2023-04-01 thomas 		return 1;
223 5dcb3a43 2023-04-01 thomas 	}
224 5dcb3a43 2023-04-01 thomas 
225 5dcb3a43 2023-04-01 thomas 	return 0;
226 5dcb3a43 2023-04-01 thomas }