3 #include <sys/socket.h>
7 #include <netinet/in.h>
16 static int log_syslog;
20 static const char daemon_usage[] =
21 "git-daemon [--verbose] [--syslog] [--inetd | --port=n] [--export-all]\n"
22 " [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
23 " [--base-path=path] [--user-path | --user-path=path]\n"
24 " [--reuseaddr] [--detach] [--pid-file=file]\n"
25 " [--user=user [[--group=group]] [directory...]";
27 /* List of acceptable pathname prefixes */
28 static char **ok_paths;
29 static int strict_paths;
31 /* If this is set, git-daemon-export-ok is not required */
32 static int export_all_trees;
34 /* Take all paths relative to this one if non-NULL */
35 static char *base_path;
37 /* If defined, ~user notation is allowed and the string is inserted
38 * after ~user/. E.g. a request to git://host/~alice/frotz would
39 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
41 static const char *user_path;
43 /* Timeout, and initial timeout */
44 static unsigned int timeout;
45 static unsigned int init_timeout;
47 static void logreport(int priority, const char *err, va_list params)
49 /* We should do a single write so that it is atomic and output
50 * of several processes do not get intermingled. */
55 /* sizeof(buf) should be big enough for "[pid] \n" */
56 buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
58 maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
59 msglen = vsnprintf(buf + buflen, maxlen, err, params);
62 syslog(priority, "%s", buf);
66 /* maxlen counted our own LF but also counts space given to
67 * vsnprintf for the terminating NUL. We want to make sure that
68 * we have space for our own LF and NUL after the "meat" of the
69 * message, so truncate it at maxlen - 1.
71 if (msglen > maxlen - 1)
74 msglen = 0; /* Protect against weird return values. */
80 write(2, buf, buflen);
83 static void logerror(const char *err, ...)
86 va_start(params, err);
87 logreport(LOG_ERR, err, params);
91 static void loginfo(const char *err, ...)
96 va_start(params, err);
97 logreport(LOG_INFO, err, params);
101 static void NORETURN daemon_die(const char *err, va_list params)
103 logreport(LOG_ERR, err, params);
107 static int avoid_alias(char *p)
112 * This resurrects the belts and suspenders paranoia check by HPA
113 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
114 * does not do getcwd() based path canonicalizations.
116 * sl becomes true immediately after seeing '/' and continues to
117 * be true as long as dots continue after that without intervening
120 if (!p || (*p != '/' && *p != '~'))
130 else if (ch == '/') {
132 /* reject //, /./ and /../ */
137 if (0 < ndot && ndot < 3)
138 /* reject /.$ and /..$ */
147 else if (ch == '/') {
154 static char *path_ok(char *dir)
156 static char rpath[PATH_MAX];
159 if (avoid_alias(dir)) {
160 logerror("'%s': aliased", dir);
166 logerror("'%s': User-path not allowed", dir);
170 /* Got either "~alice" or "~alice/foo";
171 * rewrite them to "~alice/%s" or
174 int namlen, restlen = strlen(dir);
175 char *slash = strchr(dir, '/');
177 slash = dir + restlen;
178 namlen = slash - dir;
180 loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
181 snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
182 namlen, dir, user_path, restlen, slash);
186 else if (base_path) {
188 /* Allow only absolute */
189 logerror("'%s': Non-absolute path denied (base-path active)", dir);
193 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
198 path = enter_repo(dir, strict_paths);
201 logerror("'%s': unable to chdir or not a git archive", dir);
205 if ( ok_paths && *ok_paths ) {
207 int pathlen = strlen(path);
209 /* The validation is done on the paths after enter_repo
210 * appends optional {.git,.git/.git} and friends, but
211 * it does not use getcwd(). So if your /pub is
212 * a symlink to /mnt/pub, you can whitelist /pub and
213 * do not have to say /mnt/pub.
216 for ( pp = ok_paths ; *pp ; pp++ ) {
217 int len = strlen(*pp);
218 if (len <= pathlen &&
219 !memcmp(*pp, path, len) &&
220 (path[len] == '\0' ||
221 (!strict_paths && path[len] == '/')))
226 /* be backwards compatible */
231 logerror("'%s': not in whitelist", path);
232 return NULL; /* Fallthrough. Deny by default */
235 static int upload(char *dir)
237 /* Timeout as string */
238 char timeout_buf[64];
241 loginfo("Request for '%s'", dir);
243 if (!(path = path_ok(dir)))
247 * Security on the cheap.
249 * We want a readable HEAD, usable "objects" directory, and
250 * a "git-daemon-export-ok" flag that says that the other side
251 * is ok with us doing this.
253 * path_ok() uses enter_repo() and does whitelist checking.
254 * We only need to make sure the repository is exported.
257 if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
258 logerror("'%s': repository not exported.", path);
264 * We'll ignore SIGTERM from now on, we have a
267 signal(SIGTERM, SIG_IGN);
269 snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
271 /* git-upload-pack only ever reads stuff, so this is safe */
272 execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
276 static int execute(struct sockaddr *addr)
278 static char line[1000];
282 char addrbuf[256] = "";
285 if (addr->sa_family == AF_INET) {
286 struct sockaddr_in *sin_addr = (void *) addr;
287 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
288 port = sin_addr->sin_port;
290 } else if (addr && addr->sa_family == AF_INET6) {
291 struct sockaddr_in6 *sin6_addr = (void *) addr;
294 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
295 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
298 port = sin6_addr->sin6_port;
301 loginfo("Connection from %s:%d", addrbuf, port);
304 alarm(init_timeout ? init_timeout : timeout);
305 pktlen = packet_read_line(0, line, sizeof(line));
310 loginfo("Extended attributes (%d bytes) exist <%.*s>",
312 (int) pktlen - len, line + len + 1);
313 if (len && line[len-1] == '\n')
316 if (!strncmp("git-upload-pack ", line, 16))
317 return upload(line+16);
319 logerror("Protocol error: '%s'", line);
325 * We count spawned/reaped separately, just to avoid any
326 * races when updating them from signals. The SIGCHLD handler
327 * will only update children_reaped, and the fork logic will
328 * only update children_spawned.
330 * MAX_CHILDREN should be a power-of-two to make the modulus
331 * operation cheap. It should also be at least twice
332 * the maximum number of connections we will ever allow.
334 #define MAX_CHILDREN 128
336 static int max_connections = 25;
338 /* These are updated by the signal handler */
339 static volatile unsigned int children_reaped;
340 static pid_t dead_child[MAX_CHILDREN];
342 /* These are updated by the main loop */
343 static unsigned int children_spawned;
344 static unsigned int children_deleted;
346 static struct child {
349 struct sockaddr_storage address;
350 } live_child[MAX_CHILDREN];
352 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
354 live_child[idx].pid = pid;
355 live_child[idx].addrlen = addrlen;
356 memcpy(&live_child[idx].address, addr, addrlen);
360 * Walk from "deleted" to "spawned", and remove child "pid".
362 * We move everything up by one, since the new "deleted" will
365 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
369 deleted %= MAX_CHILDREN;
370 spawned %= MAX_CHILDREN;
371 if (live_child[deleted].pid == pid) {
372 live_child[deleted].pid = -1;
375 n = live_child[deleted];
378 deleted = (deleted + 1) % MAX_CHILDREN;
379 if (deleted == spawned)
380 die("could not find dead child %d\n", pid);
381 m = live_child[deleted];
382 live_child[deleted] = n;
390 * This gets called if the number of connections grows
391 * past "max_connections".
393 * We _should_ start off by searching for connections
394 * from the same IP, and if there is some address wth
395 * multiple connections, we should kill that first.
397 * As it is, we just "randomly" kill 25% of the connections,
398 * and our pseudo-random generator sucks too. I have no
401 * Really, this is just a place-holder for a _real_ algorithm.
403 static void kill_some_children(int signo, unsigned start, unsigned stop)
405 start %= MAX_CHILDREN;
406 stop %= MAX_CHILDREN;
407 while (start != stop) {
409 kill(live_child[start].pid, signo);
410 start = (start + 1) % MAX_CHILDREN;
414 static void check_max_connections(void)
418 unsigned spawned, reaped, deleted;
420 spawned = children_spawned;
421 reaped = children_reaped;
422 deleted = children_deleted;
424 while (deleted < reaped) {
425 pid_t pid = dead_child[deleted % MAX_CHILDREN];
426 remove_child(pid, deleted, spawned);
429 children_deleted = deleted;
431 active = spawned - deleted;
432 if (active <= max_connections)
435 /* Kill some unstarted connections with SIGTERM */
436 kill_some_children(SIGTERM, deleted, spawned);
437 if (active <= max_connections << 1)
440 /* If the SIGTERM thing isn't helping use SIGKILL */
441 kill_some_children(SIGKILL, deleted, spawned);
446 static void handle(int incoming, struct sockaddr *addr, int addrlen)
457 idx = children_spawned % MAX_CHILDREN;
459 add_child(idx, pid, addr, addrlen);
461 check_max_connections();
472 static void child_handler(int signo)
476 pid_t pid = waitpid(-1, &status, WNOHANG);
479 unsigned reaped = children_reaped;
480 dead_child[reaped % MAX_CHILDREN] = pid;
481 children_reaped = reaped + 1;
482 /* XXX: Custom logging, since we don't wanna getpid() */
484 const char *dead = "";
485 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
486 dead = " (with error)";
488 syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
490 fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
498 static int set_reuse_addr(int sockfd)
504 return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
510 static int socksetup(int port, int **socklist_p)
512 int socknum = 0, *socklist = NULL;
514 char pbuf[NI_MAXSERV];
516 struct addrinfo hints, *ai0, *ai;
519 sprintf(pbuf, "%d", port);
520 memset(&hints, 0, sizeof(hints));
521 hints.ai_family = AF_UNSPEC;
522 hints.ai_socktype = SOCK_STREAM;
523 hints.ai_protocol = IPPROTO_TCP;
524 hints.ai_flags = AI_PASSIVE;
526 gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
528 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
530 for (ai = ai0; ai; ai = ai->ai_next) {
533 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
536 if (sockfd >= FD_SETSIZE) {
537 error("too large socket descriptor.");
543 if (ai->ai_family == AF_INET6) {
545 setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
547 /* Note: error is not fatal */
551 if (set_reuse_addr(sockfd)) {
556 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
558 continue; /* not fatal */
560 if (listen(sockfd, 5) < 0) {
562 continue; /* not fatal */
565 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
566 socklist[socknum++] = sockfd;
574 *socklist_p = socklist;
580 static int socksetup(int port, int **socklist_p)
582 struct sockaddr_in sin;
585 sockfd = socket(AF_INET, SOCK_STREAM, 0);
589 memset(&sin, 0, sizeof sin);
590 sin.sin_family = AF_INET;
591 sin.sin_addr.s_addr = htonl(INADDR_ANY);
592 sin.sin_port = htons(port);
594 if (set_reuse_addr(sockfd)) {
599 if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
604 if (listen(sockfd, 5) < 0) {
609 *socklist_p = xmalloc(sizeof(int));
610 **socklist_p = sockfd;
616 static int service_loop(int socknum, int *socklist)
621 pfd = xcalloc(socknum, sizeof(struct pollfd));
623 for (i = 0; i < socknum; i++) {
624 pfd[i].fd = socklist[i];
625 pfd[i].events = POLLIN;
628 signal(SIGCHLD, child_handler);
633 if (poll(pfd, socknum, -1) < 0) {
634 if (errno != EINTR) {
635 error("poll failed, resuming: %s",
642 for (i = 0; i < socknum; i++) {
643 if (pfd[i].revents & POLLIN) {
644 struct sockaddr_storage ss;
645 unsigned int sslen = sizeof(ss);
646 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
654 die("accept returned %s", strerror(errno));
657 handle(incoming, (struct sockaddr *)&ss, sslen);
663 /* if any standard file descriptor is missing open it to /dev/null */
664 static void sanitize_stdfds(void)
666 int fd = open("/dev/null", O_RDWR, 0);
667 while (fd != -1 && fd < 2)
670 die("open /dev/null or dup failed: %s", strerror(errno));
675 static void daemonize(void)
681 die("fork failed: %s", strerror(errno));
686 die("setsid failed: %s", strerror(errno));
693 static void store_pid(const char *path)
695 FILE *f = fopen(path, "w");
697 die("cannot open pid file %s: %s", path, strerror(errno));
698 fprintf(f, "%d\n", getpid());
702 static int serve(int port, struct passwd *pass, gid_t gid)
704 int socknum, *socklist;
706 socknum = socksetup(port, &socklist);
708 die("unable to allocate any listen sockets on port %u", port);
711 (initgroups(pass->pw_name, gid) || setgid (gid) ||
712 setuid(pass->pw_uid)))
713 die("cannot drop privileges");
715 return service_loop(socknum, socklist);
718 int main(int argc, char **argv)
720 int port = DEFAULT_GIT_PORT;
722 const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
724 struct passwd *pass = NULL;
729 /* Without this we cannot rely on waitpid() to tell
730 * what happened to our children.
732 signal(SIGCHLD, SIG_DFL);
734 for (i = 1; i < argc; i++) {
737 if (!strncmp(arg, "--port=", 7)) {
740 n = strtoul(arg+7, &end, 0);
741 if (arg[7] && !*end) {
746 if (!strcmp(arg, "--inetd")) {
751 if (!strcmp(arg, "--verbose")) {
755 if (!strcmp(arg, "--syslog")) {
759 if (!strcmp(arg, "--export-all")) {
760 export_all_trees = 1;
763 if (!strncmp(arg, "--timeout=", 10)) {
764 timeout = atoi(arg+10);
767 if (!strncmp(arg, "--init-timeout=", 15)) {
768 init_timeout = atoi(arg+15);
771 if (!strcmp(arg, "--strict-paths")) {
775 if (!strncmp(arg, "--base-path=", 12)) {
779 if (!strcmp(arg, "--reuseaddr")) {
783 if (!strcmp(arg, "--user-path")) {
787 if (!strncmp(arg, "--user-path=", 12)) {
788 user_path = arg + 12;
791 if (!strncmp(arg, "--pid-file=", 11)) {
795 if (!strcmp(arg, "--detach")) {
800 if (!strncmp(arg, "--user=", 7)) {
804 if (!strncmp(arg, "--group=", 8)) {
805 group_name = arg + 8;
808 if (!strcmp(arg, "--")) {
809 ok_paths = &argv[i+1];
811 } else if (arg[0] != '-') {
819 if (inetd_mode && (group_name || user_name))
820 die("--user and --group are incompatible with --inetd");
822 if (group_name && !user_name)
823 die("--group supplied without --user");
826 pass = getpwnam(user_name);
828 die("user not found - %s", user_name);
833 group = getgrnam(group_name);
835 die("group not found - %s", group_name);
842 openlog("git-daemon", 0, LOG_DAEMON);
843 set_die_routine(daemon_die);
846 if (strict_paths && (!ok_paths || !*ok_paths))
847 die("option --strict-paths requires a whitelist");
850 struct sockaddr_storage ss;
851 struct sockaddr *peer = (struct sockaddr *)&ss;
852 socklen_t slen = sizeof(ss);
854 freopen("/dev/null", "w", stderr);
856 if (getpeername(0, peer, &slen))
859 return execute(peer);
870 return serve(port, pass, gid);