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 typedef int (*daemon_service_fn)(void);
236 struct daemon_service {
238 const char *config_name;
239 daemon_service_fn fn;
244 static struct daemon_service *service_looking_at;
245 static int service_enabled;
247 static int git_daemon_config(const char *var, const char *value)
249 if (!strncmp(var, "daemon.", 7) &&
250 !strcmp(var + 7, service_looking_at->config_name)) {
251 service_enabled = git_config_bool(var, value);
255 /* we are not interested in parsing any other configuration here */
259 static int run_service(char *dir, struct daemon_service *service)
262 int enabled = service->enabled;
264 loginfo("Request %s for '%s'", service->name, dir);
266 if (!enabled && !service->overridable) {
267 logerror("'%s': service not enabled.", service->name);
272 if (!(path = path_ok(dir)))
276 * Security on the cheap.
278 * We want a readable HEAD, usable "objects" directory, and
279 * a "git-daemon-export-ok" flag that says that the other side
280 * is ok with us doing this.
282 * path_ok() uses enter_repo() and does whitelist checking.
283 * We only need to make sure the repository is exported.
286 if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
287 logerror("'%s': repository not exported.", path);
292 if (service->overridable) {
293 service_looking_at = service;
294 service_enabled = -1;
295 git_config(git_daemon_config);
296 if (0 <= service_enabled)
297 enabled = service_enabled;
300 logerror("'%s': service not enabled for '%s'",
301 service->name, path);
307 * We'll ignore SIGTERM from now on, we have a
310 signal(SIGTERM, SIG_IGN);
312 return service->fn();
315 static int upload_pack(void)
317 /* Timeout as string */
318 char timeout_buf[64];
320 snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
322 /* git-upload-pack only ever reads stuff, so this is safe */
323 execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
327 static struct daemon_service daemon_service[] = {
328 { "upload-pack", "uploadpack", upload_pack, 1, 1 },
331 static void enable_service(const char *name, int ena) {
333 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
334 if (!strcmp(daemon_service[i].name, name)) {
335 daemon_service[i].enabled = ena;
339 die("No such service %s", name);
342 static void make_service_overridable(const char *name, int ena) {
344 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
345 if (!strcmp(daemon_service[i].name, name)) {
346 daemon_service[i].overridable = ena;
350 die("No such service %s", name);
353 static int execute(struct sockaddr *addr)
355 static char line[1000];
359 char addrbuf[256] = "";
362 if (addr->sa_family == AF_INET) {
363 struct sockaddr_in *sin_addr = (void *) addr;
364 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
365 port = sin_addr->sin_port;
367 } else if (addr && addr->sa_family == AF_INET6) {
368 struct sockaddr_in6 *sin6_addr = (void *) addr;
371 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
372 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
375 port = sin6_addr->sin6_port;
378 loginfo("Connection from %s:%d", addrbuf, port);
381 alarm(init_timeout ? init_timeout : timeout);
382 pktlen = packet_read_line(0, line, sizeof(line));
387 loginfo("Extended attributes (%d bytes) exist <%.*s>",
389 (int) pktlen - len, line + len + 1);
390 if (len && line[len-1] == '\n')
393 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
394 struct daemon_service *s = &(daemon_service[i]);
395 int namelen = strlen(s->name);
396 if (!strncmp("git-", line, 4) &&
397 !strncmp(s->name, line + 4, namelen) &&
398 line[namelen + 4] == ' ')
399 return run_service(line + namelen + 5, s);
402 logerror("Protocol error: '%s'", line);
408 * We count spawned/reaped separately, just to avoid any
409 * races when updating them from signals. The SIGCHLD handler
410 * will only update children_reaped, and the fork logic will
411 * only update children_spawned.
413 * MAX_CHILDREN should be a power-of-two to make the modulus
414 * operation cheap. It should also be at least twice
415 * the maximum number of connections we will ever allow.
417 #define MAX_CHILDREN 128
419 static int max_connections = 25;
421 /* These are updated by the signal handler */
422 static volatile unsigned int children_reaped;
423 static pid_t dead_child[MAX_CHILDREN];
425 /* These are updated by the main loop */
426 static unsigned int children_spawned;
427 static unsigned int children_deleted;
429 static struct child {
432 struct sockaddr_storage address;
433 } live_child[MAX_CHILDREN];
435 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
437 live_child[idx].pid = pid;
438 live_child[idx].addrlen = addrlen;
439 memcpy(&live_child[idx].address, addr, addrlen);
443 * Walk from "deleted" to "spawned", and remove child "pid".
445 * We move everything up by one, since the new "deleted" will
448 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
452 deleted %= MAX_CHILDREN;
453 spawned %= MAX_CHILDREN;
454 if (live_child[deleted].pid == pid) {
455 live_child[deleted].pid = -1;
458 n = live_child[deleted];
461 deleted = (deleted + 1) % MAX_CHILDREN;
462 if (deleted == spawned)
463 die("could not find dead child %d\n", pid);
464 m = live_child[deleted];
465 live_child[deleted] = n;
473 * This gets called if the number of connections grows
474 * past "max_connections".
476 * We _should_ start off by searching for connections
477 * from the same IP, and if there is some address wth
478 * multiple connections, we should kill that first.
480 * As it is, we just "randomly" kill 25% of the connections,
481 * and our pseudo-random generator sucks too. I have no
484 * Really, this is just a place-holder for a _real_ algorithm.
486 static void kill_some_children(int signo, unsigned start, unsigned stop)
488 start %= MAX_CHILDREN;
489 stop %= MAX_CHILDREN;
490 while (start != stop) {
492 kill(live_child[start].pid, signo);
493 start = (start + 1) % MAX_CHILDREN;
497 static void check_max_connections(void)
501 unsigned spawned, reaped, deleted;
503 spawned = children_spawned;
504 reaped = children_reaped;
505 deleted = children_deleted;
507 while (deleted < reaped) {
508 pid_t pid = dead_child[deleted % MAX_CHILDREN];
509 remove_child(pid, deleted, spawned);
512 children_deleted = deleted;
514 active = spawned - deleted;
515 if (active <= max_connections)
518 /* Kill some unstarted connections with SIGTERM */
519 kill_some_children(SIGTERM, deleted, spawned);
520 if (active <= max_connections << 1)
523 /* If the SIGTERM thing isn't helping use SIGKILL */
524 kill_some_children(SIGKILL, deleted, spawned);
529 static void handle(int incoming, struct sockaddr *addr, int addrlen)
540 idx = children_spawned % MAX_CHILDREN;
542 add_child(idx, pid, addr, addrlen);
544 check_max_connections();
555 static void child_handler(int signo)
559 pid_t pid = waitpid(-1, &status, WNOHANG);
562 unsigned reaped = children_reaped;
563 dead_child[reaped % MAX_CHILDREN] = pid;
564 children_reaped = reaped + 1;
565 /* XXX: Custom logging, since we don't wanna getpid() */
567 const char *dead = "";
568 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
569 dead = " (with error)";
571 syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
573 fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
581 static int set_reuse_addr(int sockfd)
587 return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
593 static int socksetup(int port, int **socklist_p)
595 int socknum = 0, *socklist = NULL;
597 char pbuf[NI_MAXSERV];
599 struct addrinfo hints, *ai0, *ai;
602 sprintf(pbuf, "%d", port);
603 memset(&hints, 0, sizeof(hints));
604 hints.ai_family = AF_UNSPEC;
605 hints.ai_socktype = SOCK_STREAM;
606 hints.ai_protocol = IPPROTO_TCP;
607 hints.ai_flags = AI_PASSIVE;
609 gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
611 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
613 for (ai = ai0; ai; ai = ai->ai_next) {
616 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
619 if (sockfd >= FD_SETSIZE) {
620 error("too large socket descriptor.");
626 if (ai->ai_family == AF_INET6) {
628 setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
630 /* Note: error is not fatal */
634 if (set_reuse_addr(sockfd)) {
639 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
641 continue; /* not fatal */
643 if (listen(sockfd, 5) < 0) {
645 continue; /* not fatal */
648 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
649 socklist[socknum++] = sockfd;
657 *socklist_p = socklist;
663 static int socksetup(int port, int **socklist_p)
665 struct sockaddr_in sin;
668 sockfd = socket(AF_INET, SOCK_STREAM, 0);
672 memset(&sin, 0, sizeof sin);
673 sin.sin_family = AF_INET;
674 sin.sin_addr.s_addr = htonl(INADDR_ANY);
675 sin.sin_port = htons(port);
677 if (set_reuse_addr(sockfd)) {
682 if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
687 if (listen(sockfd, 5) < 0) {
692 *socklist_p = xmalloc(sizeof(int));
693 **socklist_p = sockfd;
699 static int service_loop(int socknum, int *socklist)
704 pfd = xcalloc(socknum, sizeof(struct pollfd));
706 for (i = 0; i < socknum; i++) {
707 pfd[i].fd = socklist[i];
708 pfd[i].events = POLLIN;
711 signal(SIGCHLD, child_handler);
716 if (poll(pfd, socknum, -1) < 0) {
717 if (errno != EINTR) {
718 error("poll failed, resuming: %s",
725 for (i = 0; i < socknum; i++) {
726 if (pfd[i].revents & POLLIN) {
727 struct sockaddr_storage ss;
728 unsigned int sslen = sizeof(ss);
729 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
737 die("accept returned %s", strerror(errno));
740 handle(incoming, (struct sockaddr *)&ss, sslen);
746 /* if any standard file descriptor is missing open it to /dev/null */
747 static void sanitize_stdfds(void)
749 int fd = open("/dev/null", O_RDWR, 0);
750 while (fd != -1 && fd < 2)
753 die("open /dev/null or dup failed: %s", strerror(errno));
758 static void daemonize(void)
764 die("fork failed: %s", strerror(errno));
769 die("setsid failed: %s", strerror(errno));
776 static void store_pid(const char *path)
778 FILE *f = fopen(path, "w");
780 die("cannot open pid file %s: %s", path, strerror(errno));
781 fprintf(f, "%d\n", getpid());
785 static int serve(int port, struct passwd *pass, gid_t gid)
787 int socknum, *socklist;
789 socknum = socksetup(port, &socklist);
791 die("unable to allocate any listen sockets on port %u", port);
794 (initgroups(pass->pw_name, gid) || setgid (gid) ||
795 setuid(pass->pw_uid)))
796 die("cannot drop privileges");
798 return service_loop(socknum, socklist);
801 int main(int argc, char **argv)
803 int port = DEFAULT_GIT_PORT;
805 const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
807 struct passwd *pass = NULL;
812 /* Without this we cannot rely on waitpid() to tell
813 * what happened to our children.
815 signal(SIGCHLD, SIG_DFL);
817 for (i = 1; i < argc; i++) {
820 if (!strncmp(arg, "--port=", 7)) {
823 n = strtoul(arg+7, &end, 0);
824 if (arg[7] && !*end) {
829 if (!strcmp(arg, "--inetd")) {
834 if (!strcmp(arg, "--verbose")) {
838 if (!strcmp(arg, "--syslog")) {
842 if (!strcmp(arg, "--export-all")) {
843 export_all_trees = 1;
846 if (!strncmp(arg, "--timeout=", 10)) {
847 timeout = atoi(arg+10);
850 if (!strncmp(arg, "--init-timeout=", 15)) {
851 init_timeout = atoi(arg+15);
854 if (!strcmp(arg, "--strict-paths")) {
858 if (!strncmp(arg, "--base-path=", 12)) {
862 if (!strcmp(arg, "--reuseaddr")) {
866 if (!strcmp(arg, "--user-path")) {
870 if (!strncmp(arg, "--user-path=", 12)) {
871 user_path = arg + 12;
874 if (!strncmp(arg, "--pid-file=", 11)) {
878 if (!strcmp(arg, "--detach")) {
883 if (!strncmp(arg, "--user=", 7)) {
887 if (!strncmp(arg, "--group=", 8)) {
888 group_name = arg + 8;
891 if (!strncmp(arg, "--enable=", 9)) {
892 enable_service(arg + 9, 1);
895 if (!strncmp(arg, "--disable=", 10)) {
896 enable_service(arg + 10, 0);
899 if (!strncmp(arg, "--enable-override=", 18)) {
900 make_service_overridable(arg + 18, 1);
903 if (!strncmp(arg, "--disable-override=", 19)) {
904 make_service_overridable(arg + 19, 0);
907 if (!strcmp(arg, "--")) {
908 ok_paths = &argv[i+1];
910 } else if (arg[0] != '-') {
918 if (inetd_mode && (group_name || user_name))
919 die("--user and --group are incompatible with --inetd");
921 if (group_name && !user_name)
922 die("--group supplied without --user");
925 pass = getpwnam(user_name);
927 die("user not found - %s", user_name);
932 group = getgrnam(group_name);
934 die("group not found - %s", group_name);
941 openlog("git-daemon", 0, LOG_DAEMON);
942 set_die_routine(daemon_die);
945 if (strict_paths && (!ok_paths || !*ok_paths))
946 die("option --strict-paths requires a whitelist");
949 struct sockaddr_storage ss;
950 struct sockaddr *peer = (struct sockaddr *)&ss;
951 socklen_t slen = sizeof(ss);
953 freopen("/dev/null", "w", stderr);
955 if (getpeername(0, peer, &slen))
958 return execute(peer);
969 return serve(port, pass, gid);