3 #include <sys/socket.h>
7 #include <netinet/in.h>
15 #include "interpolate.h"
17 static int log_syslog;
21 static const char daemon_usage[] =
22 "git-daemon [--verbose] [--syslog] [--inetd | --port=n] [--export-all]\n"
23 " [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
24 " [--base-path=path] [--user-path | --user-path=path]\n"
25 " [--interpolated-path=path]\n"
26 " [--reuseaddr] [--detach] [--pid-file=file]\n"
27 " [--[enable|disable|allow-override|forbid-override]=service]\n"
28 " [--user=user [[--group=group]] [directory...]";
30 /* List of acceptable pathname prefixes */
31 static char **ok_paths;
32 static int strict_paths;
34 /* If this is set, git-daemon-export-ok is not required */
35 static int export_all_trees;
37 /* Take all paths relative to this one if non-NULL */
38 static char *base_path;
39 static char *interpolated_path;
41 /* Flag indicating client sent extra args. */
42 static int saw_extended_args;
44 /* If defined, ~user notation is allowed and the string is inserted
45 * after ~user/. E.g. a request to git://host/~alice/frotz would
46 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
48 static const char *user_path;
50 /* Timeout, and initial timeout */
51 static unsigned int timeout;
52 static unsigned int init_timeout;
55 * Static table for now. Ugh.
56 * Feel free to make dynamic as needed.
58 #define INTERP_SLOT_HOST (0)
59 #define INTERP_SLOT_DIR (1)
60 #define INTERP_SLOT_PERCENT (2)
62 static struct interp interp_table[] = {
69 static void logreport(int priority, const char *err, va_list params)
71 /* We should do a single write so that it is atomic and output
72 * of several processes do not get intermingled. */
77 /* sizeof(buf) should be big enough for "[pid] \n" */
78 buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
80 maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
81 msglen = vsnprintf(buf + buflen, maxlen, err, params);
84 syslog(priority, "%s", buf);
88 /* maxlen counted our own LF but also counts space given to
89 * vsnprintf for the terminating NUL. We want to make sure that
90 * we have space for our own LF and NUL after the "meat" of the
91 * message, so truncate it at maxlen - 1.
93 if (msglen > maxlen - 1)
96 msglen = 0; /* Protect against weird return values. */
102 write(2, buf, buflen);
105 static void logerror(const char *err, ...)
108 va_start(params, err);
109 logreport(LOG_ERR, err, params);
113 static void loginfo(const char *err, ...)
118 va_start(params, err);
119 logreport(LOG_INFO, err, params);
123 static void NORETURN daemon_die(const char *err, va_list params)
125 logreport(LOG_ERR, err, params);
129 static int avoid_alias(char *p)
134 * This resurrects the belts and suspenders paranoia check by HPA
135 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
136 * does not do getcwd() based path canonicalizations.
138 * sl becomes true immediately after seeing '/' and continues to
139 * be true as long as dots continue after that without intervening
142 if (!p || (*p != '/' && *p != '~'))
152 else if (ch == '/') {
154 /* reject //, /./ and /../ */
159 if (0 < ndot && ndot < 3)
160 /* reject /.$ and /..$ */
169 else if (ch == '/') {
176 static char *path_ok(struct interp *itable)
178 static char rpath[PATH_MAX];
179 static char interp_path[PATH_MAX];
183 dir = itable[INTERP_SLOT_DIR].value;
185 if (avoid_alias(dir)) {
186 logerror("'%s': aliased", dir);
192 logerror("'%s': User-path not allowed", dir);
196 /* Got either "~alice" or "~alice/foo";
197 * rewrite them to "~alice/%s" or
200 int namlen, restlen = strlen(dir);
201 char *slash = strchr(dir, '/');
203 slash = dir + restlen;
204 namlen = slash - dir;
206 loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
207 snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
208 namlen, dir, user_path, restlen, slash);
212 else if (interpolated_path && saw_extended_args) {
214 /* Allow only absolute */
215 logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
219 interpolate(interp_path, PATH_MAX, interpolated_path,
220 interp_table, ARRAY_SIZE(interp_table));
221 loginfo("Interpolated dir '%s'", interp_path);
225 else if (base_path) {
227 /* Allow only absolute */
228 logerror("'%s': Non-absolute path denied (base-path active)", dir);
231 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
235 path = enter_repo(dir, strict_paths);
238 logerror("'%s': unable to chdir or not a git archive", dir);
242 if ( ok_paths && *ok_paths ) {
244 int pathlen = strlen(path);
246 /* The validation is done on the paths after enter_repo
247 * appends optional {.git,.git/.git} and friends, but
248 * it does not use getcwd(). So if your /pub is
249 * a symlink to /mnt/pub, you can whitelist /pub and
250 * do not have to say /mnt/pub.
253 for ( pp = ok_paths ; *pp ; pp++ ) {
254 int len = strlen(*pp);
255 if (len <= pathlen &&
256 !memcmp(*pp, path, len) &&
257 (path[len] == '\0' ||
258 (!strict_paths && path[len] == '/')))
263 /* be backwards compatible */
268 logerror("'%s': not in whitelist", path);
269 return NULL; /* Fallthrough. Deny by default */
272 typedef int (*daemon_service_fn)(void);
273 struct daemon_service {
275 const char *config_name;
276 daemon_service_fn fn;
281 static struct daemon_service *service_looking_at;
282 static int service_enabled;
284 static int git_daemon_config(const char *var, const char *value)
286 if (!strncmp(var, "daemon.", 7) &&
287 !strcmp(var + 7, service_looking_at->config_name)) {
288 service_enabled = git_config_bool(var, value);
292 /* we are not interested in parsing any other configuration here */
296 static int run_service(struct interp *itable, struct daemon_service *service)
299 int enabled = service->enabled;
301 loginfo("Request %s for '%s'",
303 itable[INTERP_SLOT_DIR].value);
305 if (!enabled && !service->overridable) {
306 logerror("'%s': service not enabled.", service->name);
311 if (!(path = path_ok(itable)))
315 * Security on the cheap.
317 * We want a readable HEAD, usable "objects" directory, and
318 * a "git-daemon-export-ok" flag that says that the other side
319 * is ok with us doing this.
321 * path_ok() uses enter_repo() and does whitelist checking.
322 * We only need to make sure the repository is exported.
325 if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
326 logerror("'%s': repository not exported.", path);
331 if (service->overridable) {
332 service_looking_at = service;
333 service_enabled = -1;
334 git_config(git_daemon_config);
335 if (0 <= service_enabled)
336 enabled = service_enabled;
339 logerror("'%s': service not enabled for '%s'",
340 service->name, path);
346 * We'll ignore SIGTERM from now on, we have a
349 signal(SIGTERM, SIG_IGN);
351 return service->fn();
354 static int upload_pack(void)
356 /* Timeout as string */
357 char timeout_buf[64];
359 snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
361 /* git-upload-pack only ever reads stuff, so this is safe */
362 execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
366 static int upload_archive(void)
368 execl_git_cmd("upload-archive", ".", NULL);
372 static struct daemon_service daemon_service[] = {
373 { "upload-archive", "uploadarch", upload_archive, 0, 1 },
374 { "upload-pack", "uploadpack", upload_pack, 1, 1 },
377 static void enable_service(const char *name, int ena) {
379 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
380 if (!strcmp(daemon_service[i].name, name)) {
381 daemon_service[i].enabled = ena;
385 die("No such service %s", name);
388 static void make_service_overridable(const char *name, int ena) {
390 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
391 if (!strcmp(daemon_service[i].name, name)) {
392 daemon_service[i].overridable = ena;
396 die("No such service %s", name);
399 static void parse_extra_args(char *extra_args, int buflen)
403 char *end = extra_args + buflen;
405 while (extra_args < end && *extra_args) {
406 saw_extended_args = 1;
407 if (strncasecmp("host=", extra_args, 5) == 0) {
408 val = extra_args + 5;
409 vallen = strlen(val) + 1;
411 char *save = xmalloc(vallen);
412 interp_table[INTERP_SLOT_HOST].value = save;
413 strlcpy(save, val, vallen);
415 /* On to the next one */
416 extra_args = val + vallen;
421 static int execute(struct sockaddr *addr)
423 static char line[1000];
427 char addrbuf[256] = "";
430 if (addr->sa_family == AF_INET) {
431 struct sockaddr_in *sin_addr = (void *) addr;
432 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
433 port = sin_addr->sin_port;
435 } else if (addr && addr->sa_family == AF_INET6) {
436 struct sockaddr_in6 *sin6_addr = (void *) addr;
439 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
440 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
443 port = sin6_addr->sin6_port;
446 loginfo("Connection from %s:%d", addrbuf, port);
449 alarm(init_timeout ? init_timeout : timeout);
450 pktlen = packet_read_line(0, line, sizeof(line));
455 loginfo("Extended attributes (%d bytes) exist <%.*s>",
457 (int) pktlen - len, line + len + 1);
458 if (len && line[len-1] == '\n')
462 parse_extra_args(line + len + 1, pktlen - len - 1);
464 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
465 struct daemon_service *s = &(daemon_service[i]);
466 int namelen = strlen(s->name);
467 if (!strncmp("git-", line, 4) &&
468 !strncmp(s->name, line + 4, namelen) &&
469 line[namelen + 4] == ' ') {
470 interp_table[INTERP_SLOT_DIR].value = line+namelen+5;
471 return run_service(interp_table, s);
475 logerror("Protocol error: '%s'", line);
481 * We count spawned/reaped separately, just to avoid any
482 * races when updating them from signals. The SIGCHLD handler
483 * will only update children_reaped, and the fork logic will
484 * only update children_spawned.
486 * MAX_CHILDREN should be a power-of-two to make the modulus
487 * operation cheap. It should also be at least twice
488 * the maximum number of connections we will ever allow.
490 #define MAX_CHILDREN 128
492 static int max_connections = 25;
494 /* These are updated by the signal handler */
495 static volatile unsigned int children_reaped;
496 static pid_t dead_child[MAX_CHILDREN];
498 /* These are updated by the main loop */
499 static unsigned int children_spawned;
500 static unsigned int children_deleted;
502 static struct child {
505 struct sockaddr_storage address;
506 } live_child[MAX_CHILDREN];
508 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
510 live_child[idx].pid = pid;
511 live_child[idx].addrlen = addrlen;
512 memcpy(&live_child[idx].address, addr, addrlen);
516 * Walk from "deleted" to "spawned", and remove child "pid".
518 * We move everything up by one, since the new "deleted" will
521 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
525 deleted %= MAX_CHILDREN;
526 spawned %= MAX_CHILDREN;
527 if (live_child[deleted].pid == pid) {
528 live_child[deleted].pid = -1;
531 n = live_child[deleted];
534 deleted = (deleted + 1) % MAX_CHILDREN;
535 if (deleted == spawned)
536 die("could not find dead child %d\n", pid);
537 m = live_child[deleted];
538 live_child[deleted] = n;
546 * This gets called if the number of connections grows
547 * past "max_connections".
549 * We _should_ start off by searching for connections
550 * from the same IP, and if there is some address wth
551 * multiple connections, we should kill that first.
553 * As it is, we just "randomly" kill 25% of the connections,
554 * and our pseudo-random generator sucks too. I have no
557 * Really, this is just a place-holder for a _real_ algorithm.
559 static void kill_some_children(int signo, unsigned start, unsigned stop)
561 start %= MAX_CHILDREN;
562 stop %= MAX_CHILDREN;
563 while (start != stop) {
565 kill(live_child[start].pid, signo);
566 start = (start + 1) % MAX_CHILDREN;
570 static void check_max_connections(void)
574 unsigned spawned, reaped, deleted;
576 spawned = children_spawned;
577 reaped = children_reaped;
578 deleted = children_deleted;
580 while (deleted < reaped) {
581 pid_t pid = dead_child[deleted % MAX_CHILDREN];
582 remove_child(pid, deleted, spawned);
585 children_deleted = deleted;
587 active = spawned - deleted;
588 if (active <= max_connections)
591 /* Kill some unstarted connections with SIGTERM */
592 kill_some_children(SIGTERM, deleted, spawned);
593 if (active <= max_connections << 1)
596 /* If the SIGTERM thing isn't helping use SIGKILL */
597 kill_some_children(SIGKILL, deleted, spawned);
602 static void handle(int incoming, struct sockaddr *addr, int addrlen)
613 idx = children_spawned % MAX_CHILDREN;
615 add_child(idx, pid, addr, addrlen);
617 check_max_connections();
628 static void child_handler(int signo)
632 pid_t pid = waitpid(-1, &status, WNOHANG);
635 unsigned reaped = children_reaped;
636 dead_child[reaped % MAX_CHILDREN] = pid;
637 children_reaped = reaped + 1;
638 /* XXX: Custom logging, since we don't wanna getpid() */
640 const char *dead = "";
641 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
642 dead = " (with error)";
644 syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
646 fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
654 static int set_reuse_addr(int sockfd)
660 return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
666 static int socksetup(int port, int **socklist_p)
668 int socknum = 0, *socklist = NULL;
670 char pbuf[NI_MAXSERV];
672 struct addrinfo hints, *ai0, *ai;
675 sprintf(pbuf, "%d", port);
676 memset(&hints, 0, sizeof(hints));
677 hints.ai_family = AF_UNSPEC;
678 hints.ai_socktype = SOCK_STREAM;
679 hints.ai_protocol = IPPROTO_TCP;
680 hints.ai_flags = AI_PASSIVE;
682 gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
684 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
686 for (ai = ai0; ai; ai = ai->ai_next) {
689 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
692 if (sockfd >= FD_SETSIZE) {
693 error("too large socket descriptor.");
699 if (ai->ai_family == AF_INET6) {
701 setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
703 /* Note: error is not fatal */
707 if (set_reuse_addr(sockfd)) {
712 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
714 continue; /* not fatal */
716 if (listen(sockfd, 5) < 0) {
718 continue; /* not fatal */
721 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
722 socklist[socknum++] = sockfd;
730 *socklist_p = socklist;
736 static int socksetup(int port, int **socklist_p)
738 struct sockaddr_in sin;
741 sockfd = socket(AF_INET, SOCK_STREAM, 0);
745 memset(&sin, 0, sizeof sin);
746 sin.sin_family = AF_INET;
747 sin.sin_addr.s_addr = htonl(INADDR_ANY);
748 sin.sin_port = htons(port);
750 if (set_reuse_addr(sockfd)) {
755 if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
760 if (listen(sockfd, 5) < 0) {
765 *socklist_p = xmalloc(sizeof(int));
766 **socklist_p = sockfd;
772 static int service_loop(int socknum, int *socklist)
777 pfd = xcalloc(socknum, sizeof(struct pollfd));
779 for (i = 0; i < socknum; i++) {
780 pfd[i].fd = socklist[i];
781 pfd[i].events = POLLIN;
784 signal(SIGCHLD, child_handler);
789 if (poll(pfd, socknum, -1) < 0) {
790 if (errno != EINTR) {
791 error("poll failed, resuming: %s",
798 for (i = 0; i < socknum; i++) {
799 if (pfd[i].revents & POLLIN) {
800 struct sockaddr_storage ss;
801 unsigned int sslen = sizeof(ss);
802 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
810 die("accept returned %s", strerror(errno));
813 handle(incoming, (struct sockaddr *)&ss, sslen);
819 /* if any standard file descriptor is missing open it to /dev/null */
820 static void sanitize_stdfds(void)
822 int fd = open("/dev/null", O_RDWR, 0);
823 while (fd != -1 && fd < 2)
826 die("open /dev/null or dup failed: %s", strerror(errno));
831 static void daemonize(void)
837 die("fork failed: %s", strerror(errno));
842 die("setsid failed: %s", strerror(errno));
849 static void store_pid(const char *path)
851 FILE *f = fopen(path, "w");
853 die("cannot open pid file %s: %s", path, strerror(errno));
854 fprintf(f, "%d\n", getpid());
858 static int serve(int port, struct passwd *pass, gid_t gid)
860 int socknum, *socklist;
862 socknum = socksetup(port, &socklist);
864 die("unable to allocate any listen sockets on port %u", port);
867 (initgroups(pass->pw_name, gid) || setgid (gid) ||
868 setuid(pass->pw_uid)))
869 die("cannot drop privileges");
871 return service_loop(socknum, socklist);
874 int main(int argc, char **argv)
876 int port = DEFAULT_GIT_PORT;
878 const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
880 struct passwd *pass = NULL;
885 /* Without this we cannot rely on waitpid() to tell
886 * what happened to our children.
888 signal(SIGCHLD, SIG_DFL);
890 for (i = 1; i < argc; i++) {
893 if (!strncmp(arg, "--port=", 7)) {
896 n = strtoul(arg+7, &end, 0);
897 if (arg[7] && !*end) {
902 if (!strcmp(arg, "--inetd")) {
907 if (!strcmp(arg, "--verbose")) {
911 if (!strcmp(arg, "--syslog")) {
915 if (!strcmp(arg, "--export-all")) {
916 export_all_trees = 1;
919 if (!strncmp(arg, "--timeout=", 10)) {
920 timeout = atoi(arg+10);
923 if (!strncmp(arg, "--init-timeout=", 15)) {
924 init_timeout = atoi(arg+15);
927 if (!strcmp(arg, "--strict-paths")) {
931 if (!strncmp(arg, "--base-path=", 12)) {
935 if (!strncmp(arg, "--interpolated-path=", 20)) {
936 interpolated_path = arg+20;
939 if (!strcmp(arg, "--reuseaddr")) {
943 if (!strcmp(arg, "--user-path")) {
947 if (!strncmp(arg, "--user-path=", 12)) {
948 user_path = arg + 12;
951 if (!strncmp(arg, "--pid-file=", 11)) {
955 if (!strcmp(arg, "--detach")) {
960 if (!strncmp(arg, "--user=", 7)) {
964 if (!strncmp(arg, "--group=", 8)) {
965 group_name = arg + 8;
968 if (!strncmp(arg, "--enable=", 9)) {
969 enable_service(arg + 9, 1);
972 if (!strncmp(arg, "--disable=", 10)) {
973 enable_service(arg + 10, 0);
976 if (!strncmp(arg, "--allow-override=", 17)) {
977 make_service_overridable(arg + 17, 1);
980 if (!strncmp(arg, "--forbid-override=", 18)) {
981 make_service_overridable(arg + 18, 0);
984 if (!strcmp(arg, "--")) {
985 ok_paths = &argv[i+1];
987 } else if (arg[0] != '-') {
995 if (inetd_mode && (group_name || user_name))
996 die("--user and --group are incompatible with --inetd");
998 if (group_name && !user_name)
999 die("--group supplied without --user");
1002 pass = getpwnam(user_name);
1004 die("user not found - %s", user_name);
1009 group = getgrnam(group_name);
1011 die("group not found - %s", group_name);
1013 gid = group->gr_gid;
1018 openlog("git-daemon", 0, LOG_DAEMON);
1019 set_die_routine(daemon_die);
1022 if (strict_paths && (!ok_paths || !*ok_paths))
1023 die("option --strict-paths requires a whitelist");
1026 struct sockaddr_storage ss;
1027 struct sockaddr *peer = (struct sockaddr *)&ss;
1028 socklen_t slen = sizeof(ss);
1030 freopen("/dev/null", "w", stderr);
1032 if (getpeername(0, peer, &slen))
1035 return execute(peer);
1044 store_pid(pid_file);
1046 return serve(port, pass, gid);