3 #include <sys/socket.h>
7 #include <netinet/in.h>
14 static int log_syslog;
18 static const char daemon_usage[] =
19 "git-daemon [--verbose] [--syslog] [--inetd | --port=n] [--export-all]\n"
20 " [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
21 " [--base-path=path] [--user-path | --user-path=path]\n"
22 " [--reuseaddr] [directory...]";
24 /* List of acceptable pathname prefixes */
25 static char **ok_paths = NULL;
26 static int strict_paths = 0;
28 /* If this is set, git-daemon-export-ok is not required */
29 static int export_all_trees = 0;
31 /* Take all paths relative to this one if non-NULL */
32 static char *base_path = NULL;
34 /* If defined, ~user notation is allowed and the string is inserted
35 * after ~user/. E.g. a request to git://host/~alice/frotz would
36 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
38 static char *user_path = NULL;
40 /* Timeout, and initial timeout */
41 static unsigned int timeout = 0;
42 static unsigned int init_timeout = 0;
44 static void logreport(int priority, const char *err, va_list params)
46 /* We should do a single write so that it is atomic and output
47 * of several processes do not get intermingled. */
52 /* sizeof(buf) should be big enough for "[pid] \n" */
53 buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
55 maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
56 msglen = vsnprintf(buf + buflen, maxlen, err, params);
59 syslog(priority, "%s", buf);
63 /* maxlen counted our own LF but also counts space given to
64 * vsnprintf for the terminating NUL. We want to make sure that
65 * we have space for our own LF and NUL after the "meat" of the
66 * message, so truncate it at maxlen - 1.
68 if (msglen > maxlen - 1)
71 msglen = 0; /* Protect against weird return values. */
77 write(2, buf, buflen);
80 static void logerror(const char *err, ...)
83 va_start(params, err);
84 logreport(LOG_ERR, err, params);
88 static void loginfo(const char *err, ...)
93 va_start(params, err);
94 logreport(LOG_INFO, err, params);
98 static int avoid_alias(char *p)
103 * This resurrects the belts and suspenders paranoia check by HPA
104 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
105 * does not do getcwd() based path canonicalizations.
107 * sl becomes true immediately after seeing '/' and continues to
108 * be true as long as dots continue after that without intervening
111 if (!p || (*p != '/' && *p != '~'))
121 else if (ch == '/') {
123 /* reject //, /./ and /../ */
128 if (0 < ndot && ndot < 3)
129 /* reject /.$ and /..$ */
138 else if (ch == '/') {
145 static char *path_ok(char *dir)
147 static char rpath[PATH_MAX];
150 if (avoid_alias(dir)) {
151 logerror("'%s': aliased", dir);
157 logerror("'%s': User-path not allowed", dir);
161 /* Got either "~alice" or "~alice/foo";
162 * rewrite them to "~alice/%s" or
165 int namlen, restlen = strlen(dir);
166 char *slash = strchr(dir, '/');
168 slash = dir + restlen;
169 namlen = slash - dir;
171 loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
172 snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
173 namlen, dir, user_path, restlen, slash);
177 else if (base_path) {
179 /* Allow only absolute */
180 logerror("'%s': Non-absolute path denied (base-path active)", dir);
184 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
189 path = enter_repo(dir, strict_paths);
192 logerror("'%s': unable to chdir or not a git archive", dir);
196 if ( ok_paths && *ok_paths ) {
198 int pathlen = strlen(path);
200 /* The validation is done on the paths after enter_repo
201 * appends optional {.git,.git/.git} and friends, but
202 * it does not use getcwd(). So if your /pub is
203 * a symlink to /mnt/pub, you can whitelist /pub and
204 * do not have to say /mnt/pub.
207 for ( pp = ok_paths ; *pp ; pp++ ) {
208 int len = strlen(*pp);
209 if (len <= pathlen &&
210 !memcmp(*pp, path, len) &&
211 (path[len] == '\0' ||
212 (!strict_paths && path[len] == '/')))
217 /* be backwards compatible */
222 logerror("'%s': not in whitelist", path);
223 return NULL; /* Fallthrough. Deny by default */
226 static int upload(char *dir)
228 /* Timeout as string */
229 char timeout_buf[64];
232 loginfo("Request for '%s'", dir);
234 if (!(path = path_ok(dir)))
238 * Security on the cheap.
240 * We want a readable HEAD, usable "objects" directory, and
241 * a "git-daemon-export-ok" flag that says that the other side
242 * is ok with us doing this.
244 * path_ok() uses enter_repo() and does whitelist checking.
245 * We only need to make sure the repository is exported.
248 if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
249 logerror("'%s': repository not exported.", path);
255 * We'll ignore SIGTERM from now on, we have a
258 signal(SIGTERM, SIG_IGN);
260 snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
262 /* git-upload-pack only ever reads stuff, so this is safe */
263 execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
267 static int execute(struct sockaddr *addr)
269 static char line[1000];
273 char addrbuf[256] = "";
276 if (addr->sa_family == AF_INET) {
277 struct sockaddr_in *sin_addr = (void *) addr;
278 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
279 port = sin_addr->sin_port;
281 } else if (addr && addr->sa_family == AF_INET6) {
282 struct sockaddr_in6 *sin6_addr = (void *) addr;
285 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
286 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
289 port = sin6_addr->sin6_port;
292 loginfo("Connection from %s:%d", addrbuf, port);
295 alarm(init_timeout ? init_timeout : timeout);
296 pktlen = packet_read_line(0, line, sizeof(line));
301 loginfo("Extended attributes (%d bytes) exist <%.*s>",
303 (int) pktlen - len, line + len + 1);
304 if (len && line[len-1] == '\n')
307 if (!strncmp("git-upload-pack ", line, 16))
308 return upload(line+16);
310 logerror("Protocol error: '%s'", line);
316 * We count spawned/reaped separately, just to avoid any
317 * races when updating them from signals. The SIGCHLD handler
318 * will only update children_reaped, and the fork logic will
319 * only update children_spawned.
321 * MAX_CHILDREN should be a power-of-two to make the modulus
322 * operation cheap. It should also be at least twice
323 * the maximum number of connections we will ever allow.
325 #define MAX_CHILDREN 128
327 static int max_connections = 25;
329 /* These are updated by the signal handler */
330 static volatile unsigned int children_reaped = 0;
331 static pid_t dead_child[MAX_CHILDREN];
333 /* These are updated by the main loop */
334 static unsigned int children_spawned = 0;
335 static unsigned int children_deleted = 0;
337 static struct child {
340 struct sockaddr_storage address;
341 } live_child[MAX_CHILDREN];
343 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
345 live_child[idx].pid = pid;
346 live_child[idx].addrlen = addrlen;
347 memcpy(&live_child[idx].address, addr, addrlen);
351 * Walk from "deleted" to "spawned", and remove child "pid".
353 * We move everything up by one, since the new "deleted" will
356 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
360 deleted %= MAX_CHILDREN;
361 spawned %= MAX_CHILDREN;
362 if (live_child[deleted].pid == pid) {
363 live_child[deleted].pid = -1;
366 n = live_child[deleted];
369 deleted = (deleted + 1) % MAX_CHILDREN;
370 if (deleted == spawned)
371 die("could not find dead child %d\n", pid);
372 m = live_child[deleted];
373 live_child[deleted] = n;
381 * This gets called if the number of connections grows
382 * past "max_connections".
384 * We _should_ start off by searching for connections
385 * from the same IP, and if there is some address wth
386 * multiple connections, we should kill that first.
388 * As it is, we just "randomly" kill 25% of the connections,
389 * and our pseudo-random generator sucks too. I have no
392 * Really, this is just a place-holder for a _real_ algorithm.
394 static void kill_some_children(int signo, unsigned start, unsigned stop)
396 start %= MAX_CHILDREN;
397 stop %= MAX_CHILDREN;
398 while (start != stop) {
400 kill(live_child[start].pid, signo);
401 start = (start + 1) % MAX_CHILDREN;
405 static void check_max_connections(void)
409 unsigned spawned, reaped, deleted;
411 spawned = children_spawned;
412 reaped = children_reaped;
413 deleted = children_deleted;
415 while (deleted < reaped) {
416 pid_t pid = dead_child[deleted % MAX_CHILDREN];
417 remove_child(pid, deleted, spawned);
420 children_deleted = deleted;
422 active = spawned - deleted;
423 if (active <= max_connections)
426 /* Kill some unstarted connections with SIGTERM */
427 kill_some_children(SIGTERM, deleted, spawned);
428 if (active <= max_connections << 1)
431 /* If the SIGTERM thing isn't helping use SIGKILL */
432 kill_some_children(SIGKILL, deleted, spawned);
437 static void handle(int incoming, struct sockaddr *addr, int addrlen)
448 idx = children_spawned % MAX_CHILDREN;
450 add_child(idx, pid, addr, addrlen);
452 check_max_connections();
463 static void child_handler(int signo)
467 pid_t pid = waitpid(-1, &status, WNOHANG);
470 unsigned reaped = children_reaped;
471 dead_child[reaped % MAX_CHILDREN] = pid;
472 children_reaped = reaped + 1;
473 /* XXX: Custom logging, since we don't wanna getpid() */
476 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
477 dead = " (with error)";
479 syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
481 fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
489 static int set_reuse_addr(int sockfd)
495 return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
501 static int socksetup(int port, int **socklist_p)
503 int socknum = 0, *socklist = NULL;
505 char pbuf[NI_MAXSERV];
507 struct addrinfo hints, *ai0, *ai;
510 sprintf(pbuf, "%d", port);
511 memset(&hints, 0, sizeof(hints));
512 hints.ai_family = AF_UNSPEC;
513 hints.ai_socktype = SOCK_STREAM;
514 hints.ai_protocol = IPPROTO_TCP;
515 hints.ai_flags = AI_PASSIVE;
517 gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
519 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
521 for (ai = ai0; ai; ai = ai->ai_next) {
525 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
528 if (sockfd >= FD_SETSIZE) {
529 error("too large socket descriptor.");
535 if (ai->ai_family == AF_INET6) {
537 setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
539 /* Note: error is not fatal */
543 if (set_reuse_addr(sockfd)) {
548 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
550 continue; /* not fatal */
552 if (listen(sockfd, 5) < 0) {
554 continue; /* not fatal */
557 newlist = realloc(socklist, sizeof(int) * (socknum + 1));
559 die("memory allocation failed: %s", strerror(errno));
562 socklist[socknum++] = sockfd;
570 *socklist_p = socklist;
576 static int socksetup(int port, int **socklist_p)
578 struct sockaddr_in sin;
581 sockfd = socket(AF_INET, SOCK_STREAM, 0);
585 memset(&sin, 0, sizeof sin);
586 sin.sin_family = AF_INET;
587 sin.sin_addr.s_addr = htonl(INADDR_ANY);
588 sin.sin_port = htons(port);
590 if (set_reuse_addr(sockfd)) {
595 if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
600 if (listen(sockfd, 5) < 0) {
605 *socklist_p = xmalloc(sizeof(int));
606 **socklist_p = sockfd;
612 static int service_loop(int socknum, int *socklist)
617 pfd = xcalloc(socknum, sizeof(struct pollfd));
619 for (i = 0; i < socknum; i++) {
620 pfd[i].fd = socklist[i];
621 pfd[i].events = POLLIN;
624 signal(SIGCHLD, child_handler);
629 if (poll(pfd, socknum, -1) < 0) {
630 if (errno != EINTR) {
631 error("poll failed, resuming: %s",
638 for (i = 0; i < socknum; i++) {
639 if (pfd[i].revents & POLLIN) {
640 struct sockaddr_storage ss;
641 unsigned int sslen = sizeof(ss);
642 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
650 die("accept returned %s", strerror(errno));
653 handle(incoming, (struct sockaddr *)&ss, sslen);
659 static int serve(int port)
661 int socknum, *socklist;
663 socknum = socksetup(port, &socklist);
665 die("unable to allocate any listen sockets on port %u", port);
667 return service_loop(socknum, socklist);
670 int main(int argc, char **argv)
672 int port = DEFAULT_GIT_PORT;
676 /* Without this we cannot rely on waitpid() to tell
677 * what happened to our children.
679 signal(SIGCHLD, SIG_DFL);
681 for (i = 1; i < argc; i++) {
684 if (!strncmp(arg, "--port=", 7)) {
687 n = strtoul(arg+7, &end, 0);
688 if (arg[7] && !*end) {
693 if (!strcmp(arg, "--inetd")) {
698 if (!strcmp(arg, "--verbose")) {
702 if (!strcmp(arg, "--syslog")) {
706 if (!strcmp(arg, "--export-all")) {
707 export_all_trees = 1;
710 if (!strncmp(arg, "--timeout=", 10)) {
711 timeout = atoi(arg+10);
714 if (!strncmp(arg, "--init-timeout=", 15)) {
715 init_timeout = atoi(arg+15);
718 if (!strcmp(arg, "--strict-paths")) {
722 if (!strncmp(arg, "--base-path=", 12)) {
726 if (!strcmp(arg, "--reuseaddr")) {
730 if (!strcmp(arg, "--user-path")) {
734 if (!strncmp(arg, "--user-path=", 12)) {
735 user_path = arg + 12;
738 if (!strcmp(arg, "--")) {
739 ok_paths = &argv[i+1];
741 } else if (arg[0] != '-') {
750 openlog("git-daemon", 0, LOG_DAEMON);
752 if (strict_paths && (!ok_paths || !*ok_paths)) {
754 die("git-daemon: option --strict-paths requires a whitelist");
756 logerror("option --strict-paths requires a whitelist");
761 struct sockaddr_storage ss;
762 struct sockaddr *peer = (struct sockaddr *)&ss;
763 socklen_t slen = sizeof(ss);
765 fclose(stderr); //FIXME: workaround
767 if (getpeername(0, peer, &slen))
770 return execute(peer);