3 #include <sys/socket.h>
7 #include <netinet/in.h>
13 static int log_syslog;
16 static const char daemon_usage[] =
17 "git-daemon [--verbose] [--syslog] [--inetd | --port=n] [--export-all]\n"
18 " [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
19 " [--base-path=path] [directory...]";
21 /* List of acceptable pathname prefixes */
22 static char **ok_paths = NULL;
23 static int strict_paths = 0;
25 /* If this is set, git-daemon-export-ok is not required */
26 static int export_all_trees = 0;
28 /* Take all paths relative to this one if non-NULL */
29 static char *base_path = NULL;
31 /* Timeout, and initial timeout */
32 static unsigned int timeout = 0;
33 static unsigned int init_timeout = 0;
35 static void logreport(int priority, const char *err, va_list params)
37 /* We should do a single write so that it is atomic and output
38 * of several processes do not get intermingled. */
43 /* sizeof(buf) should be big enough for "[pid] \n" */
44 buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
46 maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
47 msglen = vsnprintf(buf + buflen, maxlen, err, params);
50 syslog(priority, "%s", buf);
54 /* maxlen counted our own LF but also counts space given to
55 * vsnprintf for the terminating NUL. We want to make sure that
56 * we have space for our own LF and NUL after the "meat" of the
57 * message, so truncate it at maxlen - 1.
59 if (msglen > maxlen - 1)
62 msglen = 0; /* Protect against weird return values. */
68 write(2, buf, buflen);
71 static void logerror(const char *err, ...)
74 va_start(params, err);
75 logreport(LOG_ERR, err, params);
79 static void loginfo(const char *err, ...)
84 va_start(params, err);
85 logreport(LOG_INFO, err, params);
89 static int avoid_alias(char *p)
94 * This resurrects the belts and suspenders paranoia check by HPA
95 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
96 * does not do getcwd() based path canonicalizations.
98 * sl becomes true immediately after seeing '/' and continues to
99 * be true as long as dots continue after that without intervening
102 if (!p || (*p != '/' && *p != '~'))
112 else if (ch == '/') {
114 /* reject //, /./ and /../ */
119 if (0 < ndot && ndot < 3)
120 /* reject /.$ and /..$ */
129 else if (ch == '/') {
136 static char *path_ok(char *dir)
140 if (avoid_alias(dir)) {
141 logerror("'%s': aliased", dir);
146 static char rpath[PATH_MAX];
148 /* Forbid possible base-path evasion using ~paths. */
149 logerror("'%s': Non-absolute path denied (base-path active)");
152 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
156 path = enter_repo(dir, strict_paths);
159 logerror("'%s': unable to chdir or not a git archive", dir);
163 if ( ok_paths && *ok_paths ) {
165 int pathlen = strlen(path);
167 /* The validation is done on the paths after enter_repo
168 * appends optional {.git,.git/.git} and friends, but
169 * it does not use getcwd(). So if your /pub is
170 * a symlink to /mnt/pub, you can whitelist /pub and
171 * do not have to say /mnt/pub.
174 for ( pp = ok_paths ; *pp ; pp++ ) {
175 int len = strlen(*pp);
176 if (len <= pathlen &&
177 !memcmp(*pp, path, len) &&
178 (path[len] == '\0' ||
179 (!strict_paths && path[len] == '/')))
184 /* be backwards compatible */
189 logerror("'%s': not in whitelist", path);
190 return NULL; /* Fallthrough. Deny by default */
193 static int upload(char *dir)
195 /* Timeout as string */
196 char timeout_buf[64];
199 loginfo("Request for '%s'", dir);
201 if (!(path = path_ok(dir)))
205 * Security on the cheap.
207 * We want a readable HEAD, usable "objects" directory, and
208 * a "git-daemon-export-ok" flag that says that the other side
209 * is ok with us doing this.
211 * path_ok() uses enter_repo() and does whitelist checking.
212 * We only need to make sure the repository is exported.
215 if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
216 logerror("'%s': repository not exported.", path);
222 * We'll ignore SIGTERM from now on, we have a
225 signal(SIGTERM, SIG_IGN);
227 snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
229 /* git-upload-pack only ever reads stuff, so this is safe */
230 execlp("git-upload-pack", "git-upload-pack", "--strict", timeout_buf, ".", NULL);
234 static int execute(void)
236 static char line[1000];
239 alarm(init_timeout ? init_timeout : timeout);
240 len = packet_read_line(0, line, sizeof(line));
243 if (len && line[len-1] == '\n')
246 if (!strncmp("git-upload-pack ", line, 16))
247 return upload(line+16);
249 logerror("Protocol error: '%s'", line);
255 * We count spawned/reaped separately, just to avoid any
256 * races when updating them from signals. The SIGCHLD handler
257 * will only update children_reaped, and the fork logic will
258 * only update children_spawned.
260 * MAX_CHILDREN should be a power-of-two to make the modulus
261 * operation cheap. It should also be at least twice
262 * the maximum number of connections we will ever allow.
264 #define MAX_CHILDREN 128
266 static int max_connections = 25;
268 /* These are updated by the signal handler */
269 static volatile unsigned int children_reaped = 0;
270 static pid_t dead_child[MAX_CHILDREN];
272 /* These are updated by the main loop */
273 static unsigned int children_spawned = 0;
274 static unsigned int children_deleted = 0;
276 static struct child {
279 struct sockaddr_storage address;
280 } live_child[MAX_CHILDREN];
282 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
284 live_child[idx].pid = pid;
285 live_child[idx].addrlen = addrlen;
286 memcpy(&live_child[idx].address, addr, addrlen);
290 * Walk from "deleted" to "spawned", and remove child "pid".
292 * We move everything up by one, since the new "deleted" will
295 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
299 deleted %= MAX_CHILDREN;
300 spawned %= MAX_CHILDREN;
301 if (live_child[deleted].pid == pid) {
302 live_child[deleted].pid = -1;
305 n = live_child[deleted];
308 deleted = (deleted + 1) % MAX_CHILDREN;
309 if (deleted == spawned)
310 die("could not find dead child %d\n", pid);
311 m = live_child[deleted];
312 live_child[deleted] = n;
320 * This gets called if the number of connections grows
321 * past "max_connections".
323 * We _should_ start off by searching for connections
324 * from the same IP, and if there is some address wth
325 * multiple connections, we should kill that first.
327 * As it is, we just "randomly" kill 25% of the connections,
328 * and our pseudo-random generator sucks too. I have no
331 * Really, this is just a place-holder for a _real_ algorithm.
333 static void kill_some_children(int signo, unsigned start, unsigned stop)
335 start %= MAX_CHILDREN;
336 stop %= MAX_CHILDREN;
337 while (start != stop) {
339 kill(live_child[start].pid, signo);
340 start = (start + 1) % MAX_CHILDREN;
344 static void check_max_connections(void)
348 unsigned spawned, reaped, deleted;
350 spawned = children_spawned;
351 reaped = children_reaped;
352 deleted = children_deleted;
354 while (deleted < reaped) {
355 pid_t pid = dead_child[deleted % MAX_CHILDREN];
356 remove_child(pid, deleted, spawned);
359 children_deleted = deleted;
361 active = spawned - deleted;
362 if (active <= max_connections)
365 /* Kill some unstarted connections with SIGTERM */
366 kill_some_children(SIGTERM, deleted, spawned);
367 if (active <= max_connections << 1)
370 /* If the SIGTERM thing isn't helping use SIGKILL */
371 kill_some_children(SIGKILL, deleted, spawned);
376 static void handle(int incoming, struct sockaddr *addr, int addrlen)
379 char addrbuf[256] = "";
389 idx = children_spawned % MAX_CHILDREN;
391 add_child(idx, pid, addr, addrlen);
393 check_max_connections();
401 if (addr->sa_family == AF_INET) {
402 struct sockaddr_in *sin_addr = (void *) addr;
403 inet_ntop(AF_INET, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
404 port = sin_addr->sin_port;
407 } else if (addr->sa_family == AF_INET6) {
408 struct sockaddr_in6 *sin6_addr = (void *) addr;
411 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
412 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
415 port = sin6_addr->sin6_port;
418 loginfo("Connection from %s:%d", addrbuf, port);
423 static void child_handler(int signo)
427 pid_t pid = waitpid(-1, &status, WNOHANG);
430 unsigned reaped = children_reaped;
431 dead_child[reaped % MAX_CHILDREN] = pid;
432 children_reaped = reaped + 1;
433 /* XXX: Custom logging, since we don't wanna getpid() */
436 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
437 dead = " (with error)";
439 syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
441 fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
451 static int socksetup(int port, int **socklist_p)
453 int socknum = 0, *socklist = NULL;
455 char pbuf[NI_MAXSERV];
457 struct addrinfo hints, *ai0, *ai;
460 sprintf(pbuf, "%d", port);
461 memset(&hints, 0, sizeof(hints));
462 hints.ai_family = AF_UNSPEC;
463 hints.ai_socktype = SOCK_STREAM;
464 hints.ai_protocol = IPPROTO_TCP;
465 hints.ai_flags = AI_PASSIVE;
467 gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
469 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
471 for (ai = ai0; ai; ai = ai->ai_next) {
475 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
478 if (sockfd >= FD_SETSIZE) {
479 error("too large socket descriptor.");
485 if (ai->ai_family == AF_INET6) {
487 setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
489 /* Note: error is not fatal */
493 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
495 continue; /* not fatal */
497 if (listen(sockfd, 5) < 0) {
499 continue; /* not fatal */
502 newlist = realloc(socklist, sizeof(int) * (socknum + 1));
504 die("memory allocation failed: %s", strerror(errno));
507 socklist[socknum++] = sockfd;
515 *socklist_p = socklist;
521 static int socksetup(int port, int **socklist_p)
523 struct sockaddr_in sin;
526 sockfd = socket(AF_INET, SOCK_STREAM, 0);
530 memset(&sin, 0, sizeof sin);
531 sin.sin_family = AF_INET;
532 sin.sin_addr.s_addr = htonl(INADDR_ANY);
533 sin.sin_port = htons(port);
535 if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
540 if (listen(sockfd, 5) < 0) {
545 *socklist_p = xmalloc(sizeof(int));
546 **socklist_p = sockfd;
552 static int service_loop(int socknum, int *socklist)
557 pfd = xcalloc(socknum, sizeof(struct pollfd));
559 for (i = 0; i < socknum; i++) {
560 pfd[i].fd = socklist[i];
561 pfd[i].events = POLLIN;
564 signal(SIGCHLD, child_handler);
569 if (poll(pfd, socknum, -1) < 0) {
570 if (errno != EINTR) {
571 error("poll failed, resuming: %s",
578 for (i = 0; i < socknum; i++) {
579 if (pfd[i].revents & POLLIN) {
580 struct sockaddr_storage ss;
581 unsigned int sslen = sizeof(ss);
582 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
590 die("accept returned %s", strerror(errno));
593 handle(incoming, (struct sockaddr *)&ss, sslen);
599 static int serve(int port)
601 int socknum, *socklist;
603 socknum = socksetup(port, &socklist);
605 die("unable to allocate any listen sockets on port %u", port);
607 return service_loop(socknum, socklist);
610 int main(int argc, char **argv)
612 int port = DEFAULT_GIT_PORT;
616 for (i = 1; i < argc; i++) {
619 if (!strncmp(arg, "--port=", 7)) {
622 n = strtoul(arg+7, &end, 0);
623 if (arg[7] && !*end) {
628 if (!strcmp(arg, "--inetd")) {
633 if (!strcmp(arg, "--verbose")) {
637 if (!strcmp(arg, "--syslog")) {
641 if (!strcmp(arg, "--export-all")) {
642 export_all_trees = 1;
645 if (!strncmp(arg, "--timeout=", 10)) {
646 timeout = atoi(arg+10);
649 if (!strncmp(arg, "--init-timeout=", 15)) {
650 init_timeout = atoi(arg+15);
653 if (!strcmp(arg, "--strict-paths")) {
657 if (!strncmp(arg, "--base-path=", 12)) {
661 if (!strcmp(arg, "--")) {
662 ok_paths = &argv[i+1];
664 } else if (arg[0] != '-') {
673 openlog("git-daemon", 0, LOG_DAEMON);
675 if (strict_paths && (!ok_paths || !*ok_paths)) {
677 die("git-daemon: option --strict-paths requires a whitelist");
679 logerror("option --strict-paths requires a whitelist");
684 fclose(stderr); //FIXME: workaround