X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=daemon.c;h=2f03f99d2d9f2ed9a23932e5104456f69b721116;hb=HEAD;hp=32196156bf9776af75c9adfcaacbef44cad13651;hpb=66e631def8ad6a15eed57bcbde4157e0964ad8fc;p=git.git

diff --git a/daemon.c b/daemon.c
index 32196156..2f03f99d 100644
--- a/daemon.c
+++ b/daemon.c
@@ -1,50 +1,290 @@
-#include "cache.h"
-#include "pkt-line.h"
 #include <signal.h>
 #include <sys/wait.h>
 #include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/poll.h>
+#include <netdb.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
+#include <syslog.h>
+#include "pkt-line.h"
+#include "cache.h"
+#include "exec_cmd.h"
+
+static int log_syslog;
+static int verbose;
+static int reuseaddr;
+
+static const char daemon_usage[] =
+"git-daemon [--verbose] [--syslog] [--inetd | --port=n] [--export-all]\n"
+"           [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
+"           [--base-path=path] [--user-path | --user-path=path]\n"
+"           [--reuseaddr] [directory...]";
+
+/* List of acceptable pathname prefixes */
+static char **ok_paths = NULL;
+static int strict_paths = 0;
+
+/* If this is set, git-daemon-export-ok is not required */
+static int export_all_trees = 0;
+
+/* Take all paths relative to this one if non-NULL */
+static char *base_path = NULL;
+
+/* If defined, ~user notation is allowed and the string is inserted
+ * after ~user/.  E.g. a request to git://host/~alice/frotz would
+ * go to /home/alice/pub_git/frotz with --user-path=pub_git.
+ */
+static char *user_path = NULL;
+
+/* Timeout, and initial timeout */
+static unsigned int timeout = 0;
+static unsigned int init_timeout = 0;
+
+static void logreport(int priority, const char *err, va_list params)
+{
+	/* We should do a single write so that it is atomic and output
+	 * of several processes do not get intermingled. */
+	char buf[1024];
+	int buflen;
+	int maxlen, msglen;
+
+	/* sizeof(buf) should be big enough for "[pid] \n" */
+	buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
+
+	maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
+	msglen = vsnprintf(buf + buflen, maxlen, err, params);
+
+	if (log_syslog) {
+		syslog(priority, "%s", buf);
+		return;
+	}
+
+	/* maxlen counted our own LF but also counts space given to
+	 * vsnprintf for the terminating NUL.  We want to make sure that
+	 * we have space for our own LF and NUL after the "meat" of the
+	 * message, so truncate it at maxlen - 1.
+	 */
+	if (msglen > maxlen - 1)
+		msglen = maxlen - 1;
+	else if (msglen < 0)
+		msglen = 0; /* Protect against weird return values. */
+	buflen += msglen;
+
+	buf[buflen++] = '\n';
+	buf[buflen] = '\0';
+
+	write(2, buf, buflen);
+}
+
+static void logerror(const char *err, ...)
+{
+	va_list params;
+	va_start(params, err);
+	logreport(LOG_ERR, err, params);
+	va_end(params);
+}
+
+static void loginfo(const char *err, ...)
+{
+	va_list params;
+	if (!verbose)
+		return;
+	va_start(params, err);
+	logreport(LOG_INFO, err, params);
+	va_end(params);
+}
+
+static int avoid_alias(char *p)
+{
+	int sl, ndot;
+
+	/* 
+	 * This resurrects the belts and suspenders paranoia check by HPA
+	 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
+	 * does not do getcwd() based path canonicalizations.
+	 *
+	 * sl becomes true immediately after seeing '/' and continues to
+	 * be true as long as dots continue after that without intervening
+	 * non-dot character.
+	 */
+	if (!p || (*p != '/' && *p != '~'))
+		return -1;
+	sl = 1; ndot = 0;
+	p++;
+
+	while (1) {
+		char ch = *p++;
+		if (sl) {
+			if (ch == '.')
+				ndot++;
+			else if (ch == '/') {
+				if (ndot < 3)
+					/* reject //, /./ and /../ */
+					return -1;
+				ndot = 0;
+			}
+			else if (ch == 0) {
+				if (0 < ndot && ndot < 3)
+					/* reject /.$ and /..$ */
+					return -1;
+				return 0;
+			}
+			else
+				sl = ndot = 0;
+		}
+		else if (ch == 0)
+			return 0;
+		else if (ch == '/') {
+			sl = 1;
+			ndot = 0;
+		}
+	}
+}
+
+static char *path_ok(char *dir)
+{
+	static char rpath[PATH_MAX];
+	char *path;
+
+	if (avoid_alias(dir)) {
+		logerror("'%s': aliased", dir);
+		return NULL;
+	}
 
-static const char daemon_usage[] = "git-daemon [--inetd | --port=n]";
+	if (*dir == '~') {
+		if (!user_path) {
+			logerror("'%s': User-path not allowed", dir);
+			return NULL;
+		}
+		if (*user_path) {
+			/* Got either "~alice" or "~alice/foo";
+			 * rewrite them to "~alice/%s" or
+			 * "~alice/%s/foo".
+			 */
+			int namlen, restlen = strlen(dir);
+			char *slash = strchr(dir, '/');
+			if (!slash)
+				slash = dir + restlen;
+			namlen = slash - dir;
+			restlen -= namlen;
+			loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
+			snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
+				 namlen, dir, user_path, restlen, slash);
+			dir = rpath;
+		}
+	}
+	else if (base_path) {
+		if (*dir != '/') {
+			/* Allow only absolute */
+			logerror("'%s': Non-absolute path denied (base-path active)", dir);
+			return NULL;
+		}
+		else {
+			snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
+			dir = rpath;
+		}
+	}
+
+	path = enter_repo(dir, strict_paths);
+
+	if (!path) {
+		logerror("'%s': unable to chdir or not a git archive", dir);
+		return NULL;
+	}
+
+	if ( ok_paths && *ok_paths ) {
+		char **pp;
+		int pathlen = strlen(path);
+
+		/* The validation is done on the paths after enter_repo
+		 * appends optional {.git,.git/.git} and friends, but 
+		 * it does not use getcwd().  So if your /pub is
+		 * a symlink to /mnt/pub, you can whitelist /pub and
+		 * do not have to say /mnt/pub.
+		 * Do not say /pub/.
+		 */
+		for ( pp = ok_paths ; *pp ; pp++ ) {
+			int len = strlen(*pp);
+			if (len <= pathlen &&
+			    !memcmp(*pp, path, len) &&
+			    (path[len] == '\0' ||
+			     (!strict_paths && path[len] == '/')))
+				return path;
+		}
+	}
+	else {
+		/* be backwards compatible */
+		if (!strict_paths)
+			return path;
+	}
+
+	logerror("'%s': not in whitelist", path);
+	return NULL;		/* Fallthrough. Deny by default */
+}
 
-static int upload(char *dir, int dirlen)
+static int upload(char *dir)
 {
-	if (chdir(dir) < 0)
+	/* Timeout as string */
+	char timeout_buf[64];
+	const char *path;
+
+	loginfo("Request for '%s'", dir);
+
+	if (!(path = path_ok(dir)))
 		return -1;
-	chdir(".git");
 
 	/*
 	 * Security on the cheap.
 	 *
-	 * We want a readable HEAD, usable "objects" directory, and 
+	 * We want a readable HEAD, usable "objects" directory, and
 	 * a "git-daemon-export-ok" flag that says that the other side
 	 * is ok with us doing this.
+	 *
+	 * path_ok() uses enter_repo() and does whitelist checking.
+	 * We only need to make sure the repository is exported.
 	 */
-	if (access("git-daemon-export-ok", F_OK) ||
-	    access("objects/00", X_OK) ||
-	    access("HEAD", R_OK))
+
+	if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
+		logerror("'%s': repository not exported.", path);
+		errno = EACCES;
 		return -1;
+	}
+
+	/*
+	 * We'll ignore SIGTERM from now on, we have a
+	 * good client.
+	 */
+	signal(SIGTERM, SIG_IGN);
+
+	snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 
 	/* git-upload-pack only ever reads stuff, so this is safe */
-	execlp("git-upload-pack", "git-upload-pack", ".", NULL);
+	execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
 	return -1;
 }
 
 static int execute(void)
 {
 	static char line[1000];
-	int len;
+	int pktlen, len;
 
-	len = packet_read_line(0, line, sizeof(line));
+	alarm(init_timeout ? init_timeout : timeout);
+	pktlen = packet_read_line(0, line, sizeof(line));
+	alarm(0);
 
+	len = strlen(line);
+	if (pktlen != len)
+		loginfo("Extended attributes (%d bytes) exist <%.*s>",
+			(int) pktlen - len,
+			(int) pktlen - len, line + len + 1);
 	if (len && line[len-1] == '\n')
 		line[--len] = 0;
 
-	if (!strncmp("git-upload-pack /", line, 17))
-		return upload(line + 16, len - 16);
+	if (!strncmp("git-upload-pack ", line, 16))
+		return upload(line+16);
 
-	fprintf(stderr, "got bad connection '%s'\n", line);
+	logerror("Protocol error: '%s'", line);
 	return -1;
 }
 
@@ -65,23 +305,23 @@ static int max_connections = 25;
 
 /* These are updated by the signal handler */
 static volatile unsigned int children_reaped = 0;
-pid_t dead_child[MAX_CHILDREN];
+static pid_t dead_child[MAX_CHILDREN];
 
 /* These are updated by the main loop */
 static unsigned int children_spawned = 0;
 static unsigned int children_deleted = 0;
 
-struct child {
+static struct child {
 	pid_t pid;
 	int addrlen;
-	struct sockaddr_in address;
+	struct sockaddr_storage address;
 } live_child[MAX_CHILDREN];
 
-static void add_child(int idx, pid_t pid, struct sockaddr_in *addr, int addrlen)
+static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
 {
 	live_child[idx].pid = pid;
 	live_child[idx].addrlen = addrlen;
-	live_child[idx].address = *addr;
+	memcpy(&live_child[idx].address, addr, addrlen);
 }
 
 /*
@@ -128,33 +368,24 @@ static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
  *
  * Really, this is just a place-holder for a _real_ algorithm.
  */
-static void kill_some_children(int connections, unsigned start, unsigned stop)
+static void kill_some_children(int signo, unsigned start, unsigned stop)
 {
 	start %= MAX_CHILDREN;
 	stop %= MAX_CHILDREN;
 	while (start != stop) {
 		if (!(start & 3))
-			kill(live_child[start].pid, SIGTERM);
+			kill(live_child[start].pid, signo);
 		start = (start + 1) % MAX_CHILDREN;
 	}
 }
 
-static void handle(int incoming, struct sockaddr_in *addr, int addrlen)
+static void check_max_connections(void)
 {
-	pid_t pid = fork();
-
-	if (pid) {
+	for (;;) {
 		int active;
 		unsigned spawned, reaped, deleted;
 
-		close(incoming);
-		if (pid < 0)
-			return;
-
 		spawned = children_spawned;
-		add_child(spawned % MAX_CHILDREN, pid, addr, addrlen);
-		children_spawned = ++spawned;
-
 		reaped = children_reaped;
 		deleted = children_deleted;
 
@@ -166,75 +397,274 @@ static void handle(int incoming, struct sockaddr_in *addr, int addrlen)
 		children_deleted = deleted;
 
 		active = spawned - deleted;
-		if (active > max_connections) {
-			kill_some_children(active, deleted, spawned);
+		if (active <= max_connections)
+			break;
 
-			/* Wait to make sure they're gone */
-			while (spawned - children_reaped > max_connections)
-				sleep(1);
-		}
-			
+		/* Kill some unstarted connections with SIGTERM */
+		kill_some_children(SIGTERM, deleted, spawned);
+		if (active <= max_connections << 1)
+			break;
+
+		/* If the SIGTERM thing isn't helping use SIGKILL */
+		kill_some_children(SIGKILL, deleted, spawned);
+		sleep(1);
+	}
+}
+
+static void handle(int incoming, struct sockaddr *addr, int addrlen)
+{
+	pid_t pid = fork();
+	char addrbuf[256] = "";
+	int port = -1;
+
+	if (pid) {
+		unsigned idx;
+
+		close(incoming);
+		if (pid < 0)
+			return;
 
+		idx = children_spawned % MAX_CHILDREN;
+		children_spawned++;
+		add_child(idx, pid, addr, addrlen);
+
+		check_max_connections();
 		return;
 	}
 
 	dup2(incoming, 0);
 	dup2(incoming, 1);
 	close(incoming);
+
+	if (addr->sa_family == AF_INET) {
+		struct sockaddr_in *sin_addr = (void *) addr;
+		inet_ntop(AF_INET, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
+		port = sin_addr->sin_port;
+
+#ifndef NO_IPV6
+	} else if (addr->sa_family == AF_INET6) {
+		struct sockaddr_in6 *sin6_addr = (void *) addr;
+
+		char *buf = addrbuf;
+		*buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
+		inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
+		strcat(buf, "]");
+
+		port = sin6_addr->sin6_port;
+#endif
+	}
+	loginfo("Connection from %s:%d", addrbuf, port);
+
 	exit(execute());
 }
 
 static void child_handler(int signo)
 {
 	for (;;) {
-		pid_t pid = waitpid(-1, NULL, WNOHANG);
+		int status;
+		pid_t pid = waitpid(-1, &status, WNOHANG);
 
 		if (pid > 0) {
 			unsigned reaped = children_reaped;
 			dead_child[reaped % MAX_CHILDREN] = pid;
 			children_reaped = reaped + 1;
+			/* XXX: Custom logging, since we don't wanna getpid() */
+			if (verbose) {
+				char *dead = "";
+				if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
+					dead = " (with error)";
+				if (log_syslog)
+					syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
+				else
+					fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
+			}
 			continue;
 		}
 		break;
 	}
 }
 
-static int serve(int port)
+static int set_reuse_addr(int sockfd)
+{
+	int on = 1;
+
+	if (!reuseaddr)
+		return 0;
+	return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
+			  &on, sizeof(on));
+}
+
+#ifndef NO_IPV6
+
+static int socksetup(int port, int **socklist_p)
 {
+	int socknum = 0, *socklist = NULL;
+	int maxfd = -1;
+	char pbuf[NI_MAXSERV];
+
+	struct addrinfo hints, *ai0, *ai;
+	int gai;
+
+	sprintf(pbuf, "%d", port);
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = AF_UNSPEC;
+	hints.ai_socktype = SOCK_STREAM;
+	hints.ai_protocol = IPPROTO_TCP;
+	hints.ai_flags = AI_PASSIVE;
+
+	gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
+	if (gai)
+		die("getaddrinfo() failed: %s\n", gai_strerror(gai));
+
+	for (ai = ai0; ai; ai = ai->ai_next) {
+		int sockfd;
+		int *newlist;
+
+		sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+		if (sockfd < 0)
+			continue;
+		if (sockfd >= FD_SETSIZE) {
+			error("too large socket descriptor.");
+			close(sockfd);
+			continue;
+		}
+
+#ifdef IPV6_V6ONLY
+		if (ai->ai_family == AF_INET6) {
+			int on = 1;
+			setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
+				   &on, sizeof(on));
+			/* Note: error is not fatal */
+		}
+#endif
+
+		if (set_reuse_addr(sockfd)) {
+			close(sockfd);
+			continue;
+		}
+
+		if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
+			close(sockfd);
+			continue;	/* not fatal */
+		}
+		if (listen(sockfd, 5) < 0) {
+			close(sockfd);
+			continue;	/* not fatal */
+		}
+
+		newlist = realloc(socklist, sizeof(int) * (socknum + 1));
+		if (!newlist)
+			die("memory allocation failed: %s", strerror(errno));
+
+		socklist = newlist;
+		socklist[socknum++] = sockfd;
+
+		if (maxfd < sockfd)
+			maxfd = sockfd;
+	}
+
+	freeaddrinfo(ai0);
+
+	*socklist_p = socklist;
+	return socknum;
+}
+
+#else /* NO_IPV6 */
+
+static int socksetup(int port, int **socklist_p)
+{
+	struct sockaddr_in sin;
 	int sockfd;
-	struct sockaddr_in addr;
 
-	signal(SIGCHLD, child_handler);
-	sockfd = socket(PF_INET, SOCK_STREAM, IPPROTO_IP);
+	sockfd = socket(AF_INET, SOCK_STREAM, 0);
 	if (sockfd < 0)
-		die("unable to open socket (%s)", strerror(errno));
-	memset(&addr, 0, sizeof(addr));
-	addr.sin_port = htons(port);
-	addr.sin_family = AF_INET;
-	if (bind(sockfd, (void *)&addr, sizeof(addr)) < 0)
-		die("unable to bind to port %d (%s)", port, strerror(errno));
-	if (listen(sockfd, 5) < 0)
-		die("unable to listen to port %d (%s)", port, strerror(errno));
+		return 0;
+
+	memset(&sin, 0, sizeof sin);
+	sin.sin_family = AF_INET;
+	sin.sin_addr.s_addr = htonl(INADDR_ANY);
+	sin.sin_port = htons(port);
+
+	if (set_reuse_addr(sockfd)) {
+		close(sockfd);
+		return 0;
+	}
+
+	if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
+		close(sockfd);
+		return 0;
+	}
+
+	if (listen(sockfd, 5) < 0) {
+		close(sockfd);
+		return 0;
+	}
+
+	*socklist_p = xmalloc(sizeof(int));
+	**socklist_p = sockfd;
+	return 1;
+}
+
+#endif
+
+static int service_loop(int socknum, int *socklist)
+{
+	struct pollfd *pfd;
+	int i;
+
+	pfd = xcalloc(socknum, sizeof(struct pollfd));
+
+	for (i = 0; i < socknum; i++) {
+		pfd[i].fd = socklist[i];
+		pfd[i].events = POLLIN;
+	}
+
+	signal(SIGCHLD, child_handler);
 
 	for (;;) {
-		struct sockaddr_in in;
-		socklen_t addrlen = sizeof(in);
-		int incoming = accept(sockfd, (void *)&in, &addrlen);
-
-		if (incoming < 0) {
-			switch (errno) {
-			case EAGAIN:
-			case EINTR:
-			case ECONNABORTED:
-				continue;
-			default:
-				die("accept returned %s", strerror(errno));
+		int i;
+
+		if (poll(pfd, socknum, -1) < 0) {
+			if (errno != EINTR) {
+				error("poll failed, resuming: %s",
+				      strerror(errno));
+				sleep(1);
+			}
+			continue;
+		}
+
+		for (i = 0; i < socknum; i++) {
+			if (pfd[i].revents & POLLIN) {
+				struct sockaddr_storage ss;
+				unsigned int sslen = sizeof(ss);
+				int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
+				if (incoming < 0) {
+					switch (errno) {
+					case EAGAIN:
+					case EINTR:
+					case ECONNABORTED:
+						continue;
+					default:
+						die("accept returned %s", strerror(errno));
+					}
+				}
+				handle(incoming, (struct sockaddr *)&ss, sslen);
 			}
 		}
-		handle(incoming, &in, addrlen);
 	}
 }
 
+static int serve(int port)
+{
+	int socknum, *socklist;
+
+	socknum = socksetup(port, &socklist);
+	if (socknum == 0)
+		die("unable to allocate any listen sockets on port %u", port);
+
+	return service_loop(socknum, socklist);
+}
+
 int main(int argc, char **argv)
 {
 	int port = DEFAULT_GIT_PORT;
@@ -253,17 +683,77 @@ int main(int argc, char **argv)
 				continue;
 			}
 		}
-
 		if (!strcmp(arg, "--inetd")) {
 			inetd_mode = 1;
+			log_syslog = 1;
 			continue;
 		}
+		if (!strcmp(arg, "--verbose")) {
+			verbose = 1;
+			continue;
+		}
+		if (!strcmp(arg, "--syslog")) {
+			log_syslog = 1;
+			continue;
+		}
+		if (!strcmp(arg, "--export-all")) {
+			export_all_trees = 1;
+			continue;
+		}
+		if (!strncmp(arg, "--timeout=", 10)) {
+			timeout = atoi(arg+10);
+			continue;
+		}
+		if (!strncmp(arg, "--init-timeout=", 15)) {
+			init_timeout = atoi(arg+15);
+			continue;
+		}
+		if (!strcmp(arg, "--strict-paths")) {
+			strict_paths = 1;
+			continue;
+		}
+		if (!strncmp(arg, "--base-path=", 12)) {
+			base_path = arg+12;
+			continue;
+		}
+		if (!strcmp(arg, "--reuseaddr")) {
+			reuseaddr = 1;
+			continue;
+		}
+		if (!strcmp(arg, "--user-path")) {
+			user_path = "";
+			continue;
+		}
+		if (!strncmp(arg, "--user-path=", 12)) {
+			user_path = arg + 12;
+			continue;
+		}
+		if (!strcmp(arg, "--")) {
+			ok_paths = &argv[i+1];
+			break;
+		} else if (arg[0] != '-') {
+			ok_paths = &argv[i];
+			break;
+		}
 
 		usage(daemon_usage);
 	}
 
-	if (inetd_mode)
+	if (log_syslog)
+		openlog("git-daemon", 0, LOG_DAEMON);
+
+	if (strict_paths && (!ok_paths || !*ok_paths)) {
+		if (!inetd_mode)
+			die("git-daemon: option --strict-paths requires a whitelist");
+
+		logerror("option --strict-paths requires a whitelist");
+		exit (1);
+	}
+
+	if (inetd_mode) {
+		fclose(stderr); //FIXME: workaround
 		return execute();
+	}
 
 	return serve(port);
 }