path: root/x11vnc/inet.c

/* -- inet.c -- */

#include "x11vnc.h"

/*
 * Simple utility to map host name to dotted IP address.  Ignores aliases.
 * Up to caller to free returned string.
 */
char *host2ip(char *host);
char *raw2host(char *raw, int len);
char *raw2ip(char *raw);
char *ip2host(char *ip);
int dotted_ip(char *host);
int get_remote_port(int sock);
int get_local_port(int sock);
char *get_remote_host(int sock);
char *get_local_host(int sock);
char *ident_username(rfbClientPtr client);
int find_free_port(int start, int end);
int have_ssh_env(void);

static int get_port(int sock, int remote);
static char *get_host(int sock, int remote);


char *host2ip(char *host) {
	struct hostent *hp;
	struct sockaddr_in addr;
	char *str;

	if (! host_lookup) {
		return NULL;
	}

	hp = gethostbyname(host);
	if (!hp) {
		return NULL;
	}
	memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_addr.s_addr =  *(unsigned long *)hp->h_addr;
	str = strdup(inet_ntoa(addr.sin_addr));
	return str;
}

char *raw2host(char *raw, int len) {
	char *str;
#if LIBVNCSERVER_HAVE_NETDB_H && LIBVNCSERVER_HAVE_NETINET_IN_H
	struct hostent *hp;

	if (! host_lookup) {
		return strdup("unknown");
	}

	hp = gethostbyaddr(raw, len, AF_INET);
	if (!hp) {
		return strdup(inet_ntoa(*((struct in_addr *)raw)));
	}
	str = strdup(hp->h_name);
#else
	str = strdup("unknown");
#endif
	return str;
}

char *raw2ip(char *raw) {
	return strdup(inet_ntoa(*((struct in_addr *)raw)));
}

char *ip2host(char *ip) {
	char *str;
#if LIBVNCSERVER_HAVE_NETDB_H && LIBVNCSERVER_HAVE_NETINET_IN_H
	struct hostent *hp;
	in_addr_t iaddr;

	if (! host_lookup) {
		return strdup("unknown");
	}

	iaddr = inet_addr(ip);
	if (iaddr == htonl(INADDR_NONE)) {
		return strdup("unknown");
	}

	hp = gethostbyaddr((char *)&iaddr, sizeof(in_addr_t), AF_INET);
	if (!hp) {
		return strdup("unknown");
	}
	str = strdup(hp->h_name);
#else
	str = strdup("unknown");
#endif
	return str;
}

int dotted_ip(char *host) {
	char *p = host;
	while (*p != '\0') {
		if (*p == '.' || isdigit(*p)) {
			p++;
			continue;
		}
		return 0;
	}
	return 1;
}

static int get_port(int sock, int remote) {
	struct sockaddr_in saddr;
	unsigned int saddr_len;
	int saddr_port;
	
	saddr_len = sizeof(saddr);
	memset(&saddr, 0, sizeof(saddr));
	saddr_port = -1;
	if (remote) {
		if (!getpeername(sock, (struct sockaddr *)&saddr, &saddr_len)) {
			saddr_port = ntohs(saddr.sin_port);
		}
	} else {
		if (!getsockname(sock, (struct sockaddr *)&saddr, &saddr_len)) {
			saddr_port = ntohs(saddr.sin_port);
		}
	}
	return saddr_port;
}

int get_remote_port(int sock) {
	return get_port(sock, 1);
}

int get_local_port(int sock) {
	return get_port(sock, 0);
}

static char *get_host(int sock, int remote) {
	struct sockaddr_in saddr;
	unsigned int saddr_len;
	int saddr_port;
	char *saddr_ip_str = NULL;
	
	saddr_len = sizeof(saddr);
	memset(&saddr, 0, sizeof(saddr));
	saddr_port = -1;
#if LIBVNCSERVER_HAVE_NETINET_IN_H
	if (remote) {
		if (!getpeername(sock, (struct sockaddr *)&saddr, &saddr_len)) {
			saddr_ip_str = inet_ntoa(saddr.sin_addr);
		}
	} else {
		if (!getsockname(sock, (struct sockaddr *)&saddr, &saddr_len)) {
			saddr_ip_str = inet_ntoa(saddr.sin_addr);
		}
	}
#endif
	if (! saddr_ip_str) {
		saddr_ip_str = "unknown";
	}
	return strdup(saddr_ip_str);
}

char *get_remote_host(int sock) {
	return get_host(sock, 1);
}

char *get_local_host(int sock) {
	return get_host(sock, 0);
}

char *ident_username(rfbClientPtr client) {
	ClientData *cd = (ClientData *) client->clientData;
	char *str, *newhost, *user = NULL, *newuser = NULL;
	int len;

	if (cd) {
		user = cd->username;
	}
	if (!user || *user == '\0') {
		char msg[128];
		int n, sock, ok = 0;
		int block = 0;

		/*
		 * need to check to see if the operation will block for
		 * a long time: a firewall may just ignore our packets.
		 */
#if LIBVNCSERVER_HAVE_FORK
	    {	pid_t pid, pidw;
		int rc;
		if ((pid = fork()) > 0) {
			usleep(100 * 1000);	/* 0.1 sec */
			pidw = waitpid(pid, &rc, WNOHANG);
			if (pidw <= 0) {
				usleep(1000 * 1000);	/* 1.0 sec */
				pidw = waitpid(pid, &rc, WNOHANG);
				if (pidw <= 0) {
					block = 1;
					kill(pid, SIGTERM);
				}
			}
		} else if (pid == -1) {
			;
		} else {
			/* child */
			signal(SIGHUP,  SIG_DFL);
			signal(SIGINT,  SIG_DFL);
			signal(SIGQUIT, SIG_DFL);
			signal(SIGTERM, SIG_DFL);

			if ((sock = rfbConnectToTcpAddr(client->host, 113)) < 0) {
				exit(1);
			} else {
				close(sock);
				exit(0);
			}
		}
	    }
#endif
		if (block) {
			;
		} else if ((sock = rfbConnectToTcpAddr(client->host, 113)) < 0) {
			rfbLog("could not connect to ident: %s:%d\n",
			    client->host, 113);
		} else {
			int ret;
			fd_set rfds;
			struct timeval tv;
			int rport = get_remote_port(client->sock);
			int lport = get_local_port(client->sock);

			sprintf(msg, "%d, %d\r\n", rport, lport);
			n = write(sock, msg, strlen(msg));

			FD_ZERO(&rfds);
			FD_SET(sock, &rfds);
			tv.tv_sec  = 4;
			tv.tv_usec = 0;
			ret = select(sock+1, &rfds, NULL, NULL, &tv); 

			if (ret > 0) {
				int i;
				char *q, *p;
				for (i=0; i<128; i++) {
					msg[i] = '\0';
				}
				usleep(250*1000);
				n = read(sock, msg, 127);
				close(sock);
				if (n <= 0) goto badreply;

				/* 32782 , 6000 : USERID : UNIX :runge */
				q = strstr(msg, "USERID");
				if (!q) goto badreply;
				q = strstr(q, ":");
				if (!q) goto badreply;
				q++;
				q = strstr(q, ":");
				if (!q) goto badreply;
				q++;
				q = lblanks(q);
				p = q;
				while (*p) {
					if (*p == '\r' || *p == '\n') {
						*p = '\0';
					}
					p++;
				}
				ok = 1;
				if (strlen(q) > 24) {
					*(q+24) = '\0';
				}
				newuser = strdup(q);

				badreply:
				n = 0;	/* avoid syntax error */
			} else {
				close(sock);
			}
		}
		if (! ok || !newuser) {
			newuser = strdup("unknown-user");
		}
		if (cd) {
			if (cd->username) {
				free(cd->username);
			}
			cd->username = newuser;
		}
		user = newuser;
	}
	if (!strcmp(user, "unknown-user") && cd && cd->unixname[0] != '\0') {
		user = cd->unixname;
	}
	newhost = ip2host(client->host);
	len = strlen(user) + 1 + strlen(newhost) + 1;
	str = (char *) malloc(len);
	sprintf(str, "%s@%s", user, newhost);
	free(newhost);
	return str;
}

int find_free_port(int start, int end) {
	int port;
	if (start <= 0) {
		start = 1024;
	}
	if (end <= 0) {
		end = 65530;
	}
	for (port = start; port <= end; port++)  {
		int sock = rfbListenOnTCPPort(port, htonl(INADDR_ANY));
		if (sock >= 0) {
			close(sock);
			return port;
		}
	}
	return 0;
}

int have_ssh_env(void) {
	char *str, *p = getenv("SSH_CONNECTION");
	char *rhost, *rport, *lhost, *lport;
	
	if (! p) {
		char *q = getenv("SSH_CLIENT");
		if (! q) {
			return 0;
		}
		if (strstr(q, "127.0.0.1") != NULL) {
			return 0;
		}
		return 1;
	}

	if (strstr(p, "127.0.0.1") != NULL) {
		return 0;
	}

	str = strdup(p);
	
	p = strtok(str, " ");
	rhost = p;

	p = strtok(NULL, " ");
	if (! p) goto fail;

	rport = p;

	p = strtok(NULL, " ");
	if (! p) goto fail;

	lhost = p;
	
	p = strtok(NULL, " ");
	if (! p) goto fail;

	lport = p;

if (0) fprintf(stderr, "%d/%d - '%s' '%s'\n", atoi(rport), atoi(lport), rhost, lhost);

	if (atoi(rport) <= 16 || atoi(rport) > 65535) {
		goto fail;
	}
	if (atoi(lport) <= 16 || atoi(lport) > 65535) {
		goto fail;
	}

	if (!strcmp(rhost, lhost)) {
		goto fail;
	}

	free(str);

	return 1;
	
	fail:

	free(str);

	return 0;
}