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https://github.com/yarrick/iodine.git
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Update server login protocol handling for TCP forwarding
This commit is contained in:
frekky
parent
cfd2411e45
commit
d46766bcc9
@ -485,14 +485,14 @@ main(int argc, char **argv)
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}
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}
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if (server.addrfamily == AF_UNSPEC || server.addrfamily == AF_INET6) {
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server.dns6addr_len = get_addr(listen_ip6, server.port,AF_INET6,
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server.dns6addr_len = get_addr(listen_ip6, server.port, AF_INET6,
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AI_PASSIVE | AI_NUMERICHOST, &server.dns6addr);
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if (server.dns6addr_len < 0) {
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warnx("Bad IPv6 address to listen on.");
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usage();
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}
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}
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if(server.bind_enable) {
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if (server.bind_enable) {
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in_addr_t dns_ip = ((struct sockaddr_in *) &server.dns4addr)->sin_addr.s_addr;
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if (server.bind_port < 1 || server.bind_port > 65535) {
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warnx("Bad DNS server port number given.");
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@ -500,7 +500,7 @@ main(int argc, char **argv)
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/* NOTREACHED */
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}
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/* Avoid forwarding loops */
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if (server.bind_port == server.port && (dns_ip == INADDR_ANY || dns_ip == htonl(0x7f000001L))) {
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if (server.bind_port == server.port && (dns_ip == INADDR_ANY || dns_ip == INADDR_LOOPBACK)) {
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warnx("Forward port is same as listen port (%d), will create a loop!", server.bind_port);
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fprintf(stderr, "Use -l to set listen ip to avoid this.\n");
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usage();
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125
src/server.c
125
src/server.c
@ -29,6 +29,7 @@
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#include <time.h>
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#include <zlib.h>
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#include <ctype.h>
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#include <errno.h>
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#include "common.h"
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#include "version.h"
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@ -1168,8 +1169,8 @@ handle_dns_version(int dns_fd, struct query *q, uint8_t *domain, int domain_len)
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memcpy(&(u->host), &(q->from), q->fromlen);
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u->hostlen = q->fromlen;
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u->remote_forward_connected = 0;
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u->remote_port = 0;
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u->remoteforward_addr_len = 0;
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u->remoteforward_addr.ss_family = AF_UNSPEC;
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u->fragsize = 100; /* very safe */
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u->conn = CONN_DNS_NULL;
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u->encoder = get_base32_encoder();
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@ -1249,9 +1250,14 @@ handle_dns_login(int dns_fd, struct query *q, uint8_t *domain, int domain_len, i
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{
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uint8_t unpacked[512], flags;
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char logindata[16], *tmp[2], out[512], *reason = NULL;
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char *errormsg = NULL;
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struct in_addr tempip;
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char remote_tcp, remote_isnt_localhost, use_ipv6, drop_packets;
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char remote_tcp, remote_isnt_localhost, use_ipv6, poll_status; //, drop_packets;
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int length = 17, read, addrlen, login_ok = 1;
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uint16_t port;
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struct tun_user *u = &users[userid];
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struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *) &u->remoteforward_addr;
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struct sockaddr_in *addr = (struct sockaddr_in *) &u->remoteforward_addr;
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read = unpack_data(unpacked, sizeof(unpacked), (uint8_t *) domain + 2, domain_len - 2, b32);
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@ -1260,24 +1266,30 @@ handle_dns_login(int dns_fd, struct query *q, uint8_t *domain, int domain_len, i
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remote_tcp = flags & 1;
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remote_isnt_localhost = (flags & 2) >> 1;
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use_ipv6 = (flags & 4) >> 2;
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drop_packets = (flags & 8) >> 3; /* currently unimplemented */
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//drop_packets = (flags & 8) >> 3; /* currently unimplemented */
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poll_status = (flags & 0x10) >> 4;
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addrlen = (remote_tcp && remote_isnt_localhost) ? (use_ipv6 ? 16 : 4) : 0;
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length += (remote_tcp ? 2 : 0) + addrlen;
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/* There should be no extra data if only polling forwarding status */
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if (poll_status) {
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length = 17;
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}
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CHECK_LEN(read, length);
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DEBUG(2, "Received login request for user %d from %s.",
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DEBUG(2, "Received login request for user %d from %s",
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userid, format_addr(&q->from, q->fromlen));
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DEBUG(6, "Login: length=%d, flags=0x%02x, seed=0x%08x, hash=0x%016llx%016llx",
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length, flags, users[userid].seed, *(unsigned long long *) (unpacked + 1),
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length, flags, u->seed, *(unsigned long long *) (unpacked + 1),
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*(unsigned long long *) (unpacked + 9));
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if (check_user_and_ip(userid, q, server.check_ip) != 0) {
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write_dns(dns_fd, q, "BADIP", 5, 'T');
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syslog(LOG_WARNING, "rejected login request from user #%d from %s; expected source %s",
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userid, format_addr(&q->from, q->fromlen), format_addr(&users[userid].host, users[userid].hostlen));
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userid, format_addr(&q->from, q->fromlen), format_addr(&u->host, u->hostlen));
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DEBUG(1, "Rejected login request from user %d: BADIP", userid);
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return;
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}
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@ -1289,39 +1301,54 @@ handle_dns_login(int dns_fd, struct query *q, uint8_t *domain, int domain_len, i
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reason = "requested bad TCP forward options";
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}
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users[userid].last_pkt = time(NULL);
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login_calculate(logindata, 16, server.password, users[userid].seed);
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u->last_pkt = time(NULL);
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login_calculate(logindata, 16, server.password, u->seed);
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if (memcmp(logindata, unpacked + 1, 16) != 0) {
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login_ok = 0;
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reason = "bad password";
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}
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if (remote_tcp && addrlen > 0) {
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if (remote_tcp) {
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port = ntohs(*(uint16_t *) (unpacked + 17));
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if (addrlen > 0) {
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if (use_ipv6) {
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struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *) &users[userid].remoteforward_addr;
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addr6->sin6_family = AF_INET6;
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users[userid].remoteforward_addr_len = sizeof(*addr6);
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addr6->sin6_port = port;
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u->remoteforward_addr_len = sizeof(*addr6);
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memcpy(&addr6->sin6_addr, unpacked + 19, MIN(sizeof(*addr6), addrlen));
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} else {
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struct sockaddr_in *addr = (struct sockaddr_in *) &users[userid].remoteforward_addr;
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addr->sin_family = AF_INET;
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users[userid].remoteforward_addr_len = sizeof(*addr);
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addr->sin_port = port;
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u->remoteforward_addr_len = sizeof(*addr);
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memcpy(&addr->sin_addr, unpacked + 19, MIN(sizeof(*addr), addrlen));
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}
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users[userid].remote_port = ntohs(*(uint16_t *) (unpacked + 17));
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DEBUG(1, "User %d requested TCP connection to %s:%d, %s.", userid,
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format_addr(&users[userid].remoteforward_addr, users[userid].remoteforward_addr_len),
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users[userid].remote_port, login_ok ? "allowed" : "rejected");
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DEBUG(1, "User %d requested TCP connection to %s:%hu, %s.", userid,
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format_addr(&u->remoteforward_addr, u->remoteforward_addr_len),
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port, login_ok ? "allowed" : "rejected");
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} else {
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addr->sin_family = AF_INET;
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addr->sin_port = port;
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addr->sin_addr.s_addr = INADDR_LOOPBACK;
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DEBUG(1, "User %d requested TCP connection to localhost:%hu, %s.", userid,
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port, login_ok ? "allowed" : "rejected");
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}
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}
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if (poll_status && login_ok) {
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if (addrlen > 0 || (flags ^ 0x10)) {
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login_ok = 0;
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reason = "invalid flags";
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}
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}
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if (!login_ok) {
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write_dns(dns_fd, q, "LNAK", 4, 'T');
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if (--users[userid].authenticated >= 0)
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users[userid].authenticated = -1;
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if (--u->authenticated >= 0)
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u->authenticated = -1;
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char *src_ip = format_addr(&q->from, q->fromlen);
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int tries = abs(users[userid].authenticated);
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int tries = abs(u->authenticated);
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DEBUG(1, "rejected login from user %d (%s), tries: %d, reason: %s",
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userid, src_ip, tries, reason);
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syslog(LOG_WARNING, "rejected login request from user #%d from %s, %s; incorrect attempts: %d",
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@ -1330,31 +1357,59 @@ handle_dns_login(int dns_fd, struct query *q, uint8_t *domain, int domain_len, i
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}
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/* Store user auth OK, count number of logins */
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users[userid].authenticated++;
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if (users[userid].authenticated > 1)
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u->authenticated++;
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if (u->authenticated > 1 && !poll_status)
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syslog(LOG_WARNING, "duplicate login request from user #%d from %s",
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userid, format_addr(&users[userid].host, users[userid].hostlen));
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userid, format_addr(&u->host, u->hostlen));
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if (remote_tcp) {
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int retval;
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int tcp_fd;
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retval = socket(users[userid].remoteforward_addr.ss_family,
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SOCK_STREAM, );
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DEBUG(1, "User %d connected from %s, starting TCP connection to %s.", userid,
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format_addr(&q->from, q->fromlen), format_addr(&u->remoteforward_addr, sizeof(struct sockaddr_storage)));
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syslog(LOG_NOTICE, "accepted password from user #%d, connecting TCP forward", userid);
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/* Open socket and connect to TCP forward host:port */
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tcp_fd = open_tcp_nonblocking(&u->remoteforward_addr, &errormsg);
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if (tcp_fd < 0) {
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if (!errormsg)
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errormsg = "Error opening socket.";
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goto tcp_forward_error;
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}
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out[0] = 'W';
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read = 1;
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write_dns(dns_fd, q, out, read + 1, u->downenc);
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u->tcp_fd = tcp_fd;
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return;
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} else if (poll_status) {
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int retval;
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DEBUG(1, "User %d connected from %s, starting TCP connection.", userid,
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format_addr(&q->from, q->fromlen), tmp[1]);
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syslog(LOG_NOTICE, "accepted password from user #%d, connecting TCP forward", userid, tmp[1]);
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if ((retval = check_tcp_status(u->tcp_fd, &errormsg)) == -1) {
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goto tcp_forward_error;
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}
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read = 1;
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out[1] = 0;
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if (retval == 0) {
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out[0] = 'C';
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u->remote_forward_connected = 1;
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} else if (retval == EINPROGRESS) {
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out[0] = 'W';
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} else {
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goto tcp_forward_error;
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}
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write_dns(dns_fd, q, out, read + 1, u->downenc);
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return;
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} else {
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out[0] = 'I';
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/* Send ip/mtu/netmask info */
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tempip.s_addr = server.my_ip;
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tmp[0] = strdup(inet_ntoa(tempip));
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tempip.s_addr = users[userid].tun_ip;
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tempip.s_addr = u->tun_ip;
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tmp[1] = strdup(inet_ntoa(tempip));
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read = snprintf(out, sizeof(out) - 1, "-%s-%s-%d-%d",
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@ -1366,9 +1421,15 @@ handle_dns_login(int dns_fd, struct query *q, uint8_t *domain, int domain_len, i
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free(tmp[1]);
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free(tmp[0]);
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write_dns(dns_fd, q, out, read + 1, u->downenc);
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return;
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}
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write_dns(dns_fd, q, out, read + 1, users[userid].downenc);
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tcp_forward_error:
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DEBUG(1, "Failed to connect TCP forward for user %d: %s", userid, errormsg);
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out[0] = 'E';
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strncat(out + 1, errormsg, sizeof(out) - 1);
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read = strlen(out);
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write_dns(dns_fd, q, out, read + 1, u->downenc);
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}
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void
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@ -36,8 +36,8 @@ struct tun_user {
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struct sockaddr_storage host;
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socklen_t hostlen;
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struct sockaddr_storage remoteforward_addr;
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socklen_t remoteforward_addr_len; /* 0 if connecting to localhost */
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uint16_t remote_port; /* 0 if no remote forwarding enabled */
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socklen_t remoteforward_addr_len; /* 0 if no remote forwarding enabled */
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int tcp_fd;
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int remote_forward_connected;
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struct frag_buffer *incoming;
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struct frag_buffer *outgoing;
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