diff options
Diffstat (limited to 'ipsvd/tcpudp.c')
| -rw-r--r-- | ipsvd/tcpudp.c | 446 |
1 files changed, 120 insertions, 326 deletions
diff --git a/ipsvd/tcpudp.c b/ipsvd/tcpudp.c index 419551d..6e8ec32 100644 --- a/ipsvd/tcpudp.c +++ b/ipsvd/tcpudp.c @@ -7,12 +7,51 @@ * Licensed under GPLv2, see file LICENSE in this tarball for details. */ -/* TCP and UDP server are using a lot of same string constants - * We reuse them by keeping both in one source file */ +/* Based on ipsvd ipsvd-0.12.1. This tcpsvd accepts all options + * which are supported by one from ipsvd-0.12.1, but not all are + * functional. See help text at the end of this file for details. + * + * Code inside "#ifdef SSLSVD" is for sslsvd and is currently unused. + * + * Output of verbose mode matches original (modulo bugs and + * unimplemented stuff). Unnatural splitting of IP and PORT + * is retained (personally I prefer one-value "IP:PORT" notation - + * it is a natural string representation of struct sockaddr_XX). + * + * TCPORIGDST{IP,PORT} is busybox-specific addition + * + * udp server is hacked up by reusing TCP code. It has the following + * limitation inherent in Unix DGRAM sockets implementation: + * - local IP address is reptrieved (using recvmsg voodoo) but + * child's socket is not bound to it (bind cannot be called on + * already bound socket). Thus you still can get outgoing packets + * with wrong sorce IP... + * - don't know how to retrieve ORIGDST for udp. + */ + +#include <limits.h> +#include <linux/netfilter_ipv4.h> /* wants <limits.h> */ #include "busybox.h" +#include "udp_io.c" +#include "ipsvd_perhost.h" + +#ifdef SSLSVD +#include "matrixSsl.h" +#include "ssl_io.h" +#endif + static unsigned verbose; +static unsigned max_per_host; +static unsigned cur_per_host; +static unsigned cnum; +static unsigned cmax = 30; + +static void xsetenv_proto(const char *proto, const char *n, const char *v) +{ + putenv(xasprintf("%s%s=%s", proto, n, v)); +} static void sig_term_handler(int sig) { @@ -38,287 +77,6 @@ static void print_waitstat(unsigned pid, int wstat) printf("%s: info: end %d %s %d\n", applet_name, pid, cause, e); } - -#if ENABLE_UDPSVD -/* Based on ipsvd ipsvd-0.12.1. This udpsvd accepts all options - * which are supported by one from ipsvd-0.12.1, but not all are - * functional. See help text at the end of this file for details. - * - * Output of verbose mode matches original (modulo bugs and - * unimplemented stuff). Unnatural splitting of IP and PORT - * is retained (personally I prefer one-value "IP:PORT" notation - - * it is a natural string representation of struct sockaddr_XX). - */ - -#include "udp_io.c" - -int udpsvd_main(int argc, char **argv); -int udpsvd_main(int argc, char **argv) -{ - const char *instructs; - char *str_t, *user; - unsigned opt; - - char *remote_hostname = (char*)""; /* used if no -h */ - char *local_hostname = NULL; - char *remote_ip; - char *local_ip;// = local_ip; /* gcc */ - uint16_t local_port, remote_port; - len_and_sockaddr remote; - len_and_sockaddr *localp; - int wstat; - unsigned pid; - struct bb_uidgid_t ugid; - - enum { - OPT_v = (1 << 0), - OPT_u = (1 << 1), - OPT_l = (1 << 2), - OPT_h = (1 << 3), - OPT_p = (1 << 4), - OPT_i = (1 << 5), - OPT_x = (1 << 6), - OPT_t = (1 << 7), - }; - - opt_complementary = "-3:ph:vv"; - opt = getopt32(argc, argv, "vu:l:hpi:x:t:", - &user, &local_hostname, &instructs, &instructs, &str_t, &verbose); - if (opt & OPT_u) { - if (!get_uidgid(&ugid, user, 1)) - bb_error_msg_and_die("unknown user/group: %s", user); - } - argv += optind; - if (!argv[0][0] || LONE_CHAR(argv[0], '0')) - argv[0] = (char*)"0.0.0.0"; - - /* stdout is used for logging, don't buffer */ - setlinebuf(stdout); - bb_sanitize_stdio(); /* fd# 1,2 must be opened */ - - signal(SIGTERM, sig_term_handler); - signal(SIGPIPE, SIG_IGN); - - local_port = bb_lookup_port(argv[1], "udp", 0); - localp = xhost2sockaddr(argv[0], local_port); - /* fd #0 is the open UDP socket */ - xmove_fd(xsocket(localp->sa.sa_family, SOCK_DGRAM, 0), 0); - setsockopt_reuseaddr(0); /* crucial */ - xbind(0, &localp->sa, localp->len); - socket_want_pktinfo(0); /* needed for recv_from_to to work */ - - if (opt & OPT_u) { /* drop permissions */ - xsetgid(ugid.gid); - xsetuid(ugid.uid); - } - - if (verbose) { - /* we do it only for ":port" cosmetics... oh well */ - char *addr = xmalloc_sockaddr2dotted(&localp->sa, localp->len); - - printf("%s: info: listening on %s", applet_name, addr); - free(addr); - if (option_mask32 & OPT_u) - printf(", uid %u, gid %u", - (unsigned)ugid.uid, (unsigned)ugid.gid); - puts(", starting"); - } - - again: - /* if (recvfrom(0, NULL, 0, MSG_PEEK, &remote.sa, &localp->len) < 0) { */ - if (recv_from_to(0, NULL, 0, MSG_PEEK, &remote.sa, &localp->sa, localp->len) < 0) { - bb_perror_msg("recvfrom"); - goto again; - } - - while ((pid = fork()) < 0) { - bb_perror_msg("fork failed, sleeping"); - sleep(5); - } - if (pid > 0) { /* parent */ - while (wait_pid(&wstat, pid) < 0) - bb_perror_msg("error waiting for child"); - if (verbose) - print_waitstat(pid, wstat); - goto again; - } - - /* Child */ - - if (verbose) { - remote_ip = xmalloc_sockaddr2dotted_noport(&remote.sa, localp->len); - local_ip = xmalloc_sockaddr2dotted_noport(&localp->sa, localp->len); - - pid = getpid(); - printf("%s: info: pid %u from %s\n", applet_name, pid, remote_ip); - - if (!local_hostname) { - local_hostname = xmalloc_sockaddr2host_noport(&localp->sa, localp->len); - if (!local_hostname) - bb_error_msg_and_die("cannot look up local hostname for %s", local_ip); - } - if (opt & OPT_h) { - remote_hostname = xmalloc_sockaddr2host(&remote.sa, localp->len); - if (!remote_hostname) { - bb_error_msg("warning: cannot look up hostname for %s", remote_ip); - remote_hostname = (char*)""; - } - } - - remote_port = get_nport(&remote.sa); - remote_port = ntohs(remote_port); - printf("%s: info: %u %s:%s :%s:%s:%u\n", - applet_name, pid, local_hostname, local_ip, - remote_hostname, remote_ip, remote_port); - } - - /* Doesn't work: - * we cannot replace fd #0 - we will lose pending packet - * which is already buffered for us! And we cannot use fd #1 - * instead - it will "intercept" all following packets, but child - * do not expect data coming *from fd #1*! */ -#if 0 - /* Make it so that local addr is fixed to localp->sa - * and we don't accidentally accept packets to other local IPs. */ - /* NB: we possibly bind to the _very_ same_ address & port as the one - * already bound in parent! This seems to work in Linux. - * (otherwise we can move socket to fd #0 only if bind succeeds) */ - close(0); - set_nport(localp, htons(local_port)); - xmove_fd(xsocket(localp->sa.sa_family, SOCK_DGRAM, 0), 0); - setsockopt_reuseaddr(0); /* crucial */ - xbind(0, &localp->sa, localp->len); -#endif - - /* Make plain write to fd #1 work for the child by supplying default - * destination address. This also restricts incoming packets - * to ones coming from this remote IP. */ - xconnect(0, &remote.sa, localp->len); - dup2(0 ,1); - - signal(SIGTERM, SIG_DFL); - signal(SIGPIPE, SIG_DFL); - - argv += 2; - BB_EXECVP(argv[0], argv); - bb_perror_msg_and_die("exec '%s'", argv[0]); -} - - -/* -udpsvd [-hpvv] [-u user] [-l name] [-i dir|-x cdb] [-t sec] host port prog - -udpsvd creates an UDP/IP socket, binds it to the address host:port, -and listens on the socket for incoming datagrams. - -If a datagram is available on the socket, udpsvd conditionally starts -a program, with standard input reading from the socket, and standard -output redirected to standard error, to handle this, and possibly -more datagrams. udpsvd does not start the program if another program -that it has started before still is running. If the program exits, -udpsvd again listens to the socket until a new datagram is available. -If there are still datagrams available on the socket, the program -is restarted immediately. - -udpsvd optionally checks for special intructions depending on -the IP address or hostname of the client sending the datagram which -not yet was handled by a running program, see ipsvd-instruct(5) -for details. - -Attention: -UDP is a connectionless protocol. Most programs that handle user datagrams, -such as talkd(8), keep running after receiving a datagram, and process -subsequent datagrams sent to the socket until a timeout is reached. -udpsvd only checks special instructions for a datagram that causes a startup -of the program; not if a program handling datagrams already is running. -It doesn't make much sense to restrict access through special instructions -when using such a program. - -On the other hand, it makes perfectly sense with programs like tftpd(8), -that fork to establish a separate connection to the client when receiving -the datagram. In general it's adequate to set up special instructions for -programs that support being run by tcpwrapper. -Options - -host - host either is a hostname, or a dotted-decimal IP address, or 0. - If host is 0, udpsvd accepts datagrams to any local IP address. -port - udpsvd accepts datagrams to host:port. port may be a name from - /etc/services or a number. -prog - prog consists of one or more arguments. udpsvd normally runs prog - to handle a datagram, and possibly more, that is sent to the socket, - if there is no program that was started before by udpsvd still running - and handling datagrams. --i dir - read instructions for handling new connections from the instructions - directory dir. See ipsvd-instruct(5) for details. --x cdb - read instructions for handling new connections from the constant - database cdb. The constant database normally is created from - an instructions directory by running ipsvd-cdb(8). --t sec - timeout. This option only takes effect if the -i option is given. - While checking the instructions directory, check the time of last - access of the file that matches the clients address or hostname if any, - discard and remove the file if it wasn't accessed within the last - sec seconds; udpsvd does not discard or remove a file if the user's - write permission is not set, for those files the timeout is disabled. - Default is 0, which means that the timeout is disabled. --l name - local hostname. Do not look up the local hostname in DNS, but use name - as hostname. By default udpsvd looks up the local hostname once at startup. --u user[:group] - drop permissions. Switch user ID to user's UID, and group ID to user's - primary GID after creating and binding to the socket. If user - is followed by a colon and a group name, the group ID is switched - to the GID of group instead. All supplementary groups are removed. --h - Look up the client's hostname in DNS. --p - paranoid. After looking up the client's hostname in DNS, look up - the IP addresses in DNS for that hostname, and forget the hostname - if none of the addresses match the client's IP address. You should - set this option if you use hostname based instructions. The -p option - implies the -h option. --v - verbose. Print verbose messages to standard output. --vv - more verbose. Print more verbose messages to standard output. -*/ -#endif - - -#if ENABLE_TCPSVD -/* Based on ipsvd ipsvd-0.12.1. This tcpsvd accepts all options - * which are supported by one from ipsvd-0.12.1, but not all are - * functional. See help text at the end of this file for details. - * - * Code inside "#ifdef SSLSVD" is for sslsvd and is currently unused. - * - * Output of verbose mode matches original (modulo bugs and - * unimplemented stuff). Unnatural splitting of IP and PORT - * is retained (personally I prefer one-value "IP:PORT" notation - - * it is a natural string representation of struct sockaddr_XX). - * - * TCPORIGDST{IP,PORT} is busybox-specific addition - */ - -#include <limits.h> -#include <linux/netfilter_ipv4.h> /* wants <limits.h> */ -#include "ipsvd_perhost.h" - -#ifdef SSLSVD -#include "matrixSsl.h" -#include "ssl_io.h" -#endif - -static unsigned max_per_host; /* originally in ipsvd_check.c */ -static unsigned cur_per_host; -static unsigned cnum; -static unsigned cmax = 30; - /* Must match getopt32 in main! */ enum { OPT_c = (1 << 0), @@ -342,7 +100,9 @@ enum { static void connection_status(void) { - printf("%s: info: status %u/%u\n", applet_name, cnum, cmax); + /* UDP and "only 1 client max" TCP don't need this */ + if (cmax > 1) + printf("%s: info: status %u/%u\n", applet_name, cnum, cmax); } static void sig_child_handler(int sig) @@ -362,8 +122,8 @@ static void sig_child_handler(int sig) connection_status(); } -int tcpsvd_main(int argc, char **argv); -int tcpsvd_main(int argc, char **argv) +int tcpudpsvd_main(int argc, char **argv); +int tcpudpsvd_main(int argc, char **argv) { char *str_c, *str_C, *str_b, *str_t; char *user; @@ -372,11 +132,13 @@ int tcpsvd_main(int argc, char **argv) char *msg_per_host = NULL; unsigned len_per_host = len_per_host; /* gcc */ int need_hostnames, need_remote_ip; + int tcp; int pid; int sock; int conn; unsigned backlog = 20; len_and_sockaddr *lsa; + len_and_sockaddr local, remote; uint16_t local_port; uint16_t remote_port = remote_port; /* gcc */ char *local_hostname = NULL; @@ -386,6 +148,7 @@ int tcpsvd_main(int argc, char **argv) #ifndef SSLSVD struct bb_uidgid_t ugid; #endif + tcp = (applet_name[0] == 't'); /* 3+ args, -i at most once, -p implies -h, -v is counter */ opt_complementary = "-3:?:i--i:ph:vv"; @@ -420,18 +183,22 @@ int tcpsvd_main(int argc, char **argv) if (option_mask32 & OPT_b) backlog = xatou(str_b); #ifdef SSLSVD - if (option_mask32 & OPT_U) ssluser = (char*)optarg; break; - if (option_mask32 & OPT_slash) root = (char*)optarg; break; - if (option_mask32 & OPT_Z) cert = (char*)optarg; break; - if (option_mask32 & OPT_K) key = (char*)optarg; break; + if (option_mask32 & OPT_U) ssluser = optarg; + if (option_mask32 & OPT_slash) root = optarg; + if (option_mask32 & OPT_Z) cert = optarg; + if (option_mask32 & OPT_K) key = optarg; #endif argv += optind; if (!argv[0][0] || LONE_CHAR(argv[0], '0')) argv[0] = (char*)"0.0.0.0"; + /* Per-IP flood protection is not thought-out for UDP */ + if (!tcp) + max_per_host = 0; + /* stdout is used for logging, don't buffer */ setlinebuf(stdout); - bb_sanitize_stdio(); /* fd# 1,2 must be opened */ + bb_sanitize_stdio(); /* fd# 0,1,2 must be opened */ need_hostnames = verbose || !(option_mask32 & OPT_E); need_remote_ip = max_per_host || need_hostnames; @@ -473,12 +240,15 @@ int tcpsvd_main(int argc, char **argv) if (max_per_host) ipsvd_perhost_init(cmax); - local_port = bb_lookup_port(argv[1], "tcp", 0); + local_port = bb_lookup_port(argv[1], tcp ? "tcp" : "udp", 0); lsa = xhost2sockaddr(argv[0], local_port); - sock = xsocket(lsa->sa.sa_family, SOCK_STREAM, 0); - setsockopt_reuseaddr(sock); /* desirable */ + sock = xsocket(lsa->sa.sa_family, tcp ? SOCK_STREAM : SOCK_DGRAM, 0); + setsockopt_reuseaddr(sock); xbind(sock, &lsa->sa, lsa->len); - xlisten(sock, backlog); + if (tcp) + xlisten(sock, backlog); + else /* udp: needed for recv_from_to to work: */ + socket_want_pktinfo(sock); /* ndelay_off(sock); - it is the default I think? */ #ifndef SSLSVD @@ -503,7 +273,7 @@ int tcpsvd_main(int argc, char **argv) puts(", starting"); } - /* The rest is a main accept() loop */ + /* Main accept() loop */ again: hccp = NULL; @@ -516,19 +286,23 @@ int tcpsvd_main(int argc, char **argv) close(0); again2: sig_unblock(SIGCHLD); - conn = accept(sock, &lsa->sa, &lsa->len); + if (tcp) { + remote.len = lsa->len; + conn = accept(sock, &remote.sa, &remote.len); + } else + conn = recv_from_to(sock, NULL, 0, MSG_PEEK, &remote.sa, &local.sa, lsa->len); sig_block(SIGCHLD); if (conn < 0) { if (errno != EINTR) - bb_perror_msg("accept"); + bb_perror_msg(tcp ? "accept" : "recv"); goto again2; } - xmove_fd(conn, 0); + xmove_fd(tcp ? conn : sock, 0); if (max_per_host) { /* Drop connection immediately if cur_per_host > max_per_host * (minimizing load under SYN flood) */ - remote_ip = xmalloc_sockaddr2dotted_noport(&lsa->sa, lsa->len); + remote_ip = xmalloc_sockaddr2dotted_noport(&remote.sa, lsa->len); cur_per_host = ipsvd_perhost_add(remote_ip, max_per_host, &hccp); if (cur_per_host > max_per_host) { /* ipsvd_perhost_add detected that max is exceeded @@ -543,17 +317,33 @@ int tcpsvd_main(int argc, char **argv) } } - cnum++; - if (verbose) - connection_status(); + if (!tcp) { + /* Voodoo magic: making udp sockets each receive its own + * packets is not trivial */ + + /* Make plain write work for this socket by supplying default + * destination address. This also restricts incoming packets + * to ones coming from this remote IP. */ + xconnect(0, &remote.sa, lsa->len); + /* Open new non-connected UDP socket for further clients */ + sock = xsocket(lsa->sa.sa_family, tcp ? SOCK_STREAM : SOCK_DGRAM, 0); + setsockopt_reuseaddr(sock); + xbind(sock, &lsa->sa, lsa->len); + socket_want_pktinfo(sock); + } pid = fork(); if (pid == -1) { bb_perror_msg("fork"); goto again; } + + if (pid != 0) { /* parent */ + cnum++; + if (verbose) + connection_status(); if (hccp) hccp->pid = pid; goto again; @@ -561,35 +351,38 @@ int tcpsvd_main(int argc, char **argv) /* Child: prepare env, log, and exec prog */ - close(sock); /* listening socket */ - /* Find out local IP peer connected to. - * Errors ignored (I'm not paranoid enough to imagine kernel - * which doesn't know local IP). */ - getsockname(0, &lsa->sa, &lsa->len); + /* Closing tcp listening socket */ + if (tcp) + close(sock); if (need_remote_ip) { if (!max_per_host) - remote_ip = xmalloc_sockaddr2dotted_noport(&lsa->sa, lsa->len); + remote_ip = xmalloc_sockaddr2dotted_noport(&remote.sa, lsa->len); /* else it is already done */ - remote_port = get_nport(&lsa->sa); + remote_port = get_nport(&remote.sa); remote_port = ntohs(remote_port); } if (need_hostnames) { if (option_mask32 & OPT_h) { - remote_hostname = xmalloc_sockaddr2host(&lsa->sa, lsa->len); + remote_hostname = xmalloc_sockaddr2host(&remote.sa, lsa->len); if (!remote_hostname) { bb_error_msg("warning: cannot look up hostname for %s", remote_ip); remote_hostname = (char*)""; } } - local_ip = xmalloc_sockaddr2dotted_noport(&lsa->sa, lsa->len); - local_port = get_nport(&lsa->sa); + /* Find out local IP peer connected to. + * Errors ignored (I'm not paranoid enough to imagine kernel + * which doesn't know local IP). */ + if (tcp) + getsockname(0, &local.sa, &local.len); + local_ip = xmalloc_sockaddr2dotted_noport(&local.sa, lsa->len); + local_port = get_nport(&local.sa); local_port = ntohs(local_port); if (!local_hostname) { - local_hostname = xmalloc_sockaddr2host_noport(&lsa->sa, lsa->len); + local_hostname = xmalloc_sockaddr2host_noport(&local.sa, lsa->len); if (!local_hostname) - bb_error_msg_and_die("cannot look up local hostname for %s", local_ip); + bb_error_msg_and_die("warning: cannot look up hostname for %s"+9, local_ip); } } @@ -605,14 +398,16 @@ int tcpsvd_main(int argc, char **argv) remote_hostname, remote_ip, (unsigned)remote_port); } +// TODO: stop splitiing port# from IP? if (!(option_mask32 & OPT_E)) { /* setup ucspi env */ + const char *proto = tcp ? "TCP" : "UDP"; /* Extract "original" destination addr:port * from Linux firewall. Useful when you redirect * an outbond connection to local handler, and it needs * to know where it originally tried to connect */ - if (getsockopt(0, SOL_IP, SO_ORIGINAL_DST, &lsa->sa, &lsa->len) == 0) { + if (tcp && getsockopt(0, SOL_IP, SO_ORIGINAL_DST, &lsa->sa, &lsa->len) == 0) { char *ip = xmalloc_sockaddr2dotted_noport(&lsa->sa, lsa->len); unsigned port = get_nport(&lsa->sa); port = ntohs(port); @@ -620,18 +415,18 @@ int tcpsvd_main(int argc, char **argv) xsetenv("TCPORIGDSTPORT", utoa(port)); free(ip); } - xsetenv("PROTO", "TCP"); - xsetenv("TCPLOCALIP", local_ip); - xsetenv("TCPLOCALPORT", utoa(local_port)); - xsetenv("TCPLOCALHOST", local_hostname); - xsetenv("TCPREMOTEIP", remote_ip); - xsetenv("TCPREMOTEPORT", utoa(remote_port)); + xsetenv("PROTO", proto); + xsetenv_proto(proto, "LOCALIP", local_ip); + xsetenv_proto(proto, "LOCALPORT", utoa(local_port)); + xsetenv_proto(proto, "LOCALHOST", local_hostname); + xsetenv_proto(proto, "REMOTEIP", remote_ip); + xsetenv_proto(proto, "REMOTEPORT", utoa(remote_port)); if (option_mask32 & OPT_h) { - xsetenv("TCPREMOTEHOST", remote_hostname); + xsetenv_proto(proto, "REMOTEHOST", remote_hostname); } - xsetenv("TCPREMOTEINFO", ""); + xsetenv_proto(proto, "REMOTEINFO", ""); /* additional */ - if (cur_per_host > 0) + if (cur_per_host > 0) /* can not be true for udp */ xsetenv("TCPCONCURRENCY", utoa(cur_per_host)); } @@ -747,4 +542,3 @@ prog more verbose. Print more verbose messages to standard output. * no difference between -v and -vv in busyboxed version */ -#endif |