/* * rfc931() speaks a common subset of the RFC 931, AUTH, TAP, IDENT and RFC * 1413 protocols. It queries an RFC 931 etc. compatible daemon on a remote * host to look up the owner of a connection. The information should not be * used for authentication purposes. This routine intercepts alarm signals. * * Diagnostics are reported through syslog(3). * * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands. * * $FreeBSD: src/contrib/tcp_wrappers/rfc931.c,v 1.2.2.1 2000/07/18 16:41:11 dwmalone Exp $ * $DragonFly: src/contrib/tcp_wrappers/rfc931.c,v 1.2 2003/06/17 04:24:06 dillon Exp $ */ #ifndef lint static char sccsid[] = "@(#) rfc931.c 1.10 95/01/02 16:11:34"; #endif /* System libraries. */ #include #include #include #include #include #include #include #include #ifndef SEEK_SET #define SEEK_SET 0 #endif /* Local stuff. */ #include "tcpd.h" #define RFC931_PORT 113 /* Semi-well-known port */ #define ANY_PORT 0 /* Any old port will do */ int rfc931_timeout = RFC931_TIMEOUT;/* Global so it can be changed */ static jmp_buf timebuf; /* fsocket - open stdio stream on top of socket */ static FILE *fsocket(domain, type, protocol) int domain; int type; int protocol; { int s; FILE *fp; if ((s = socket(domain, type, protocol)) < 0) { tcpd_warn("socket: %m"); return (0); } else { if ((fp = fdopen(s, "r+")) == 0) { tcpd_warn("fdopen: %m"); close(s); } return (fp); } } /* timeout - handle timeouts */ static void timeout(sig) int sig; { longjmp(timebuf, sig); } /* rfc931 - return remote user name, given socket structures */ void rfc931(rmt_sin, our_sin, dest) #ifdef INET6 struct sockaddr *rmt_sin; struct sockaddr *our_sin; #else struct sockaddr_in *rmt_sin; struct sockaddr_in *our_sin; #endif char *dest; { unsigned rmt_port; unsigned our_port; #ifdef INET6 struct sockaddr_storage rmt_query_sin; struct sockaddr_storage our_query_sin; int alen; #else struct sockaddr_in rmt_query_sin; struct sockaddr_in our_query_sin; #endif char user[256]; /* XXX */ char buffer[512]; /* XXX */ char *cp; char *result = unknown; FILE *fp; #ifdef INET6 /* address family must be the same */ if (rmt_sin->sa_family != our_sin->sa_family) { STRN_CPY(dest, result, STRING_LENGTH); return; } switch (our_sin->sa_family) { case AF_INET: alen = sizeof(struct sockaddr_in); break; case AF_INET6: alen = sizeof(struct sockaddr_in6); break; default: STRN_CPY(dest, result, STRING_LENGTH); return; } #endif /* * If we use a single, buffered, bidirectional stdio stream ("r+" or * "w+" mode) we may read our own output. Such behaviour would make sense * with resources that support random-access operations, but not with * sockets. ANSI C suggests several functions which can be called when * you want to change IO direction, fseek seems the most portable. */ #ifdef INET6 if ((fp = fsocket(our_sin->sa_family, SOCK_STREAM, 0)) != 0) { #else if ((fp = fsocket(AF_INET, SOCK_STREAM, 0)) != 0) { #endif /* * Set up a timer so we won't get stuck while waiting for the server. */ if (setjmp(timebuf) == 0) { signal(SIGALRM, timeout); alarm(rfc931_timeout); /* * Bind the local and remote ends of the query socket to the same * IP addresses as the connection under investigation. We go * through all this trouble because the local or remote system * might have more than one network address. The RFC931 etc. * client sends only port numbers; the server takes the IP * addresses from the query socket. */ #ifdef INET6 memcpy(&our_query_sin, our_sin, alen); memcpy(&rmt_query_sin, rmt_sin, alen); switch (our_sin->sa_family) { case AF_INET: ((struct sockaddr_in *)&our_query_sin)->sin_port = htons(ANY_PORT); ((struct sockaddr_in *)&rmt_query_sin)->sin_port = htons(RFC931_PORT); break; case AF_INET6: ((struct sockaddr_in6 *)&our_query_sin)->sin6_port = htons(ANY_PORT); ((struct sockaddr_in6 *)&rmt_query_sin)->sin6_port = htons(RFC931_PORT); break; } if (bind(fileno(fp), (struct sockaddr *) & our_query_sin, alen) >= 0 && connect(fileno(fp), (struct sockaddr *) & rmt_query_sin, alen) >= 0) { #else our_query_sin = *our_sin; our_query_sin.sin_port = htons(ANY_PORT); rmt_query_sin = *rmt_sin; rmt_query_sin.sin_port = htons(RFC931_PORT); if (bind(fileno(fp), (struct sockaddr *) & our_query_sin, sizeof(our_query_sin)) >= 0 && connect(fileno(fp), (struct sockaddr *) & rmt_query_sin, sizeof(rmt_query_sin)) >= 0) { #endif /* * Send query to server. Neglect the risk that a 13-byte * write would have to be fragmented by the local system and * cause trouble with buggy System V stdio libraries. */ fprintf(fp, "%u,%u\r\n", #ifdef INET6 ntohs(((struct sockaddr_in *)rmt_sin)->sin_port), ntohs(((struct sockaddr_in *)our_sin)->sin_port)); #else ntohs(rmt_sin->sin_port), ntohs(our_sin->sin_port)); #endif fflush(fp); fseek(fp, 0, SEEK_SET); /* * Read response from server. Use fgets()/sscanf() so we can * work around System V stdio libraries that incorrectly * assume EOF when a read from a socket returns less than * requested. */ if (fgets(buffer, sizeof(buffer), fp) != 0 && ferror(fp) == 0 && feof(fp) == 0 && sscanf(buffer, "%u , %u : USERID :%*[^:]:%255s", &rmt_port, &our_port, user) == 3 #ifdef INET6 && ntohs(((struct sockaddr_in *)rmt_sin)->sin_port) == rmt_port && ntohs(((struct sockaddr_in *)our_sin)->sin_port) == our_port) { #else && ntohs(rmt_sin->sin_port) == rmt_port && ntohs(our_sin->sin_port) == our_port) { #endif /* * Strip trailing carriage return. It is part of the * protocol, not part of the data. */ if (cp = strchr(user, '\r')) *cp = 0; result = user; } } alarm(0); } fclose(fp); } STRN_CPY(dest, result, STRING_LENGTH); }