X-Git-Url: https://arthur.barton.de/cgi-bin/gitweb.cgi?p=ngircd-alex.git;a=blobdiff_plain;f=src%2Fngircd%2Fresolve.c;h=999ef9906df241f3c3d195524df8fb86c1082907;hp=e46e4823b31792a83f198a540e6ef15e065888b0;hb=4c113d8850dfc423e3dae2d2f90e7e9a9d42f0b0;hpb=0701afedee21b33e22f663ca265a7ca0f4c43974

diff --git a/src/ngircd/resolve.c b/src/ngircd/resolve.c
index e46e4823..999ef990 100644
--- a/src/ngircd/resolve.c
+++ b/src/ngircd/resolve.c
@@ -14,7 +14,7 @@
 
 #include "portab.h"
 
-static char UNUSED id[] = "$Id: resolve.c,v 1.23 2006/02/08 15:24:10 fw Exp $";
+static char UNUSED id[] = "$Id: resolve.c,v 1.29 2008/02/26 22:04:17 fw Exp $";
 
 #include "imp.h"
 #include <assert.h>
@@ -24,7 +24,6 @@ static char UNUSED id[] = "$Id: resolve.c,v 1.23 2006/02/08 15:24:10 fw Exp $";
 #include <unistd.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
-#include <arpa/inet.h>
 #include <netdb.h>
 
 #ifdef IDENTAUTH
@@ -42,18 +41,20 @@ static char UNUSED id[] = "$Id: resolve.c,v 1.23 2006/02/08 15:24:10 fw Exp $";
 #include "io.h"
 
 
-static void Do_ResolveAddr PARAMS(( struct sockaddr_in *Addr, int Sock, int w_fd ));
+static void Do_ResolveAddr PARAMS(( const ng_ipaddr_t *Addr, int Sock, int w_fd ));
 static void Do_ResolveName PARAMS(( const char *Host, int w_fd ));
 static bool register_callback PARAMS((RES_STAT *s, void (*cbfunc)(int, short)));
 
-#ifdef h_errno
-static char *Get_Error PARAMS(( int H_Error ));
+#ifdef WANT_IPV6
+extern bool Conf_ConnectIPv4;
+extern bool Conf_ConnectIPv6;
 #endif
 
-static int
+static pid_t
 Resolver_fork(int *pipefds)
 {
-	int pid;
+	pid_t pid;
+
 	if (pipe(pipefds) != 0) {
                 Log( LOG_ALERT, "Resolver: Can't create output pipe: %s!", strerror( errno ));
                 return -1;
@@ -77,18 +78,22 @@ Resolver_fork(int *pipefds)
 }
 
 
+/**
+ * Resolve IP (asynchronous!).
+ */
 GLOBAL bool
-Resolve_Addr( RES_STAT *s, struct sockaddr_in *Addr, int identsock, void (*cbfunc)(int, short))
+Resolve_Addr(RES_STAT * s, const ng_ipaddr_t *Addr, int identsock,
+	     void (*cbfunc) (int, short))
 {
-	/* Resolve IP (asynchronous!). */
-	int pid, pipefd[2];
+	int pipefd[2];
+	pid_t pid;
+
 	assert(s != NULL);
 
 	pid = Resolver_fork(pipefd);
 	if (pid > 0) {
-#ifdef DEBUG
-		Log( LOG_DEBUG, "Resolver for %s created (PID %d).", inet_ntoa( Addr->sin_addr ), pid );
-#endif
+		Log(LOG_DEBUG, "Resolver for %s created (PID %d).", ng_ipaddr_tostr(Addr), pid);
+
 		s->pid = pid;
 		s->resolver_fd = pipefd[0];
 		return register_callback(s, cbfunc);
@@ -102,11 +107,15 @@ Resolve_Addr( RES_STAT *s, struct sockaddr_in *Addr, int identsock, void (*cbfun
 } /* Resolve_Addr */
 
 
+/**
+ * Resolve hostname (asynchronous!).
+ */
 GLOBAL bool
 Resolve_Name( RES_STAT *s, const char *Host, void (*cbfunc)(int, short))
 {
-	/* Resolve hostname (asynchronous!). */
-	int pid, pipefd[2];
+	int pipefd[2];
+	pid_t pid;
+
 	assert(s != NULL);
 
 	pid = Resolver_fork(pipefd);
@@ -137,164 +146,346 @@ Resolve_Init(RES_STAT *s)
 }
 
 
-static void
-Do_ResolveAddr( struct sockaddr_in *Addr, int identsock, int w_fd )
+#ifndef WANT_IPV6
+#ifdef h_errno
+static char *
+Get_Error( int H_Error )
 {
-	/* Resolver sub-process: resolve IP address and write result into
-	 * pipe to parent. */
+	/* Get error message for H_Error */
+	switch( H_Error ) {
+	case HOST_NOT_FOUND:
+		return "host not found";
+	case NO_DATA:
+		return "name valid but no IP address defined";
+	case NO_RECOVERY:
+		return "name server error";
+	case TRY_AGAIN:
+		return "name server temporary not available";
+	}
+	return "unknown error";
+}
+#endif /* h_errno */
+#endif /* WANT_IPV6 */
 
-	char hostname[HOST_LEN];
-	char ipstr[HOST_LEN];
-	struct hostent *h;
-	size_t len;
-	struct in_addr *addr;
-	char *ntoaptr;
-	array resolved_addr;
+
+/* Do "IDENT" (aka "AUTH") lookup and append result to resolved_addr array */
+static void
+Do_IdentQuery(int identsock, array *resolved_addr)
+{
 #ifdef IDENTAUTH
 	char *res;
+
+	if (identsock < 0)
+		return;
+
+#ifdef DEBUG
+	Log_Resolver(LOG_DEBUG, "Doing IDENT lookup on socket %d ...", identsock);
 #endif
-	array_init(&resolved_addr);
-	/* Resolve IP address */
+	res = ident_id( identsock, 10 );
 #ifdef DEBUG
-	Log_Resolver( LOG_DEBUG, "Now resolving %s ...", inet_ntoa( Addr->sin_addr ));
+	Log_Resolver(LOG_DEBUG, "Ok, IDENT lookup on socket %d done: \"%s\"",
+						identsock, res ? res : "(NULL)" );
 #endif
-	h = gethostbyaddr( (char *)&Addr->sin_addr, sizeof( Addr->sin_addr ), AF_INET );
-	if (!h) {
-#ifdef h_errno
-		Log_Resolver( LOG_WARNING, "Can't resolve address \"%s\": %s!", inet_ntoa( Addr->sin_addr ), Get_Error( h_errno ));
+	if (!res) /* no result */
+		return;
+	if (!array_cats(resolved_addr, res))
+		Log_Resolver(LOG_WARNING, "Resolver: Cannot copy IDENT result: %s!", strerror(errno));
+
+	free(res);
+#else
+	(void) identsock;
+	(void) resolved_addr;
+#endif
+}
+
+
+/**
+ * perform reverse DNS lookup and put result string into resbuf.
+ * If no hostname could be obtained, this function stores the string representation of
+ * the IP address in resbuf and returns false.
+ * @param IpAddr ip address to resolve
+ * @param resbuf result buffer to store DNS name/string representation of ip address
+ * @reslen size of result buffer (must be >= NGT_INET_ADDRSTRLEN)
+ * @return true if reverse lookup successful, false otherwise
+ */
+static bool
+ReverseLookup(const ng_ipaddr_t *IpAddr, char *resbuf, size_t reslen)
+{
+	char tmp_ip_str[NG_INET_ADDRSTRLEN];
+	const char *errmsg;
+#ifdef HAVE_GETNAMEINFO
+	static const char funcname[]="getnameinfo";
+	int res;
+
+	*resbuf = 0;
+
+	res = getnameinfo((struct sockaddr *) IpAddr, ng_ipaddr_salen(IpAddr),
+				resbuf, reslen, NULL, 0, NI_NAMEREQD);
+	if (res == 0)
+		return true;
+
+	if (res == EAI_SYSTEM)
+		errmsg = strerror(errno);
+	else
+		errmsg = gai_strerror(res);
 #else
-		Log_Resolver( LOG_WARNING, "Can't resolve address \"%s\"!", inet_ntoa( Addr->sin_addr ));
-#endif	
-		strlcpy( hostname, inet_ntoa( Addr->sin_addr ), sizeof( hostname ));
+	const struct sockaddr_in *Addr = (const struct sockaddr_in *) IpAddr;
+	struct hostent *h;
+	static const char funcname[]="gethostbyaddr";
+
+	h = gethostbyaddr((char *)&Addr->sin_addr, sizeof(Addr->sin_addr), AF_INET);
+	if (h) {
+		if (strlcpy(resbuf, h->h_name, reslen) < reslen)
+			return true;
+		errmsg = "hostname too long";
 	} else {
- 		strlcpy( hostname, h->h_name, sizeof( hostname ));
-
-		h = gethostbyname( hostname );
-		if ( h ) {
-			if (memcmp(h->h_addr, &Addr->sin_addr, sizeof (struct in_addr))) {
-				addr = (struct in_addr*) h->h_addr;
-				strlcpy(ipstr, inet_ntoa(*addr), sizeof ipstr); 
-				ntoaptr = inet_ntoa( Addr->sin_addr );
-				Log(LOG_WARNING,"Possible forgery: %s resolved to %s (which is at ip %s!)",
-										ntoaptr, hostname, ipstr);
-				strlcpy( hostname, ntoaptr, sizeof hostname);
-			}
-		} else {
-			ntoaptr = inet_ntoa( Addr->sin_addr );
-			Log(LOG_WARNING, "Possible forgery: %s resolved to %s (which has no ip address)",
-											ntoaptr, hostname);
-			strlcpy( hostname, ntoaptr, sizeof hostname);
-		}
+# ifdef h_errno
+		errmsg = Get_Error(h_errno);
+# else
+		errmsg = "unknown error";
+# endif /* h_errno */
 	}
-	Log_Resolver( LOG_DEBUG, "Ok, translated %s to \"%s\".", inet_ntoa( Addr->sin_addr ), hostname );
+#endif	/* HAVE_GETNAMEINFO */
 
-	len = strlen( hostname ); 
-	hostname[len] = '\n'; len++;
-	if (!array_copyb(&resolved_addr, hostname, len )) {
-		Log_Resolver( LOG_CRIT, "Resolver: Can't copy resolved name: %s!", strerror( errno ));
-		close( w_fd );
-		return;
-	}
+	assert(errmsg);
+	assert(reslen >= NG_INET_ADDRSTRLEN);
+	ng_ipaddr_tostr_r(IpAddr, tmp_ip_str);
 
-#ifdef IDENTAUTH
-	assert(identsock >= 0);
-	if (identsock >= 0) {
-		/* Do "IDENT" (aka "AUTH") lookup and append result to resolved_addr array */
-#ifdef DEBUG
-		Log_Resolver( LOG_DEBUG, "Doing IDENT lookup on socket %d ...", identsock );
+	Log_Resolver(LOG_WARNING, "%s: Can't resolve address \"%s\": %s",
+				funcname, tmp_ip_str, errmsg);
+	strlcpy(resbuf, tmp_ip_str, reslen);
+	return false;
+}
+
+
+/**
+ * perform DNS lookup of given host name and fill IpAddr with a list of
+ * ip addresses associated with that name.
+ * ip addresses found are stored in the "array *IpAddr" argument (type ng_ipaddr_t)
+ * @param hostname The domain name to look up.
+ * @param IpAddr pointer to empty and initialized array to store results
+ * @return true if lookup successful, false if domain name not found
+ */
+static bool
+ForwardLookup(const char *hostname, array *IpAddr)
+{
+	ng_ipaddr_t addr;
+
+#ifdef HAVE_GETADDRINFO
+	int res;
+	struct addrinfo *a, *ai_results;
+	static struct addrinfo hints;
+
+#ifndef WANT_IPV6
+	hints.ai_family = AF_INET;
 #endif
-		res = ident_id( identsock, 10 );
-#ifdef DEBUG
-		Log_Resolver(LOG_DEBUG, "Ok, IDENT lookup on socket %d done: \"%s\"",
-							identsock, res ? res : "(NULL)" );
+#ifdef AI_ADDRCONFIG	/* glibc has this, but not e.g. netbsd 4.0 */
+	hints.ai_flags = AI_ADDRCONFIG;
 #endif
-		if (res && !array_cats(&resolved_addr, res)) {
-			Log_Resolver(LOG_WARNING, "Resolver: Cannot copy IDENT result: %s!", strerror(errno));
-			/* omit ident and return hostname only */ 
-		}
+	hints.ai_socktype = SOCK_STREAM;
+	hints.ai_protocol = IPPROTO_TCP;
+
+#ifdef WANT_IPV6
+	assert(Conf_ConnectIPv6 || Conf_ConnectIPv4);
 
-		if (res) free(res);
+	if (!Conf_ConnectIPv6)
+		hints.ai_family = AF_INET;
+	if (!Conf_ConnectIPv4)
+		hints.ai_family = AF_INET6;
+#endif
+	res = getaddrinfo(hostname, NULL, &hints, &ai_results);
+	switch (res) {
+	case 0:	break;
+	case EAI_SYSTEM:
+		Log_Resolver(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, strerror(errno));
+		return false;
+	default:
+		Log_Resolver(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, gai_strerror(res));
+		return false;
+	}
+
+	for (a = ai_results; a != NULL; a = a->ai_next) {
+		assert(a->ai_addrlen <= sizeof(addr));
+
+		if (a->ai_addrlen > sizeof(addr))
+			continue;
+
+		memcpy(&addr, a->ai_addr, a->ai_addrlen);
+
+		if (!array_catb(IpAddr, (char *)&addr, sizeof(addr)))
+			break;
 	}
+
+	freeaddrinfo(ai_results);
+	return a == NULL;
+#else
+	struct hostent *h = gethostbyname(hostname);
+
+	if (!h) {
+#ifdef h_errno
+		Log_Resolver(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, Get_Error(h_errno));
 #else
-	(void)identsock;
+		Log_Resolver(LOG_WARNING, "Can't resolve \"%s\"", hostname);
 #endif
-	len = array_bytes(&resolved_addr);
-	if( (size_t)write( w_fd, array_start(&resolved_addr), len) != len )
-		Log_Resolver( LOG_CRIT, "Resolver: Can't write result to parent: %s!", strerror( errno ));
+		return false;
+	}
+	memset(&addr, 0, sizeof(addr));
 
-	close(w_fd);
-	array_free(&resolved_addr);
-} /* Do_ResolveAddr */
+	addr.sin4.sin_family = AF_INET;
+	memcpy(&addr.sin4.sin_addr, h->h_addr, sizeof(struct in_addr));
+
+	return array_copyb(IpAddr, (char *)&addr, sizeof(addr));
+#endif /* HAVE_GETADDRINFO */
+}
+
+
+static bool
+Addr_in_list(const array *resolved_addr, const ng_ipaddr_t *Addr)
+{
+	char tmp_ip_str[NG_INET_ADDRSTRLEN];
+	const ng_ipaddr_t *tmpAddrs = array_start(resolved_addr);
+	size_t len = array_length(resolved_addr, sizeof(*tmpAddrs));
+
+	assert(len > 0);
+	assert(tmpAddrs);
+
+	while (len > 0) {
+		if (ng_ipaddr_ipequal(Addr, tmpAddrs))
+			return true;
+		tmpAddrs++;
+		len--;
+	}
+	/* failed; print list of addresses */
+	ng_ipaddr_tostr_r(Addr, tmp_ip_str);
+	len = array_length(resolved_addr, sizeof(*tmpAddrs));
+	tmpAddrs = array_start(resolved_addr);
+
+	while (len > 0) {
+		Log_Resolver(LOG_WARNING, "Address mismatch: %s != %s",
+			tmp_ip_str, ng_ipaddr_tostr(tmpAddrs));
+		tmpAddrs++;
+		len--;
+	}
+
+	return false;
+}
 
 
 static void
-Do_ResolveName( const char *Host, int w_fd )
+Log_Forgery_NoIP(const char *ip, const char *host)
 {
-	/* Resolver sub-process: resolve name and write result into pipe
-	 * to parent. */
+	Log_Resolver(LOG_WARNING, "Possible forgery: %s resolved to %s "
+		"(which has no ip address)", ip, host);
+}
 
-	char ip[16];
-	struct hostent *h;
-	struct in_addr *addr;
-	int len;
+static void
+Log_Forgery_WrongIP(const char *ip, const char *host)
+{
+	Log_Resolver(LOG_WARNING,"Possible forgery: %s resolved to %s "
+		"(which points to different address)", ip, host);
+}
 
-	Log_Resolver( LOG_DEBUG, "Now resolving \"%s\" ...", Host );
 
-	/* Resolve hostname */
-	h = gethostbyname( Host );
-	if( h ) {
-		addr = (struct in_addr *)h->h_addr;
-		strlcpy( ip, inet_ntoa( *addr ), sizeof( ip ));
-	} else {
-#ifdef h_errno
-		Log_Resolver( LOG_WARNING, "Can't resolve \"%s\": %s!", Host, Get_Error( h_errno ));
-#else
-		Log_Resolver( LOG_WARNING, "Can't resolve \"%s\"!", Host );
+static void
+ArrayWrite(int fd, const array *a)
+{
+	size_t len = array_bytes(a);
+	const char *data = array_start(a);
+
+	assert(data);
+
+	if( (size_t)write(fd, data, len) != len )
+		Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!",
+							strerror(errno));
+}
+
+
+static void
+Do_ResolveAddr(const ng_ipaddr_t *Addr, int identsock, int w_fd)
+{
+	/* Resolver sub-process: resolve IP address and write result into
+	 * pipe to parent. */
+	char hostname[CLIENT_HOST_LEN];
+	char tmp_ip_str[NG_INET_ADDRSTRLEN];
+	size_t len;
+	array resolved_addr;
+
+	array_init(&resolved_addr);
+	ng_ipaddr_tostr_r(Addr, tmp_ip_str);
+#ifdef DEBUG
+	Log_Resolver(LOG_DEBUG, "Now resolving %s ...", tmp_ip_str);
 #endif
-		close(w_fd);
-		return;
+	if (!ReverseLookup(Addr, hostname, sizeof(hostname)))
+		goto dns_done;
+
+	if (ForwardLookup(hostname, &resolved_addr)) {
+		if (!Addr_in_list(&resolved_addr, Addr)) {
+			Log_Forgery_WrongIP(tmp_ip_str, hostname);
+			strlcpy(hostname, tmp_ip_str, sizeof(hostname));
+		}
+	} else {
+		Log_Forgery_NoIP(tmp_ip_str, hostname);
+		strlcpy(hostname, tmp_ip_str, sizeof(hostname));
 	}
 #ifdef DEBUG
-	Log_Resolver( LOG_DEBUG, "Ok, translated \"%s\" to %s.", Host, ip );
+	Log_Resolver(LOG_DEBUG, "Ok, translated %s to \"%s\".", tmp_ip_str, hostname);
 #endif
-	/* Write result into pipe to parent */
-	len = strlen( ip );
-	if( write( w_fd, ip, len ) != len) {
-		Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!", strerror( errno ));
-		close( w_fd );
+ dns_done:
+	len = strlen(hostname);
+	hostname[len] = '\n';
+	if (!array_copyb(&resolved_addr, hostname, ++len)) {
+		Log_Resolver(LOG_CRIT, "Resolver: Can't copy resolved name: %s!", strerror(errno));
+		array_free(&resolved_addr);
+		return;
 	}
-} /* Do_ResolveName */
 
+	Do_IdentQuery(identsock, &resolved_addr);
 
-#ifdef h_errno
+	ArrayWrite(w_fd, &resolved_addr);
 
-static char *
-Get_Error( int H_Error )
+	array_free(&resolved_addr);
+} /* Do_ResolveAddr */
+
+
+static void
+Do_ResolveName( const char *Host, int w_fd )
 {
-	/* Get error message for H_Error */
+	/* Resolver sub-process: resolve name and write result into pipe
+	 * to parent. */
+	array IpAddrs;
+#ifdef DEBUG
+	ng_ipaddr_t *addr;
+	size_t len;
+#endif
+	Log_Resolver(LOG_DEBUG, "Now resolving \"%s\" ...", Host);
 
-	switch( H_Error )
-	{
-		case HOST_NOT_FOUND:
-			return "host not found";
-		case NO_DATA:
-			return "name valid but no IP address defined";
-		case NO_RECOVERY:
-			return "name server error";
-		case TRY_AGAIN:
-			return "name server temporary not available";
-		default:
-			return "unknown error";
+	array_init(&IpAddrs);
+	/* Resolve hostname */
+	if (!ForwardLookup(Host, &IpAddrs)) {
+		close(w_fd);
+		return;
+	}
+#ifdef DEBUG
+	len = array_length(&IpAddrs, sizeof(*addr));
+	assert(len > 0);
+	addr = array_start(&IpAddrs);
+	assert(addr);
+	for (; len > 0; --len,addr++) {
+		Log_Resolver(LOG_DEBUG, "translated \"%s\" to %s.",
+					Host, ng_ipaddr_tostr(addr));
 	}
-} /* Get_Error */
-
 #endif
+	/* Write result into pipe to parent */
+	ArrayWrite(w_fd, &IpAddrs);
+
+	array_free(&IpAddrs);
+} /* Do_ResolveName */
 
 
 static bool
 register_callback( RES_STAT *s, void (*cbfunc)(int, short))
 {
-	assert(cbfunc);
+	assert(cbfunc != NULL);
 	assert(s != NULL);
 	assert(s->resolver_fd >= 0);
 
@@ -303,7 +494,8 @@ register_callback( RES_STAT *s, void (*cbfunc)(int, short))
 			return true;
 
 	Log( LOG_CRIT, "Resolver: Could not register callback function: %s!", strerror(errno));
-	Resolve_Shutdown(s);
+	close(s->resolver_fd);
+	Resolve_Init(s);
 	return false;
 }
 
@@ -323,37 +515,32 @@ Resolve_Shutdown( RES_STAT *s)
 	return ret;
 }
 
-                
+
+/**
+ * Read result of resolver sub-process from pipe
+ */
 GLOBAL size_t
 Resolve_Read( RES_STAT *s, void* readbuf, size_t buflen)
 {
-	/* Read result of resolver sub-process from pipe */
-	int err, bytes_read;
+	ssize_t bytes_read;
+
 	assert(buflen > 0);
 
 	/* Read result from pipe */
-	errno = 0;
 	bytes_read = read(s->resolver_fd, readbuf, buflen);
 	if (bytes_read < 0) {
-		if (errno != EAGAIN) {
-			err = errno;
-			Log( LOG_CRIT, "Resolver: Can't read result: %s!", strerror(err));
-			Resolve_Shutdown(s);
-			errno = err;
+		if (errno == EAGAIN)
 			return 0;
-		}
-		return 0;
-	}
 
-	Resolve_Shutdown(s);
-	if (bytes_read == 0) {	/* EOF: lookup failed */
+		Log( LOG_CRIT, "Resolver: Can't read result: %s!", strerror(errno));
+		bytes_read = 0;
+	}
 #ifdef DEBUG
+	else if (bytes_read == 0)
 		Log( LOG_DEBUG, "Resolver: Can't read result: EOF");
 #endif
-		return 0;
-	}
-
-	return bytes_read;
+	Resolve_Shutdown(s);
+	return (size_t)bytes_read;
 }
 /* -eof- */