X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/0cd2f40764dd156de309f7536f3867968b6c0fdd..fcb69e5cdcfdfd0bdcea2127e5f4c9133a2282b9:/clientname.c

diff --git a/clientname.c b/clientname.c
index aedf05e7..e1aeb35b 100644
--- a/clientname.c
+++ b/clientname.c
@@ -74,6 +74,9 @@ static int get_sockaddr_family(const struct sockaddr_storage *ss)
  * If anything goes wrong, including the name->addr->name check, then
  * we just use "UNKNOWN", so you can use that value in hosts allow
  * lines.
+ *
+ * After translation from sockaddr to name we do a forward lookup to
+ * make sure nobody is spoofing PTR records.
  **/
 char *client_name(int fd)
 {
@@ -90,8 +93,9 @@ char *client_name(int fd)
 
 	client_sockaddr(fd, &ss, &ss_len);
 
-	if (!lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf, port_buf, sizeof port_buf))
-		check_name(fd, &ss, ss_len, name_buf, port_buf);
+	if (!lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf,
+			 port_buf, sizeof port_buf))
+		check_name(fd, &ss, name_buf);
 
 	return name_buf;
 }
@@ -99,7 +103,10 @@ char *client_name(int fd)
 
 
 /**
- * Get the sockaddr for the client.  
+ * Get the sockaddr for the client.
+ *
+ * If it comes in as an ipv4 address mapped into IPv6 format then we
+ * convert it back to a regular IPv4.
  **/
 void client_sockaddr(int fd,
 		     struct sockaddr_storage *ss,
@@ -146,6 +153,8 @@ void client_sockaddr(int fd,
 
 /**
  * Look up a name from @p ss into @p name_buf.
+ *
+ * @param fd file descriptor for client socket.
  **/
 int lookup_name(int fd, const struct sockaddr_storage *ss,
 		socklen_t ss_len,
@@ -172,58 +181,89 @@ int lookup_name(int fd, const struct sockaddr_storage *ss,
 
 
 
-/* Do a forward lookup on name_buf and make sure it corresponds to ss
- * -- otherwise we may be being spoofed.  If we suspect we are, then
- * we don't abort the connection but just emit a warning. */
+/**
+ * Compare an addrinfo from the resolver to a sockinfo.
+ *
+ * Like strcmp, returns 0 for identical.
+ **/
+int compare_addrinfo_sockaddr(const struct addrinfo *ai,
+			      const struct sockaddr_storage *ss)
+{
+	int ss_family = get_sockaddr_family(ss);
+	const char fn[] = "compare_addrinfo_sockaddr";
+		      
+	if (ai->ai_family != ss_family) {
+		rprintf(FERROR,
+			"%s: response family %d != %d\n",
+			fn, ai->ai_family, ss_family);
+		return 1;
+	}
+
+	/* The comparison method depends on the particular AF. */
+	if (ss_family == AF_INET) {
+		const struct sockaddr_in *sin1, *sin2;
+
+		sin1 = (const struct sockaddr_in *) ss;
+		sin2 = (const struct sockaddr_in *) ai->ai_addr;
+		
+		return memcmp(&sin1->sin_addr, &sin2->sin_addr,
+			      sizeof sin1->sin_addr);
+	}
+#ifdef INET6
+	else if (ss_family == AF_INET6) {
+		const struct sockaddr_in6 *sin1, *sin2;
+
+		sin1 = (const struct sockaddr_in6 *) ss;
+		sin2 = (const struct sockaddr_in6 *) ai->ai_addr;
+		
+		return memcmp(&sin1->sin6_addr, &sin2->sin6_addr,
+			      sizeof sin1->sin6_addr);
+	}
+#endif /* INET6 */
+	else {
+		/* don't know */
+		return 1;
+	}
+}
+
+
+/**
+ * Do a forward lookup on @p name_buf and make sure it corresponds to
+ * @p ss -- otherwise we may be being spoofed.  If we suspect we are,
+ * then we don't abort the connection but just emit a warning, and
+ * change @p name_buf to be "UNKNOWN".
+ *
+ * We don't do anything with the service when checking the name,
+ * because it doesn't seem that it could be spoofed in any way, and
+ * getaddrinfo on random service names seems to cause problems on AIX.
+ **/
 int check_name(int fd,
 	       const struct sockaddr_storage *ss,
-	       socklen_t ss_len,
-	       char *name_buf,
-	       const char *port_buf)
+	       char *name_buf)
 {
 	struct addrinfo hints, *res, *res0;
 	int error;
 	int ss_family = get_sockaddr_family(ss);
 
 	memset(&hints, 0, sizeof(hints));
-	hints.ai_family = PF_UNSPEC;
-	hints.ai_flags = ss_family;
+	hints.ai_family = ss_family;
+	hints.ai_flags = AI_CANONNAME;
 	hints.ai_socktype = SOCK_STREAM;
-	error = getaddrinfo(name_buf, port_buf, &hints, &res0);
+	error = getaddrinfo(name_buf, NULL, &hints, &res0);
 	if (error) {
 		rprintf(FERROR,
-			RSYNC_NAME ": forward name lookup for %s:%s failed: %s\n",
-			name_buf, port_buf,
-			gai_strerror(error));
+			RSYNC_NAME ": forward name lookup for %s failed: %s\n",
+			name_buf, gai_strerror(error));
 		strcpy(name_buf, default_name);
 		return error;
 	}
 
 
-	/* We expect that one of the results will be the same as ss. */
+	/* Given all these results, we expect that one of them will be
+	 * the same as ss.  The comparison is a bit complicated. */
 	for (res = res0; res; res = res->ai_next) {
-		if (res->ai_family != ss_family) {
-			rprintf(FERROR,
-				"check_name: response family %d != %d\n",
-				res->ai_family, ss_family);
-			continue;
-		}
-		if (res->ai_addrlen != ss_len) {
-			rprintf(FERROR,
-				"check_name: addrlen %d != %d\n",
-				res->ai_addrlen, ss_len);
-			continue;
-		}
-		if (memcmp(res->ai_addr, ss, res->ai_addrlen) == 0) {
-			rprintf(FERROR,
-				"check_name: %d bytes of address identical\n",
-				res->ai_addrlen);
-			break;
-		} else{
-			rprintf(FERROR,
-				"check_name: %d bytes of address NOT identical\n",
-				res->ai_addrlen);
-		}
+		if (!compare_addrinfo_sockaddr(res, ss))
+			break;	/* OK, identical */
 	}
 
 	if (!res0) {
@@ -234,8 +274,7 @@ int check_name(int fd,
 			"spoofed address?\n",
 			name_buf);
 		strcpy(name_buf, default_name);
-	}
-	if (res == NULL) {
+	} else if (res == NULL) {
 		/* We hit the end of the list without finding an
 		 * address that was the same as ss. */
 		rprintf(FERROR, RSYNC_NAME