sync with OpenBSD -current

lib/libc/asr/asr_private.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: asr_private.h,v 1.48 2022/11/17 17:39:41 florian Exp $	*/
+/*	$OpenBSD: asr_private.h,v 1.49 2023/11/20 12:15:16 florian Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -299,6 +299,7 @@ int _asr_sockaddr_from_str(struct sockaddr *, int, const char *);
 ssize_t _asr_dname_from_fqdn(const char *, char *, size_t);
 ssize_t _asr_addr_as_fqdn(const char *, int, char *, size_t);
 int hnok_lenient(const char *);
+int _asr_is_localhost(const char*);
 
 /* asr.c */
 void _asr_resolver_done(void *);

lib/libc/asr/asr_utils.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: asr_utils.c,v 1.21 2023/03/15 22:12:00 millert Exp $	*/
+/*	$OpenBSD: asr_utils.c,v 1.22 2023/11/20 12:15:16 florian Exp $	*/
 /*
  * Copyright (c) 2009-2012	Eric Faurot	<eric@faurot.net>
  *
@@ -582,3 +582,35 @@ hnok_lenient(const char *dn)
 	}
 	return 1;
 }
+
+/* Check if the hostname is localhost or if it's in the localhost domain */
+int
+_asr_is_localhost(const char *hn)
+{
+	size_t	 hnlen, localhostlen;
+
+	if (hn == NULL)
+		return 0;
+
+	if (strcasecmp(hn, "localhost") == 0 ||
+	    strcasecmp(hn, "localhost.") == 0)
+		return 1;
+
+	hnlen = strlen(hn);
+	localhostlen = strlen(".localhost");
+
+	if (hnlen < localhostlen)
+		return 0;
+
+	if (strcasecmp(hn + hnlen - localhostlen, ".localhost") == 0)
+		return 1;
+
+	localhostlen++;
+	if (hnlen < localhostlen)
+		return 0;
+
+	if (strcasecmp(hn + hnlen - localhostlen, ".localhost.") == 0)
+		return 1;
+
+	return 0;
+}

lib/libc/asr/getaddrinfo_async.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: getaddrinfo_async.c,v 1.59 2022/12/27 17:10:06 jmc Exp $	*/
+/*	$OpenBSD: getaddrinfo_async.c,v 1.60 2023/11/20 12:15:16 florian Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -115,7 +115,7 @@ getaddrinfo_async_run(struct asr_query *as, struct asr_result *ar)
 	char		 fqdn[MAXDNAME];
 	const char	*str;
 	struct addrinfo	*ai;
-	int		 i, family, r;
+	int		 i, family, r, is_localhost;
 	FILE		*f;
 	union {
 		struct sockaddr		sa;
@@ -228,8 +228,19 @@ getaddrinfo_async_run(struct asr_query *as, struct asr_result *ar)
 
 		ar->ar_gai_errno = 0;
 
-		/* If hostname is NULL, use local address */
-		if (as->as.ai.hostname == NULL) {
+		is_localhost = _asr_is_localhost(as->as.ai.hostname);
+		/*
+		 * If hostname is NULL, "localhost" or falls within the
+		 * ".localhost." domain, use local address.
+		 * RFC 6761, 6.3:
+		 * 3. Name resolution APIs and libraries SHOULD recognize
+		 * localhost names as special and SHOULD always return the IP
+		 * loopback address for address queries and negative responses
+		 * for all other query types.  Name resolution APIs SHOULD NOT
+		 * send queries for localhost names to their configured caching
+		 * DNS server(s).
+		 */
+		if (as->as.ai.hostname == NULL || is_localhost) {
 			for (family = iter_family(as, 1);
 			    family != -1;
 			    family = iter_family(as, 0)) {
@@ -238,11 +249,12 @@ getaddrinfo_async_run(struct asr_query *as, struct asr_result *ar)
 				 * those, rather than parsing over and over.
 				 */
 				if (family == PF_INET)
-					str = (ai->ai_flags & AI_PASSIVE) ? \
-						"0.0.0.0" : "127.0.0.1";
+					str = (ai->ai_flags & AI_PASSIVE &&
+					    !is_localhost) ? "0.0.0.0" :
+					    "127.0.0.1";
 				else /* PF_INET6 */
-					str = (ai->ai_flags & AI_PASSIVE) ? \
-						"::" : "::1";
+					str = (ai->ai_flags & AI_PASSIVE &&
+					    !is_localhost) ? "::" : "::1";
 				 /* This can't fail */
 				_asr_sockaddr_from_str(&sa.sa, family, str);
 				if ((r = addrinfo_add(as, &sa.sa, NULL))) {

lib/libc/asr/gethostnamadr_async.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: gethostnamadr_async.c,v 1.47 2023/11/14 08:27:33 florian Exp $	*/
+/*	$OpenBSD: gethostnamadr_async.c,v 1.48 2023/11/20 12:15:16 florian Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -209,6 +209,37 @@ gethostnamadr_async_run(struct asr_query *as, struct asr_result *ar)
 				async_set_state(as, ASR_STATE_HALT);
 				break;
 			}
+
+			/*
+			 * If hostname is "localhost" or falls within the
+			 * ".localhost." domain, use local address.
+			 * RFC 6761, 6.3:
+			 * 3. Name resolution APIs and libraries SHOULD
+			 * recognize localhost names as special and SHOULD
+			 * always return the IP loopback address for address
+			 * queries and negative responses for all other query
+			 * types.  Name resolution APIs SHOULD NOT send queries
+			 * for localhost names to their configured caching DNS
+			 * server(s).
+			 */
+
+			if (_asr_is_localhost(as->as.hostnamadr.name)) {
+				inet_pton(as->as.hostnamadr.family,
+				    as->as.hostnamadr.family == AF_INET ?
+				    "127.0.0.1" : "::1", addr);
+				h = hostent_from_addr(as->as.hostnamadr.family,
+				    as->as.hostnamadr.name, addr);
+				if (h == NULL) {
+					ar->ar_errno = errno;
+					ar->ar_h_errno = NETDB_INTERNAL;
+				}
+				else {
+					ar->ar_hostent = &h->h;
+					ar->ar_h_errno = NETDB_SUCCESS;
+				}
+				async_set_state(as, ASR_STATE_HALT);
+				break;
+			}
 		}
 		async_set_state(as, ASR_STATE_NEXT_DB);
 		break;