add preliminary DoH client support to dig

add options "+https", "+https-get" and "+http-plain" to allow dig to connect over HTTP/2 channels.
2026-06-11 02:49:59 -04:00 · 2021-01-27 15:49:27 +01:00 · 2021-01-27 15:49:27 +01:00 · 9c8b7a5c45
commit 9c8b7a5c45
parent 13d23b0c8e
5 changed files with 248 additions and 108 deletions
--- a/bin/dig/dig.c
+++ b/bin/dig/dig.c
@ -228,6 +228,10 @@ help(void) {
 	       "SERVFAIL)\n"
 	       "                 +[no]header-only    (Send query without a "
 	       "question section)\n"
+	       "                 +[no]https[=###]    (DNS over HTTPS mode) "
+	       "[/]\n"
+	       "                 +[no]https-get      (Use GET instead of "
+	       "default POST method\n"
 	       "                 +[no]identify       (ID responders in short "
 	       "answers)\n"
 #ifdef HAVE_LIBIDN2
@ -348,12 +352,18 @@ received(unsigned int bytes, isc_sockaddr_t *from, dig_query_t *query) {
 		}
 		if (query->lookup->tls_mode) {
 			proto = "TLS";
+		} else if (query->lookup->https_mode) {
+			if (query->lookup->http_plain) {
+				proto = "HTTP";
+			} else {
+				proto = "HTTPS";
+			}
 		} else if (query->lookup->tcp_mode) {
 			proto = "TCP";
 		} else {
 			proto = "UDP";
 		}
-		printf(";; SERVER: %s(%s) (%s)\n", fromtext, query->servname,
+		printf(";; SERVER: %s(%s) (%s)\n", fromtext, query->userarg,
 		       proto);
 		time(&tnow);
 		(void)localtime_r(&tnow, &tmnow);
@ -1066,6 +1076,17 @@ plus_option(char *option, bool is_batchfile, bool *need_clone,
 		    (_l >= sizeof(B) || strncasecmp(cmd, B, _l) != 0))   \
 			goto invalid_option;                             \
 	} while (0)
+#define FULLCHECK6(A, B, C, D, E, F)                                     \
+	do {                                                             \
+		size_t _l = strlen(cmd);                                 \
+		if ((_l >= sizeof(A) || strncasecmp(cmd, A, _l) != 0) && \
+		    (_l >= sizeof(B) || strncasecmp(cmd, B, _l) != 0) && \
+		    (_l >= sizeof(C) || strncasecmp(cmd, C, _l) != 0) && \
+		    (_l >= sizeof(D) || strncasecmp(cmd, D, _l) != 0) && \
+		    (_l >= sizeof(E) || strncasecmp(cmd, E, _l) != 0) && \
+		    (_l >= sizeof(F) || strncasecmp(cmd, F, _l) != 0))   \
+			goto invalid_option;                             \
+	} while (0)

 	switch (cmd[0]) {
 	case 'a':
@ -1412,8 +1433,78 @@ plus_option(char *option, bool is_batchfile, bool *need_clone,
 		lookup->servfail_stops = state;
 		break;
 	case 'h':
-		FULLCHECK("header-only");
-		lookup->header_only = state;
+		switch (cmd[1]) {
+		case 'e': /* header-only */
+			FULLCHECK("header-only");
+			lookup->header_only = state;
+			break;
+		case 't':
+			FULLCHECK6("https", "https-get", "https-post",
+				   "http-plain", "http-plain-get",
+				   "http-plain-post");
+			if (lookup->https_path != NULL) {
+				isc_mem_free(mctx, lookup->https_path);
+				lookup->https_path = NULL;
+			}
+			if (!state) {
+				lookup->https_mode = false;
+				break;
+			}
+			lookup->https_mode = true;
+			if (cmd[4] == '-') {
+				lookup->http_plain = true;
+				switch (cmd[10]) {
+				case '\0':
+					FULLCHECK("http-plain");
+					break;
+				case '-':
+					switch (cmd[6]) {
+					case 'p':
+						FULLCHECK("https-plain-post");
+						break;
+					case 'g':
+						FULLCHECK("https-plain-get");
+						lookup->https_get = true;
+						break;
+					}
+					break;
+				default:
+					goto invalid_option;
+				}
+			} else {
+				switch (cmd[5]) {
+				case '\0':
+					FULLCHECK("https");
+					break;
+				case '-':
+					switch (cmd[6]) {
+					case 'p':
+						FULLCHECK("https-post");
+						break;
+					case 'g':
+						FULLCHECK("https-get");
+						lookup->https_get = true;
+						break;
+					}
+					break;
+				default:
+					goto invalid_option;
+				}
+			}
+			if (!lookup->tcp_mode_set) {
+				lookup->tcp_mode = state;
+			}
+			if (value == NULL) {
+				lookup->https_path = isc_mem_strdup(
+					mctx, DEFAULT_HTTPS_PATH);
+			} else {
+				lookup->https_path = isc_mem_strdup(mctx,
+								    value);
+			}
+			break;
+		default:
+			goto invalid_option;
+		}
 		break;
 	case 'i':
 		switch (cmd[1]) {
--- a/bin/dig/dig.rst
+++ b/bin/dig/dig.rst
@ -349,11 +349,38 @@ abbreviation is unambiguous; for example, ``+cd`` is equivalent to
   default is to add a question section. The query type and query name
   are ignored when this is set.

+``+[no]https[=value]``
+   This option indicates whether to use DNS-over-HTTPS (DoH) when querying
+   name servers.  When this option is in use, the port number defaults to 443.
+   The HTTP POST request mode is used when sending the query.
+
+   If ``value`` is specified, it will be used as the HTTP endpoint in the
+   query URI; the default is ``/dns-query``. So, for example, ``dig
+   @example.com +https`` will use the URI ``https://example.com/dns-query``.
+
+``+[no]https-get[=value]``
+   Similar to ``+https``, except that the HTTP GET request mode is used
+   when sending the query.
+
+``+[no]https-post[=value]``
+   Same as ``+https``.
+
+``+[no]http-plain[=value]``
+   Similar to ``+https``, except that HTTP queries will be sent over a
+   non-encrypted channel. When this option is in use, the port number
+   defaults to 80 and the HTTP request mode is POST.
+
+``+[no]http-plain-get[=value]``
+   Similar to ``+http-plain``, except that the HTTP request mode is GET.
+
+``+[no]http-plain-post[=value]``
+   Same as ``+http-plain``.
+
 ``+[no]identify``
-   This option shows [or does not show] the IP address and port number that supplied
-   the answer, when the ``+short`` option is enabled. If short form
-   answers are requested, the default is not to show the source address
-   and port number of the server that provided the answer.
+   This option shows [or does not show] the IP address and port number that
+   supplied the answer, when the ``+short`` option is enabled. If short
+   form answers are requested, the default is not to show the source
+   address and port number of the server that provided the answer.

 ``+[no]idnin``
   This option processes [or does not process] IDN domain names on input. This requires
@ -519,8 +546,9 @@ abbreviation is unambiguous; for example, ``+cd`` is equivalent to
   5 seconds. An attempt to set ``T`` to less than 1 is silently set to 1.

 ``+[no]tls``
-   This option indicates whether to use DNS over TLS (DoT) when querying
-   name servers.
+   This option indicates whether to use DNS-over-TLS (DoT) when querying
+   name servers. When this option is in use, the port number defaults
+   to 853.

 ``+[no]topdown``
   This feature is related to ``dig +sigchase``, which is obsolete and
--- a/bin/dig/dighost.c
+++ b/bin/dig/dighost.c
@ -603,102 +603,43 @@ clone_server_list(dig_serverlist_t src, dig_serverlist_t *dest) {
 dig_lookup_t *
 make_empty_lookup(void) {
 	dig_lookup_t *looknew;
+#ifdef HAVE_LIBIDN2
+	bool idn_allowed = isatty(1) ? (getenv("IDN_DISABLE") == NULL) : false;
+#endif /* HAVE_LIBIDN2 */

 	debug("make_empty_lookup()");

 	INSIST(!free_now);

-	looknew = isc_mem_allocate(mctx, sizeof(struct dig_lookup));
-	looknew->pending = true;
-	looknew->textname[0] = 0;
-	looknew->cmdline[0] = 0;
-	looknew->rdtype = dns_rdatatype_a;
-	looknew->qrdtype = dns_rdatatype_a;
-	looknew->rdclass = dns_rdataclass_in;
-	looknew->rdtypeset = false;
-	looknew->rdclassset = false;
-	looknew->sendspace = NULL;
-	looknew->sendmsg = NULL;
-	looknew->name = NULL;
-	looknew->oname = NULL;
-	looknew->xfr_q = NULL;
-	looknew->current_query = NULL;
-	looknew->doing_xfr = false;
-	looknew->ixfr_serial = 0;
-	looknew->trace = false;
-	looknew->trace_root = false;
-	looknew->identify = false;
-	looknew->identify_previous_line = false;
-	looknew->ignore = false;
-	looknew->servfail_stops = true;
-	looknew->besteffort = true;
-	looknew->dns64prefix = false;
-	looknew->dnssec = false;
-	looknew->ednsflags = 0;
-	looknew->opcode = dns_opcode_query;
-	looknew->expire = false;
-	looknew->nsid = false;
-	looknew->tcp_keepalive = false;
-	looknew->padding = 0;
-	looknew->header_only = false;
-	looknew->sendcookie = false;
-	looknew->seenbadcookie = false;
-	looknew->badcookie = true;
-	looknew->multiline = false;
-	looknew->nottl = false;
-	looknew->noclass = false;
-	looknew->onesoa = false;
-	looknew->use_usec = false;
-	looknew->nocrypto = false;
-	looknew->ttlunits = false;
-	looknew->expandaaaa = false;
-	looknew->qr = false;
+	looknew = isc_mem_allocate(mctx, sizeof(*looknew));
+	*looknew = (dig_lookup_t){
+		.pending = true,
+		.rdtype = dns_rdatatype_a,
+		.qrdtype = dns_rdatatype_a,
+		.rdclass = dns_rdataclass_in,
+		.servfail_stops = true,
+		.besteffort = true,
+		.opcode = dns_opcode_query,
+		.badcookie = true,
 #ifdef HAVE_LIBIDN2
-	looknew->idnin = isatty(1) ? (getenv("IDN_DISABLE") == NULL) : false;
-	looknew->idnout = looknew->idnin;
-#else  /* ifdef HAVE_LIBIDN2 */
-	looknew->idnin = false;
-	looknew->idnout = false;
+		.idnin = idn_allowed,
+		.idnout = idn_allowed,
 #endif /* HAVE_LIBIDN2 */
-	looknew->udpsize = -1;
-	looknew->edns = -1;
-	looknew->recurse = true;
-	looknew->aaonly = false;
-	looknew->adflag = false;
-	looknew->cdflag = false;
-	looknew->raflag = false;
-	looknew->tcflag = false;
-	looknew->print_unknown_format = false;
-	looknew->zflag = false;
-	looknew->setqid = false;
-	looknew->qid = 0;
-	looknew->ns_search_only = false;
-	looknew->origin = NULL;
-	looknew->tsigctx = NULL;
-	looknew->querysig = NULL;
-	looknew->retries = tries;
-	looknew->nsfound = 0;
-	looknew->tcp_mode = false;
-	looknew->tcp_mode_set = false;
-	looknew->tls_mode = false;
-	looknew->comments = true;
-	looknew->stats = true;
-	looknew->section_question = true;
-	looknew->section_answer = true;
-	looknew->section_authority = true;
-	looknew->section_additional = true;
-	looknew->new_search = false;
-	looknew->done_as_is = false;
-	looknew->need_search = false;
-	looknew->ecs_addr = NULL;
-	looknew->cookie = NULL;
-	looknew->ednsopts = NULL;
-	looknew->ednsoptscnt = 0;
-	looknew->ednsneg = true;
-	looknew->mapped = true;
-	looknew->dscp = -1;
-	looknew->rrcomments = 0;
-	looknew->eoferr = 0;
+		.udpsize = -1,
+		.edns = -1,
+		.recurse = true,
+		.retries = tries,
+		.comments = true,
+		.stats = true,
+		.section_question = true,
+		.section_answer = true,
+		.section_authority = true,
+		.section_additional = true,
+		.ednsneg = true,
+		.mapped = true,
+		.dscp = -1,
+	};
+
 	dns_fixedname_init(&looknew->fdomain);
 	ISC_LINK_INIT(looknew, link);
 	ISC_LIST_INIT(looknew->q);
@ -787,6 +728,12 @@ clone_lookup(dig_lookup_t *lookold, bool servers) {
 	looknew->nsid = lookold->nsid;
 	looknew->tcp_keepalive = lookold->tcp_keepalive;
 	looknew->header_only = lookold->header_only;
+	looknew->https_mode = lookold->https_mode;
+	if (lookold->https_path != NULL) {
+		looknew->https_path = isc_mem_strdup(mctx, lookold->https_path);
+	}
+	looknew->https_get = lookold->https_get;
+	looknew->http_plain = lookold->http_plain;
 	looknew->sendcookie = lookold->sendcookie;
 	looknew->seenbadcookie = lookold->seenbadcookie;
 	looknew->badcookie = lookold->badcookie;
@ -1638,6 +1585,10 @@ _destroy_lookup(dig_lookup_t *lookup) {
 		isc_mem_free(mctx, lookup->ednsopts);
 	}

+	if (lookup->https_path) {
+		isc_mem_free(mctx, lookup->https_path);
+	}
+
 	isc_mem_free(mctx, lookup);
 }

@ -2760,7 +2711,20 @@ start_tcp(dig_query_t *query) {
 	 * For TLS connections, we want to override the default
 	 * port number.
 	 */
-	port = port_set ? port : (query->lookup->tls_mode ? 853 : 53);
+	if (!port_set) {
+		if (query->lookup->tls_mode) {
+			port = 853;
+		} else if (query->lookup->https_mode &&
+			   !query->lookup->http_plain) {
+			port = 443;
+		} else if (query->lookup->https_mode) {
+			port = 80;
+		} else {
+			port = 53;
+		}
+	}
+
+	debug("query->servname = %s\n", query->servname);

 	result = get_address(query->servname, port, &query->sockaddr);
 	if (result != ISC_R_SUCCESS) {
@ -2835,7 +2799,27 @@ start_tcp(dig_query_t *query) {
 				(isc_nmiface_t *)&query->sockaddr,
 				tcp_connected, query, local_timeout, 0,
 				query->tlsctx);
-			check_result(result, "isc_nm_tcpdnsconnect");
+			check_result(result, "isc_nm_tlsdnsconnect");
+		} else if (query->lookup->https_mode) {
+			char uri[4096] = { 0 };
+			snprintf(uri, sizeof(uri), "https://%s:%u%s",
+				 query->userarg, (uint16_t)port,
+				 query->lookup->https_path);
+
+			if (!query->lookup->http_plain) {
+				result =
+					isc_tlsctx_createclient(&query->tlsctx);
+				RUNTIME_CHECK(result == ISC_R_SUCCESS);
+				isc_tlsctx_enable_http2client_alpn(
+					query->tlsctx);
+			}
+
+			result = isc_nm_httpconnect(
+				netmgr, (isc_nmiface_t *)&localaddr,
+				(isc_nmiface_t *)&query->sockaddr, uri,
+				!query->lookup->https_get, tcp_connected, query,
+				query->tlsctx, local_timeout, 0);
+			check_result(result, "isc_nm_httpconnect");
 		} else {
 			result = isc_nm_tcpdnsconnect(
 				netmgr, (isc_nmiface_t *)&localaddr,
@ -3211,6 +3195,7 @@ launch_next_query(dig_query_t *query) {
 			}
 		}
 	}
+
 	lookup_detach(&l);
 	return;
 }
@ -3582,8 +3567,7 @@ recv_done(isc_nmhandle_t *handle, isc_result_t eresult, isc_region_t *region,
 	isc_sockaddr_t peer;

 	REQUIRE(DIG_VALID_QUERY(query));
-	INSIST(query->readhandle != NULL);
-	INSIST(handle == query->readhandle);
+	REQUIRE(query->readhandle != NULL);
 	INSIST(!free_now);

 	debug("recv_done(%p, %s, %p, %p)", handle, isc_result_totext(eresult),
--- a/bin/dig/dighost.h
+++ b/bin/dig/dighost.h
@ -76,6 +76,9 @@
 #define DEFAULT_EDNS_VERSION 0
 #define DEFAULT_EDNS_BUFSIZE 1232

+#define DEFAULT_HTTPS_PATH  "/dns-query"
+#define DEFAULT_HTTPS_QUERY "?dns="
+
 /*%
 * Lookup_limit is just a limiter, keeping too many lookups from being
 * created.  It's job is mainly to prevent the program from running away
@ -168,6 +171,12 @@ struct dig_lookup {
 	int rrcomments;
 	unsigned int eoferr;
 	uint16_t qid;
+	struct {
+		bool http_plain;
+		bool https_mode;
+		bool https_get;
+		char *https_path;
+	};
 };

 /*% The dig_query structure */
--- a/doc/man/dig.1in
+++ b/doc/man/dig.1in
@ -361,11 +361,38 @@ This option sends a query with a DNS header without a question section. The
 default is to add a question section. The query type and query name
 are ignored when this is set.
 .TP
+.B \fB+[no]https[=value]\fP
+This option indicates whether to use DNS\-over\-HTTPS (DoH) when querying
+name servers.  When this option is in use, the port number defaults to 443.
+The HTTP POST request mode is used when sending the query.
+.sp
+If \fBvalue\fP is specified, it will be used as the HTTP endpoint in the
+query URI; the default is \fB/dns\-query\fP\&. So, for example, \fBdig
+@example.com +https\fP will use the URI \fBhttps://example.com/dns\-query\fP\&.
+.TP
+.B \fB+[no]https\-get[=value]\fP
+Similar to \fB+https\fP, except that the HTTP GET request mode is used
+when sending the query.
+.TP
+.B \fB+[no]https\-post[=value]\fP
+Same as \fB+https\fP\&.
+.TP
+.B \fB+[no]http\-plain[=value]\fP
+Similar to \fB+https\fP, except that HTTP queries will be sent over a
+non\-encrypted channel. When this option is in use, the port number
+defaults to 80 and the HTTP request mode is POST.
+.TP
+.B \fB+[no]http\-plain\-get[=value]\fP
+Similar to \fB+http\-plain\fP, except that the HTTP request mode is GET.
+.TP
+.B \fB+[no]http\-plain\-post[=value]\fP
+Same as \fB+http\-plain\fP\&.
+.TP
 .B \fB+[no]identify\fP
-This option shows [or does not show] the IP address and port number that supplied
-the answer, when the \fB+short\fP option is enabled. If short form
-answers are requested, the default is not to show the source address
-and port number of the server that provided the answer.
+This option shows [or does not show] the IP address and port number that
+supplied the answer, when the \fB+short\fP option is enabled. If short
+form answers are requested, the default is not to show the source
+address and port number of the server that provided the answer.
 .TP
 .B \fB+[no]idnin\fP
 This option processes [or does not process] IDN domain names on input. This requires
@ -531,8 +558,9 @@ This option sets the timeout for a query to \fBT\fP seconds. The default timeout
 5 seconds. An attempt to set \fBT\fP to less than 1 is silently set to 1.
 .TP
 .B \fB+[no]tls\fP
-This option indicates whether to use DNS over TLS (DoT) when querying
-name servers.
+This option indicates whether to use DNS\-over\-TLS (DoT) when querying
+name servers. When this option is in use, the port number defaults
+to 853.
 .TP
 .B \fB+[no]topdown\fP
 This feature is related to \fBdig +sigchase\fP, which is obsolete and