From 48039fa25e081ce743f62ca2d074c06a5d15fc6b Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Tue, 22 Feb 2022 12:27:17 +1100
Subject: [PATCH] Do not return ISC_R_UNEXPECTEDEND

All rdata passed to dns_rdata_tostruct is supposed to be well formed,
assert if it isn't.
---
 lib/dns/rdata/generic/caa_257.c     | 10 +---------
 lib/dns/rdata/generic/doa_259.c     | 14 +-------------
 lib/dns/rdata/generic/ipseckey_45.c |  5 +----
 lib/dns/rdata/generic/key_25.c      | 11 +----------
 lib/dns/rdata/generic/sink_40.c     |  9 ---------
 lib/dns/rdata/generic/uri_256.c     |  8 +-------
 6 files changed, 5 insertions(+), 52 deletions(-)

diff --git a/lib/dns/rdata/generic/caa_257.c b/lib/dns/rdata/generic/caa_257.c
index eac735fc6b..6b9431634b 100644
--- a/lib/dns/rdata/generic/caa_257.c
+++ b/lib/dns/rdata/generic/caa_257.c
@@ -507,27 +507,19 @@ tostruct_caa(ARGS_TOSTRUCT) {
 	/*
 	 * Flags
 	 */
-	if (sr.length < 1) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	caa->flags = uint8_fromregion(&sr);
 	isc_region_consume(&sr, 1);
 
 	/*
 	 * Tag length
 	 */
-	if (sr.length < 1) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	caa->tag_len = uint8_fromregion(&sr);
 	isc_region_consume(&sr, 1);
 
 	/*
 	 * Tag
 	 */
-	if (sr.length < caa->tag_len) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
+	INSIST(sr.length >= caa->tag_len);
 	caa->tag = mem_maybedup(mctx, sr.base, caa->tag_len);
 	isc_region_consume(&sr, caa->tag_len);
 
diff --git a/lib/dns/rdata/generic/doa_259.c b/lib/dns/rdata/generic/doa_259.c
index d7c6129dd8..78e8b7b863 100644
--- a/lib/dns/rdata/generic/doa_259.c
+++ b/lib/dns/rdata/generic/doa_259.c
@@ -213,7 +213,7 @@ tostruct_doa(ARGS_TOSTRUCT) {
 	REQUIRE(rdata != NULL);
 	REQUIRE(rdata->type == dns_rdatatype_doa);
 	REQUIRE(doa != NULL);
-	REQUIRE(rdata->length != 0);
+	REQUIRE(rdata->length >= 10);
 
 	doa->common.rdclass = rdata->rdclass;
 	doa->common.rdtype = rdata->type;
@@ -224,36 +224,24 @@ tostruct_doa(ARGS_TOSTRUCT) {
 	/*
 	 * DOA-ENTERPRISE
 	 */
-	if (region.length < 4) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	doa->enterprise = uint32_fromregion(&region);
 	isc_region_consume(&region, 4);
 
 	/*
 	 * DOA-TYPE
 	 */
-	if (region.length < 4) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	doa->type = uint32_fromregion(&region);
 	isc_region_consume(&region, 4);
 
 	/*
 	 * DOA-LOCATION
 	 */
-	if (region.length < 1) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	doa->location = uint8_fromregion(&region);
 	isc_region_consume(&region, 1);
 
 	/*
 	 * DOA-MEDIA-TYPE
 	 */
-	if (region.length < 1) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	doa->mediatype_len = uint8_fromregion(&region);
 	isc_region_consume(&region, 1);
 	INSIST(doa->mediatype_len <= region.length);
diff --git a/lib/dns/rdata/generic/ipseckey_45.c b/lib/dns/rdata/generic/ipseckey_45.c
index 2813818086..33a8ca1894 100644
--- a/lib/dns/rdata/generic/ipseckey_45.c
+++ b/lib/dns/rdata/generic/ipseckey_45.c
@@ -353,10 +353,6 @@ tostruct_ipseckey(ARGS_TOSTRUCT) {
 	REQUIRE(ipseckey != NULL);
 	REQUIRE(rdata->length >= 3);
 
-	if (rdata->data[1] > 3U) {
-		return (ISC_R_NOTIMPLEMENTED);
-	}
-
 	ipseckey->common.rdclass = rdata->rdclass;
 	ipseckey->common.rdtype = rdata->type;
 	ISC_LINK_INIT(&ipseckey->common, link);
@@ -384,6 +380,7 @@ tostruct_ipseckey(ARGS_TOSTRUCT) {
 		break;
 
 	case 2:
+		INSIST(region.length >= 16U);
 		memmove(ipseckey->in6_addr.s6_addr, region.base, 16);
 		isc_region_consume(&region, 16);
 		break;
diff --git a/lib/dns/rdata/generic/key_25.c b/lib/dns/rdata/generic/key_25.c
index 688b6684ec..7c13af60c0 100644
--- a/lib/dns/rdata/generic/key_25.c
+++ b/lib/dns/rdata/generic/key_25.c
@@ -322,7 +322,7 @@ generic_tostruct_key(ARGS_TOSTRUCT) {
 	isc_region_t sr;
 
 	REQUIRE(key != NULL);
-	REQUIRE(rdata->length != 0);
+	REQUIRE(rdata->length >= 4U);
 
 	REQUIRE(key != NULL);
 	REQUIRE(key->common.rdclass == rdata->rdclass);
@@ -332,23 +332,14 @@ generic_tostruct_key(ARGS_TOSTRUCT) {
 	dns_rdata_toregion(rdata, &sr);
 
 	/* Flags */
-	if (sr.length < 2) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	key->flags = uint16_fromregion(&sr);
 	isc_region_consume(&sr, 2);
 
 	/* Protocol */
-	if (sr.length < 1) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	key->protocol = uint8_fromregion(&sr);
 	isc_region_consume(&sr, 1);
 
 	/* Algorithm */
-	if (sr.length < 1) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	key->algorithm = uint8_fromregion(&sr);
 	isc_region_consume(&sr, 1);
 
diff --git a/lib/dns/rdata/generic/sink_40.c b/lib/dns/rdata/generic/sink_40.c
index 38104cf90c..d0c5825d92 100644
--- a/lib/dns/rdata/generic/sink_40.c
+++ b/lib/dns/rdata/generic/sink_40.c
@@ -191,23 +191,14 @@ tostruct_sink(ARGS_TOSTRUCT) {
 	dns_rdata_toregion(rdata, &sr);
 
 	/* Meaning */
-	if (sr.length < 1) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	sink->meaning = uint8_fromregion(&sr);
 	isc_region_consume(&sr, 1);
 
 	/* Coding */
-	if (sr.length < 1) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	sink->coding = uint8_fromregion(&sr);
 	isc_region_consume(&sr, 1);
 
 	/* Subcoding */
-	if (sr.length < 1) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	sink->subcoding = uint8_fromregion(&sr);
 	isc_region_consume(&sr, 1);
 
diff --git a/lib/dns/rdata/generic/uri_256.c b/lib/dns/rdata/generic/uri_256.c
index a613e4d9bb..0e1bb00604 100644
--- a/lib/dns/rdata/generic/uri_256.c
+++ b/lib/dns/rdata/generic/uri_256.c
@@ -209,7 +209,7 @@ tostruct_uri(ARGS_TOSTRUCT) {
 
 	REQUIRE(rdata->type == dns_rdatatype_uri);
 	REQUIRE(uri != NULL);
-	REQUIRE(rdata->length != 0);
+	REQUIRE(rdata->length >= 4);
 
 	uri->common.rdclass = rdata->rdclass;
 	uri->common.rdtype = rdata->type;
@@ -220,18 +220,12 @@ tostruct_uri(ARGS_TOSTRUCT) {
 	/*
 	 * Priority
 	 */
-	if (sr.length < 2) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	uri->priority = uint16_fromregion(&sr);
 	isc_region_consume(&sr, 2);
 
 	/*
 	 * Weight
 	 */
-	if (sr.length < 2) {
-		return (ISC_R_UNEXPECTEDEND);
-	}
 	uri->weight = uint16_fromregion(&sr);
 	isc_region_consume(&sr, 2);