From: Mark Andrews <marka@isc.org>
Date: Wed, 8 Jul 2026 01:18:44 +0000 (+1000)
Subject: Malformed Label: data in .private files was not detected
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=0a51e1f3268abc26cf1cf6e57f63c8431fbe811d;p=thirdparty%2Fbind9.git

Malformed Label: data in .private files was not detected

Check that the string encoded in the Label: field of the .private
file of a key pair is NUL terminated and the correct length.  Reject
the .private file if it is not.
---

diff --git a/lib/dns/dst_parse.c b/lib/dns/dst_parse.c
index d058697ab46..8fbb00fa616 100644
--- a/lib/dns/dst_parse.c
+++ b/lib/dns/dst_parse.c
@@ -761,4 +761,14 @@ dst__privstruct_writefile(const dst_key_t *key, const dst_private_t *priv,
 	return result;
 }
 
+isc_result_t
+dst__privelement_is_nul_terminated(const dst_private_element_t *element) {
+	if (element->length < 1 || element->data[element->length - 1] != 0 ||
+	    strlen((char *)element->data) != (size_t)element->length - 1)
+	{
+		return DST_R_INVALIDPRIVATEKEY;
+	}
+	return ISC_R_SUCCESS;
+}
+
 /*! \file */
diff --git a/lib/dns/dst_parse.h b/lib/dns/dst_parse.h
index 80612ec253f..ddf707854a5 100644
--- a/lib/dns/dst_parse.h
+++ b/lib/dns/dst_parse.h
@@ -117,3 +117,7 @@ dst__privstruct_parse(dst_key_t *key, unsigned int alg, isc_lex_t *lex,
 isc_result_t
 dst__privstruct_writefile(const dst_key_t *key, const dst_private_t *priv,
 			  const char *directory);
+
+isc_result_t
+dst__privelement_is_nul_terminated(
+	const dst_private_element_t *dst_private_element_t);
diff --git a/lib/dns/opensslecdsa_link.c b/lib/dns/opensslecdsa_link.c
index 2b7518c5760..3c8c014faad 100644
--- a/lib/dns/opensslecdsa_link.c
+++ b/lib/dns/opensslecdsa_link.c
@@ -548,6 +548,9 @@ opensslecdsa_parse(dst_key_t *key, isc_lex_t *lexer, dst_key_t *pub) {
 			/* The Engine: tag is explicitly ignored */
 			break;
 		case TAG_ECDSA_LABEL:
+			/* NUL terminated data? */
+			CHECK(dst__privelement_is_nul_terminated(
+				&priv.elements[i]));
 			label = (char *)priv.elements[i].data;
 			break;
 		case TAG_ECDSA_PRIVATEKEY:
diff --git a/lib/dns/openssleddsa_link.c b/lib/dns/openssleddsa_link.c
index 0d30defcc4b..72c0d02cd5b 100644
--- a/lib/dns/openssleddsa_link.c
+++ b/lib/dns/openssleddsa_link.c
@@ -464,6 +464,9 @@ openssleddsa_parse(dst_key_t *key, isc_lex_t *lexer, dst_key_t *pub) {
 			/* The Engine: tag is explicitly ignored */
 			break;
 		case TAG_EDDSA_LABEL:
+			/* NUL terminated data? */
+			CHECK(dst__privelement_is_nul_terminated(
+				&priv.elements[i]));
 			label = (char *)priv.elements[i].data;
 			break;
 		case TAG_EDDSA_PRIVATEKEY:
diff --git a/lib/dns/opensslrsa_link.c b/lib/dns/opensslrsa_link.c
index 1b6dcb40343..65a8b481b70 100644
--- a/lib/dns/opensslrsa_link.c
+++ b/lib/dns/opensslrsa_link.c
@@ -662,6 +662,9 @@ opensslrsa_parse(dst_key_t *key, isc_lex_t *lexer, dst_key_t *pub) {
 			/* The Engine: tag is explicitly ignored */
 			break;
 		case TAG_RSA_LABEL:
+			/* NUL terminated data? */
+			CHECK(dst__privelement_is_nul_terminated(
+				&priv.elements[i]));
 			label = (char *)priv.elements[i].data;
 			break;
 		default: