From: Willem Toorop <willem@nlnetlabs.nl>
Date: Wed, 21 Jan 2026 09:32:42 +0000 (+0100)
Subject: Skip memcpy if nothing to be copied
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ee714dd313aa62c8041bd9db167d007a8d95cdfd;p=thirdparty%2Fldns.git

Skip memcpy if nothing to be copied

This came out of running ldns-nsec3-hash with ldns compiled with -fsanitize=address,undefined
---

diff --git a/dnssec.c b/dnssec.c
index 1339e73c..5b5d5699 100644
--- a/dnssec.c
+++ b/dnssec.c
@@ -1047,7 +1047,9 @@ ldns_nsec3_hash_name(const ldns_rdf *name,
                 return NULL;
         }
 	memcpy(hashed_owner_str, ldns_rdf_data(cann), ldns_rdf_size(cann));
-	memcpy(hashed_owner_str + ldns_rdf_size(cann), salt, salt_length);
+	if (salt_length) {
+		memcpy(hashed_owner_str + ldns_rdf_size(cann), salt, salt_length);
+	}
 	ldns_rdf_deep_free(cann);
 
 	for (cur_it = iterations + 1; cur_it > 0; cur_it--) {
@@ -1061,7 +1063,9 @@ ldns_nsec3_hash_name(const ldns_rdf *name,
 			return NULL;
 		}
 		memcpy(hashed_owner_str, hash, LDNS_SHA1_DIGEST_LENGTH);
-		memcpy(hashed_owner_str + LDNS_SHA1_DIGEST_LENGTH, salt, salt_length);
+		if (salt_length) {
+			memcpy(hashed_owner_str + LDNS_SHA1_DIGEST_LENGTH, salt, salt_length);
+		}
 		hashed_owner_str_len = LDNS_SHA1_DIGEST_LENGTH + salt_length;
 	}