From: Tommi Rantala <tommi.rantala@cujo.com>
Date: Mon, 20 Jan 2025 11:05:49 +0000 (+0200)
Subject: resolved: empty "ipv4hint" and "ipv6hint" SvcParams are invalid
X-Git-Tag: v258-rc1~1551
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=26551c0f67d41dfbc2038db99e31a42632f15db6;p=thirdparty%2Fsystemd.git

resolved: empty "ipv4hint" and "ipv6hint" SvcParams are invalid

According to RFC 9460 "An empty list of addresses is invalid."

https://www.rfc-editor.org/rfc/rfc9460.html#section-7.3
---

diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c
index 4c82d38bcc2..1d235b4aff7 100644
--- a/src/resolve/resolved-dns-packet.c
+++ b/src/resolve/resolved-dns-packet.c
@@ -1789,9 +1789,9 @@ static bool dns_svc_param_is_valid(DnsSvcParam *i) {
 
         /* RFC 9460, section 7.3: addrs must exactly fill SvcParamValue */
         case DNS_SVC_PARAM_KEY_IPV4HINT:
-                return i->length % (sizeof (struct in_addr)) == 0;
+                return i->length > 0 && i->length % (sizeof (struct in_addr)) == 0;
         case DNS_SVC_PARAM_KEY_IPV6HINT:
-                return i->length % (sizeof (struct in6_addr)) == 0;
+                return i->length > 0 && i->length % (sizeof (struct in6_addr)) == 0;
 
         /* Otherwise, permit any value */
         default: