From: Mark Andrews <marka@isc.org>
Date: Mon, 29 Jun 2026 22:40:15 +0000 (+1000)
Subject: Set the active region for the dst_algorithm_fromprivatedns() call
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7bf7d245d2462c7183d22c56637f044516fc5544;p=thirdparty%2Fbind9.git

Set the active region for the dst_algorithm_fromprivatedns() call

dst_algorithm_fromprivatedns() reads the name with dns_name_fromwire(),
which parses only the active region of the buffer. frombuffer() did not
set it, so the name could never be parsed and every PRIVATEDNS key was
rejected with DST_R_UNSUPPORTEDALG. Document the requirement in dst.h.
---

diff --git a/lib/dns/dst_api.c b/lib/dns/dst_api.c
index d4307b309a8..c84a7f9ba36 100644
--- a/lib/dns/dst_api.c
+++ b/lib/dns/dst_api.c
@@ -2099,6 +2099,7 @@ frombuffer(const dns_name_t *name, unsigned int alg, unsigned int flags,
 
 	if (alg == DNS_KEYALG_PRIVATEDNS) {
 		isc_buffer_t b = *source;
+		isc_buffer_setactive(&b, isc_buffer_remaininglength(&b));
 		alg = dst_algorithm_fromprivatedns(&b);
 		if (alg == 0) {
 			return DST_R_UNSUPPORTEDALG;
diff --git a/lib/dns/include/dst/dst.h b/lib/dns/include/dst/dst.h
index 0da1c5f0d6c..bb24b63c07a 100644
--- a/lib/dns/include/dst/dst.h
+++ b/lib/dns/include/dst/dst.h
@@ -226,10 +226,13 @@ dst_algorithm_fromprivateoid(isc_buffer_t *buffer);
  */
 
 dst_algorithm_t
-dst_algorithm_fromprivatedns(isc_buffer_t *buf);
+dst_algorithm_fromprivatedns(isc_buffer_t *buffer);
 /*
  * Extract the dst algorithm identifier that matches
  * the DNS name found at the start of 'buffer'.
+ *
+ * The active region needs to be set on 'buffer' as
+ * dns_name_fromwire is called.
  */
 
 bool