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From: =?utf-8?b?UGV0ciDFoHBhxI1law==?= <pspacek@isc.org>
Date: Thu, 16 May 2024 12:10:41 +0200
Subject: Remove support for SIG(0) message verification
(cherry picked from commit 857fd5c346e3309ee8e280c29174b46579af5a13)
---
lib/dns/message.c | 99 ++++---------------------------------------------------
lib/ns/client.c | 7 ++++
2 files changed, 13 insertions(+), 93 deletions(-)
diff --git a/lib/dns/message.c b/lib/dns/message.c
index 22aa552..12331ab 100644
--- a/lib/dns/message.c
+++ b/lib/dns/message.c
@@ -3301,111 +3301,24 @@ dns_message_dumpsig(dns_message_t *msg, char *txt1) {
isc_result_t
dns_message_checksig(dns_message_t *msg, dns_view_t *view) {
- isc_buffer_t b, msgb;
+ isc_buffer_t msgb;
REQUIRE(DNS_MESSAGE_VALID(msg));
- if (msg->tsigkey == NULL && msg->tsig == NULL && msg->sig0 == NULL) {
+ if (msg->tsigkey == NULL && msg->tsig == NULL) {
return (ISC_R_SUCCESS);
}
INSIST(msg->saved.base != NULL);
isc_buffer_init(&msgb, msg->saved.base, msg->saved.length);
isc_buffer_add(&msgb, msg->saved.length);
- if (msg->tsigkey != NULL || msg->tsig != NULL) {
#ifdef SKAN_MSG_DEBUG
- dns_message_dumpsig(msg, "dns_message_checksig#1");
+ dns_message_dumpsig(msg, "dns_message_checksig#1");
#endif /* ifdef SKAN_MSG_DEBUG */
- if (view != NULL) {
- return (dns_view_checksig(view, &msgb, msg));
- } else {
- return (dns_tsig_verify(&msgb, msg, NULL, NULL));
- }
+ if (view != NULL) {
+ return (dns_view_checksig(view, &msgb, msg));
} else {
- dns_rdata_t rdata = DNS_RDATA_INIT;
- dns_rdata_sig_t sig;
- dns_rdataset_t keyset;
- isc_result_t result;
-
- result = dns_rdataset_first(msg->sig0);
- INSIST(result == ISC_R_SUCCESS);
- dns_rdataset_current(msg->sig0, &rdata);
-
- /*
- * This can occur when the message is a dynamic update, since
- * the rdata length checking is relaxed. This should not
- * happen in a well-formed message, since the SIG(0) is only
- * looked for in the additional section, and the dynamic update
- * meta-records are in the prerequisite and update sections.
- */
- if (rdata.length == 0) {
- return (ISC_R_UNEXPECTEDEND);
- }
-
- result = dns_rdata_tostruct(&rdata, &sig, NULL);
- if (result != ISC_R_SUCCESS) {
- return (result);
- }
-
- dns_rdataset_init(&keyset);
- if (view == NULL) {
- result = DNS_R_KEYUNAUTHORIZED;
- goto freesig;
- }
- result = dns_view_simplefind(view, &sig.signer,
- dns_rdatatype_key /* SIG(0) */, 0,
- 0, false, &keyset, NULL);
-
- if (result != ISC_R_SUCCESS) {
- /* XXXBEW Should possibly create a fetch here */
- result = DNS_R_KEYUNAUTHORIZED;
- goto freesig;
- } else if (keyset.trust < dns_trust_secure) {
- /* XXXBEW Should call a validator here */
- result = DNS_R_KEYUNAUTHORIZED;
- goto freesig;
- }
- result = dns_rdataset_first(&keyset);
- INSIST(result == ISC_R_SUCCESS);
- for (; result == ISC_R_SUCCESS;
- result = dns_rdataset_next(&keyset))
- {
- dst_key_t *key = NULL;
-
- dns_rdata_reset(&rdata);
- dns_rdataset_current(&keyset, &rdata);
- isc_buffer_init(&b, rdata.data, rdata.length);
- isc_buffer_add(&b, rdata.length);
-
- result = dst_key_fromdns(&sig.signer, rdata.rdclass, &b,
- view->mctx, &key);
- if (result != ISC_R_SUCCESS) {
- continue;
- }
- if (dst_key_alg(key) != sig.algorithm ||
- dst_key_id(key) != sig.keyid ||
- !(dst_key_proto(key) == DNS_KEYPROTO_DNSSEC ||
- dst_key_proto(key) == DNS_KEYPROTO_ANY))
- {
- dst_key_free(&key);
- continue;
- }
- result = dns_dnssec_verifymessage(&msgb, msg, key);
- dst_key_free(&key);
- if (result == ISC_R_SUCCESS) {
- break;
- }
- }
- if (result == ISC_R_NOMORE) {
- result = DNS_R_KEYUNAUTHORIZED;
- }
-
- freesig:
- if (dns_rdataset_isassociated(&keyset)) {
- dns_rdataset_disassociate(&keyset);
- }
- dns_rdata_freestruct(&sig);
- return (result);
+ return (dns_tsig_verify(&msgb, msg, NULL, NULL));
}
}
diff --git a/lib/ns/client.c b/lib/ns/client.c
index d4ce000..2679a5e 100644
--- a/lib/ns/client.c
+++ b/lib/ns/client.c
@@ -2041,6 +2041,13 @@ ns__client_request(isc_nmhandle_t *handle, isc_result_t eresult,
ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
"request is signed by a nonauthoritative key");
+ } else if (result == DNS_R_NOTVERIFIEDYET &&
+ client->message->sig0 != NULL)
+ {
+ ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+ NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+ "request has a SIG(0) signature but its support "
+ "was removed (CVE-2024-1975)");
} else {
char tsigrcode[64];
isc_buffer_t b;
|
