File bind-9.11-CVE-2024-1975.patch of Package bind.35132
commit f01421dfbf79af6c8c553466551cc00167ba649d
Author: Nicki Křížek <nicki@isc.org>
Date: Wed Jul 24 11:14:16 2024 +0000
[9.11] [CVE-2024-1975] Remove support for SIG(0) message verification
Backport of isc-private/bind9!690
Fixes: isc-projects/bind9#4480
Merge branch '4480-drop-sig0-support-bind-9.11' into 'bind-9.11'
See merge request isc-projects/bind9!9173
diff --git a/CHANGES b/CHANGES
index 5d807db8f5..f80da5c70f 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+6396. [security] Remove SIG(0) support from named as a countermeasure
+ for CVE-2024-1975. [GL #4480]
+
6322. [security] Specific DNS answers could cause a denial-of-service
condition due to DNS validation taking a long time.
(CVE-2023-50387) [GL #4424]
diff --git a/bin/named/client.c b/bin/named/client.c
index f4a5ff9f9b..863a8abfc1 100644
--- a/bin/named/client.c
+++ b/bin/named/client.c
@@ -2984,6 +2984,12 @@ client_request(isc_task_t *task, isc_event_t *event) {
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;
diff --git a/bin/tests/system/tsiggss/authsock.pl b/bin/tests/system/tsiggss/authsock.pl
index 57a72b2a3d..3afaa83169 100644
--- a/bin/tests/system/tsiggss/authsock.pl
+++ b/bin/tests/system/tsiggss/authsock.pl
@@ -31,6 +31,10 @@ if (!defined($path)) {
exit(1);
}
+# Enable output autoflush so that it's not lost when the parent sends TERM.
+select STDOUT;
+$| = 1;
+
unlink($path);
my $server = IO::Socket::UNIX->new(Local => $path, Type => SOCK_STREAM, Listen => 8) or
die "unable to create socket $path";
@@ -48,6 +52,7 @@ if ($timeout != 0) {
}
while (my $client = $server->accept()) {
+ printf("accept()\n");
$client->recv(my $buf, 8, 0);
my ($version, $req_len) = unpack('N N', $buf);
diff --git a/bin/tests/system/tsiggss/clean.sh b/bin/tests/system/tsiggss/clean.sh
index 332a87f383..52fd81b407 100644
--- a/bin/tests/system/tsiggss/clean.sh
+++ b/bin/tests/system/tsiggss/clean.sh
@@ -19,7 +19,7 @@ rm -f ns1/_default.tsigkeys
rm -f */named.memstats
rm -f */named.conf
rm -f */named.run
-rm -f authsock.pid
+rm -f authsock.log authsock.pid
rm -f ns1/core
rm -f nsupdate.out*
rm -f ns*/named.lock
diff --git a/bin/tests/system/tsiggss/tests.sh b/bin/tests/system/tsiggss/tests.sh
index e4c32dcc46..5f87ff5e4e 100644
--- a/bin/tests/system/tsiggss/tests.sh
+++ b/bin/tests/system/tsiggss/tests.sh
@@ -116,7 +116,7 @@ status=$((status+ret))
echo "I:testing external update policy (CNAME) with auth sock ($n)"
ret=0
-$PERL ./authsock.pl --type=CNAME --path=ns1/auth.sock --pidfile=authsock.pid --timeout=120 > /dev/null 2>&1 &
+$PERL ./authsock.pl --type=CNAME --path=ns1/auth.sock --pidfile=authsock.pid --timeout=120 >authsock.log 2>&1 &
sleep 1
test_update $n testcname.example.nil. CNAME "86400 CNAME testdenied.example.nil" "testdenied" || ret=1
n=$((n+1))
@@ -130,17 +130,19 @@ n=$((n+1))
if [ "$ret" -ne 0 ]; then echo_i "failed"; fi
status=$((status+ret))
-echo "I:testing external policy with SIG(0) key ($n)"
+echo "I:testing external policy with unsupported SIG(0) key ($n)"
ret=0
-$NSUPDATE -R $RANDFILE -k ns1/Kkey.example.nil.*.private <<END > /dev/null 2>&1 || ret=1
+$NSUPDATE -R $RANDFILE -d -k ns1/Kkey.example.nil.*.private <<END >nsupdate.out${n} 2>&1 || true
+debug
server 10.53.0.1 ${PORT}
zone example.nil
update add fred.example.nil 120 cname foo.bar.
send
END
output=`$DIG $DIGOPTS +short cname fred.example.nil.`
-[ -n "$output" ] || ret=1
-[ $ret -eq 0 ] || echo "I:failed"
+# update must have failed - SIG(0) signer is not supported
+[ -n "$output" ] && ret=1
+grep -F "signer=key.example.nil" authsock.log >/dev/null && ret=1
n=$((n+1))
if [ "$ret" -ne 0 ]; then echo_i "failed"; fi
status=$((status+ret))
diff --git a/bin/tests/system/upforwd/tests.sh b/bin/tests/system/upforwd/tests.sh
index b0694bbd5c..fe311c36c1 100644
--- a/bin/tests/system/upforwd/tests.sh
+++ b/bin/tests/system/upforwd/tests.sh
@@ -177,9 +177,10 @@ n=`expr $n + 1`
if test -f keyname
then
- echo_i "checking update forwarding to with sig0 ($n)"
+ echo_i "checking update forwarding to with sig0 (expected to fail) ($n)"
ret=0
keyname=`cat keyname`
+ # SIG(0) is removed, update is expected to fail.
$NSUPDATE -k $keyname.private -- - <<EOF
server 10.53.0.3 ${PORT}
zone example2
@@ -187,8 +188,9 @@ then
update add unsigned.example2. 600 TXT Foo
send
EOF
- $DIG -p ${PORT} unsigned.example2 A @10.53.0.1 > dig.out.ns1.test$n
- grep "status: NOERROR" dig.out.ns1.test$n > /dev/null || ret=1
+ >nsupdate.out.$n 2>&1 && ret=1
+ $DIG -p ${PORT} unsigned.example2 A @10.53.0.1 > dig.out.ns1.test$n || ret=1
+ grep "status: NOERROR" dig.out.ns1.test$n > /dev/null && ret=1
if [ $ret != 0 ] ; then echo_i "failed"; fi
status=`expr $status + $ret`
n=`expr $n + 1`
diff --git a/lib/dns/message.c b/lib/dns/message.c
index 00cd81e8cd..e6d090f94c 100644
--- a/lib/dns/message.c
+++ b/lib/dns/message.c
@@ -3350,102 +3350,24 @@ 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");
-#endif
- if (view != NULL)
- return (dns_view_checksig(view, &msgb, msg));
- else
- return (dns_tsig_verify(&msgb, msg, NULL, NULL));
+ dns_message_dumpsig(msg, "dns_message_checksig#1");
+#endif /* ifdef SKAN_MSG_DEBUG */
+ 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, msg->mctx);
- if (result != ISC_R_SUCCESS)
- return (result);
-
- dns_rdataset_init(&keyset);
- if (view == NULL)
- return (DNS_R_KEYUNAUTHORIZED);
- 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));
}
}
