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- fall back to insecure mode when no supported DNSSEC algorithm is found

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instead of SERVFAIL
- don't fall back to non-EDNS0 queries when DO bit is set
This commit is contained in:
Adam Tkac 2009-03-17 11:41:17 +00:00
parent fc276131b5
commit 913b3afd3d
2 changed files with 227 additions and 1 deletions
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9
bind.spec
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@ -20,7 +20,7 @@ Summary: The Berkeley Internet Name Domain (BIND) DNS (Domain Name System) serv
Name: bind
License: ISC
Version: 9.6.0
Release: 10.%{PATCHVER}%{?dist}
Release: 11.%{PATCHVER}%{?dist}
Epoch: 32
Url: http://www.isc.org/products/BIND/
Buildroot:%{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
@ -54,6 +54,7 @@ Patch99: bind-96-libtool2.patch
Patch101:bind-96-old-api.patch
Patch102:bind-95-rh452060.patch
Patch103:bind-96-realloc.patch
Patch106:bind9-fedora-0001.diff
# SDB patches
Patch11: bind-9.3.2b2-sdbsrc.patch
@ -220,6 +221,7 @@ mkdir m4
%patch102 -p1 -b .rh452060
%patch103 -p0 -b .realloc
%patch106 -p1 -b .nsec3
# Sparc and s390 arches need to use -fPIE
%ifarch sparcv9 sparc64 s390 s390x
@ -569,6 +571,11 @@ rm -rf ${RPM_BUILD_ROOT}
%ghost %{chroot_prefix}/etc/localtime
%changelog
* Tue Mar 17 2009 Adam Tkac <atkac redhat com> 32:9.6.0-11.P1
- fall back to insecure mode when no supported DNSSEC algorithm is found
instead of SERVFAIL
- don't fall back to non-EDNS0 queries when DO bit is set
* Tue Mar 10 2009 Adam Tkac <atkac redhat com> 32:9.6.0-10.P1
- enable DNSSEC only if it is enabled in sysconfig/dnssec

219
bind9-fedora-0001.diff Normal file
View File

@ -0,0 +1,219 @@
diff -ur bind-9.6.0-P1.pristine/lib/dns/resolver.c bind-9.6.0-P1/lib/dns/resolver.c
--- bind-9.6.0-P1.pristine/lib/dns/resolver.c 2008-11-06 18:52:34.000000000 -0600
+++ bind-9.6.0-P1/lib/dns/resolver.c 2009-03-16 21:15:44.000000000 -0500
@@ -222,6 +222,7 @@
* is used for EDNS0 black hole detection.
*/
unsigned int timeouts;
+
/*%
* Look aside state for DS lookups.
*/
@@ -245,6 +246,7 @@
*/
isc_uint32_t rand_buf;
isc_uint32_t rand_bits;
+ isc_boolean_t timeout;
};
#define FCTX_MAGIC ISC_MAGIC('F', '!', '!', '!')
@@ -1575,28 +1577,44 @@
DNS_FETCHOPT_NOEDNS0);
}
- /* Sync NOEDNS0 flag in addrinfo->flags and options now */
+ /* Sync NOEDNS0 flag in addrinfo->flags and options now. */
if ((query->addrinfo->flags & DNS_FETCHOPT_NOEDNS0) != 0)
query->options |= DNS_FETCHOPT_NOEDNS0;
/*
+ * Handle timeouts by reducing the UDP response size to 512 bytes
+ * then if that doesn't work disabling EDNS (includes DO) and CD.
+ *
+ * These timeout can be due to:
+ * * broken nameservers that don't respond to EDNS queries.
+ * * broken/misconfigured firewalls and NAT implementations
+ * that don't handle IP fragmentation.
+ * * broken/misconfigured firewalls that don't handle responses
+ * greater than 512 bytes.
+ * * broken/misconfigured firewalls that don't handle EDNS, DO
+ * or CD.
+ * * packet loss / link outage.
+ */
+ if (fctx->timeout) {
+ if ((triededns512(fctx, &query->addrinfo->sockaddr) ||
+ fctx->timeouts >= (MAX_EDNS0_TIMEOUTS * 2)) &&
+ (query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
+ query->options |= DNS_FETCHOPT_NOEDNS0;
+ fctx->reason = "disabling EDNS";
+ } else if ((triededns(fctx, &query->addrinfo->sockaddr) ||
+ fctx->timeouts >= MAX_EDNS0_TIMEOUTS) &&
+ (query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
+ query->options |= DNS_FETCHOPT_EDNS512;
+ fctx->reason = "reducing the advertised EDNS UDP "
+ "packet size to 512 octets";
+ }
+ fctx->timeout = ISC_FALSE;
+ }
+
+ /*
* Use EDNS0, unless the caller doesn't want it, or we know that
* the remote server doesn't like it.
*/
-
- if ((triededns512(fctx, &query->addrinfo->sockaddr) ||
- fctx->timeouts >= (MAX_EDNS0_TIMEOUTS * 2)) &&
- (query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
- query->options |= DNS_FETCHOPT_NOEDNS0;
- fctx->reason = "disabling EDNS";
- } else if ((triededns(fctx, &query->addrinfo->sockaddr) ||
- fctx->timeouts >= MAX_EDNS0_TIMEOUTS) &&
- (query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
- query->options |= DNS_FETCHOPT_EDNS512;
- fctx->reason = "reducing the advertised EDNS UDP packet "
- "size to 512 octets";
- }
-
if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
if ((query->addrinfo->flags & DNS_FETCHOPT_NOEDNS0) == 0) {
unsigned int version = 0; /* Default version. */
@@ -2909,6 +2927,7 @@
isc_result_t result;
fctx->timeouts++;
+ fctx->timeout = ISC_TRUE;
/*
* We could cancel the running queries here, or we could let
* them keep going. Since we normally use separate sockets for
@@ -3242,6 +3261,7 @@
fctx->reason = NULL;
fctx->rand_buf = 0;
fctx->rand_bits = 0;
+ fctx->timeout = ISC_FALSE;
dns_name_init(&fctx->nsname, NULL);
fctx->nsfetch = NULL;
@@ -4508,7 +4528,8 @@
*/
ttl = fctx->res->view->maxncachettl;
if (fctx->type == dns_rdatatype_soa &&
- covers == dns_rdatatype_any)
+ covers == dns_rdatatype_any &&
+ fctx->res->zero_no_soa_ttl)
ttl = 0;
result = ncache_adderesult(fctx->rmessage, fctx->cache, node,
@@ -5768,6 +5789,7 @@
}
fctx->timeouts = 0;
+ fctx->timeout = ISC_FALSE;
/*
* XXXRTH We should really get the current time just once. We
diff -ur bind-9.6.0-P1.pristine/lib/dns/validator.c bind-9.6.0-P1/lib/dns/validator.c
--- bind-9.6.0-P1.pristine/lib/dns/validator.c 2008-11-14 17:47:33.000000000 -0600
+++ bind-9.6.0-P1/lib/dns/validator.c 2009-03-16 21:13:56.000000000 -0500
@@ -218,6 +218,37 @@
return (ISC_TRUE);
}
+/*
+ * Check that we have atleast one supported algorithm in the DLV RRset.
+ */
+static inline isc_boolean_t
+dlv_algorithm_supported(dns_validator_t *val) {
+ dns_rdata_t rdata = DNS_RDATA_INIT;
+ dns_rdata_dlv_t dlv;
+ isc_result_t result;
+
+ for (result = dns_rdataset_first(&val->dlv);
+ result == ISC_R_SUCCESS;
+ result = dns_rdataset_next(&val->dlv)) {
+ dns_rdata_reset(&rdata);
+ dns_rdataset_current(&val->dlv, &rdata);
+ result = dns_rdata_tostruct(&rdata, &dlv, NULL);
+ RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+ if (!dns_resolver_algorithm_supported(val->view->resolver,
+ val->event->name,
+ dlv.algorithm))
+ continue;
+
+ if (dlv.digest_type != DNS_DSDIGEST_SHA256 &&
+ dlv.digest_type != DNS_DSDIGEST_SHA1)
+ continue;
+
+ return (ISC_TRUE);
+ }
+ return (ISC_FALSE);
+}
+
/*%
* Look in the NSEC record returned from a DS query to see if there is
* a NS RRset at this name. If it is found we are at a delegation point.
@@ -2957,19 +2988,36 @@
sizeof(namebuf));
dns_rdataset_clone(&val->frdataset, &val->dlv);
val->havedlvsep = ISC_TRUE;
- validator_log(val, ISC_LOG_DEBUG(3), "DLV %s found", namebuf);
- dlv_validator_start(val);
+ if (dlv_algorithm_supported(val)) {
+ validator_log(val, ISC_LOG_DEBUG(3), "DLV %s found",
+ namebuf);
+ dlv_validator_start(val);
+ } else {
+ validator_log(val, ISC_LOG_DEBUG(3),
+ "DLV %s found with no supported algorithms",
+ namebuf);
+ markanswer(val);
+ validator_done(val, ISC_R_SUCCESS);
+ }
} else if (eresult == DNS_R_NXRRSET ||
eresult == DNS_R_NXDOMAIN ||
eresult == DNS_R_NCACHENXRRSET ||
eresult == DNS_R_NCACHENXDOMAIN) {
- result = finddlvsep(val, ISC_TRUE);
+ result = finddlvsep(val, ISC_TRUE);
if (result == ISC_R_SUCCESS) {
- dns_name_format(dns_fixedname_name(&val->dlvsep),
- namebuf, sizeof(namebuf));
- validator_log(val, ISC_LOG_DEBUG(3), "DLV %s found",
- namebuf);
- dlv_validator_start(val);
+ if (dlv_algorithm_supported(val)) {
+ dns_name_format(dns_fixedname_name(&val->dlvsep),
+ namebuf, sizeof(namebuf));
+ validator_log(val, ISC_LOG_DEBUG(3),
+ "DLV %s found", namebuf);
+ dlv_validator_start(val);
+ } else {
+ validator_log(val, ISC_LOG_DEBUG(3),
+ "DLV %s found with no supported "
+ "algorithms", namebuf);
+ markanswer(val);
+ validator_done(val, ISC_R_SUCCESS);
+ }
} else if (result == ISC_R_NOTFOUND) {
validator_log(val, ISC_LOG_DEBUG(3), "DLV not found");
markanswer(val);
@@ -3032,9 +3080,16 @@
}
dns_name_format(dns_fixedname_name(&val->dlvsep), namebuf,
sizeof(namebuf));
- validator_log(val, ISC_LOG_DEBUG(3), "DLV %s found", namebuf);
- dlv_validator_start(val);
- return (DNS_R_WAIT);
+ if (dlv_algorithm_supported(val)) {
+ validator_log(val, ISC_LOG_DEBUG(3), "DLV %s found", namebuf);
+ dlv_validator_start(val);
+ return (DNS_R_WAIT);
+ }
+ validator_log(val, ISC_LOG_DEBUG(3), "DLV %s found with no supported "
+ "algorithms", namebuf);
+ markanswer(val);
+ validator_done(val, ISC_R_SUCCESS);
+ return (ISC_R_SUCCESS);
}
/*%