allow-recursion could incorrectly inherit from the default allow-query

diff --git a/CHANGES b/CHANGES
index 59487847d4c911ea4549242fe9d974ce2f4e4202..75b5a0aac9cc8847c57f437ec418c8e86be1a641 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -18,6 +18,13 @@
 4962.  [cleanup]       Move 'named -T' processing to its own function.
                        [GL #316]
 
+4960.  [security]      When recursion is enabled, but the "allow-recursion"
+                       and "allow-query-cache" ACLs are not specified,
+                       they should be limited to local networks,
+                       but were inadvertently set to match the default
+                       "allow-query", thus allowing remote queries.
+                       (CVE-2018-5738) [GL #309]
+
 4958.  [bug]           Remove redundant space from NSEC3 record. [GL #281]
 
 4955.  [cleanup]       Silence cppcheck warnings in lib/dns/master.c.

diff --git a/bin/named/server.c b/bin/named/server.c
index 5f5c39c3080cf23392f92dfe0a6e18d9e9b77f51..de6d726172e19ba25d323af4a8ee00091d35620c 100644 (file)
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -2308,10 +2308,6 @@ configure_view(dns_view_t *view, cfg_obj_t *config, cfg_obj_t *vconfig,
                dns_acache_setcachesize(view->acache, max_acache_size);
        }
 
-       CHECK(configure_view_acl(vconfig, config, ns_g_config,
-                                "allow-query", NULL, actx,
-                                ns_g_mctx, &view->queryacl));
-
        /*
         * Make the list of response policy zone names for a view that
         * is used for real lookups and so cares about hints.
@@ -3120,10 +3116,6 @@ configure_view(dns_view_t *view, cfg_obj_t *config, cfg_obj_t *vconfig,
        INSIST(result == ISC_R_SUCCESS);
        view->root_key_sentinel = cfg_obj_asboolean(obj);
 
-       CHECK(configure_view_acl(vconfig, config, ns_g_config,
-                                "allow-query-cache-on", NULL, actx,
-                                ns_g_mctx, &view->cacheonacl));
-
        /*
         * Set sources where additional data and CNAME/DNAME
         * targets for authoritative answers may be found.
@@ -3150,22 +3142,40 @@ configure_view(dns_view_t *view, cfg_obj_t *config, cfg_obj_t *vconfig,
                view->additionalfromcache = ISC_TRUE;
        }
 
+       CHECK(configure_view_acl(vconfig, config, ns_g_config,
+                                "allow-query-cache-on", NULL, actx,
+                                ns_g_mctx, &view->cacheonacl));
+
        /*
-        * Set "allow-query-cache", "allow-recursion", and
-        * "allow-recursion-on" acls if configured in named.conf.
-        * (Ignore the global defaults for now, because these ACLs
-        * can inherit from each other when only some of them set at
-        * the options/view level.)
+        * Set the "allow-query", "allow-query-cache", "allow-recursion",
+        * and "allow-recursion-on" ACLs if configured in named.conf, but
+        * NOT from the global defaults. This is done by leaving the third
+        * argument to configure_view_acl() NULL.
+        *
+        * We ignore the global defaults here because these ACLs
+        * can inherit from each other.  If any are still unset after
+        * applying the inheritance rules, we'll look up the defaults at
+        * that time.
         */
-       CHECK(configure_view_acl(vconfig, config, NULL, "allow-query-cache",
-                                NULL, actx, ns_g_mctx, &view->cacheacl));
+
+       /* named.conf only */
+       CHECK(configure_view_acl(vconfig, config, NULL,
+                                "allow-query", NULL, actx,
+                                ns_g_mctx, &view->queryacl));
+
+       /* named.conf only */
+       CHECK(configure_view_acl(vconfig, config, NULL,
+                                "allow-query-cache", NULL, actx,
+                                ns_g_mctx, &view->cacheacl));
 
        if (strcmp(view->name, "_bind") != 0 &&
            view->rdclass != dns_rdataclass_chaos)
        {
+               /* named.conf only */
                CHECK(configure_view_acl(vconfig, config, NULL,
                                         "allow-recursion", NULL, actx,
                                         ns_g_mctx, &view->recursionacl));
+               /* named.conf only */
                CHECK(configure_view_acl(vconfig, config, NULL,
                                         "allow-recursion-on", NULL, actx,
                                         ns_g_mctx, &view->recursiononacl));
@@ -3203,18 +3213,21 @@ configure_view(dns_view_t *view, cfg_obj_t *config, cfg_obj_t *vconfig,
                 * the global config.
                 */
                if (view->recursionacl == NULL) {
+                       /* global default only */
                        CHECK(configure_view_acl(NULL, NULL, ns_g_config,
                                                 "allow-recursion", NULL,
                                                 actx, ns_g_mctx,
                                                 &view->recursionacl));
                }
                if (view->recursiononacl == NULL) {
+                       /* global default only */
                        CHECK(configure_view_acl(NULL, NULL, ns_g_config,
                                                 "allow-recursion-on", NULL,
                                                 actx, ns_g_mctx,
                                                 &view->recursiononacl));
                }
                if (view->cacheacl == NULL) {
+                       /* global default only */
                        CHECK(configure_view_acl(NULL, NULL, ns_g_config,
                                                 "allow-query-cache", NULL,
                                                 actx, ns_g_mctx,
@@ -3228,6 +3241,14 @@ configure_view(dns_view_t *view, cfg_obj_t *config, cfg_obj_t *vconfig,
                CHECK(dns_acl_none(mctx, &view->cacheacl));
        }
 
+       if (view->queryacl == NULL) {
+               /* global default only */
+               CHECK(configure_view_acl(NULL, NULL, ns_g_config,
+                                        "allow-query", NULL,
+                                        actx, ns_g_mctx,
+                                        &view->queryacl));
+       }
+
        /*
         * Ignore case when compressing responses to the specified
         * clients. This causes case not always to be preserved,

diff --git a/doc/arm/notes.xml b/doc/arm/notes.xml
index aecf5c4971d65c3e7299147e313d1f905e2b762e..2dd7e4098b3780e6b83c43725938299b2dee8de6 100644 (file)
--- a/doc/arm/notes.xml
+++ b/doc/arm/notes.xml
@@ -52,42 +52,11 @@
     <itemizedlist>
       <listitem>
        <para>
-         An error in TSIG handling could permit unauthorized zone
-         transfers or zone updates. These flaws are disclosed in
-         CVE-2017-3142 and CVE-2017-3143. [RT #45383]
-       </para>
-      </listitem>
-      <listitem>
-       <para>
-         The BIND installer on Windows used an unquoted service path,
-         which can enable privilege escalation. This flaw is disclosed
-         in CVE-2017-3141. [RT #45229]
-       </para>
-      </listitem>
-      <listitem>
-       <para>
-         With certain RPZ configurations, a response with TTL 0
-         could cause <command>named</command> to go into an infinite
-         query loop. This flaw is disclosed in CVE-2017-3140.
-         [RT #45181]
-       </para>
-      </listitem>
-      <listitem>
-       <para>
-         Addresses could be referenced after being freed during resolver
-         processing, causing an assertion failure. The chances of this
-         happening were remote, but the introduction of a delay in
-         resolution increased them. This bug is disclosed in
-         CVE-2017-3145. [RT #46839]
-       </para>
-      </listitem>
-      <listitem>
-       <para>
-         update-policy rules that otherwise ignore the name field now
-         require that it be set to "." to ensure that any type list
-         present is properly interpreted.  If the name field was omitted
-         from the rule declaration and a type list was present it wouldn't
-         be interpreted as expected.
+         When recursion is enabled but the <command>allow-recursion</command>
+         and <command>allow-query-cache</command> ACLs are not specified, they
+         should be limited to local networks, but they were inadvertently set
+         to match the default <command>allow-query</command>, thus allowing
+         remote queries. This flaw is disclosed in CVE-2018-5738. [GL #309]
        </para>
       </listitem>
     </itemizedlist>