819. [bug] In certain cases, the resolver's attempts to

                        restart an address lookup at the root could cause
                        the fetch to deadlock (with itself) instead of
                        restarting. [RT #1225]

diff --git a/CHANGES b/CHANGES
index fe4df3a049530346ddbd78954a0d2cfd93f850f0..43e56c80832c8d2a3b0dfe0db921d24c4895b990 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -1,4 +1,9 @@
 
+ 819.  [bug]           In certain cases, the resolver's attempts to
+                       restart an address lookup at the root could cause
+                       the fetch to deadlock (with itself) instead of
+                       restarting. [RT #1225]
+
  818.  [bug]           Certain pathological responses to ANY queries could
                        cause an assertion failure. [RT #1218]
 

diff --git a/lib/dns/adb.c b/lib/dns/adb.c
index f5f7b67861cf59132347609cb085b864109ae0d6..8b80685d1ff5cd181d58aced78cba0e40cb7536f 100644 (file)
--- a/lib/dns/adb.c
+++ b/lib/dns/adb.c
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: adb.c,v 1.162.2.5 2001/05/01 23:38:54 gson Exp $ */
+/* $Id: adb.c,v 1.162.2.6 2001/05/02 17:52:14 gson Exp $ */
 
 /*
  * Implementation notes
@@ -345,6 +345,7 @@ static isc_result_t dbfind_a6(dns_adbname_t *, isc_stdtime_t);
 #define NAME_IS_DEAD           0x40000000
 #define NAME_HINT_OK           DNS_ADBFIND_HINTOK
 #define NAME_GLUE_OK           DNS_ADBFIND_GLUEOK
+#define NAME_STARTATROOT       DNS_ADBFIND_STARTATROOT
 #define NAME_DEAD(n)           (((n)->flags & NAME_IS_DEAD) != 0)
 #define NAME_NEEDSPOKE(n)      (((n)->flags & NAME_NEEDS_POKE) != 0)
 #define NAME_GLUEOK(n)         (((n)->flags & NAME_GLUE_OK) != 0)
@@ -409,6 +410,8 @@ static isc_result_t dbfind_a6(dns_adbname_t *, isc_stdtime_t);
 #define GLUE_OK(nf, o) (!NAME_GLUEOK(nf) || (((o) & DNS_ADBFIND_GLUEOK) != 0))
 #define HINT_OK(nf, o) (!NAME_HINTOK(nf) || (((o) & DNS_ADBFIND_HINTOK) != 0))
 #define GLUEHINT_OK(nf, o) (GLUE_OK(nf, o) || HINT_OK(nf, o))
+#define STARTATROOT_MATCHES(nf, o) (((nf)->flags & NAME_STARTATROOT) == \
+                                   ((o) & DNS_ADBFIND_STARTATROOT))
 
 #define ENTER_LEVEL            50
 #define EXIT_LEVEL             ENTER_LEVEL
@@ -1769,7 +1772,8 @@ find_name_and_lock(dns_adb_t *adb, dns_name_t *name,
        while (adbname != NULL) {
                if (!NAME_DEAD(adbname)) {
                        if (dns_name_equal(name, &adbname->name)
-                           && GLUEHINT_OK(adbname, options))
+                           && GLUEHINT_OK(adbname, options)
+                           && STARTATROOT_MATCHES(adbname, options))
                                return (adbname);
                }
                adbname = ISC_LIST_NEXT(adbname, plink);
@@ -2528,6 +2532,8 @@ dns_adb_createfind(dns_adb_t *adb, isc_task_t *task, isc_taskaction_t action,
                        adbname->flags |= NAME_HINT_OK;
                if (FIND_GLUEOK(find))
                        adbname->flags |= NAME_GLUE_OK;
+               if (FIND_STARTATROOT(find))
+                       adbname->flags |= NAME_STARTATROOT;
        }
 
        /*
@@ -3738,6 +3744,7 @@ fetch_name_v4(dns_adbname_t *adbname, isc_boolean_t start_at_root) {
        dns_name_t *name;
        dns_rdataset_t rdataset;
        dns_rdataset_t *nameservers;
+       unsigned int options;
 
        INSIST(DNS_ADBNAME_VALID(adbname));
        adb = adbname->adb;
@@ -3751,6 +3758,7 @@ fetch_name_v4(dns_adbname_t *adbname, isc_boolean_t start_at_root) {
        nameservers = NULL;
        dns_rdataset_init(&rdataset);
 
+       options = 0;
        if (start_at_root) {
                DP(50, "fetch_name_v4: starting at DNS root for name %p",
                   adbname);
@@ -3760,6 +3768,7 @@ fetch_name_v4(dns_adbname_t *adbname, isc_boolean_t start_at_root) {
                if (result != ISC_R_SUCCESS && result != DNS_R_HINT)
                        goto cleanup;
                nameservers = &rdataset;
+               options |= DNS_FETCHOPT_UNSHARED;
        }
 
        fetch = new_adbfetch(adb);
@@ -3770,7 +3779,7 @@ fetch_name_v4(dns_adbname_t *adbname, isc_boolean_t start_at_root) {
 
        result = dns_resolver_createfetch(adb->view->resolver, &adbname->name,
                                          dns_rdatatype_a,
-                                         name, nameservers, NULL, 0,
+                                         name, nameservers, NULL, options,
                                          adb->task, fetch_callback,
                                          adbname, &fetch->rdataset, NULL,
                                          &fetch->fetch);
@@ -3837,6 +3846,7 @@ fetch_name_a6(dns_adbname_t *adbname, isc_boolean_t start_at_root) {
        dns_name_t *name;
        dns_rdataset_t rdataset;
        dns_rdataset_t *nameservers;
+       unsigned int options;
 
        INSIST(DNS_ADBNAME_VALID(adbname));
        adb = adbname->adb;
@@ -3850,6 +3860,7 @@ fetch_name_a6(dns_adbname_t *adbname, isc_boolean_t start_at_root) {
        nameservers = NULL;
        dns_rdataset_init(&rdataset);
 
+       options = 0;
        if (start_at_root) {
                DP(50, "fetch_name_a6: starting at DNS root for name %p",
                   adbname);
@@ -3859,6 +3870,7 @@ fetch_name_a6(dns_adbname_t *adbname, isc_boolean_t start_at_root) {
                if (result != ISC_R_SUCCESS && result != DNS_R_HINT)
                        goto cleanup;
                nameservers = &rdataset;
+               options |= DNS_FETCHOPT_UNSHARED;
        }
 
        fetch = new_adbfetch6(adb, adbname, NULL);
@@ -3870,7 +3882,7 @@ fetch_name_a6(dns_adbname_t *adbname, isc_boolean_t start_at_root) {
 
        result = dns_resolver_createfetch(adb->view->resolver, &adbname->name,
                                          dns_rdatatype_a6,
-                                         name, nameservers, NULL, 0,
+                                         name, nameservers, NULL, options,
                                          adb->task, fetch_callback_a6,
                                          adbname, &fetch->rdataset, NULL,
                                          &fetch->fetch);