r18880@catbus: nickm | 2008-03-17 12:51:24 -0400

 Fix policy-related crash bug found by lodger.


svn:r14077

ChangeLog

@@ -29,6 +29,9 @@ Changes in version 0.2.1.1-alpha - 2008-??-??
     - Detect mismatched page sizes when using --enable-openbsd-malloc.
       Bugfix on 0.2.0.x.
     - Stop giving double-close warn when we reject an address for client DNS.
+    - Make sure that the "NULL-means-reject *:*" convention is followed by
+      all the policy manipulation functions, avoiding some possible crash
+      bugs. Bug found by lodger. Bugfix on 0.2.0.16-alpha.
 
   o Minor features:
     - Allow separate log levels to be configured for different logging

src/or/or.h

@@ -1118,7 +1118,7 @@ typedef enum {
   ADDR_POLICY_REJECT=2,
 } addr_policy_action_t;
 
-/** A linked list of policy rules */
+/** A reference-counted address policy rule. */
 typedef struct addr_policy_t {
   int refcnt; /**< Reference count */
   addr_policy_action_t policy_type:2;/**< What to do when the policy matches.*/

src/or/policies.c

@@ -530,7 +530,10 @@ compare_addr_to_addr_policy(uint32_t addr, uint16_t port,
   int match = 0;
   int maybe = 0;
   int i, len;
-  len = policy ? smartlist_len(policy) : 0;
+  if (!policy)
+    return ADDR_POLICY_REJECTED;
+
+  len = smartlist_len(policy);
 
   for (i = 0; i < len; ++i) {
     addr_policy_t *tmpe = smartlist_get(policy, i);
@@ -764,6 +767,9 @@ exit_policy_is_general_exit(smartlist_t *policy)
   static const int ports[] = { 80, 443, 6667 };
   int n_allowed = 0;
   int i;
+  if (!policy)
+    return 0;
+
   for (i = 0; i < 3; ++i) {
     SMARTLIST_FOREACH(policy, addr_policy_t *, p, {
       if (p->prt_min > ports[i] || p->prt_max < ports[i])
@@ -787,6 +793,8 @@ exit_policy_is_general_exit(smartlist_t *policy)
 int
 policy_is_reject_star(smartlist_t *policy)
 {
+  if (!policy)
+    return 1;
   SMARTLIST_FOREACH(policy, addr_policy_t *, p, {
     if (p->policy_type == ADDR_POLICY_ACCEPT)
       return 0;

src/or/test.c

@@ -3034,6 +3034,8 @@ test_policies(void)
           compare_addr_to_addr_policy(0, 2, policy));
   test_assert(ADDR_POLICY_REJECTED ==
           compare_addr_to_addr_policy(0xc0a80102, 2, policy));
+  test_assert(ADDR_POLICY_REJECTED ==
+          compare_addr_to_addr_policy(0x01020304u, 2, NULL));
 
   policy2 = NULL;
   test_assert(0 == policies_parse_exit_policy(NULL, &policy2, 1, NULL));
@@ -3041,12 +3043,16 @@ test_policies(void)
 
   test_assert(!exit_policy_is_general_exit(policy));
   test_assert(exit_policy_is_general_exit(policy2));
+  test_assert(!exit_policy_is_general_exit(NULL));
 
   test_assert(cmp_addr_policies(policy, policy2));
+  test_assert(cmp_addr_policies(policy, NULL));
   test_assert(!cmp_addr_policies(policy2, policy2));
+  test_assert(!cmp_addr_policies(NULL, NULL));
 
   test_assert(!policy_is_reject_star(policy2));
   test_assert(policy_is_reject_star(policy));
+  test_assert(policy_is_reject_star(NULL));
 
   addr_policy_list_free(policy);
   addr_policy_list_free(policy2);