Fix unit test failures in response to DNS hijacking.

Some DNS NXDOMAIN hijackers hijack truly ridiculous domains, like
"invalid-stuff!!" or "1.2.3.4.5".  This would provoke unit test
failures where we used addresses like that to force
tor_addr_lookup() to fail.  The fix, for testing, is to mock
tor_addr_lookup() with a variant that always fails when it gets
a name with a !.

Fixes bugs 20862 and 20863.

changes/bug20862

@@ -0,0 +1,6 @@
+  o Minor bugfixes (unit tests):
+    - Allow the unit tests to pass even when DNS lookups of bogus
+      addresses do not fail as expected. Fixes bug 20862 and 20863;
+      bugfix on unit tests introduced in 0.2.8.1-alpha through
+      0.2.9.4-alpha.
+

src/test/test_config.c

@@ -46,6 +46,8 @@
 #include "transports.h"
 #include "util.h"
 
+#include "test_helpers.h"
+
 static void
 test_config_addressmap(void *arg)
 {
@@ -4701,8 +4703,10 @@ test_config_parse_port_config__ports__ports_given(void *data)
   // Test failure when asked to parse an invalid address followed by auto
   config_free_lines(config_port_invalid); config_port_invalid = NULL;
   config_port_invalid = mock_config_line("DNSPort", "invalidstuff!!:auto");
+  MOCK(tor_addr_lookup, mock_tor_addr_lookup__fail_on_bad_addrs);
   ret = parse_port_config(NULL, config_port_invalid, NULL, "DNS", 0,
                           "127.0.0.46", 0, 0);
+  UNMOCK(tor_addr_lookup);
   tt_int_op(ret, OP_EQ, -1);
 
   // Test success with parsing both an address and a real port

src/test/test_controller.c

@@ -10,6 +10,7 @@
 #include "rendservice.h"
 #include "routerlist.h"
 #include "test.h"
+#include "test_helpers.h"
 
 static void
 test_add_onion_helper_keyarg(void *arg)
@@ -186,8 +187,10 @@ test_rend_service_parse_port_config(void *arg)
   tor_free(err_msg);
 
   /* bogus IP address */
-  cfg = rend_service_parse_port_config("100 1.2.3.4.5:9000",
+  MOCK(tor_addr_lookup, mock_tor_addr_lookup__fail_on_bad_addrs);
+  cfg = rend_service_parse_port_config("100 foo!!.example.com:9000",
                                        " ", &err_msg);
+  UNMOCK(tor_addr_lookup);
   tt_assert(!cfg);
   tt_str_op(err_msg, OP_EQ, "Unparseable address in hidden service port "
             "configuration.");

src/test/test_helpers.c

@@ -128,3 +128,18 @@ dummy_origin_circuit_new(int n_cells)
   return TO_CIRCUIT(circ);
 }
 
+/** Mock-replacement. As tor_addr_lookup, but always fails on any
+ * address containing a !.  This is necessary for running the unit tests
+ * on networks where DNS hijackers think it's helpful to give answers
+ * for things like 1.2.3.4.5 or "invalidstuff!!"
+ */
+int
+mock_tor_addr_lookup__fail_on_bad_addrs(const char *name,
+                                        uint16_t family, tor_addr_t *out)
+{
+  if (name && strchr(name, '!')) {
+    return -1;
+  }
+  return tor_addr_lookup__real(name, family, out);
+}
+

src/test/test_helpers.h

@@ -17,6 +17,9 @@ void helper_setup_fake_routerlist(void);
 void connection_write_to_buf_mock(const char *string, size_t len,
                                   connection_t *conn, int zlib);
 
+int mock_tor_addr_lookup__fail_on_bad_addrs(const char *name,
+                                            uint16_t family, tor_addr_t *out);
+
 extern const char TEST_DESCRIPTORS[];
 
 #endif

src/test/test_options.c

@@ -18,6 +18,7 @@
 #include "sandbox.h"
 #include "memarea.h"
 #include "policies.h"
+#include "test_helpers.h"
 
 #define NS_MODULE test_options
 
@@ -648,18 +649,21 @@ test_options_validate__authdir(void *ignored)
   int ret;
   char *msg;
   setup_capture_of_logs(LOG_INFO);
+  // XXXX But it _can_ exist, if you're DNS-hijacked.
   options_test_data_t *tdata = get_options_test_data(
                                  "AuthoritativeDirectory 1\n"
-                                 "Address this.should.not_exist.example.org");
+                                 "Address this.should.not!exist!.example.org");
 
   sandbox_disable_getaddrinfo_cache();
 
+  MOCK(tor_addr_lookup, mock_tor_addr_lookup__fail_on_bad_addrs);
   ret = options_validate(tdata->old_opt, tdata->opt, tdata->def_opt, 0, &msg);
+  UNMOCK(tor_addr_lookup);
   tt_int_op(ret, OP_EQ, -1);
   tt_str_op(msg, OP_EQ, "Failed to resolve/guess local address. See logs for"
             " details.");
   expect_log_msg("Could not resolve local Address "
-            "'this.should.not_exist.example.org'. Failing.\n");
+            "'this.should.not!exist!.example.org'. Failing.\n");
   tor_free(msg);
 
   free_options_test_data(tdata);
@@ -3037,6 +3041,7 @@ test_options_validate__proxy(void *ignored)
   options_test_data_t *tdata = NULL;
   sandbox_disable_getaddrinfo_cache();
   setup_capture_of_logs(LOG_WARN);
+  MOCK(tor_addr_lookup, mock_tor_addr_lookup__fail_on_bad_addrs);
 
   free_options_test_data(tdata);
   tdata = get_options_test_data(TEST_OPTIONS_DEFAULT_VALUES
@@ -3057,6 +3062,7 @@ test_options_validate__proxy(void *ignored)
   tor_free(msg);
 
   free_options_test_data(tdata);
+
   tdata = get_options_test_data(TEST_OPTIONS_DEFAULT_VALUES
                                 "HttpProxy not_so_valid!\n"
                                 );
@@ -3357,6 +3363,7 @@ test_options_validate__proxy(void *ignored)
   policies_free_all();
   // sandbox_free_getaddrinfo_cache();
   tor_free(msg);
+  UNMOCK(tor_addr_lookup);
 }
 
 static void