Add get_interface_address[6]_list for a list of interface IP addresses

Add get_interface_address[6]_list by refactoring
get_interface_address6. Add unit tests for new and existing functions.

Preparation for ticket 17027. Patch by "teor".
Patch on 42b8fb5a15 (11 Nov 2007), released in 0.2.0.11-alpha.

changes/bug17027-reject-private-all-interfaces

@@ -0,0 +1,5 @@
+  o Minor bug fixes (security, exit policies):
+    - Add get_interface_address[6]_list by refactoring
+      get_interface_address6. Add unit tests for new and existing functions.
+      Preparation for ticket 17027. Patch by "teor".
+      Patch on 42b8fb5a1523 (11 Nov 2007), released in 0.2.0.11-alpha.

src/common/address.c

@@ -1503,7 +1503,7 @@ get_interface_addresses_raw(int severity)
 }
 
 /** Return true iff <b>a</b> is a multicast address.  */
-static int
+STATIC int
 tor_addr_is_multicast(const tor_addr_t *a)
 {
   sa_family_t family = tor_addr_family(a);
@@ -1593,27 +1593,26 @@ get_interface_address6_via_udp_socket_hack(int severity,
   return r;
 }
 
-/** Set *<b>addr</b> to the IP address (if any) of whatever interface
- * connects to the Internet.  This address should only be used in checking
- * whether our address has changed.  Return 0 on success, -1 on failure.
+/** Set *<b>addr</b> to an arbitrary IP address (if any) of an interface that
+ * connects to the Internet.  Prefer public IP addresses to internal IP
+ * addresses.  This address should only be used in checking whether our
+ * address has changed, as it may be an internal IP address.  Return 0 on
+ * success, -1 on failure.
+ * Prefer get_interface_address6_list for a list of all addresses on all
+ * interfaces which connect to the Internet.
  */
 MOCK_IMPL(int,
 get_interface_address6,(int severity, sa_family_t family, tor_addr_t *addr))
 {
-  /* XXX really, this function should yield a smartlist of addresses. */
   smartlist_t *addrs;
   tor_assert(addr);
 
-  /* Try to do this the smart way if possible. */
-  if ((addrs = get_interface_addresses_raw(severity))) {
+  /* Get a list of public or internal IPs in arbitrary order */
+  if ((addrs = get_interface_address6_list(severity, family, 1))) {
     int rv = -1;
+    /* Find the first non-internal address, or the last internal address
+     * Ideally, we want the default route, see #12377 for details */
     SMARTLIST_FOREACH_BEGIN(addrs, tor_addr_t *, a) {
-      if (family != AF_UNSPEC && family != tor_addr_family(a))
-        continue;
-      if (tor_addr_is_loopback(a) ||
-          tor_addr_is_multicast(a))
-        continue;
-
       tor_addr_copy(addr, a);
       rv = 0;
 
@@ -1623,13 +1622,78 @@ get_interface_address6,(int severity, sa_family_t family, tor_addr_t *addr))
         break;
     } SMARTLIST_FOREACH_END(a);
 
-    SMARTLIST_FOREACH(addrs, tor_addr_t *, a, tor_free(a));
-    smartlist_free(addrs);
+    free_interface_address6_list(addrs);
     return rv;
   }
 
+  return -1;
+}
+
+/** Free a smartlist of IP addresses returned by get_interface_address6_list.
+ */
+void free_interface_address6_list(smartlist_t *addrs) {
+  SMARTLIST_FOREACH(addrs, tor_addr_t *, a, tor_free(a));
+  smartlist_free(addrs);
+}
+
+/** Return a smartlist of the IP addresses of type family from all interfaces
+ * on the server. Excludes loopback and multicast addresses. Only includes
+ * internal addresses if include_internal is true. (Note that a relay behind
+ * NAT may use an internal address to connect to the Internet.)
+ * An empty smartlist means that there are no addresses of the selected type
+ * matching these criteria.
+ * Returns NULL on failure.
+ * Use free_interface_address6_list to free the returned list.
+ */
+MOCK_IMPL(smartlist_t *,get_interface_address6_list,(int severity,
+                                                     sa_family_t family,
+                                                     int include_internal))
+{
+  smartlist_t *addrs;
+  tor_addr_t addr;
+
+  /* Try to do this the smart way if possible. */
+  if ((addrs = get_interface_addresses_raw(severity))) {
+    SMARTLIST_FOREACH_BEGIN(addrs, tor_addr_t *, a) {
+      if (family != AF_UNSPEC && family != tor_addr_family(a)){
+        SMARTLIST_DEL_CURRENT(addrs, a);
+        tor_free(a);
+        continue;
+      }
+
+      if (tor_addr_is_loopback(a) ||
+          tor_addr_is_multicast(a)) {
+        SMARTLIST_DEL_CURRENT(addrs, a);
+        tor_free(a);
+        continue;
+      }
+
+      if (!include_internal && tor_addr_is_internal(a, 0)){
+        SMARTLIST_DEL_CURRENT(addrs, a);
+        tor_free(a);
+        continue;
+      }
+    } SMARTLIST_FOREACH_END(a);
+  }
+
+  if (addrs && smartlist_len(addrs) > 0) {
+    return addrs;
+  }
+
+  /* if we removed all entries as unsuitable */
+  if (addrs) {
+    smartlist_free(addrs);
+  }
+
   /* Okay, the smart way is out. */
-  return get_interface_address6_via_udp_socket_hack(severity,family,addr);
+  get_interface_address6_via_udp_socket_hack(severity,family,&addr);
+  if (!include_internal && tor_addr_is_internal(&addr, 0)) {
+    return smartlist_new();
+  } else {
+    addrs = smartlist_new();
+    smartlist_add(addrs, tor_dup_addr(&addr));
+    return addrs;
+  }
 }
 
 /* ======
@@ -1871,10 +1935,13 @@ tor_dup_ip(uint32_t addr)
 }
 
 /**
- * Set *<b>addr</b> to the host-order IPv4 address (if any) of whatever
- * interface connects to the Internet.  This address should only be used in
- * checking whether our address has changed.  Return 0 on success, -1 on
- * failure.
+ * Set *<b>addr</b> to a host-order IPv4 address (if any) of an
+ * interface that connects to the Internet.  Prefer public IP addresses to
+ * internal IP addresses.  This address should only be used in checking
+ * whether our address has changed, as it may be an internal IPv4 address.
+ * Return 0 on success, -1 on failure.
+ * Prefer get_interface_address_list6 for a list of all IPv4 and IPv6
+ * addresses on all interfaces which connect to the Internet.
  */
 MOCK_IMPL(int,
 get_interface_address,(int severity, uint32_t *addr))

src/common/address.h

@@ -15,6 +15,7 @@
 #include "orconfig.h"
 #include "torint.h"
 #include "compat.h"
+#include "container.h"
 
 #ifdef ADDRESS_PRIVATE
 
@@ -43,7 +44,6 @@
 #endif
 
 // TODO win32 specific includes
-#include "container.h"
 #endif // ADDRESS_PRIVATE
 
 /** The number of bits from an address to consider while doing a masked
@@ -190,8 +190,13 @@ char *tor_dup_addr(const tor_addr_t *addr) ATTR_MALLOC;
 const char *fmt_addr_impl(const tor_addr_t *addr, int decorate);
 const char *fmt_addrport(const tor_addr_t *addr, uint16_t port);
 const char * fmt_addr32(uint32_t addr);
+
 MOCK_DECL(int,get_interface_address6,(int severity, sa_family_t family,
 tor_addr_t *addr));
+void free_interface_address6_list(smartlist_t * addrs);
+MOCK_DECL(smartlist_t *,get_interface_address6_list,(int severity,
+                                                     sa_family_t family,
+                                                     int include_internal));
 
 /** Flag to specify how to do a comparison between addresses.  In an "exact"
  * comparison, addresses are equivalent only if they are in the same family
@@ -269,11 +274,32 @@ int addr_mask_get_bits(uint32_t mask);
 int tor_inet_ntoa(const struct in_addr *in, char *buf, size_t buf_len);
 char *tor_dup_ip(uint32_t addr) ATTR_MALLOC;
 MOCK_DECL(int,get_interface_address,(int severity, uint32_t *addr));
+/** Free a smartlist of IP addresses returned by get_interface_address_list.
+ */
+static INLINE void
+free_interface_address_list(smartlist_t *addrs)
+{
+  free_interface_address6_list(addrs);
+}
+/** Return a smartlist of the IPv4 addresses of all interfaces on the server.
+ * Excludes loopback and multicast addresses. Only includes internal addresses
+ * if include_internal is true. (Note that a relay behind NAT may use an
+ * internal address to connect to the Internet.)
+ * An empty smartlist means that there are no IPv4 addresses.
+ * Returns NULL on failure.
+ * Use free_interface_address_list to free the returned list.
+ */
+static INLINE smartlist_t *
+get_interface_address_list(int severity, int include_internal)
+{
+  return get_interface_address6_list(severity, AF_INET, include_internal);
+}
 
 tor_addr_port_t *tor_addr_port_new(const tor_addr_t *addr, uint16_t port);
 
 #ifdef ADDRESS_PRIVATE
 STATIC smartlist_t *get_interface_addresses_raw(int severity);
+STATIC int tor_addr_is_multicast(const tor_addr_t *a);
 STATIC int get_interface_address6_via_udp_socket_hack(int severity,
                                                       sa_family_t family,
                                                       tor_addr_t *addr);

src/test/test_address.c

@@ -74,37 +74,82 @@ sockaddr_in_from_string(const char *ip_str, struct sockaddr_in *out)
 }
 
 /** Return 1 iff <b>smartlist</b> contains a tor_addr_t structure
- * that points to 127.0.0.1. Otherwise, return 0.
+ * that is an IPv4 or IPv6 localhost address. Otherwise, return 0.
  */
 static int
 smartlist_contains_localhost_tor_addr(smartlist_t *smartlist)
 {
-  int found_localhost = 0;
-
-  struct sockaddr_in *sockaddr_localhost;
-  struct sockaddr_storage *sockaddr_to_check;
-
-  sockaddr_localhost = sockaddr_in_from_string("127.0.0.1",NULL);
-
-  sockaddr_to_check = tor_malloc(sizeof(struct sockaddr_in));
-
   SMARTLIST_FOREACH_BEGIN(smartlist, tor_addr_t *, tor_addr) {
-    tor_addr_to_sockaddr(tor_addr,0,(struct sockaddr *)sockaddr_to_check,
-                         sizeof(struct sockaddr_in));
-
-    if (sockaddr_in_are_equal((struct sockaddr_in *)sockaddr_to_check,
-                              sockaddr_localhost)) {
-      found_localhost = 1;
-      break;
+    if (tor_addr_is_loopback(tor_addr)) {
+      return 1;
     }
   } SMARTLIST_FOREACH_END(tor_addr);
 
-  tor_free(sockaddr_localhost);
-  tor_free(sockaddr_to_check);
-
-  return found_localhost;
+  return 0;
 }
 
+/** Return 1 iff <b>smartlist</b> contains a tor_addr_t structure
+ * that is an IPv4 or IPv6 multicast address. Otherwise, return 0.
+ */
+static int
+smartlist_contains_multicast_tor_addr(smartlist_t *smartlist)
+{
+  SMARTLIST_FOREACH_BEGIN(smartlist, tor_addr_t *, tor_addr) {
+    if (tor_addr_is_multicast(tor_addr)) {
+      return 1;
+    }
+  } SMARTLIST_FOREACH_END(tor_addr);
+
+  return 0;
+}
+
+/** Return 1 iff <b>smartlist</b> contains a tor_addr_t structure
+ * that is an IPv4 or IPv6 internal address. Otherwise, return 0.
+ */
+static int
+smartlist_contains_internal_tor_addr(smartlist_t *smartlist)
+{
+  SMARTLIST_FOREACH_BEGIN(smartlist, tor_addr_t *, tor_addr) {
+    if (tor_addr_is_internal(tor_addr, 0)) {
+      return 1;
+    }
+  } SMARTLIST_FOREACH_END(tor_addr);
+
+  return 0;
+}
+
+/** Return 1 iff <b>smartlist</b> contains a tor_addr_t structure
+ * that is an IPv4 address. Otherwise, return 0.
+ */
+static int
+smartlist_contains_ipv4_tor_addr(smartlist_t *smartlist)
+{
+  SMARTLIST_FOREACH_BEGIN(smartlist, tor_addr_t *, tor_addr) {
+    if (tor_addr_is_v4(tor_addr)) {
+      return 1;
+    }
+  } SMARTLIST_FOREACH_END(tor_addr);
+
+  return 0;
+}
+
+/** Return 1 iff <b>smartlist</b> contains a tor_addr_t structure
+ * that is an IPv6 address. Otherwise, return 0.
+ */
+static int
+smartlist_contains_ipv6_tor_addr(smartlist_t *smartlist)
+{
+  SMARTLIST_FOREACH_BEGIN(smartlist, tor_addr_t *, tor_addr) {
+    /* Since there's no tor_addr_is_v6, assume all non-v4s are v6 */
+    if (!tor_addr_is_v4(tor_addr)) {
+      return 1;
+    }
+  } SMARTLIST_FOREACH_END(tor_addr);
+
+  return 0;
+}
+
+
 #ifdef HAVE_IFADDRS_TO_SMARTLIST
 static void
 test_address_ifaddrs_to_smartlist(void *arg)
@@ -634,12 +679,168 @@ test_address_udp_socket_trick_blackbox(void *arg)
   return;
 }
 
+static void
+test_address_get_if_addrs_list_internal(void *arg)
+{
+  smartlist_t *results = NULL;
+
+  (void)arg;
+
+  results = get_interface_address_list(LOG_ERR, 1);
+
+  tt_assert(results != NULL);
+  /* Assume every system has at least 1 non-local non-multicast IPv4
+   * interface, even if it is an internal one */
+  tt_int_op(smartlist_len(results),>=,1);
+
+  tt_assert(!smartlist_contains_localhost_tor_addr(results));
+  tt_assert(!smartlist_contains_multicast_tor_addr(results));
+  /* The list may or may not contain internal addresses */
+
+  tt_assert(smartlist_contains_ipv4_tor_addr(results));
+  tt_assert(!smartlist_contains_ipv6_tor_addr(results));
+
+done:
+  free_interface_address_list(results);
+  return;
+}
+
+static void
+test_address_get_if_addrs_list_no_internal(void *arg)
+{
+  smartlist_t *results = NULL;
+
+  (void)arg;
+
+  results = get_interface_address_list(LOG_ERR, 0);
+
+  tt_assert(results != NULL);
+  /* Work even on systems with only internal IPv4 addresses */
+  tt_int_op(smartlist_len(results),>=,0);
+
+  tt_assert(!smartlist_contains_localhost_tor_addr(results));
+  tt_assert(!smartlist_contains_multicast_tor_addr(results));
+  tt_assert(!smartlist_contains_internal_tor_addr(results));
+
+    /* The list may or may not contain IPv4 addresses */
+  tt_assert(!smartlist_contains_ipv6_tor_addr(results));
+
+done:
+  free_interface_address_list(results);
+  return;
+}
+
+static void
+test_address_get_if_addrs6_list_internal(void *arg)
+{
+  smartlist_t *results = NULL;
+
+  (void)arg;
+
+  results = get_interface_address6_list(LOG_ERR, AF_INET6, 1);
+
+  tt_assert(results != NULL);
+  /* Work even on systems without IPv6 interfaces */
+  tt_int_op(smartlist_len(results),>=,0);
+
+  tt_assert(!smartlist_contains_localhost_tor_addr(results));
+  tt_assert(!smartlist_contains_multicast_tor_addr(results));
+  /* The list may or may not contain internal addresses */
+
+  tt_assert(!smartlist_contains_ipv4_tor_addr(results));
+  /* The list may or may not contain IPv6 addresses */
+
+done:
+  free_interface_address6_list(results);
+  return;
+}
+
+static void
+test_address_get_if_addrs6_list_no_internal(void *arg)
+{
+  smartlist_t *results = NULL;
+
+  (void)arg;
+
+  results = get_interface_address6_list(LOG_ERR, AF_INET6, 0);
+
+  tt_assert(results != NULL);
+  /* Work even on systems without IPv6 interfaces */
+  tt_int_op(smartlist_len(results),>=,0);
+
+  tt_assert(!smartlist_contains_localhost_tor_addr(results));
+  tt_assert(!smartlist_contains_multicast_tor_addr(results));
+  tt_assert(!smartlist_contains_internal_tor_addr(results));
+
+  tt_assert(!smartlist_contains_ipv4_tor_addr(results));
+  /* The list may or may not contain IPv6 addresses */
+
+done:
+  free_interface_address6_list(results);
+  return;
+}
+
+static void
+test_address_get_if_addrs(void *arg)
+{
+  int rv;
+  uint32_t addr_h = 0;
+  tor_addr_t tor_addr;
+
+  (void)arg;
+
+  rv = get_interface_address(LOG_ERR, &addr_h);
+
+  /* Assume every system has at least 1 non-local non-multicast IPv4
+   * interface, even if it is an internal one */
+  tt_assert(rv == 0);
+  tor_addr_from_ipv4h(&tor_addr, addr_h);
+
+  tt_assert(!tor_addr_is_loopback(&tor_addr));
+  tt_assert(!tor_addr_is_multicast(&tor_addr));
+  /* The address may or may not be an internal address */
+
+  tt_assert(tor_addr_is_v4(&tor_addr));
+
+done:
+  return;
+}
+
+static void
+test_address_get_if_addrs6(void *arg)
+{
+  int rv;
+  tor_addr_t tor_addr;
+
+  (void)arg;
+
+  rv = get_interface_address6(LOG_ERR, AF_INET6, &tor_addr);
+
+  /* Work even on systems without IPv6 interfaces */
+  if (rv == 0) {
+    tt_assert(!tor_addr_is_loopback(&tor_addr));
+    tt_assert(!tor_addr_is_multicast(&tor_addr));
+    /* The address may or may not be an internal address */
+
+    tt_assert(!tor_addr_is_v4(&tor_addr));
+  }
+
+done:
+  return;
+}
+
 #define ADDRESS_TEST(name, flags) \
   { #name, test_address_ ## name, flags, NULL, NULL }
 
 struct testcase_t address_tests[] = {
   ADDRESS_TEST(udp_socket_trick_whitebox, TT_FORK),
   ADDRESS_TEST(udp_socket_trick_blackbox, TT_FORK),
+  ADDRESS_TEST(get_if_addrs_list_internal, 0),
+  ADDRESS_TEST(get_if_addrs_list_no_internal, 0),
+  ADDRESS_TEST(get_if_addrs6_list_internal, 0),
+  ADDRESS_TEST(get_if_addrs6_list_no_internal, 0),
+  ADDRESS_TEST(get_if_addrs, 0),
+  ADDRESS_TEST(get_if_addrs6, 0),
 #ifdef HAVE_IFADDRS_TO_SMARTLIST
   ADDRESS_TEST(get_if_addrs_ifaddrs, TT_FORK),
   ADDRESS_TEST(ifaddrs_to_smartlist, 0),