addr: Refactor is_local_addr() to support IPv6

Series of changes:

  1. Rename function to reflect the namespace of the file.

  2. Use the new last resolved cache instead of the unused
     last_resolved_addr_v4 (which is also removed in this commit).

  3. Make the entire code base use the new resolved_addr_is_local() function.

You will notice that this function uses /24 to differentiate subnets where the
rest of tor uses /16 (including documentation of EnforceDistinctSubnets).
Ticket #40009 has been opened for that.

But that the moment, the function keeps looking at /24.

Part of #33233

Signed-off-by: David Goulet <dgoulet@torproject.org>
This commit is contained in:
David Goulet 2020-06-23 10:43:39 -04:00
parent 7795dd7ef6
commit 2f3b4e3888
5 changed files with 56 additions and 42 deletions

View File

@ -44,9 +44,6 @@
/** Last resolved addresses. */
static tor_addr_t last_resolved_addrs[IDX_SIZE];
/** Last value actually set by resolve_my_address. */
static uint32_t last_resolved_addr_v4 = 0;
/** Copy the last resolved address of family into addr_out.
*
* If not last resolved address existed, the addr_out is a null address (use
@ -598,27 +595,44 @@ resolve_my_address_v4(int warn_severity, const or_options_t *options,
/** Return true iff <b>addr</b> is judged to be on the same network as us, or
* on a private network.
*/
MOCK_IMPL(int,
is_local_addr, (const tor_addr_t *addr))
MOCK_IMPL(bool,
resolved_addr_is_local, (const tor_addr_t *addr))
{
if (tor_addr_is_internal(addr, 0))
return 1;
/* Check whether ip is on the same /24 as we are. */
if (get_options()->EnforceDistinctSubnets == 0)
return 0;
if (tor_addr_family(addr) == AF_INET) {
uint32_t ip = tor_addr_to_ipv4h(addr);
const int family = tor_addr_family(addr);
const tor_addr_t *last_resolved_addr = &last_resolved_addrs[family];
/* Internal address is always local. */
if (tor_addr_is_internal(addr, 0)) {
return true;
}
/* Address is not local if we don't enforce subnet distinction. */
if (get_options()->EnforceDistinctSubnets == 0) {
return false;
}
switch (family) {
case AF_INET:
/* XXX: Why is this /24 and not /16 which the rest of tor does? Unknown
* reasons at the moment highlighted in ticket #40009. Because of that, we
* can't use addrs_in_same_network_family(). */
/* It's possible that this next check will hit before the first time
* resolve_my_address actually succeeds. (For clients, it is likely that
* resolve_my_address will never be called at all). In those cases,
* resolve_my_address_v4 actually succeeds. For clients, it is likely that
* resolve_my_address_v4 will never be called at all. In those cases,
* last_resolved_addr_v4 will be 0, and so checking to see whether ip is
* on the same /24 as last_resolved_addr_v4 will be the same as checking
* whether it was on net 0, which is already done by tor_addr_is_internal.
*/
if ((last_resolved_addr_v4 & (uint32_t)0xffffff00ul)
== (ip & (uint32_t)0xffffff00ul))
return 1;
* on the same /24 as last_resolved_addrs[AF_INET] will be the same as
* checking whether it was on net 0, which is already done by
* tor_addr_is_internal. */
return tor_addr_compare_masked(addr, last_resolved_addr, 24,
CMP_SEMANTIC) == 0;
case AF_INET6:
/* Look at the /32 like addrs_in_same_network_family() does. */
return tor_addr_compare_masked(addr, last_resolved_addr, 32,
CMP_SEMANTIC) == 0;
break;
default:
/* Unknown address type so not local. */
return false;
}
return 0;
}

View File

@ -22,7 +22,7 @@ bool find_my_address(const or_options_t *options, int family,
void resolved_addr_get_last(int family, tor_addr_t *addr_out);
void resolved_addr_reset_last(int family);
MOCK_DECL(int, is_local_addr, (const tor_addr_t *addr));
MOCK_DECL(bool, resolved_addr_is_local, (const tor_addr_t *addr));
#ifdef RESOLVE_ADDR_PRIVATE

View File

@ -203,7 +203,7 @@ channel_tls_connect(const tor_addr_t *addr, uint16_t port,
tlschan,
(chan->global_identifier));
if (is_local_addr(addr)) {
if (resolved_addr_is_local(addr)) {
log_debug(LD_CHANNEL,
"Marking new outgoing channel %"PRIu64 " at %p as local",
(chan->global_identifier), chan);
@ -340,7 +340,7 @@ channel_tls_handle_incoming(or_connection_t *orconn)
tlschan->conn = orconn;
orconn->chan = tlschan;
if (is_local_addr(&(TO_CONN(orconn)->addr))) {
if (resolved_addr_is_local(&(TO_CONN(orconn)->addr))) {
log_debug(LD_CHANNEL,
"Marking new incoming channel %"PRIu64 " at %p as local",
(chan->global_identifier), chan);
@ -1353,7 +1353,7 @@ channel_tls_update_marks(or_connection_t *conn)
chan = TLS_CHAN_TO_BASE(conn->chan);
if (is_local_addr(&(TO_CONN(conn)->addr))) {
if (resolved_addr_is_local(&(TO_CONN(conn)->addr))) {
if (!channel_is_local(chan)) {
log_debug(LD_CHANNEL,
"Marking channel %"PRIu64 " at %p as local",

View File

@ -142,7 +142,7 @@ write_http_response_header_impl(dir_connection_t *conn, ssize_t length,
if (type) {
buf_add_printf(buf, "Content-Type: %s\r\n", type);
}
if (!is_local_addr(&conn->base_.addr)) {
if (!resolved_addr_is_local(&conn->base_.addr)) {
/* Don't report the source address for a nearby/private connection.
* Otherwise we tend to mis-report in cases where incoming ports are
* being forwarded to a Tor server running behind the firewall. */

View File

@ -38,13 +38,13 @@ static or_connection_t * tlschan_connection_or_connect_mock(
const char *digest,
const ed25519_public_key_t *ed_id,
channel_tls_t *tlschan);
static int tlschan_is_local_addr_mock(const tor_addr_t *addr);
static bool tlschan_resolved_addr_is_local_mock(const tor_addr_t *addr);
/* Fake close method */
static void tlschan_fake_close_method(channel_t *chan);
/* Flags controlling behavior of channeltls unit test mocks */
static int tlschan_local = 0;
static bool tlschan_local = false;
static const buf_t * tlschan_buf_datalen_mock_target = NULL;
static size_t tlschan_buf_datalen_mock_size = 0;
@ -67,9 +67,9 @@ test_channeltls_create(void *arg)
test_addr.addr.in_addr.s_addr = htonl(0x01020304);
/* For this test we always want the address to be treated as non-local */
tlschan_local = 0;
/* Install is_local_addr() mock */
MOCK(is_local_addr, tlschan_is_local_addr_mock);
tlschan_local = false;
/* Install resolved_addr_is_local() mock */
MOCK(resolved_addr_is_local, tlschan_resolved_addr_is_local_mock);
/* Install mock for connection_or_connect() */
MOCK(connection_or_connect, tlschan_connection_or_connect_mock);
@ -92,7 +92,7 @@ test_channeltls_create(void *arg)
}
UNMOCK(connection_or_connect);
UNMOCK(is_local_addr);
UNMOCK(resolved_addr_is_local);
return;
}
@ -116,9 +116,9 @@ test_channeltls_num_bytes_queued(void *arg)
test_addr.addr.in_addr.s_addr = htonl(0x01020304);
/* For this test we always want the address to be treated as non-local */
tlschan_local = 0;
/* Install is_local_addr() mock */
MOCK(is_local_addr, tlschan_is_local_addr_mock);
tlschan_local = false;
/* Install resolved_addr_is_local() mock */
MOCK(resolved_addr_is_local, tlschan_resolved_addr_is_local_mock);
/* Install mock for connection_or_connect() */
MOCK(connection_or_connect, tlschan_connection_or_connect_mock);
@ -178,7 +178,7 @@ test_channeltls_num_bytes_queued(void *arg)
}
UNMOCK(connection_or_connect);
UNMOCK(is_local_addr);
UNMOCK(resolved_addr_is_local);
return;
}
@ -201,9 +201,9 @@ test_channeltls_overhead_estimate(void *arg)
test_addr.addr.in_addr.s_addr = htonl(0x01020304);
/* For this test we always want the address to be treated as non-local */
tlschan_local = 0;
/* Install is_local_addr() mock */
MOCK(is_local_addr, tlschan_is_local_addr_mock);
tlschan_local = false;
/* Install resolved_addr_is_local() mock */
MOCK(resolved_addr_is_local, tlschan_resolved_addr_is_local_mock);
/* Install mock for connection_or_connect() */
MOCK(connection_or_connect, tlschan_connection_or_connect_mock);
@ -252,7 +252,7 @@ test_channeltls_overhead_estimate(void *arg)
}
UNMOCK(connection_or_connect);
UNMOCK(is_local_addr);
UNMOCK(resolved_addr_is_local);
return;
}
@ -321,8 +321,8 @@ tlschan_fake_close_method(channel_t *chan)
return;
}
static int
tlschan_is_local_addr_mock(const tor_addr_t *addr)
static bool
tlschan_resolved_addr_is_local_mock(const tor_addr_t *addr)
{
tt_ptr_op(addr, OP_NE, NULL);