Make tor_addr_is_internal_() RFC6598 (Carrier Grade NAT) aware (63b40491) · Commits · David Goulet / Tor

changes/bug28525

0 → 100644

+8 −0

Original line number	Diff line number	Diff line
		o Minor bugfixes (address selection):
		- Make Tor aware of the RFC 6598 (Carrier Grade NAT) IP range, which is the
		subnet 100.64.0.0/10. This is deployed by many ISPs as an alternative to
		RFC 1918 that does not break existing internal networks. This patch fixes
		security issues caused by RFC 6518 by blocking control ports on these
		addresses and warns users if client ports or ExtORPorts are listening on
		a RFC 6598 address. Fixes bug 28525; bugfix on 0.4.1.1-alpha. Patch by
		Neel Chauhan.

src/common/address.c

+15 −4

Original line number	Diff line number	Diff line
		@@ -348,9 +348,18 @@ tor_addr_lookup(const char name, uint16_t family, tor_addr_t addr)
		}
		}

		/** Return true iff <b>ip</b> is an IP reserved to localhost or local networks
		* in RFC1918 or RFC4193 or RFC4291. (fec0::/10, deprecated by RFC3879, is
		* also treated as internal for now.)
		/** Return true iff <b>ip</b> is an IP reserved to localhost or local networks.
		*
		* If <b>ip</b> is in RFC1918 or RFC4193 or RFC4291, we will return true.
		* (fec0::/10, deprecated by RFC3879, is also treated as internal for now
		* and will return true.)
		*
		* If <b>ip</b> is 0.0.0.0 or 100.64.0.0/10 (RFC6598), we will act as:
		* - Internal if <b>for_listening</b> is 0, as these addresses are not
		* routable on the internet and we won't be publicly accessible to clients.
		* - External if <b>for_listening</b> is 1, as clients could connect to us
		* from the internet (in the case of 0.0.0.0) or a service provider's
		* internal network (in the case of RFC6598).
		*/
		int
		tor_addr_is_internal_(const tor_addr_t *addr, int for_listening,
		@@ -398,11 +407,13 @@ tor_addr_is_internal_(const tor_addr_t *addr, int for_listening,

		return 0;
		} else if (v_family == AF_INET) {
		if (for_listening && !iph4) /* special case for binding to 0.0.0.0 */
		/* special case for binding to 0.0.0.0 or 100.64/10 (RFC6598) */
		if (for_listening && (!iph4 \|\| ((iph4 & 0xffc00000) == 0x64400000)))
		return 0;
		if (((iph4 & 0xff000000) == 0x0a000000) \|\| /* 10/8 */
		((iph4 & 0xff000000) == 0x00000000) \|\| /* 0/8 */
		((iph4 & 0xff000000) == 0x7f000000) \|\| /* 127/8 */
		((iph4 & 0xffc00000) == 0x64400000) \|\| /* 100.64/10 */
		((iph4 & 0xffff0000) == 0xa9fe0000) \|\| /* 169.254/16 */
		((iph4 & 0xfff00000) == 0xac100000) \|\| /* 172.16/12 */
		((iph4 & 0xffff0000) == 0xc0a80000)) /* 192.168/16 */

src/test/test_addr.c

+18 −0

Original line number	Diff line number	Diff line
		@@ -1063,6 +1063,23 @@ test_addr_make_null(void *data)
		tor_free(zeros);
		}

		#define TEST_ADDR_INTERNAL(a, for_listening, rv) STMT_BEGIN \
		tor_addr_t t; \
		tt_int_op(tor_inet_pton(AF_INET, a, &t.addr.in_addr), OP_EQ, 1); \
		t.family = AF_INET; \
		tt_int_op(tor_addr_is_internal(&t, for_listening), OP_EQ, rv); \
		STMT_END;

		static void
		test_addr_rfc6598(void *arg)
		{
		(void)arg;
		TEST_ADDR_INTERNAL("100.64.0.1", 0, 1);
		TEST_ADDR_INTERNAL("100.64.0.1", 1, 0);
		done:
		;
		}

		#define ADDR_LEGACY(name) \
		{ #name, test_addr_ ## name , 0, NULL, NULL }

		@@ -1076,6 +1093,7 @@ struct testcase_t addr_tests[] = {
		{ "sockaddr_to_str", test_addr_sockaddr_to_str, 0, NULL, NULL },
		{ "is_loopback", test_addr_is_loopback, 0, NULL, NULL },
		{ "make_null", test_addr_make_null, 0, NULL, NULL },
		{ "rfc6598", test_addr_rfc6598, 0, NULL, NULL },
		END_OF_TESTCASES
		};