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[or-cvs] Implement "Dont-Care" from addresses to MapAddress control ...
- To: or-cvs@xxxxxxxxxxxxx
- Subject: [or-cvs] Implement "Dont-Care" from addresses to MapAddress control ...
- From: nickm@xxxxxxxx (Nick Mathewson)
- Date: Wed, 2 Mar 2005 14:26:49 -0500 (EST)
- Delivered-to: archiver@seul.org
- Delivered-to: or-cvs-outgoing@seul.org
- Delivered-to: or-cvs@seul.org
- Delivery-date: Wed, 02 Mar 2005 14:27:24 -0500
- Reply-to: or-dev@xxxxxxxxxxxxx
- Sender: owner-or-cvs@xxxxxxxxxxxxx
Update of /home/or/cvsroot/tor/src/or
In directory moria.mit.edu:/tmp/cvs-serv25365/src/or
Modified Files:
connection_edge.c control.c or.h
Log Message:
Implement "Dont-Care" from addresses to MapAddress control message. For safety, refuse to launch connections to unmapped addresses in the dont-care range.
Index: connection_edge.c
===================================================================
RCS file: /home/or/cvsroot/tor/src/or/connection_edge.c,v
retrieving revision 1.288
retrieving revision 1.289
diff -u -d -r1.288 -r1.289
--- connection_edge.c 2 Mar 2005 03:13:05 -0000 1.288
+++ connection_edge.c 2 Mar 2005 19:26:46 -0000 1.289
@@ -534,6 +534,77 @@
time(NULL) + MAX_DNS_ENTRY_AGE);
}
+/* Currently, we hand out 127.192.0.1 through 127.254.254.254.
+ * These addresses should map to localhost, so even if the
+ * application accidentally tried to connect to them directly (not
+ * via Tor), it wouldn't get too far astray.
+ *
+ * Eventually, we should probably make this configurable.
+ */
+#define MIN_UNUSED_IPV4 0x7fc00001u
+#define MAX_UNUSED_IPV4 0x7ffefefeu
+
+/**
+ * Return true iff <b>addr</b> is likely to have been returned by
+ * client_dns_get_unmapped_address.
+ **/
+static int
+address_is_in_unmapped_range(const char *addr)
+{
+ struct in_addr in;
+ tor_assert(addr);
+ if (!strcasecmpend(addr, ".virtual")) {
+ return 1;
+ } else if (tor_inet_aton(addr, &in)) {
+ uint32_t a = ntohl(in.s_addr);
+ if (a >= MIN_UNUSED_IPV4 && a <= MAX_UNUSED_IPV4)
+ return 1;
+ }
+ return 0;
+}
+
+/** Return a newly allocated string holding an address of <b>type</b>
+ * (one of RESOLVED_TYPE_{IPV4|HOSTNAME}) that has not yet been mapped,
+ * and that is very unlikely to be the address of any real host.
+ */
+char *
+client_dns_get_unmapped_address(int type)
+{
+ char buf[64];
+ static uint32_t next_ipv4 = MIN_UNUSED_IPV4;
+ struct in_addr in;
+
+ if (type == RESOLVED_TYPE_HOSTNAME) {
+ char rand[16];
+ do {
+ crypto_rand(rand, sizeof(rand));
+ base32_encode(buf,sizeof(buf),rand,sizeof(rand));
+ strlcat(buf, ".virtual", sizeof(buf));
+ } while (strmap_get(addressmap, buf));
+ return tor_strdup(buf);
+ } else if (type == RESOLVED_TYPE_IPV4) {
+ while (1) {
+ /* Don't hand out any .0 or .255 address. */
+ while ((next_ipv4 & 0xff) == 0 ||
+ (next_ipv4 & 0xff) == 0xff)
+ ++next_ipv4;
+ in.s_addr = htonl(next_ipv4);
+ tor_inet_ntoa(&in, buf, sizeof(buf));
+ if (!strmap_get(addressmap, buf))
+ break;
+
+ ++next_ipv4;
+ if (next_ipv4 > MAX_UNUSED_IPV4)
+ next_ipv4 = MIN_UNUSED_IPV4;
+ }
+ return tor_strdup(buf);
+ } else {
+ log_fn(LOG_WARN, "Called with unsupported address type (%d)",
+ type);
+ return NULL;
+ }
+}
+
/** Return 1 if <b>address</b> has funny characters in it like
* colons. Return 0 if it's fine.
*/
@@ -593,6 +664,17 @@
/* For address map controls, remap the address */
addressmap_rewrite(socks->address, sizeof(socks->address));
+ if (address_is_in_unmapped_range(socks->address)) {
+ /* This address was probably handed out by client_dns_get_unmapped_address,
+ * but the mapping was discarded for some reason. We *don't* want to send
+ * the address through tor; that's likely to fail, and may leak
+ * information.
+ */
+ log_fn(LOG_WARN,"Missing mapping for virtual address '%s'. Refusing.",
+ socks->address);
+ return -1;
+ }
+
/* Parse the address provided by SOCKS. Modify it in-place if it
* specifies a hidden-service (.onion) or particular exit node (.exit).
*/
Index: control.c
===================================================================
RCS file: /home/or/cvsroot/tor/src/or/control.c,v
retrieving revision 1.46
retrieving revision 1.47
diff -u -d -r1.46 -r1.47
--- control.c 1 Mar 2005 01:15:00 -0000 1.46
+++ control.c 2 Mar 2005 19:26:46 -0000 1.47
@@ -471,6 +471,18 @@
log_fn(LOG_WARN,"Skipping invalid argument '%s' in MapAddress msg",from);
} else if (!is_plausible_address(to)) {
log_fn(LOG_WARN,"Skipping invalid argument '%s' in AddressMap msg",to);
+ } else if (!strcmp(from, ".") || !strcmp(from, "0.0.0.0")) {
+ char *addr = client_dns_get_unmapped_address(
+ strcmp(from,".") ? RESOLVED_TYPE_HOSTNAME : RESOLVED_TYPE_IPV4);
+ if (!addr) {
+ log_fn(LOG_WARN,
+ "Unable to allocate address for '%s' in AdressMap msg", line);
+ } else {
+ char *ans = tor_malloc(strlen(addr)+strlen(to)+2);
+ tor_snprintf(ans, "%s %s", addr, to);
+ addressmap_register(addr, tor_strdup(to), 0);
+ smartlist_add(reply, ans);
+ }
} else {
addressmap_register(from, tor_strdup(to), 0);
smartlist_add(reply, tor_strdup(line));
Index: or.h
===================================================================
RCS file: /home/or/cvsroot/tor/src/or/or.h,v
retrieving revision 1.547
retrieving revision 1.548
diff -u -d -r1.547 -r1.548
--- or.h 1 Mar 2005 22:42:31 -0000 1.547
+++ or.h 2 Mar 2005 19:26:46 -0000 1.548
@@ -427,6 +427,7 @@
#define END_STREAM_REASON_CONNRESET 12
#define END_STREAM_REASON_TORPROTOCOL 13
+#define RESOLVED_TYPE_HOSTNAME 0
#define RESOLVED_TYPE_IPV4 4
#define RESOLVED_TYPE_IPV6 6
#define RESOLVED_TYPE_ERROR_TRANSIENT 0xF0
@@ -1318,6 +1319,7 @@
void addressmap_register(const char *address, char *new_address, time_t expires);
int client_dns_incr_failures(const char *address);
void client_dns_set_addressmap(const char *address, uint32_t val, const char *exitname);
+char *client_dns_get_unmapped_address(int type);
void parse_socks_policy(void);
void free_socks_policy(void);