r8894@Kushana: nickm | 2006-09-21 18:30:42 -0400

 Specify and implement SOCKS5 interface for reverse hostname lookup.


svn:r8451

3 files changed, 62 insertions, 16 deletions

diff --git a/src/or/buffers.c b/src/or/buffers.c
index b6e775da86..290a81c8b2 100644
--- a/src/or/buffers.c
+++ b/src/or/buffers.c
@@ -974,8 +974,9 @@ fetch_from_buf_socks(buf_t *buf, socks_request_t *req,
         return 0; /* not yet */
       req->command = (unsigned char) *(buf->cur+1);
       if (req->command != SOCKS_COMMAND_CONNECT &&
-          req->command != SOCKS_COMMAND_RESOLVE) {
-        /* not a connect or resolve? we don't support it. */
+          req->command != SOCKS_COMMAND_RESOLVE &&
+          req->command != SOCKS_COMMAND_RESOLVE_PTR) {
+        /* not a connect or resolve or a resolve_ptr? we don't support it. */
         log_warn(LD_APP,"socks5: command %d not recognized. Rejecting.",
                  req->command);
         return -1;
@@ -999,7 +1000,8 @@ fetch_from_buf_socks(buf_t *buf, socks_request_t *req,
           strlcpy(req->address,tmpbuf,sizeof(req->address));
           req->port = ntohs(*(uint16_t*)(buf->cur+8));
           buf_remove_from_front(buf, 10);
-          if (!addressmap_have_mapping(req->address) &&
+          if (req->command != SOCKS_COMMAND_RESOLVE_PTR &&
+              !addressmap_have_mapping(req->address) &&
               !have_warned_about_unsafe_socks) {
             log_warn(LD_APP,
                 "Your application (using socks5 on port %d) is giving "
@@ -1025,6 +1027,11 @@ fetch_from_buf_socks(buf_t *buf, socks_request_t *req,
                      "%d. Rejecting.", len+1,MAX_SOCKS_ADDR_LEN);
             return -1;
           }
+          if (req->command == SOCKS_COMMAND_RESOLVE_PTR) {
+            log_warn(LD_APP, "socks5 received RESOLVE_PTR command with "
+                     "hostname type. Rejecting.");
+            return -1;
+          }
           memcpy(req->address,buf->cur+5,len);
           req->address[len] = 0;
           req->port = ntohs(get_uint16(buf->cur+5+len));
@@ -1059,7 +1066,8 @@ fetch_from_buf_socks(buf_t *buf, socks_request_t *req,
       req->command = (unsigned char) *(buf->cur+1);
       if (req->command != SOCKS_COMMAND_CONNECT &&
           req->command != SOCKS_COMMAND_RESOLVE) {
-        /* not a connect or resolve? we don't support it. */
+        /* not a connect or resolve? we don't support it. (No resolve_ptr with
+         * socks4.) */
         log_warn(LD_APP,"socks4: command %d not recognized. Rejecting.",
                  req->command);
         return -1;
diff --git a/src/or/connection_edge.c b/src/or/connection_edge.c
index 3ed8aa9f28..8d6c9273ba 100644
--- a/src/or/connection_edge.c
+++ b/src/or/connection_edge.c
@@ -1120,7 +1120,7 @@ connection_ap_handshake_rewrite_and_attach(edge_connection_t *conn,
       return -1;
     }
 
-    if (socks->command == SOCKS_COMMAND_RESOLVE) {
+    if (socks->command == SOCKS_COMMAND_RESOLVE) { // resolve_ptr XXXX NM
       uint32_t answer;
       struct in_addr in;
       /* Reply to resolves immediately if we can. */
@@ -1181,7 +1181,7 @@ connection_ap_handshake_rewrite_and_attach(edge_connection_t *conn,
     rend_cache_entry_t *entry;
     int r;
 
-    if (socks->command == SOCKS_COMMAND_RESOLVE) {
+    if (socks->command != SOCKS_COMMAND_CONNECT) {
       /* if it's a resolve request, fail it right now, rather than
        * building all the circuits and then realizing it won't work. */
       log_warn(LD_APP,
@@ -1524,13 +1524,17 @@ int
 connection_ap_handshake_send_resolve(edge_connection_t *ap_conn,
                                      origin_circuit_t *circ)
 {
-  int payload_len;
+  int payload_len, command;
   const char *string_addr;
+  char inaddr_buf[32];
+
+  command = ap_conn->socks_request->command;
 
   tor_assert(ap_conn->_base.type == CONN_TYPE_AP);
   tor_assert(ap_conn->_base.state == AP_CONN_STATE_CIRCUIT_WAIT);
   tor_assert(ap_conn->socks_request);
-  tor_assert(ap_conn->socks_request->command == SOCKS_COMMAND_RESOLVE);
+  tor_assert(command == SOCKS_COMMAND_RESOLVE ||
+             command == SOCKS_COMMAND_RESOLVE_PTR);
   tor_assert(circ->_base.purpose == CIRCUIT_PURPOSE_C_GENERAL);
 
   ap_conn->stream_id = get_unique_stream_id_by_circ(circ);
@@ -1540,9 +1544,27 @@ connection_ap_handshake_send_resolve(edge_connection_t *ap_conn,
     return -1;
   }
 
-  string_addr = ap_conn->socks_request->address;
-  payload_len = strlen(string_addr)+1;
-  tor_assert(payload_len <= RELAY_PAYLOAD_SIZE);
+  if (command == SOCKS_COMMAND_RESOLVE) {
+    string_addr = ap_conn->socks_request->address;
+    payload_len = strlen(string_addr)+1;
+    tor_assert(payload_len <= RELAY_PAYLOAD_SIZE);
+  } else {
+    struct in_addr in;
+    uint32_t a;
+    if (tor_inet_aton(ap_conn->socks_request->address, &in) == 0) {
+      connection_mark_unattached_ap(ap_conn, END_STREAM_REASON_INTERNAL);
+      return -1;
+    }
+    a = ntohl(in.s_addr);
+    tor_snprintf(inaddr_buf, sizeof(inaddr_buf), "%d.%d.%d.%d.in-addr.arpa",
+                 (int)(uint8_t)((a    )&0xff),
+                 (int)(uint8_t)((a>>8 )&0xff),
+                 (int)(uint8_t)((a>>16)&0xff),
+                 (int)(uint8_t)((a>>24)&0xff));
+    string_addr = inaddr_buf;
+    payload_len = strlen(inaddr_buf)+1;
+    tor_assert(payload_len <= RELAY_PAYLOAD_SIZE);
+  }
 
   log_debug(LD_APP,
             "Sending relay cell to begin stream %d.", ap_conn->stream_id);
@@ -1625,7 +1647,7 @@ connection_ap_make_bridge(char *address, uint16_t port)
 }
 
 /** Send an answer to an AP connection that has requested a DNS lookup
- * via SOCKS.  The type should be one of RESOLVED_TYPE_(IPV4|IPV6) or
+ * via SOCKS.  The type should be one of RESOLVED_TYPE_(IPV4|IPV6|HOSTNAME) or
  * -1 for unreachable; the answer should be in the format specified
  * in the socks extensions document.
  **/
@@ -1636,7 +1658,7 @@ connection_ap_handshake_socks_resolved(edge_connection_t *conn,
                                        const char *answer,
                                        int ttl)
 {
-  char buf[256];
+  char buf[384];
   size_t replylen;
 
   if (answer_type == RESOLVED_TYPE_IPV4) {
@@ -1675,6 +1697,14 @@ connection_ap_handshake_socks_resolved(edge_connection_t *conn,
       memcpy(buf+4, answer, 16); /* address */
       set_uint16(buf+20, 0); /* port == 0. */
       replylen = 22;
+    } else if (answer_type == RESOLVED_TYPE_HOSTNAME && answer_len < 256) {
+      buf[1] = SOCKS5_SUCCEEDED;
+      buf[2] = 0; /* reserved */
+      buf[3] = 0x03; /* Domainname address type */
+      memcpy(buf+4, answer, answer_len); /* address */
+      buf[4+answer_len] = '\0';
+      set_uint16(buf+4+answer_len+1, 0); /* port == 0. */
+      replylen = 4+answer_len+1+2;
     } else {
       buf[1] = SOCKS5_HOST_UNREACHABLE;
       memset(buf+2, 0, 8);
@@ -1699,7 +1729,8 @@ connection_ap_handshake_socks_resolved(edge_connection_t *conn,
 void
 connection_ap_handshake_socks_reply(edge_connection_t *conn, char *reply,
                                     size_t replylen,
-                                    socks5_reply_status_t status) {
+                                    socks5_reply_status_t status)
+{
   char buf[256];
   tor_assert(conn->socks_request); /* make sure it's an AP stream */
 
@@ -2072,7 +2103,7 @@ connection_ap_can_use_exit(edge_connection_t *conn, routerinfo_t *exit)
     }
   }
 
-  if (conn->socks_request->command != SOCKS_COMMAND_RESOLVE) {
+  if (conn->socks_request->command == SOCKS_COMMAND_CONNECT) {
     struct in_addr in;
     uint32_t addr = 0;
     addr_policy_result_t r;
@@ -2082,7 +2113,13 @@ connection_ap_can_use_exit(edge_connection_t *conn, routerinfo_t *exit)
                                     exit->exit_policy);
     if (r == ADDR_POLICY_REJECTED || r == ADDR_POLICY_PROBABLY_REJECTED)
       return 0;
-  } else {
+  } else { /* Some kind of a resolve. */
+
+    /* Can't support reverse lookups without eventdns. */
+    if (conn->socks_request->command == SOCKS_COMMAND_RESOLVE_PTR &&
+        exit->has_old_dnsworkers)
+      return 0;
+
     /* Don't send DNS requests to non-exit servers by default. */
     if (policy_is_reject_star(exit->exit_policy))
       return 0;
diff --git a/src/or/or.h b/src/or/or.h
index 217cb260f0..f8852b2e13 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -1612,6 +1612,7 @@ typedef struct {
 #define MAX_SOCKS_ADDR_LEN 256
 #define SOCKS_COMMAND_CONNECT 0x01
 #define SOCKS_COMMAND_RESOLVE 0xF0
+#define SOCKS_COMMAND_RESOLVE_PTR 0xF1
 /** State of a SOCKS request from a user to an OP */
 struct socks_request_t {
   char socks_version; /**< Which version of SOCKS did the client use? */