Commit 7197c9f1 authored by Nick Mathewson's avatar Nick Mathewson 🥔
Browse files

Repair DNS NEXIST hijacking workaround 

The code previously detected wildcarding and replaced wildcarded
answers with DNS_STATUS_FAILED_PERMANENT.  But that status variable
was no longer used!  Remove the status variable, and instead change
the value of 'result' in evdns_callback.

Thank goodness for compiler warnings. In this case,
unused-but-set-variable.

Thanks to Linus for finding this one.
parent 363cf024

src/or/dns.c

+2 −9
Original line number Diff line number Diff line
@@ -1530,7 +1530,6 @@ evdns_callback(int result, char type, int count, int ttl, void *addresses, 
  char *arg_ = arg;

  uint8_t orig_query_type = arg_[0];

  char *string_address = arg_ + 1;

  int status = DNS_RESOLVE_FAILED_PERMANENT;

  tor_addr_t addr;

  const char *hostname = NULL;

  int was_wildcarded = 0;
@@ -1560,7 +1559,6 @@ evdns_callback(int result, char type, int count, int ttl, void *addresses, 
      char *escaped_address;

      uint32_t *addrs = addresses;

      tor_addr_from_ipv4n(&addr, addrs[0]);

      status = DNS_RESOLVE_SUCCEEDED;



      tor_addr_to_str(answer_buf, &addr, sizeof(answer_buf), 0);

      escaped_address = esc_for_log(string_address);
@@ -1572,7 +1570,7 @@ evdns_callback(int result, char type, int count, int ttl, void *addresses, 
                  escaped_safe_str(answer_buf));

        was_wildcarded = 1;

        tor_addr_make_null(&addr, AF_INET); /* ???? */

        status = DNS_RESOLVE_FAILED_PERMANENT;

        result = DNS_ERR_NOTEXIST;

      } else {

        log_debug(LD_EXIT, "eventdns said that %s resolves to %s",

                  safe_str(escaped_address),
@@ -1584,7 +1582,6 @@ evdns_callback(int result, char type, int count, int ttl, void *addresses, 
      char *escaped_address;

      struct in6_addr *addrs = addresses;

      tor_addr_from_in6(&addr, &addrs[0]);

      status = DNS_RESOLVE_SUCCEEDED;

      tor_inet_ntop(AF_INET6, &addrs[0], answer_buf, sizeof(answer_buf));

      escaped_address = esc_for_log(string_address);
@@ -1595,7 +1592,7 @@ evdns_callback(int result, char type, int count, int ttl, void *addresses, 
                  escaped_safe_str(answer_buf));

        was_wildcarded = 1;

        tor_addr_make_unspec(&addr); /* WRONG WRONG ETC XXXXXXXX */

        status = DNS_RESOLVE_FAILED_PERMANENT;

        result = DNS_ERR_NOTEXIST;

      } else {

        log_debug(LD_EXIT, "eventdns said that %s resolves to %s",

                  safe_str(escaped_address),
@@ -1605,7 +1602,6 @@ evdns_callback(int result, char type, int count, int ttl, void *addresses, 
    } else if (type == DNS_PTR && count) {

      char *escaped_address;

      hostname = ((char**)addresses)[0];

      status = DNS_RESOLVE_SUCCEEDED;

      escaped_address = esc_for_log(string_address);

      log_debug(LD_EXIT, "eventdns said that %s resolves to %s",

                safe_str(escaped_address),
@@ -1618,9 +1614,6 @@ evdns_callback(int result, char type, int count, int ttl, void *addresses, 
      log_warn(LD_BUG, "eventdns returned no addresses or error for %s!",

               escaped_safe_str(string_address));

    }

  } else {

    if (evdns_err_is_transient(result))

      status = DNS_RESOLVE_FAILED_TRANSIENT;

  }

  if (was_wildcarded) {

    if (is_test_address(string_address)) {