Commit bc9492a9 authored by Nick Mathewson's avatar Nick Mathewson 🦀
Browse files

Merge branch 'ticket31343_029' into ticket31343_035

parents 1dd95278 0849d2a2

changes/bug31343

0 → 100644
+9 −0
Original line number Diff line number Diff line 
  o Minor bugfixes (compilation):

    - Avoid using labs() on time_t, which can cause compilation warnings

      on 64-bit Windows builds.  Fixes bug 31343; bugfix on 0.2.4.4-alpha.



  o Minor bugfixes (clock skew detection):

    - Don't believe clock skew results from NETINFO cells that appear to

      arrive before the VERSIONS cells they are responding to were sent.

      Previously, we would accept them up to 3 minutes "in the past".

      Fixes bug 31343; bugfix on 0.2.4.4-alpha.

src/core/or/channeltls.c

+20 −4
Original line number Diff line number Diff line
@@ -1637,7 +1637,19 @@ channel_tls_process_padding_negotiate_cell(cell_t *cell, channel_tls_t *chan) 
}



/**

 * Process a 'netinfo' cell.

 * Helper: compute the absolute value of a time_t.

 *

 * (we need this because labs() doesn't always work for time_t, since

 * long can be shorter than time_t.)

 */

static inline time_t

time_abs(time_t val)

{

  return (val < 0) ? -val : val;

}



/**

 * Process a 'netinfo' cell

 *

 * This function is called to handle an incoming NETINFO cell; read and act

 * on its contents, and set the connection state to "open".
@@ -1654,7 +1666,7 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan) 
  time_t now = time(NULL);

  const routerinfo_t *me = router_get_my_routerinfo();



  long apparent_skew = 0;

  time_t apparent_skew = 0;

  tor_addr_t my_apparent_addr = TOR_ADDR_NULL;

  int started_here = 0;

  const char *identity_digest = NULL;
@@ -1721,7 +1733,11 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan) 


  /* Decode the cell. */

  timestamp = ntohl(get_uint32(cell->payload));

  if (labs(now - chan->conn->handshake_state->sent_versions_at) < 180) {

  const time_t sent_versions_at =

    chan->conn->handshake_state->sent_versions_at;

  if (now > sent_versions_at && (now - sent_versions_at) < 180) {

    /* If we have gotten the NETINFO cell reasonably soon after having

     * sent our VERSIONS cell, maybe we can learn skew information from it. */

    apparent_skew = now - timestamp;

  }
@@ -1801,7 +1817,7 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan) 
  /* Act on apparent skew. */

  /** Warn when we get a netinfo skew with at least this value. */

#define NETINFO_NOTICE_SKEW 3600

  if (labs(apparent_skew) > NETINFO_NOTICE_SKEW &&

  if (time_abs(apparent_skew) > NETINFO_NOTICE_SKEW &&

      (started_here ||

       connection_or_digest_is_known_relay(chan->conn->identity_digest))) {

    int trusted = router_digest_is_trusted_dir(chan->conn->identity_digest);