Commit 856baf5a authored by Anders Bakken's avatar Anders Bakken Committed by Daniel Stenberg
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TLS: SSL_peek is not a const operation 

Calling SSL_peek can cause bytes to be read from the raw socket which in
turn can upset the select machinery that determines whether there's data
available on the socket.

Since Curl_ossl_check_cxn only tries to determine whether the socket is
alive and doesn't actually need to see the bytes SSL_peek seems like
the wrong function to call.

We're able to occasionally reproduce a connect timeout due to this
bug. What happens is that Curl doesn't know to call SSL_connect again
after the peek happens since data is buffered in the SSL buffer and thus
select won't fire for this socket.

Closes #795
parent f6767f54

lib/vtls/openssl.c

+8 −8
Original line number Diff line number Diff line
@@ -759,17 +759,17 @@ void Curl_ossl_cleanup(void) 
 */

int Curl_ossl_check_cxn(struct connectdata *conn)

{

  int rc;

#ifdef MSG_PEEK

  char buf;



  rc = SSL_peek(conn->ssl[FIRSTSOCKET].handle, (void*)&buf, 1);

  if(rc > 0)

    return 1; /* connection still in place */



  if(rc == 0)

  if(recv((RECV_TYPE_ARG1)conn->sock[FIRSTSOCKET], (RECV_TYPE_ARG2)&buf,

          (RECV_TYPE_ARG3)1, (RECV_TYPE_ARG4)MSG_PEEK) == 0) {

    return 0; /* connection has been closed */



  }

  else

    return 1; /* connection still in place */

#else

  return -1; /* connection status unknown */

#endif

}



/* Selects an OpenSSL crypto engine