tree e564cbc8b3e05a1cfc9eb94d9ea57a31ad1fec6a
parent 761bc39b4d1954f1b3632f4e308e554ca64ef019
author Sergey Kandaurov <pluknet@nginx.com> 1492520924 +0300
committer Sergey Kandaurov <pluknet@nginx.com> 1492520924 +0300

SSL: disabled renegotiation detection in client mode.

CVE-2009-3555 is no longer relevant and mitigated by the renegotiation
info extension (secure renegotiation).  On the other hand, unexpected
renegotiation still introduces potential security risks, and hence we do
not allow renegotiation on the server side, as we never request renegotiation.

On the client side the situation is different though.  There are backends
which explicitly request renegotiation, and disabled renegotiation
introduces interoperability problems.  This change allows renegotiation
on the client side, and fixes interoperability problems as observed with
such backends (ticket #872).

Additionally, with TLSv1.3 the SSL_CB_HANDSHAKE_START flag is currently set
by OpenSSL when receiving a NewSessionTicket message, and was detected by
nginx as a renegotiation attempt.  This looks like a bug in OpenSSL, though
this change also allows better interoperability till the problem is fixed.