SSL: enabled TLSv1.3 with BoringSSL. BoringSSL currently requires SSL_CTX_set_max_proto_version(TLS1_3_VERSION) to be able to enable TLS 1.3. This is because by default max protocol version is set to TLS 1.2, and the SSL_OP_NO_* options are merely used as a blacklist within the version range specified using the SSL_CTX_set_min_proto_version() and SSL_CTX_set_max_proto_version() functions. With this change, we now call SSL_CTX_set_max_proto_version() with an explicit maximum version set. This enables TLS 1.3 with BoringSSL. As a side effect, this change also limits maximum protocol version to the newest protocol we know about, TLS 1.3. This seems to be a good change, as enabling unknown protocols might have unexpected results. Additionally, we now explicitly call SSL_CTX_set_min_proto_version() with 0. This is expected to help with Debian system-wide default of MinProtocol set to TLSv1.2, see http://mailman.nginx.org/pipermail/nginx-ru/2017-October/060411.html. Note that there is no SSL_CTX_set_min_proto_version macro in BoringSSL, so we call SSL_CTX_set_min_proto_version() and SSL_CTX_set_max_proto_version() as long as the TLS1_3_VERSION macro is defined.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


echo $ngx_n "checking for $ngx_include ...$ngx_c"

cat << END >> $NGX_AUTOCONF_ERR

----------------------------------------
checking for $ngx_include

END


ngx_found=no

cat << END > $NGX_AUTOTEST.c

$NGX_INCLUDE_SYS_PARAM_H
#include <$ngx_include>

int main(void) {
    return 0;
}

END


ngx_test="$CC -o $NGX_AUTOTEST $NGX_AUTOTEST.c"

eval "$ngx_test >> $NGX_AUTOCONF_ERR 2>&1"

if [ -x $NGX_AUTOTEST ]; then

    ngx_found=yes

    echo " found"

    ngx_name=`echo $ngx_include \
              | tr abcdefghijklmnopqrstuvwxyz/. ABCDEFGHIJKLMNOPQRSTUVWXYZ__`


    have=NGX_HAVE_$ngx_name . auto/have_headers

    eval "NGX_INCLUDE_$ngx_name='#include <$ngx_include>'"

else
    echo " not found"

    echo "----------"    >> $NGX_AUTOCONF_ERR
    cat $NGX_AUTOTEST.c  >> $NGX_AUTOCONF_ERR
    echo "----------"    >> $NGX_AUTOCONF_ERR
    echo $ngx_test       >> $NGX_AUTOCONF_ERR
    echo "----------"    >> $NGX_AUTOCONF_ERR
fi

rm -rf $NGX_AUTOTEST*