JezK

Edit File: ssl.lua

-- Copyright (C) Yichun Zhang (agentzh)

local base = require "resty.core.base"
base.allows_subsystem('http', 'stream')

local ffi = require "ffi"
local C = ffi.C
local ffi_str = ffi.string
local ffi_gc = ffi.gc
local ffi_new = ffi.new
local get_request = base.get_request
local error = error
local tonumber = tonumber
local errmsg = base.get_errmsg_ptr()
local get_string_buf = base.get_string_buf
local get_size_ptr = base.get_size_ptr
local FFI_DECLINED = base.FFI_DECLINED
local FFI_OK = base.FFI_OK
local subsystem = ngx.config.subsystem

local ngx_lua_ffi_ssl_set_der_certificate
local ngx_lua_ffi_ssl_clear_certs
local ngx_lua_ffi_ssl_set_der_private_key
local ngx_lua_ffi_ssl_raw_server_addr
local ngx_lua_ffi_ssl_server_port
local ngx_lua_ffi_ssl_server_name
local ngx_lua_ffi_ssl_raw_client_addr
local ngx_lua_ffi_cert_pem_to_der
local ngx_lua_ffi_priv_key_pem_to_der
local ngx_lua_ffi_ssl_get_tls1_version
local ngx_lua_ffi_parse_pem_cert
local ngx_lua_ffi_parse_pem_priv_key
local ngx_lua_ffi_parse_der_cert
local ngx_lua_ffi_parse_der_priv_key
local ngx_lua_ffi_set_cert
local ngx_lua_ffi_set_priv_key
local ngx_lua_ffi_free_cert
local ngx_lua_ffi_free_priv_key
local ngx_lua_ffi_ssl_verify_client
local ngx_lua_ffi_ssl_client_random
local ngx_lua_ffi_ssl_server_random
local ngx_lua_ffi_ssl_session_master_key
local ngx_lua_ffi_ssl_export_keying_material
local ngx_lua_ffi_ssl_export_keying_material_early
local ngx_lua_ffi_get_req_ssl_pointer
local ngx_lua_ffi_get_upstream_ssl_pointer
local ngx_lua_ffi_req_shared_ssl_ciphers

ffi.cdef[[
typedef struct SSL SSL;
int SSL_session_reused(const SSL *ssl);
]]

if subsystem == 'http' then
    ffi.cdef[[
    int ngx_http_lua_ffi_ssl_set_der_certificate(ngx_http_request_t *r,
        const char *data, size_t len, char **err);

int ngx_http_lua_ffi_ssl_clear_certs(ngx_http_request_t *r, char **err);

int ngx_http_lua_ffi_ssl_set_der_private_key(ngx_http_request_t *r,
        const char *data, size_t len, char **err);

int ngx_http_lua_ffi_ssl_raw_server_addr(ngx_http_request_t *r, char **addr,
        size_t *addrlen, int *addrtype, char **err);

int ngx_http_lua_ffi_ssl_server_port(ngx_http_request_t *r,
        unsigned short *server_port, char **err);

int ngx_http_lua_ffi_ssl_server_name(ngx_http_request_t *r, char **name,
        size_t *namelen, char **err);

int ngx_http_lua_ffi_ssl_raw_client_addr(ngx_http_request_t *r, char **addr,
        size_t *addrlen, int *addrtype, char **err);

int ngx_http_lua_ffi_cert_pem_to_der(const unsigned char *pem,
        size_t pem_len, unsigned char *der, char **err);

int ngx_http_lua_ffi_priv_key_pem_to_der(const unsigned char *pem,
        size_t pem_len, const unsigned char *passphrase,
        unsigned char *der, char **err);

int ngx_http_lua_ffi_ssl_get_tls1_version(ngx_http_request_t *r,
        char **err);

void *ngx_http_lua_ffi_parse_pem_cert(const unsigned char *pem,
        size_t pem_len, char **err);

void *ngx_http_lua_ffi_parse_pem_priv_key(const unsigned char *pem,
        size_t pem_len, char **err);

void *ngx_http_lua_ffi_parse_der_cert(const char *data,
        size_t len, char **err);

void *ngx_http_lua_ffi_parse_der_priv_key(const char *data, size_t len,
        char **err) ;

void *ngx_http_lua_ffi_get_req_ssl_pointer(ngx_http_request_t *r,
        char **err);

void *ngx_http_lua_ffi_get_upstream_ssl_pointer(
        ngx_http_request_t *r, char **err);

int ngx_http_lua_ffi_set_cert(void *r, void *cdata, char **err);

int ngx_http_lua_ffi_set_priv_key(void *r, void *cdata, char **err);

void ngx_http_lua_ffi_free_cert(void *cdata);

void ngx_http_lua_ffi_free_priv_key(void *cdata);

int ngx_http_lua_ffi_ssl_verify_client(void *r,
        void *client_certs, void *trusted_certs, int depth, char **err);

int ngx_http_lua_ffi_ssl_client_random(ngx_http_request_t *r,
        const unsigned char *out, size_t *outlen, char **err);

int ngx_http_lua_ffi_ssl_server_random(ngx_http_request_t *r,
        const unsigned char *out, size_t *outlen, char **err);

int ngx_http_lua_ffi_ssl_session_master_key(ngx_http_request_t *r,
        const unsigned char *out, size_t *outlen, char **err);

int ngx_http_lua_ffi_ssl_export_keying_material(void *r,
        unsigned char *out, size_t out_size,
        const char *label, size_t llen,
        const unsigned char *ctx, size_t ctxlen, int use_ctx, char **err);

int ngx_http_lua_ffi_ssl_export_keying_material_early(void *r,
        unsigned char *out, size_t out_size,
        const char *label, size_t llen,
        const unsigned char *ctx, size_t ctxlen, char **err);

int ngx_http_lua_ffi_req_shared_ssl_ciphers(ngx_http_request_t *r,
        unsigned short *ciphers, unsigned short *nciphers,
        int filter_grease, char **err);
    ]]

ngx_lua_ffi_ssl_set_der_certificate =
        C.ngx_http_lua_ffi_ssl_set_der_certificate
    ngx_lua_ffi_ssl_clear_certs = C.ngx_http_lua_ffi_ssl_clear_certs
    ngx_lua_ffi_ssl_set_der_private_key =
        C.ngx_http_lua_ffi_ssl_set_der_private_key
    ngx_lua_ffi_ssl_raw_server_addr = C.ngx_http_lua_ffi_ssl_raw_server_addr
    ngx_lua_ffi_ssl_server_port = C.ngx_http_lua_ffi_ssl_server_port
    ngx_lua_ffi_ssl_server_name = C.ngx_http_lua_ffi_ssl_server_name
    ngx_lua_ffi_ssl_raw_client_addr = C.ngx_http_lua_ffi_ssl_raw_client_addr
    ngx_lua_ffi_cert_pem_to_der = C.ngx_http_lua_ffi_cert_pem_to_der
    ngx_lua_ffi_priv_key_pem_to_der = C.ngx_http_lua_ffi_priv_key_pem_to_der
    ngx_lua_ffi_ssl_get_tls1_version = C.ngx_http_lua_ffi_ssl_get_tls1_version
    ngx_lua_ffi_parse_pem_cert = C.ngx_http_lua_ffi_parse_pem_cert
    ngx_lua_ffi_parse_pem_priv_key = C.ngx_http_lua_ffi_parse_pem_priv_key
    ngx_lua_ffi_parse_der_cert = C.ngx_http_lua_ffi_parse_der_cert
    ngx_lua_ffi_parse_der_priv_key = C.ngx_http_lua_ffi_parse_der_priv_key
    ngx_lua_ffi_set_cert = C.ngx_http_lua_ffi_set_cert
    ngx_lua_ffi_set_priv_key = C.ngx_http_lua_ffi_set_priv_key
    ngx_lua_ffi_free_cert = C.ngx_http_lua_ffi_free_cert
    ngx_lua_ffi_free_priv_key = C.ngx_http_lua_ffi_free_priv_key
    ngx_lua_ffi_ssl_verify_client = C.ngx_http_lua_ffi_ssl_verify_client
    ngx_lua_ffi_ssl_client_random = C.ngx_http_lua_ffi_ssl_client_random
    ngx_lua_ffi_ssl_server_random = C.ngx_http_lua_ffi_ssl_server_random
    ngx_lua_ffi_ssl_session_master_key =
        C.ngx_http_lua_ffi_ssl_session_master_key
    ngx_lua_ffi_ssl_export_keying_material =
        C.ngx_http_lua_ffi_ssl_export_keying_material
    ngx_lua_ffi_ssl_export_keying_material_early =
        C.ngx_http_lua_ffi_ssl_export_keying_material_early
    ngx_lua_ffi_get_req_ssl_pointer = C.ngx_http_lua_ffi_get_req_ssl_pointer
    ngx_lua_ffi_get_upstream_ssl_pointer
        = C.ngx_http_lua_ffi_get_upstream_ssl_pointer
    ngx_lua_ffi_req_shared_ssl_ciphers =
        C.ngx_http_lua_ffi_req_shared_ssl_ciphers

elseif subsystem == 'stream' then
    ffi.cdef[[
    int ngx_stream_lua_ffi_ssl_set_der_certificate(ngx_stream_lua_request_t *r,
        const char *data, size_t len, char **err);

int ngx_stream_lua_ffi_ssl_clear_certs(ngx_stream_lua_request_t *r,
        char **err);

int ngx_stream_lua_ffi_ssl_set_der_private_key(ngx_stream_lua_request_t *r,
        const char *data, size_t len, char **err);

int ngx_stream_lua_ffi_ssl_raw_server_addr(ngx_stream_lua_request_t *r,
        char **addr, size_t *addrlen, int *addrtype, char **err);

int ngx_stream_lua_ffi_ssl_server_port(ngx_stream_lua_request_t *r,
        unsigned short *server_port, char **err);

int ngx_stream_lua_ffi_ssl_server_name(ngx_stream_lua_request_t *r,
        char **name, size_t *namelen, char **err);

int ngx_stream_lua_ffi_ssl_raw_client_addr(ngx_stream_lua_request_t *r,
        char **addr, size_t *addrlen, int *addrtype, char **err);

int ngx_stream_lua_ffi_cert_pem_to_der(const unsigned char *pem,
        size_t pem_len, unsigned char *der, char **err);

int ngx_stream_lua_ffi_priv_key_pem_to_der(const unsigned char *pem,
        size_t pem_len, const unsigned char *passphrase,
        unsigned char *der, char **err);

int ngx_stream_lua_ffi_ssl_get_tls1_version(ngx_stream_lua_request_t *r,
        char **err);

void *ngx_stream_lua_ffi_parse_pem_cert(const unsigned char *pem,
        size_t pem_len, char **err);

void *ngx_stream_lua_ffi_parse_der_cert(const unsigned char *der,
        size_t der_len, char **err);

void *ngx_stream_lua_ffi_parse_pem_priv_key(const unsigned char *pem,
        size_t pem_len, char **err);

void *ngx_stream_lua_ffi_parse_der_priv_key(const unsigned char *der,
        size_t der_len, char **err);

void *ngx_stream_lua_ffi_get_req_ssl_pointer(ngx_stream_lua_request_t *r,
       char **err);

void *ngx_stream_lua_ffi_get_upstream_ssl_pointer(
        ngx_stream_lua_request_t *r, char **err);

int ngx_stream_lua_ffi_set_cert(void *r, void *cdata, char **err);

int ngx_stream_lua_ffi_set_priv_key(void *r, void *cdata, char **err);

void ngx_stream_lua_ffi_free_cert(void *cdata);

void ngx_stream_lua_ffi_free_priv_key(void *cdata);

int ngx_stream_lua_ffi_ssl_verify_client(void *r,
        void *client_certs, void *trusted_certs, int depth, char **err);

int ngx_stream_lua_ffi_ssl_client_random(ngx_stream_lua_request_t *r,
        unsigned char *out, size_t *outlen, char **err);

int ngx_stream_lua_ffi_req_shared_ssl_ciphers(ngx_stream_lua_request_t *r,
        unsigned short *ciphers, unsigned short *nciphers,
        int filter_grease, char **err);
    ]]

ngx_lua_ffi_ssl_set_der_certificate =
        C.ngx_stream_lua_ffi_ssl_set_der_certificate
    ngx_lua_ffi_ssl_clear_certs = C.ngx_stream_lua_ffi_ssl_clear_certs
    ngx_lua_ffi_ssl_set_der_private_key =
        C.ngx_stream_lua_ffi_ssl_set_der_private_key
    ngx_lua_ffi_ssl_raw_server_addr = C.ngx_stream_lua_ffi_ssl_raw_server_addr
    ngx_lua_ffi_ssl_server_port = C.ngx_stream_lua_ffi_ssl_server_port
    ngx_lua_ffi_ssl_server_name = C.ngx_stream_lua_ffi_ssl_server_name
    ngx_lua_ffi_ssl_raw_client_addr = C.ngx_stream_lua_ffi_ssl_raw_client_addr
    ngx_lua_ffi_cert_pem_to_der = C.ngx_stream_lua_ffi_cert_pem_to_der
    ngx_lua_ffi_priv_key_pem_to_der = C.ngx_stream_lua_ffi_priv_key_pem_to_der
    ngx_lua_ffi_ssl_get_tls1_version =
        C.ngx_stream_lua_ffi_ssl_get_tls1_version
    ngx_lua_ffi_parse_pem_cert = C.ngx_stream_lua_ffi_parse_pem_cert
    ngx_lua_ffi_parse_der_cert = C.ngx_stream_lua_ffi_parse_der_cert
    ngx_lua_ffi_parse_pem_priv_key = C.ngx_stream_lua_ffi_parse_pem_priv_key
    ngx_lua_ffi_parse_der_priv_key = C.ngx_stream_lua_ffi_parse_der_priv_key
    ngx_lua_ffi_set_cert = C.ngx_stream_lua_ffi_set_cert
    ngx_lua_ffi_set_priv_key = C.ngx_stream_lua_ffi_set_priv_key
    ngx_lua_ffi_free_cert = C.ngx_stream_lua_ffi_free_cert
    ngx_lua_ffi_free_priv_key = C.ngx_stream_lua_ffi_free_priv_key
    ngx_lua_ffi_ssl_verify_client = C.ngx_stream_lua_ffi_ssl_verify_client
    ngx_lua_ffi_ssl_client_random = C.ngx_stream_lua_ffi_ssl_client_random
    ngx_lua_ffi_get_req_ssl_pointer = C.ngx_stream_lua_ffi_get_req_ssl_pointer
    ngx_lua_ffi_get_upstream_ssl_pointer
        = C.ngx_stream_lua_ffi_get_upstream_ssl_pointer
    ngx_lua_ffi_req_shared_ssl_ciphers =
        C.ngx_stream_lua_ffi_req_shared_ssl_ciphers
end

local _M = { version = base.version }

local charpp = ffi.new("char*[1]")
local intp = ffi.new("int[1]")
local ushortp = ffi.new("unsigned short[1]")

do
    local ciphers_buf = ffi_new("uint16_t [?]", 256)

function _M.get_req_shared_ssl_ciphers(filter_grease)
        local r = get_request()
        if not r then
            error("no request found")
        end

if filter_grease == nil then
            filter_grease = true  -- Default to filter GREASE
        end

ciphers_buf[0] = 255  -- Set max number of ciphers we can hold
        local filter_flag = filter_grease and 1 or 0
        local rc = ngx_lua_ffi_req_shared_ssl_ciphers(r, ciphers_buf + 1,
                                                      ciphers_buf, filter_flag,
                                                      errmsg)
        if rc ~= FFI_OK then
            return nil, ffi_str(errmsg[0])
        end

-- Build result table
        local result = {}
        for i = 1, ciphers_buf[0] do
            result[i] = tonumber(ciphers_buf[i])
        end

return result
    end
end

function _M.clear_certs()
    local r = get_request()
    if not r then
        error("no request found")
    end

local rc = ngx_lua_ffi_ssl_clear_certs(r, errmsg)
    if rc == FFI_OK then
        return true
    end

return nil, ffi_str(errmsg[0])
end

function _M.set_der_cert(data)
    local r = get_request()
    if not r then
        error("no request found")
    end

local rc = ngx_lua_ffi_ssl_set_der_certificate(r, data, #data, errmsg)
    if rc == FFI_OK then
        return true
    end

return nil, ffi_str(errmsg[0])
end

function _M.set_der_priv_key(data)
    local r = get_request()
    if not r then
        error("no request found")
    end

local rc = ngx_lua_ffi_ssl_set_der_private_key(r, data, #data, errmsg)
    if rc == FFI_OK then
        return true
    end

return nil, ffi_str(errmsg[0])
end

local addr_types = {
    [0] = "unix",
    [1] = "inet",
    [2] = "inet6",
}

function _M.raw_server_addr()
    local r = get_request()
    if not r then
        error("no request found")
    end

local sizep = get_size_ptr()

local rc = ngx_lua_ffi_ssl_raw_server_addr(r, charpp, sizep, intp, errmsg)
    if rc == FFI_OK then
        local typ = addr_types[intp[0]]
        if not typ then
            return nil, nil, "unknown address type: " .. intp[0]
        end
        return ffi_str(charpp[0], sizep[0]), typ
    end

return nil, nil, ffi_str(errmsg[0])
end

function _M.server_port()
    local r = get_request()
    if not r then
        error("no request found")
    end

local rc = ngx_lua_ffi_ssl_server_port(r, ushortp, errmsg)
    if rc == FFI_OK then
        return ushortp[0]
    end

return nil, ffi_str(errmsg[0])
end

function _M.server_name()
    local r = get_request()
    if not r then
        error("no request found")
    end

local sizep = get_size_ptr()

local rc = ngx_lua_ffi_ssl_server_name(r, charpp, sizep, errmsg)
    if rc == FFI_OK then
        return ffi_str(charpp[0], sizep[0])
    end

if rc == FFI_DECLINED then
        return nil
    end

return nil, ffi_str(errmsg[0])
end

function _M.raw_client_addr()
    local r = get_request()
    if not r then
        error("no request found")
    end

local sizep = get_size_ptr()

local rc = ngx_lua_ffi_ssl_raw_client_addr(r, charpp, sizep, intp, errmsg)
    if rc == FFI_OK then
        local typ = addr_types[intp[0]]
        if not typ then
            return nil, nil, "unknown address type: " .. intp[0]
        end
        return ffi_str(charpp[0], sizep[0]), typ
    end

return nil, nil, ffi_str(errmsg[0])
end

function _M.cert_pem_to_der(pem)
    local outbuf = get_string_buf(#pem)

local sz = ngx_lua_ffi_cert_pem_to_der(pem, #pem, outbuf, errmsg)
    if sz > 0 then
        return ffi_str(outbuf, sz)
    end

return nil, ffi_str(errmsg[0])
end

function _M.priv_key_pem_to_der(pem, passphrase)
    local outbuf = get_string_buf(#pem)

local sz = ngx_lua_ffi_priv_key_pem_to_der(pem, #pem,
                                               passphrase, outbuf, errmsg)
    if sz > 0 then
        return ffi_str(outbuf, sz)
    end

return nil, ffi_str(errmsg[0])
end

local function get_tls1_version()

local r = get_request()
    if not r then
        error("no request found")
    end

local ver = ngx_lua_ffi_ssl_get_tls1_version(r, errmsg)

ver = tonumber(ver)

if ver >= 0 then
        return ver
    end

-- rc == FFI_ERROR

return nil, ffi_str(errmsg[0])
end
_M.get_tls1_version = get_tls1_version

function _M.parse_pem_cert(pem)
    local cert = ngx_lua_ffi_parse_pem_cert(pem, #pem, errmsg)
    if cert ~= nil then
        return ffi_gc(cert, ngx_lua_ffi_free_cert)
    end

return nil, ffi_str(errmsg[0])
end

function _M.parse_pem_priv_key(pem)
    local pkey = ngx_lua_ffi_parse_pem_priv_key(pem, #pem, errmsg)
    if pkey ~= nil then
        return ffi_gc(pkey, ngx_lua_ffi_free_priv_key)
    end

return nil, ffi_str(errmsg[0])
end

function _M.parse_der_cert(der)
    local cert = ngx_lua_ffi_parse_der_cert(der, #der, errmsg)
    if cert ~= nil then
        return ffi_gc(cert, ngx_lua_ffi_free_cert)
    end

return nil, ffi_str(errmsg[0])
end

function _M.parse_der_priv_key(der)
    local pkey = ngx_lua_ffi_parse_der_priv_key(der, #der, errmsg)
    if pkey ~= nil then
        return ffi_gc(pkey, ngx_lua_ffi_free_priv_key)
    end

return nil, ffi_str(errmsg[0])
end

function _M.set_cert(cert)
    local r = get_request()
    if not r then
        error("no request found")
    end

local rc = ngx_lua_ffi_set_cert(r, cert, errmsg)
    if rc == FFI_OK then
        return true
    end

return nil, ffi_str(errmsg[0])
end

function _M.set_priv_key(priv_key)
    local r = get_request()
    if not r then
        error("no request found")
    end

local rc = ngx_lua_ffi_set_priv_key(r, priv_key, errmsg)
    if rc == FFI_OK then
        return true
    end

return nil, ffi_str(errmsg[0])
end

function _M.verify_client(client_certs, depth, trusted_certs)
    local r = get_request()
    if not r then
        error("no request found")
    end

if not depth then
        depth = -1
    end

local rc = ngx_lua_ffi_ssl_verify_client(r, client_certs, trusted_certs,
                                             depth, errmsg)
    if rc == FFI_OK then
        return true
    end

return nil, ffi_str(errmsg[0])
end

function _M.export_keying_material(length, label, context)
    local r = get_request()
    if not r then
        error("no request found")
    end

local outbuf = get_string_buf(length)
    local use_context = context and 1 or 0
    local context_len = context and #context or 0

local rc = ngx_lua_ffi_ssl_export_keying_material(r, outbuf, length,
        label, #label, context, context_len, use_context, errmsg)

if rc == FFI_OK then
        return ffi_str(outbuf, length)
    end

if rc == FFI_DECLINED then
        return nil
    end

return nil, ffi_str(errmsg[0])
end

function _M.export_keying_material_early(length, label, context)
    local r = get_request()
    if not r then
        error("no request found")
    end

local outbuf = get_string_buf(length)
    local context_len = context and #context or 0

local rc = ngx_lua_ffi_ssl_export_keying_material_early(r, outbuf, length,
        label, #label, context, context_len, errmsg)

if rc == FFI_OK then
        return ffi_str(outbuf, length)
    end

if rc == FFI_DECLINED then
        return nil
    end

return nil, ffi_str(errmsg[0])
end

function _M.get_req_ssl_pointer()
    local r = get_request()
    if not r then
        error("no request found")
    end

local ssl = ngx_lua_ffi_get_req_ssl_pointer(r, errmsg)
    if ssl == nil then
        return nil, ffi_str(errmsg[0])
    end

return ssl
end

function _M.get_upstream_ssl_pointer()
    local r = get_request()
    if not r then
        error("no request found")
    end

local ssl = ngx_lua_ffi_get_upstream_ssl_pointer(r, errmsg)
    if not ssl then
        return nil, ffi_str(errmsg[0])
    end

return ssl
end

function _M.ssl_session_reused(ssl)
    if not ssl or type(ssl) ~= "cdata"  then
        return nil, "bad ssl"
    end

local reused = C.SSL_session_reused(ssl)
    return tonumber(reused) == 1 and true or false
end

do
    _M.SSL3_VERSION = 0x0300
    _M.TLS1_VERSION = 0x0301
    _M.TLS1_1_VERSION = 0x0302
    _M.TLS1_2_VERSION = 0x0303
    _M.TLS1_3_VERSION = 0x0304

local map = {
        [_M.SSL3_VERSION] = "SSLv3",
        [_M.TLS1_VERSION] = "TLSv1",
        [_M.TLS1_1_VERSION] = "TLSv1.1",
        [_M.TLS1_2_VERSION] = "TLSv1.2",
        [_M.TLS1_3_VERSION] = "TLSv1.3",
    }

function _M.get_tls1_version_str()
        local ver, err = get_tls1_version()
        if not ver then
            return nil, err
        end

local ver_str = map[ver]
        if not ver_str then
            return nil, "unknown version"
        end

return ver_str
    end
end

function _M.get_client_random(outlen)
    local r = get_request()
    if not r then
        error("no request found")
    end

if outlen == nil then
        outlen = 32
    end

local out = get_string_buf(outlen)
    local sizep = get_size_ptr()
    sizep[0] = outlen

local rc = ngx_lua_ffi_ssl_client_random(r, out, sizep, errmsg)
    if rc == FFI_OK then
        if outlen == 0 then
            return tonumber(sizep[0])
        end

return ffi_str(out, sizep[0])
    end

return nil, ffi_str(errmsg[0])
end

function _M.get_server_random(outlen)
    local r = get_request()
    if not r then
        error("no request found")
    end

if outlen == nil then
        outlen = 32
    end

local out = get_string_buf(outlen)
    local sizep = get_size_ptr()
    sizep[0] = outlen

local rc = ngx_lua_ffi_ssl_server_random(r, out, sizep, errmsg)
    if rc == FFI_OK then
        if outlen == 0 then
            return tonumber(sizep[0])
        end

return ffi_str(out, sizep[0])
    end

return nil, ffi_str(errmsg[0])
end

function _M.get_session_master_key(outlen)
    local r = get_request()
    if not r then
        error("no request found")
    end

if outlen == nil then
        outlen = 48
    end

local out = get_string_buf(outlen)
    local sizep = get_size_ptr()
    sizep[0] = outlen

local rc = ngx_lua_ffi_ssl_session_master_key(r, out, sizep, errmsg)
    if rc == FFI_OK then
        if outlen == 0 then
            return tonumber(sizep[0])
        end

return ffi_str(out, sizep[0])
    end

return nil, ffi_str(errmsg[0])
end

return _M