id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
2449	"Allow using OpenSSL 3.0 ""provider"" API instead of deprecated ""engine"" API"	nickrbogdanov@…		"I would like to use hardware encryption to protect my webserver's TLS privkey from theft.  My server has a TPM 2.0 chip which supports this, but it's unnecessarily difficult to configure it in nginx.  I'm proposing a change to make the process more user-friendly.

For background: old versions of OpenSSL supported HSMs and hardware offloading through the ENGINE API.  In nginx this is enabled through the `ssl_engine` directive: hxxps://github.com/Infineon/optiga-tpm-cheatsheet#nginx--curl

(Please s/hxxps/https/ due to Trac spam filter)

In OpenSSL 3.0 the authors introduced a ""Provider API"" which is intended to replace the old ENGINE API.  It works in a similar way.  When using the CLI to sign or create TPM-backed keys, you add `-provider tpm2 -provider base` to the arguments: hxxps://github.com/Infineon/optiga-tpm-cheatsheet#pem-encoded-key-object-2

I'm running Ubuntu 22.04 LTS on this webserver.  This Linux distribution has a tpm2-openssl package ( hxxps://github.com/tpm2-software/tpm2-openssl ) which conforms to the new OpenSSL 3.0 Provider API.  The CLI examples on the optiga-tpm-cheatsheet work right out of the box, with no extra configuration.  This makes it quick and easy to set up hardware-backed keys, just by installing a single package.  For instance, anyone running this distro on an x86 Linux PC can do:

    sudo apt install tpm2-openssl
    openssl genpkey -provider tpm2 -algorithm EC -pkeyopt ec_paramgen_curve:P-384 -out testkey.priv
    echo ""test"" | openssl pkeyutl -provider tpm2 -provider base -digest sha256 -inkey testkey.priv -sign -rawin -hexdump

But unfortunately, at this time nginx only supports the ENGINE API, not the Provider API.  In order to use hardware backed keys with nginx, users would need to compile, install, and configure the legacy tpm2tss ENGINE implementation, and keep it up to date themselves without help from the Debian/Ubuntu package maintainers.

I believe that with a small tweak to nginx, it would be possible for users to specify e.g.

    ssl_provider tpm2,base

to tell OpenSSL 3.x to use the tpm2-openssl Provider to support hardware-backed private keys in nginx."	enhancement	new	minor		nginx-core	1.23.x		openssl, provider, tpm, pkcs11, engine		Linux www 5.15.0-58-generic #64-Ubuntu SMP Thu Jan 5 11:43:13 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux	"nginx version: nginx/1.18.0 (Ubuntu)
built with OpenSSL 3.0.2 15 Mar 2022
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -ffile-prefix-map=/build/nginx-d8gVax/nginx-1.18.0=. -flto=auto -ffat-lto-objects -flto=auto -ffat-lto-objects -fstack-protector-strong -Wformat -Werror=format-security -fPIC -Wdate-time -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-Bsymbolic-functions -flto=auto -ffat-lto-objects -flto=auto -Wl,-z,relro -Wl,-z,now -fPIC' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --modules-path=/usr/lib/nginx/modules --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-compat --with-debug --with-pcre-jit --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_v2_module --with-http_dav_module --with-http_slice_module --with-threads --add-dynamic-module=/build/nginx-d8gVax/nginx-1.18.0/debian/modules/http-geoip2 --with-http_addition_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_sub_module
"