jiri-novotny / crttys

C rewrite of rttys

crttys

C rewrite of rttys https://github.com/zhaojh329/rttys

Motivation

Reuse working client and add new features to server

• websocket proxy
• multiple users, no signup
• store device certs based on predefined CN prefix - device registration
• very simple web interface - no npm deps, xterm used from unpkg.com
• possibility to proxy web via URL only
• Device-over-DTLS

Changes from original rttys

• Only mTLS is used for device authentication
• Token field is used as target proxy path
• Dual-cert for web pages and device connection

Known limitations

• Web is using basic authorization which can be in collision with proxied web app
• File transfer to device is not implemented
• Currently tested with ~10 devices

Build

make

Dependencies

• openssl - tested with 1.1.1f
• hashmap from libds https://github.com/dgraham/libds (part of repo)
• JSON tokenizer from https://github.com/zserge/jsmn (part of repo)

Usage

Options

-h/--help               Print this help
-a/--auth               Basic authorization for web access
-A/--auth-file          User list for Basic authorization for web access
-d/--dev-port           Port for device access
-k/--dev-key            Path to device SSL key
-c/--dev-cert           Path to device SSL cert
-v/--dev-verify         Path to device verification cert dir
-V/--dev-ssl-prefix     Set device certificate prefix
-w/--web-port           Port for web access
-K/--web-key            Path to web SSL key
-C/--web-cert           Path to web SSL cert

Example

crttys -a `cat /usr/local/etc/crttys/auth` -d 1234 -w 443 -k /usr/local/etc/crttys/key.pem -c /usr/local/etc/crttys/cert.pem -v /usr/local/etc/crttys/devices/ -x /etc/ssl/private/ssl-cert-snakeoil.key -z /etc/ssl/certs/ssl-cert-snakeoil.pem