From 4c289fc6ad3d7c2afa69e36cdf2cc9a172cb1c9c Mon Sep 17 00:00:00 2001 From: Matthew Holt Date: Tue, 17 Sep 2019 23:13:21 -0600 Subject: Allow domain fronting with TLS client auth if explicitly configured --- modules/caddyhttp/caddyhttp.go | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) (limited to 'modules/caddyhttp/caddyhttp.go') diff --git a/modules/caddyhttp/caddyhttp.go b/modules/caddyhttp/caddyhttp.go index c044a9b..0a26ad1 100644 --- a/modules/caddyhttp/caddyhttp.go +++ b/modules/caddyhttp/caddyhttp.go @@ -78,16 +78,20 @@ func (app *App) Provision(ctx caddy.Context) error { srv.AutoHTTPS = new(AutoHTTPSConfig) } - // disallow TLS client auth bypass which could - // otherwise be exploited by sending an unprotected - // SNI value during TLS handshake, then a protected - // Host header during HTTP request later on that - // connection - if srv.hasTLSClientAuth() { - srv.StrictSNIHost = true + // if not explicitly configured by the user, disallow TLS + // client auth bypass (domain fronting) which could + // otherwise be exploited by sending an unprotected SNI + // value during a TLS handshake, then putting a protected + // domain in the Host header after establishing connection; + // this is a safe default, but we allow users to override + // it for example in the case of running a proxy where + // domain fronting is desired and access is not restricted + // based on hostname + if srv.StrictSNIHost == nil && srv.hasTLSClientAuth() { + trueBool := true + srv.StrictSNIHost = &trueBool } - // TODO: Test this function to ensure these replacements are performed for i := range srv.Listen { srv.Listen[i] = repl.ReplaceAll(srv.Listen[i], "") } -- cgit v1.2.3