Trim the whitelisted emails

[kuboschek]

Just stumbled on this while configuring a rules' whitelist:

If I configured [email protected], [email protected], then both [email protected] and [email protected] (note the extra space) are authorized, but [email protected] isn't.

I suggest to either trim whitespace when checking, in this function:

https://github.com/thomseddon/traefik-forward-auth/blob/c4317b7503fb0528d002eb1e5ee43c4a37f055d0/internal/auth.go#L100C1-L108C2

Or to at least warn when parsing a rule with whitespace in an email. Happy to submit patches moving in either direction.

[ljluestc]

package internal

import (
	"strings"
	"log"
)

// Function that checks the whitelist
func checkWhitelist(whitelist []string, email string) bool {
	// Trim spaces around the email before checking
	email = strings.TrimSpace(email)

	// Trim spaces around all the whitelisted emails
	for i, w := range whitelist {
		whitelist[i] = strings.TrimSpace(w)
	}

	// Now check if the trimmed email is in the whitelist
	for _, w := range whitelist {
		if w == email {
			return true
		}
	}

	// Optional: log a warning if the email has leading/trailing spaces
	if strings.Contains(email, " ") {
		log.Printf("Warning: Email %s has leading or trailing spaces.", email)
	}

	return false
}