Enhanced auth token / remember me (#27606)

Closes #27455

> The mechanism responsible for long-term authentication (the 'remember
me' cookie) uses a weak construction technique. It will hash the user's
hashed password and the rands value; it will then call the secure cookie
code, which will encrypt the user's name with the computed hash. If one
were able to dump the database, they could extract those two values to
rebuild that cookie and impersonate a user. That vulnerability exists
from the date the dump was obtained until a user changed their password.
> 
> To fix this security issue, the cookie could be created and verified
using a different technique such as the one explained at
https://paragonie.com/blog/2015/04/secure-authentication-php-with-long-term-persistence#secure-remember-me-cookies.

The PR removes the now obsolete setting `COOKIE_USERNAME`.

1 files changed, 1 insertions, 1 deletions

diff --git a/routers/web/web.go b/routers/web/web.go
index d2179a0008..6449f7716c 100644
--- a/routers/web/web.go
+++ b/routers/web/web.go
@@ -187,7 +187,7 @@ func verifyAuthWithOptions(options *common.VerifyOptions) func(ctx *context.Cont
 
 		// Redirect to log in page if auto-signin info is provided and has not signed in.
 		if !options.SignOutRequired && !ctx.IsSigned &&
-			len(ctx.GetSiteCookie(setting.CookieUserName)) > 0 {
+			ctx.GetSiteCookie(setting.CookieRememberName) != "" {
 			if ctx.Req.URL.Path != "/user/events" {
 				middleware.SetRedirectToCookie(ctx.Resp, setting.AppSubURL+ctx.Req.URL.RequestURI())
 			}