linx-server/csrf.go

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package main
import (
"net/http"
"net/url"
)
// Do a strict referrer check, matching against both the Origin header (if
// present) and the Referrer header. If a list of headers is specified, then
// Referrer checking will be skipped if any of those headers are present.
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func strictReferrerCheck(r *http.Request, prefix string, whitelistHeaders []string, allowBlank bool) bool {
p, _ := url.Parse(prefix)
// if there's an Origin header, check it and skip other checks
if origin := r.Header.Get("Origin"); origin != "" {
u, _ := url.Parse(origin)
return sameOrigin(u, p)
}
for _, header := range whitelistHeaders {
if r.Header.Get(header) != "" {
return true
}
}
referrer := r.Header.Get("Referer")
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if allowBlank && referrer == "" {
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return true
}
u, _ := url.Parse(referrer)
return sameOrigin(u, p)
}
// Check if two URLs have the same origin
func sameOrigin(u1, u2 *url.URL) bool {
// host also contains the port if one was specified
return (u1.Scheme == u2.Scheme && u1.Host == u2.Host)
}