e3ab373a0c
Strip forwarded headers (Forwarded, X-Forwarded-For, X-Real-Ip) from requests originating from untrusted proxies at the HTTP server level, reusing the existing proxy-protocol trusted-proxies config. The clientip package is now a pure extraction helper; context plumbing and middleware wrappers are removed. Signed-off-by: Émile Ré <emile@getprobo.com>
63 lines
1.8 KiB
Go
63 lines
1.8 KiB
Go
// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice appear in all copies.
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//
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// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
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// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
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// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
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// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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// PERFORMANCE OF THIS SOFTWARE.
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package trustedproxy
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import (
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"net"
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"net/http"
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)
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var forwardedHeaders = []string{
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"Forwarded",
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"X-Forwarded-For",
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}
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// NewMiddleware returns an HTTP middleware that strips forwarded
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// headers from requests that did not originate from one of the given
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// trusted proxy IPs. When the list is empty every request is treated
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// as untrusted and the headers are always removed.
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func NewMiddleware(trusted []net.IP) func(http.Handler) http.Handler {
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return func(next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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if !isTrusted(r.RemoteAddr, trusted) {
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for _, h := range forwardedHeaders {
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r.Header.Del(h)
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}
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}
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next.ServeHTTP(w, r)
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})
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}
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}
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func isTrusted(remoteAddr string, trusted []net.IP) bool {
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host, _, err := net.SplitHostPort(remoteAddr)
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if err != nil {
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host = remoteAddr
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}
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ip := net.ParseIP(host)
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if ip == nil {
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return false
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}
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for _, t := range trusted {
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if t.Equal(ip) {
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return true
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}
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}
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return false
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}
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