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>
83 lines
2.2 KiB
Go
83 lines
2.2 KiB
Go
// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
|
|
//
|
|
// Permission to use, copy, modify, and/or distribute this software for any
|
|
// purpose with or without fee is hereby granted, provided that the above
|
|
// copyright notice and this permission notice appear in all copies.
|
|
//
|
|
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
|
|
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
|
|
// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
|
|
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
|
|
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
|
|
// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
|
|
// PERFORMANCE OF THIS SOFTWARE.
|
|
|
|
package clientip
|
|
|
|
import (
|
|
"net"
|
|
"net/http"
|
|
"strings"
|
|
)
|
|
|
|
// Extract resolves the client IP address from standard proxy headers
|
|
// in priority order: RFC 7239 Forwarded, then X-Forwarded-For, then
|
|
// the connection's remote address.
|
|
func Extract(r *http.Request) string {
|
|
if fwd := r.Header.Get("Forwarded"); fwd != "" {
|
|
if ip := parseForwardedFor(fwd); ip != "" {
|
|
return ip
|
|
}
|
|
}
|
|
|
|
if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
|
|
if i := strings.IndexByte(xff, ','); i != -1 {
|
|
xff = xff[:i]
|
|
}
|
|
xff = strings.TrimSpace(xff)
|
|
|
|
if ip, _, err := net.SplitHostPort(xff); err == nil {
|
|
return ip
|
|
}
|
|
return xff
|
|
}
|
|
|
|
ip, _, err := net.SplitHostPort(r.RemoteAddr)
|
|
if err != nil {
|
|
return r.RemoteAddr
|
|
}
|
|
|
|
return ip
|
|
}
|
|
|
|
// parseForwardedFor extracts the client IP from the first "for=" directive
|
|
// of an RFC 7239 Forwarded header value.
|
|
func parseForwardedFor(header string) string {
|
|
if i := strings.IndexByte(header, ','); i != -1 {
|
|
header = header[:i]
|
|
}
|
|
|
|
for part := range strings.SplitSeq(header, ";") {
|
|
part = strings.TrimSpace(part)
|
|
if !strings.HasPrefix(strings.ToLower(part), "for=") {
|
|
continue
|
|
}
|
|
|
|
val := part[4:]
|
|
val = strings.Trim(val, "\"")
|
|
|
|
if strings.HasPrefix(val, "[") {
|
|
if end := strings.IndexByte(val, ']'); end != -1 {
|
|
return val[1:end]
|
|
}
|
|
}
|
|
|
|
if ip, _, err := net.SplitHostPort(val); err == nil {
|
|
return ip
|
|
}
|
|
return val
|
|
}
|
|
|
|
return ""
|
|
}
|