96 lines
2.1 KiB
Go
96 lines
2.1 KiB
Go
// Middleware designed to reject requests from anon users unless from 'safe'
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// IP addresses
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package middleware
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import (
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"errors"
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"fmt"
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"log"
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"net"
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"net/http"
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"strings"
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"forgejo.gwairfelin.com/max/gonotes/internal/conf"
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)
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type netList []net.IPNet
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const ipHeader = "x-forwarded-for"
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func (n *netList) Contains(ip net.IP) bool {
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for _, net := range *n {
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if contains := net.Contains(ip); contains {
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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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func RejectAnonMiddleware(redirect string, next http.Handler) http.Handler {
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safeOriginNets := make(netList, 0, len(conf.Conf.AnonCIDRs))
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for _, cidr := range conf.Conf.AnonCIDRs {
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_, net, err := net.ParseCIDR(cidr)
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if err != nil {
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log.Printf("ignoring invalid cidr: %s", err)
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continue
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}
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safeOriginNets = append(safeOriginNets, *net)
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}
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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user := r.Context().Value(ContextKey("user")).(string)
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originIP, err := getOriginIP(r)
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if err != nil {
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log.Printf("unable to check origin ip: %s", err)
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http.Redirect(w, r, redirect, http.StatusTemporaryRedirect)
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return
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}
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log.Printf("origin ip: %s", originIP)
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safeOrigin := safeOriginNets.Contains(originIP)
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if user == "anon" && !safeOrigin {
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http.Redirect(w, r, redirect, http.StatusTemporaryRedirect)
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return
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}
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next.ServeHTTP(w, r)
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})
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}
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// Get the origin ip from the x-forwarded-for header, or the source of
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// the request if not available
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func getOriginIP(r *http.Request) (net.IP, error) {
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sourceIpHeader, ok := r.Header[http.CanonicalHeaderKey(ipHeader)]
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if !ok {
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addrParts := strings.Split(r.RemoteAddr, ":")
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if len(addrParts) == 0 {
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return nil, errors.New("no source ip available")
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}
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ip := net.ParseIP(addrParts[0])
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if ip == nil {
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return nil, fmt.Errorf("ip could not be parsed: %s", addrParts[0])
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}
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return ip, nil
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}
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if len(sourceIpHeader) != 1 {
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return nil, fmt.Errorf("header has more than 1 value: %s=%v", ipHeader, sourceIpHeader)
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}
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ips := strings.Split(sourceIpHeader[0], ",")
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ip := net.ParseIP(ips[0])
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if ip == nil {
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return nil, fmt.Errorf("not parseable as ip: %s", ips[0])
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}
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return ip, nil
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}
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