From 9873ff9918224f56604048ea0ed3d3ae3953939e Mon Sep 17 00:00:00 2001 From: Matthew Holt Date: Fri, 30 Sep 2022 13:29:33 -0600 Subject: caddyhttp: Remote IP prefix placeholders See https://github.com/mholt/caddy-ratelimit/issues/12 --- modules/caddyhttp/replacer.go | 32 ++++++++++++++++++++++++++++++++ modules/caddyhttp/replacer_test.go | 20 ++++++++++++++++---- 2 files changed, 48 insertions(+), 4 deletions(-) diff --git a/modules/caddyhttp/replacer.go b/modules/caddyhttp/replacer.go index e154649..9ea5f77 100644 --- a/modules/caddyhttp/replacer.go +++ b/modules/caddyhttp/replacer.go @@ -31,6 +31,7 @@ import ( "io" "net" "net/http" + "net/netip" "net/textproto" "net/url" "path" @@ -196,6 +197,37 @@ func addHTTPVarsToReplacer(repl *caddy.Replacer, req *http.Request, w http.Respo return or.URL.RawQuery, true } + // remote IP range/prefix (e.g. keep top 24 bits of 1.2.3.4 => "1.2.3.0/24") + // syntax: "/V4,V6" where V4 = IPv4 bits, and V6 = IPv6 bits; if no comma, then same bit length used for both + // (EXPERIMENTAL) + if strings.HasPrefix(key, "http.request.remote.host/") { + host, _, err := net.SplitHostPort(req.RemoteAddr) + if err != nil { + host = req.RemoteAddr // assume no port, I guess? + } + addr, err := netip.ParseAddr(host) + if err != nil { + return host, true // not an IP address + } + // extract the bits from the end of the placeholder (start after "/") then split on "," + bitsBoth := key[strings.Index(key, "/")+1:] + ipv4BitsStr, ipv6BitsStr, cutOK := strings.Cut(bitsBoth, ",") + bitsStr := ipv4BitsStr + if addr.Is6() && cutOK { + bitsStr = ipv6BitsStr + } + // convert to integer then compute prefix + bits, err := strconv.Atoi(bitsStr) + if err != nil { + return "", true + } + prefix, err := addr.Prefix(bits) + if err != nil { + return "", true + } + return prefix.String(), true + } + // hostname labels if strings.HasPrefix(key, reqHostLabelsReplPrefix) { idxStr := key[len(reqHostLabelsReplPrefix):] diff --git a/modules/caddyhttp/replacer_test.go b/modules/caddyhttp/replacer_test.go index 18253d3..44c6f2a 100644 --- a/modules/caddyhttp/replacer_test.go +++ b/modules/caddyhttp/replacer_test.go @@ -32,7 +32,7 @@ func TestHTTPVarReplacement(t *testing.T) { ctx := context.WithValue(req.Context(), caddy.ReplacerCtxKey, repl) req = req.WithContext(ctx) req.Host = "example.com:80" - req.RemoteAddr = "localhost:1234" + req.RemoteAddr = "192.168.159.32:1234" clientCert := []byte(`-----BEGIN CERTIFICATE----- MIIB9jCCAV+gAwIBAgIBAjANBgkqhkiG9w0BAQsFADAYMRYwFAYDVQQDDA1DYWRk @@ -61,7 +61,7 @@ eqp31wM9il1n+guTNyxJd+FzVAH+hCZE5K+tCgVDdVFUlDEHHbS/wqb2PSIoouLV req.TLS = &tls.ConnectionState{ Version: tls.VersionTLS13, HandshakeComplete: true, - ServerName: "foo.com", + ServerName: "example.com", CipherSuite: tls.TLS_AES_256_GCM_SHA384, PeerCertificates: []*x509.Certificate{cert}, NegotiatedProtocol: "h2", @@ -97,7 +97,19 @@ eqp31wM9il1n+guTNyxJd+FzVAH+hCZE5K+tCgVDdVFUlDEHHbS/wqb2PSIoouLV }, { get: "http.request.remote.host", - expect: "localhost", + expect: "192.168.159.32", + }, + { + get: "http.request.remote.host/24", + expect: "192.168.159.0/24", + }, + { + get: "http.request.remote.host/24,32", + expect: "192.168.159.0/24", + }, + { + get: "http.request.remote.host/999", + expect: "", }, { get: "http.request.remote.port", @@ -146,7 +158,7 @@ eqp31wM9il1n+guTNyxJd+FzVAH+hCZE5K+tCgVDdVFUlDEHHbS/wqb2PSIoouLV }, { get: "http.request.tls.server_name", - expect: "foo.com", + expect: "example.com", }, { get: "http.request.tls.version", -- cgit v1.2.3