/* * Minio Cloud Storage, (C) 2018 Minio, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package handlers import ( "net" "net/http" "regexp" "strings" ) var ( // De-facto standard header keys. xForwardedFor = http.CanonicalHeaderKey("X-Forwarded-For") xForwardedProto = http.CanonicalHeaderKey("X-Forwarded-Proto") xForwardedScheme = http.CanonicalHeaderKey("X-Forwarded-Scheme") xRealIP = http.CanonicalHeaderKey("X-Real-IP") ) var ( // RFC7239 defines a new "Forwarded: " header designed to replace the // existing use of X-Forwarded-* headers. // e.g. Forwarded: for=192.0.2.60;proto=https;by=203.0.113.43 forwarded = http.CanonicalHeaderKey("Forwarded") // Allows for a sub-match of the first value after 'for=' to the next // comma, semi-colon or space. The match is case-insensitive. forRegex = regexp.MustCompile(`(?i)(?:for=)([^(;|,| )]+)(.*)`) // Allows for a sub-match for the first instance of scheme (http|https) // prefixed by 'proto='. The match is case-insensitive. protoRegex = regexp.MustCompile(`(?i)^(;|,| )+(?:proto=)(https|http)`) ) // GetSourceScheme retrieves the scheme from the X-Forwarded-Proto and RFC7239 // Forwarded headers (in that order). func GetSourceScheme(r *http.Request) string { var scheme string // Retrieve the scheme from X-Forwarded-Proto. if proto := r.Header.Get(xForwardedProto); proto != "" { scheme = strings.ToLower(proto) } else if proto = r.Header.Get(xForwardedScheme); proto != "" { scheme = strings.ToLower(proto) } else if proto := r.Header.Get(forwarded); proto != "" { // match should contain at least two elements if the protocol was // specified in the Forwarded header. The first element will always be // the 'for=', which we ignore, subsequently we proceed to look for // 'proto=' which should precede right after `for=` if not // we simply ignore the values and return empty. This is in line // with the approach we took for returning first ip from multiple // params. if match := forRegex.FindStringSubmatch(proto); len(match) > 1 { if match = protoRegex.FindStringSubmatch(match[2]); len(match) > 1 { scheme = strings.ToLower(match[2]) } } } return scheme } // GetSourceIP retrieves the IP from the X-Forwarded-For, X-Real-IP and RFC7239 // Forwarded headers (in that order), falls back to r.RemoteAddr when all // else fails. func GetSourceIP(r *http.Request) string { var addr string if fwd := r.Header.Get(xForwardedFor); fwd != "" { // Only grab the first (client) address. Note that '192.168.0.1, // 10.1.1.1' is a valid key for X-Forwarded-For where addresses after // the first may represent forwarding proxies earlier in the chain. s := strings.Index(fwd, ", ") if s == -1 { s = len(fwd) } addr = fwd[:s] } else if fwd := r.Header.Get(xRealIP); fwd != "" { // X-Real-IP should only contain one IP address (the client making the // request). addr = fwd } else if fwd := r.Header.Get(forwarded); fwd != "" { // match should contain at least two elements if the protocol was // specified in the Forwarded header. The first element will always be // the 'for=' capture, which we ignore. In the case of multiple IP // addresses (for=8.8.8.8, 8.8.4.4, 172.16.1.20 is valid) we only // extract the first, which should be the client IP. if match := forRegex.FindStringSubmatch(fwd); len(match) > 1 { // IPv6 addresses in Forwarded headers are quoted-strings. We strip // these quotes. addr = strings.Trim(match[1], `"`) } } if addr != "" { return addr } // Default to remote address if headers not set. addr, _, _ = net.SplitHostPort(r.RemoteAddr) return addr }