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