forked from TrueCloudLab/frostfs-s3-gw
127 lines
4.7 KiB
Go
127 lines
4.7 KiB
Go
// Copyright (c) 2015-2021 MinIO, Inc.
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//
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// This file is part of MinIO Object Storage stack
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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// Originally from https://github.com/gorilla/handlers with following license
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// https://raw.githubusercontent.com/gorilla/handlers/master/LICENSE, forked
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// and heavily modified for MinIO's internal needs.
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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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// GetSourceIPFromHeaders retrieves the IP from the X-Forwarded-For, X-Real-IP
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// and RFC7239 Forwarded headers (in that order)
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func GetSourceIPFromHeaders(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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return addr
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}
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// GetSourceIP retrieves the IP from the request headers
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// and falls back to r.RemoteAddr when necessary.
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func GetSourceIP(r *http.Request) string {
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addr := GetSourceIPFromHeaders(r)
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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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