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// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
// See License.txt for license information.
package utils
import (
"context"
"crypto/tls"
"errors"
"net"
"net/http"
"strings"
"time"
)
const (
connectTimeout = 3 * time.Second
requestTimeout = 30 * time.Second
)
var secureHttpClient *http.Client
var secureUntrustedHttpClient *http.Client
var insecureHttpClient *http.Client
var insecureUntrustedHttpClient *http.Client
// HttpClient returns a variation the default implementation of Client.
// It uses a Transport with the same settings as the default Transport
// but with the following modifications:
// - shorter timeout for dial and TLS handshake (defined as constant
// "connectTimeout")
// - timeout for the end-to-end request (defined as constant
// "requestTimeout")
// - skipping server certificate check if specified in "config.json"
// via "ServiceSettings.EnableInsecureOutgoingConnections"
func HttpClient(trustURLs bool) *http.Client {
insecure := Cfg.ServiceSettings.EnableInsecureOutgoingConnections != nil && *Cfg.ServiceSettings.EnableInsecureOutgoingConnections
switch {
case insecure && trustURLs:
return insecureHttpClient
case insecure:
return insecureUntrustedHttpClient
case trustURLs:
return secureHttpClient
default:
return secureUntrustedHttpClient
}
}
var reservedIPRanges []*net.IPNet
func isReserved(ip net.IP) bool {
for _, ipRange := range reservedIPRanges {
if ipRange.Contains(ip) {
return true
}
}
return false
}
func init() {
for _, cidr := range []string{
// See https://tools.ietf.org/html/rfc6890
"0.0.0.0/8", // This host on this network
"10.0.0.0/8", // Private-Use
"127.0.0.0/8", // Loopback
"169.254.0.0/16", // Link Local
"172.16.0.0/12", // Private-Use Networks
"192.168.0.0/16", // Private-Use Networks
"::/128", // Unspecified Address
"::1/128", // Loopback Address
"fc00::/7", // Unique-Local
"fe80::/10", // Linked-Scoped Unicast
} {
_, parsed, err := net.ParseCIDR(cidr)
if err != nil {
panic(err)
}
reservedIPRanges = append(reservedIPRanges, parsed)
}
allowHost := func(host string) bool {
if Cfg.ServiceSettings.AllowedUntrustedInternalConnections == nil {
return false
}
for _, allowed := range strings.Fields(*Cfg.ServiceSettings.AllowedUntrustedInternalConnections) {
if host == allowed {
return true
}
}
return false
}
allowIP := func(ip net.IP) bool {
if !isReserved(ip) {
return true
}
if Cfg.ServiceSettings.AllowedUntrustedInternalConnections == nil {
return false
}
for _, allowed := range strings.Fields(*Cfg.ServiceSettings.AllowedUntrustedInternalConnections) {
if _, ipRange, err := net.ParseCIDR(allowed); err == nil && ipRange.Contains(ip) {
return true
}
}
return false
}
secureHttpClient = createHttpClient(false, nil, nil)
insecureHttpClient = createHttpClient(true, nil, nil)
secureUntrustedHttpClient = createHttpClient(false, allowHost, allowIP)
insecureUntrustedHttpClient = createHttpClient(true, allowHost, allowIP)
}
type DialContextFunction func(ctx context.Context, network, addr string) (net.Conn, error)
var AddressForbidden error = errors.New("address forbidden")
func dialContextFilter(dial DialContextFunction, allowHost func(host string) bool, allowIP func(ip net.IP) bool) DialContextFunction {
return func(ctx context.Context, network, addr string) (net.Conn, error) {
host, port, err := net.SplitHostPort(addr)
if err != nil {
return nil, err
}
if allowHost != nil && allowHost(host) {
return dial(ctx, network, addr)
}
ips, err := net.LookupIP(host)
if err != nil {
return nil, err
}
var firstErr error
for _, ip := range ips {
select {
case <-ctx.Done():
return nil, ctx.Err()
default:
}
if allowIP == nil || !allowIP(ip) {
continue
}
conn, err := dial(ctx, network, net.JoinHostPort(ip.String(), port))
if err == nil {
return conn, nil
}
if firstErr == nil {
firstErr = err
}
}
if firstErr == nil {
return nil, AddressForbidden
}
return nil, firstErr
}
}
func createHttpClient(enableInsecureConnections bool, allowHost func(host string) bool, allowIP func(ip net.IP) bool) *http.Client {
dialContext := (&net.Dialer{
Timeout: connectTimeout,
KeepAlive: 30 * time.Second,
}).DialContext
if allowHost != nil || allowIP != nil {
dialContext = dialContextFilter(dialContext, allowHost, allowIP)
}
client := &http.Client{
Transport: &http.Transport{
Proxy: http.ProxyFromEnvironment,
DialContext: dialContext,
MaxIdleConns: 100,
IdleConnTimeout: 90 * time.Second,
TLSHandshakeTimeout: connectTimeout,
ExpectContinueTimeout: 1 * time.Second,
TLSClientConfig: &tls.Config{
InsecureSkipVerify: enableInsecureConnections,
},
},
Timeout: requestTimeout,
}
return client
}
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