66 lines
2.4 KiB
Go
66 lines
2.4 KiB
Go
// Copyright 2021 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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package hostmatcher
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import (
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"context"
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"fmt"
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"net"
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"net/url"
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"syscall"
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"time"
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)
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// NewDialContext returns a DialContext for Transport, the DialContext will do allow/block list check
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func NewDialContext(usage string, allowList, blockList *HostMatchList, proxy *url.URL) func(ctx context.Context, network, addr string) (net.Conn, error) {
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// How Go HTTP Client works with redirection:
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// transport.RoundTrip URL=http://domain.com, Host=domain.com
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// transport.DialContext addrOrHost=domain.com:80
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// dialer.Control tcp4:11.22.33.44:80
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// transport.RoundTrip URL=http://www.domain.com/, Host=(empty here, in the direction, HTTP client doesn't fill the Host field)
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// transport.DialContext addrOrHost=domain.com:80
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// dialer.Control tcp4:11.22.33.44:80
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return func(ctx context.Context, network, addrOrHost string) (net.Conn, error) {
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dialer := net.Dialer{
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// default values comes from http.DefaultTransport
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Timeout: 30 * time.Second,
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KeepAlive: 30 * time.Second,
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Control: func(network, ipAddr string, c syscall.RawConn) error {
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host, port, err := net.SplitHostPort(addrOrHost)
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if err != nil {
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return err
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}
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if proxy != nil {
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// Always allow the host of the proxy, but only on the specified port.
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if host == proxy.Hostname() && port == proxy.Port() {
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return nil
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}
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}
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// in Control func, the addr was already resolved to IP:PORT format, there is no cost to do ResolveTCPAddr here
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tcpAddr, err := net.ResolveTCPAddr(network, ipAddr)
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if err != nil {
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return fmt.Errorf("%s can only call HTTP servers via TCP, deny '%s(%s:%s)', err=%w", usage, host, network, ipAddr, err)
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}
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var blockedError error
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if blockList.MatchHostOrIP(host, tcpAddr.IP) {
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blockedError = fmt.Errorf("%s can not call blocked HTTP servers (check your %s setting), deny '%s(%s)'", usage, blockList.SettingKeyHint, host, ipAddr)
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}
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// if we have an allow-list, check the allow-list first
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if !allowList.IsEmpty() {
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if !allowList.MatchHostOrIP(host, tcpAddr.IP) {
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return fmt.Errorf("%s can only call allowed HTTP servers (check your %s setting), deny '%s(%s)'", usage, allowList.SettingKeyHint, host, ipAddr)
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}
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}
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// otherwise, we always follow the blocked list
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return blockedError
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},
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}
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return dialer.DialContext(ctx, network, addrOrHost)
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}
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}
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