Config option to set DNS resolver

LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
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+                        http://www.apache.org/licenses/
+
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+      any Contribution intentionally submitted for inclusion in the Work
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+      the terms of any separate license agreement you may have executed
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+   Licensed under the Apache License, Version 2.0 (the "License");
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+       http://www.apache.org/licenses/LICENSE-2.0
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+   See the License for the specific language governing permissions and
+   limitations under the License.

config.json

@@ -0,0 +1,5 @@
+{
+	"ListenAddress": "127.0.0.1:3128",
+	"ListenType": "tcp4",
+	"DNSResolver": "192.168.1.1:53"
+}

internal/conf/config.go

@@ -0,0 +1,8 @@
+package conf
+
+type Config struct {
+	ListenAddress string // Address to listen on, passed to net.Listen
+	ListenType    string // Type of network to listen on, passed to net.Listen. One of tcp, tcp4 and tcp6
+
+	DNSResolver string // Address to send UDP & TCP DNS requests to. If set, the Go resolver will also be forced.
+}

internal/http/server.go

@@ -10,6 +10,8 @@ import (
 	"net/http"
 	"strings"
 	"time"
+
+	"edgaru089.ink/go/regolith/internal/perm"
 )
 
 const (
@@ -22,6 +24,24 @@ var (
 )
 
 type Server struct {
+	Perm *perm.Perm
+}
+
+// checkPerm invokes perm.Match.
+// If s.perm is nil, then every request is Accept-ed.
+//
+// It also logs if the action is Deny.
+func (s *Server) checkPerm(src, dest string) (act perm.Action) {
+	if s.Perm == nil {
+		return perm.ActionAccept
+	}
+
+	src_host, _, _ := net.SplitHostPort(src)
+	act = s.Perm.Match(src_host, dest)
+	if act == perm.ActionDeny {
+		log.Printf("denied: [%s] -> [%s]", src, dest)
+	}
+	return
 }
 
 func (s *Server) Serve(listener net.Listener) (err error) {
@@ -120,6 +140,12 @@ func (s *Server) handle_connect(conn net.Conn, req *http.Request) {
 	}
 	req_addr := net.JoinHostPort(req.URL.Hostname(), port)
 
+	// check permission
+	if s.checkPerm(conn.RemoteAddr().String(), req_addr) != perm.ActionAccept {
+		_ = simple_respond(conn, req, http.StatusBadGateway)
+		return
+	}
+
 	// prep for error log on close
 	var close_err error
 	defer func() {
@@ -164,11 +190,22 @@ func (s *Server) handle_request(conn net.Conn, req *http.Request) (should_keepal
 	remove_hop_headers(req.Header)
 	remove_extra_host_port(req)
 
-	if req.URL.Scheme == "" || req.URL.Host == "" {
+	if req.URL.Scheme != "http" || req.URL.Host == "" {
 		_ = simple_respond(conn, req, http.StatusBadRequest)
 		return false
 	}
 
+	// Check permission
+	req_hostname := req.URL.Hostname()
+	req_port := req.URL.Port()
+	if req_port == "" {
+		req_port = "80"
+	}
+	if s.checkPerm(conn.RemoteAddr().String(), net.JoinHostPort(req_hostname, req_port)) != perm.ActionAccept {
+		_ = simple_respond(conn, req, http.StatusBadGateway)
+		return false
+	}
+
 	// Request & error log
 	var close_err error
 	defer func() {

internal/perm/config.go

@@ -1,6 +1,7 @@
 package perm
 
 import (
+	"encoding/json"
 	"errors"
 	"strconv"
 	"strings"
@@ -27,6 +28,20 @@ func MostSevere(a, b Action) Action {
 	return min(a, b)
 }
 
+func (a Action) String() (name string) {
+	switch a {
+	case ActionDeny:
+		name = "deny"
+	case ActionIgnore:
+		name = "ignore"
+	case ActionAccept:
+		name = "accept"
+	default:
+		name = "<" + strconv.Itoa(int(a)) + ">"
+	}
+	return
+}
+
 // Marshal/Unmarshal for Action
 func (a *Action) UnmarshalText(text []byte) error {
 	switch strings.ToLower(string(text)) {
@@ -42,31 +57,47 @@ func (a *Action) UnmarshalText(text []byte) error {
 	return nil
 }
 func (a Action) MarshalText() ([]byte, error) {
-	var name string
-	switch a {
-	case ActionDeny:
-		name = "deny"
-	case ActionIgnore:
-		name = "ignore"
-	case ActionAccept:
-		name = "accept"
-	default:
-		name = "<" + strconv.Itoa(int(a)) + ">"
-	}
-	return []byte(name), nil
+	return []byte(a.String()), nil
 }
 
-// Config is a list of address and actions.
+// globAction is a helper to pack globs better.
+type globAction struct {
+	Glob string
+	Act  Action
+}
+
+func (g *globAction) UnmarshalJSON(b []byte) error {
+	m := make(map[string]Action)
+	if err := json.Unmarshal(b, &m); err != nil {
+		return err
+	}
+	if len(m) != 1 {
+		return errors.New("Glob action object does not have & only have one key")
+	}
+	for k, v := range m {
+		g.Glob = k
+		g.Act = v
+	}
+	return nil
+}
+
+// Config is a list of address and actions, for each source address.
 // It can just be Marshal/Unmarshaled into/from json.
 type Config struct {
 	DefaultAction Action // What we should do when no action is matched.
-	DefaultPort   []uint // Port numbers to add to address without port numbers already in them. Don't put too many entries in here.
+	DefaultPort   []int  // Port numbers to add to address without port numbers already in them. Don't put too many entries in here.
 
 	// Object which holds addresses and optionally ports, mapping to actions.
 	//
 	// Port number is extracted by net/url.splitHostPort, copied below.
 	// Port number is optional, but must be numeric when present.
 	Match map[string]Action
+
+	// Object which holds wildcard matches.
+	// This is searched after Match. It appends the default port if not found.
+	//
+	// Unlike Match, this is a list that is searched top-to-bottom.
+	MatchWildcard []globAction
 }
 
 // validOptionalPort reports whether port is either an empty string

internal/perm/perm.go

@@ -1,74 +1,128 @@
 package perm
 
 import (
+	"log"
 	"net"
 	"strconv"
+	"strings"
 	"sync"
+
+	"edgaru089.ink/go/regolith/internal/util"
 )
 
+type int_perm struct {
+	match      map[string]Action
+	match_glob []globAction
+	def        Action
+}
+
 // Perm matches address:port strings to Actions
 // loaded from a Config.
 //
+// global permissions are stored under the "$global" address.
+//
 // It's thread safe.
 type Perm struct {
 	lock sync.RWMutex
 
-	perm map[string]Action
-	def  Action
+	global int_perm
+
+	source map[string]int_perm
 }
 
 // New creates a new Perm struct from a Config.
 //
 // You can also &perm.Perm{} and then call Load on it.
-func New(c *Config) (p *Perm) {
+func New(c map[string]Config) (p *Perm) {
 	p = &Perm{}
 	p.Load(c)
 	return
 }
 
 // Load loads/reloads the Perm struct.
-func (p *Perm) Load(c *Config) {
+func (p *Perm) Load(cs map[string]Config) {
 	p.lock.Lock()
 	defer p.lock.Unlock()
 
-	if p.perm == nil {
-		p.perm = make(map[string]Action)
+	if p.source == nil {
+		p.source = make(map[string]int_perm)
 	} else {
-		clear(p.perm)
+		clear(p.source)
 	}
 
-	p.def = c.DefaultAction
+	// helper to load every source addr
+	load_per_source := func(c Config) (p_int int_perm) {
+		p_int.match = make(map[string]Action)
+		p_int.def = c.DefaultAction
+		log.Printf("default action %s", p_int.def)
 
-	// insert helper to use the most severe action existing
-	insert := func(addrport string, action Action) {
-		existing_action, ok := p.perm[addrport]
-		if ok {
-			p.perm[addrport] = MostSevere(existing_action, action)
-		} else {
-			p.perm[addrport] = action
-		}
-	}
-
-	// loop around the Match map
-	for addrport, act := range c.Match {
-		addr, port := splitHostPort(addrport)
-		if port != "" {
-			insert(net.JoinHostPort(addr, port), act)
-		} else {
-			// so this is why def_port shouldn't be that big
-			// TODO change this to sth faster
-			for def_port := range c.DefaultPort {
-				insert(net.JoinHostPort(addr, strconv.Itoa(def_port)), act)
+		// insert helper to use the most severe action existing
+		insert := func(addrport string, action Action) {
+			log.Printf("loading target %s, action %s", addrport, action)
+			existing_action, ok := p_int.match[addrport]
+			if ok {
+				p_int.match[addrport] = MostSevere(existing_action, action)
+			} else {
+				p_int.match[addrport] = action
 			}
 		}
+
+		// loop around the Match map
+		for addrport, act := range c.Match {
+			addr, port := splitHostPort(addrport)
+			if port != "" {
+				insert(net.JoinHostPort(addr, port), act)
+			} else {
+				// so this is why def_port shouldn't be that big
+				// TODO change this to sth faster
+				for _, def_port := range c.DefaultPort {
+					insert(net.JoinHostPort(addr, strconv.Itoa(def_port)), act)
+				}
+			}
+		}
+		for _, glob := range c.MatchWildcard {
+			addr, port := splitHostPort(glob.Glob)
+			if port != "" {
+				log.Printf("loading glob target %s, action %s", glob.Glob, glob.Act)
+				p_int.match_glob = append(
+					p_int.match_glob,
+					globAction{
+						Glob: glob.Glob,
+						Act:  glob.Act,
+					})
+			} else {
+				// TODO change this to sth faster
+				for _, def_port := range c.DefaultPort {
+					log.Printf("loading glob target %s, action %s", net.JoinHostPort(addr, strconv.Itoa(def_port)), glob.Act)
+					p_int.match_glob = append(
+						p_int.match_glob,
+						globAction{
+							Glob: net.JoinHostPort(addr, strconv.Itoa(def_port)),
+							Act:  glob.Act,
+						})
+				}
+			}
+		}
+		return
+	}
+
+	for src, c := range cs {
+		log.Printf("loading source %s", src)
+		if strings.EqualFold(src, "$global") {
+			p.global = load_per_source(c)
+		} else {
+			p.source[src] = load_per_source(c)
+		}
 	}
 
 	return
 }
 
 // Match matches an address to an action.
-// addr must be in net.JoinHostPort format.
-func (p *Perm) Match(addr string) Action {
+//
+// src must be a host (either ipv4 or v6), while
+// dest must be in net.JoinHostPort format.
+func (p *Perm) Match(src, dest string) Action {
 	// sanity check
 	if p == nil {
 		return ActionDeny
@@ -77,14 +131,43 @@ func (p *Perm) Match(addr string) Action {
 	p.lock.RLock()
 	defer p.lock.RUnlock()
 
-	// sanity check no.2
-	if p.perm == nil {
-		return p.def
+	// find its source struct
+	p_int, ok_int := p.source[src]
+	// only check if dest is directly listed
+	if ok_int {
+		// first check direct match
+		if p_int.match != nil {
+			if action, ok := p_int.match[dest]; ok {
+				return action
+			}
+		}
+		// then check glob match
+		for _, g := range p_int.match_glob {
+			if util.Match(g.Glob, dest) {
+				return g.Act
+			}
+		}
 	}
 
-	action, ok := p.perm[addr]
-	if !ok {
-		return p.def
+	// then check the global struct, also only directly listed
+	if p.global.match != nil {
+		if action, ok := p.global.match[dest]; ok {
+			return action
+		}
+	}
+	// then check global glob match
+	for _, g := range p.global.match_glob {
+		if util.Match(g.Glob, dest) {
+			return g.Act
+		}
+	}
+
+	// directly listed in neither.
+	if ok_int {
+		// if source struct exists, use source struct default.
+		return p_int.def
+	} else {
+		// if not exist, use global default.
+		return p.global.def
 	}
-	return action
 }

internal/util/wildcard.go

@@ -0,0 +1,101 @@
+package util
+
+// Copied from https://github.com/minio/pkg/blob/main/wildcard/match.go
+
+// Copyright (c) 2015-2023 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+// MatchSimple - finds whether the text matches/satisfies the pattern string.
+// supports '*' wildcard in the pattern and ? for single characters.
+// Only difference to Match is that `?` at the end is optional,
+// meaning `a?` pattern will match name `a`.
+func MatchSimple(pattern, name string) bool {
+	if pattern == "" {
+		return name == pattern
+	}
+	if pattern == "*" {
+		return true
+	}
+	// Do an extended wildcard '*' and '?' match.
+	return deepMatchRune(name, pattern, true)
+}
+
+// Match -  finds whether the text matches/satisfies the pattern string.
+// supports  '*' and '?' wildcards in the pattern string.
+// unlike path.Match(), considers a path as a flat name space while matching the pattern.
+// The difference is illustrated in the example here https://play.golang.org/p/Ega9qgD4Qz .
+func Match(pattern, name string) (matched bool) {
+	if pattern == "" {
+		return name == pattern
+	}
+	if pattern == "*" {
+		return true
+	}
+	// Do an extended wildcard '*' and '?' match.
+	return deepMatchRune(name, pattern, false)
+}
+
+func deepMatchRune(str, pattern string, simple bool) bool {
+	for len(pattern) > 0 {
+		switch pattern[0] {
+		default:
+			if len(str) == 0 || str[0] != pattern[0] {
+				return false
+			}
+		case '?':
+			if len(str) == 0 {
+				return simple
+			}
+		case '*':
+			return len(pattern) == 1 || // Pattern ends with this star
+				deepMatchRune(str, pattern[1:], simple) || // Matches next part of pattern
+				(len(str) > 0 && deepMatchRune(str[1:], pattern, simple)) // Continue searching forward
+		}
+		str = str[1:]
+		pattern = pattern[1:]
+	}
+	return len(str) == 0 && len(pattern) == 0
+}
+
+// MatchAsPatternPrefix matches text as a prefix of the given pattern. Examples:
+//
+//	| Pattern | Text    | Match Result |
+//	====================================
+//	| abc*    | ab      | True         |
+//	| abc*    | abd     | False        |
+//	| abc*c   | abcd    | True         |
+//	| ab*??d  | abxxc   | True         |
+//	| ab*??d  | abxc    | True         |
+//	| ab??d   | abxc    | True         |
+//	| ab??d   | abc     | True         |
+//	| ab??d   | abcxdd  | False        |
+//
+// This function is only useful in some special situations.
+func MatchAsPatternPrefix(pattern, text string) bool {
+	for i := 0; i < len(text) && i < len(pattern); i++ {
+		if pattern[i] == '*' {
+			return true
+		}
+		if pattern[i] == '?' {
+			continue
+		}
+		if pattern[i] != text[i] {
+			return false
+		}
+	}
+	return len(text) <= len(pattern)
+}

main.go

@@ -1,29 +1,96 @@
 package main
 
 import (
+	"context"
+	"encoding/json"
 	"fmt"
+	"log"
 	"net"
 	"os"
 	"os/signal"
+	"syscall"
+	"time"
 
+	"edgaru089.ink/go/regolith/internal/conf"
 	"edgaru089.ink/go/regolith/internal/http"
+	"edgaru089.ink/go/regolith/internal/perm"
 )
 
 func main() {
+	var s *http.Server
 
-	listener, err := net.Listen("tcp", ":3128")
+	{
+		perm_buf, err := os.ReadFile("perm.json")
+		if err != nil {
+			panic(err)
+		}
+		perm_json := make(map[string]perm.Config)
+		err = json.Unmarshal(perm_buf, &perm_json)
+		if err != nil {
+			panic(err)
+		}
+		s = &http.Server{
+			Perm: perm.New(perm_json),
+		}
+	}
+
+	var conf conf.Config
+	{
+		conf_buf, err := os.ReadFile("config.json")
+		if err != nil {
+			panic(err)
+		}
+		err = json.Unmarshal(conf_buf, &conf)
+		if err != nil {
+			panic(err)
+		}
+	}
+
+	if len(conf.DNSResolver) != 0 {
+		dialer := &net.Dialer{
+			Timeout: time.Second * 10,
+		}
+		net.DefaultResolver.PreferGo = true
+		net.DefaultResolver.Dial = func(ctx context.Context, network, address string) (net.Conn, error) {
+			return dialer.Dial(network, conf.DNSResolver)
+		}
+	}
+
+	listener, err := net.Listen(conf.ListenType, conf.ListenAddress)
 	if err != nil {
 		panic(err)
 	}
+	log.Printf("listeneing on [%s], type %s", conf.ListenAddress, conf.ListenType)
 
 	sigint_chan := make(chan os.Signal, 1)
 	signal.Notify(sigint_chan, os.Interrupt)
 	go func() {
 		<-sigint_chan
+		log.Printf("SIGINT received, quitting")
 		listener.Close()
 	}()
 
-	s := &http.Server{}
+	sighup_chan := make(chan os.Signal, 1)
+	signal.Notify(sighup_chan, syscall.SIGHUP)
+	go func() {
+		for {
+			<-sighup_chan
+			log.Printf("SIGHUP received, reloading permissions")
+			perm_buf, err := os.ReadFile("perm.json")
+			if err != nil {
+				log.Printf("skipping reload: error opening perm.json: %e", err)
+				continue
+			}
+			perm_json := make(map[string]perm.Config)
+			err = json.Unmarshal(perm_buf, &perm_json)
+			if err != nil {
+				log.Printf("skipping reload: error unmarshaling perm.json: %e", err)
+				continue
+			}
+			s.Perm.Load(perm_json)
+		}
+	}()
+
 	err = s.Serve(listener)
 	if err != nil {
 		fmt.Println(err)

perm.json

@@ -0,0 +1,27 @@
+{
+	"$global": {
+		"DefaultAction": "deny",
+		"DefaultPort": [443],
+		"Match": {
+			"mirrors.tuna.tsinghua.edu.cn": "accept",
+			"mirrors6.tuna.tsinghua.edu.cn": "accept",
+
+			"incoming.telemetry.mozilla.org": "ignore"
+		},
+		"MatchWildcard": [
+			{"*.qq.com": "accept"}
+		]
+	},
+	"127.0.0.1": {
+		"DefaultAction": "deny",
+		"DefaultPort": [443],
+		"Match": {
+			"pkg.go.dev": "accept",
+			"go.dev": "accept"
+		},
+		"MatchWildcard": [
+			{"*.baidu.com": "accept"}
+		]
+	}
+}
+