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Use hostmatcher to replace matchlist, improve security (#17605)

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Use hostmacher to replace matchlist.

And we introduce a better DialContext to do a full host/IP check, otherwise the attackers can still bypass the allow/block list by a 302 redirection.
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wxiaoguang 2021-11-20 17:34:05 +08:00 • committed by GitHub
parent c96be0cd98
commit 013fb73068
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33 changed files with 377 additions and 293 deletions
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138
modules/hostmatcher/hostmatcher.go
View file

@ -13,15 +13,18 @@ import (
)
// HostMatchList is used to check if a host or IP is in a list.
// If you only need to do wildcard matching, consider to use modules/matchlist
type HostMatchList struct {
hosts []string
SettingKeyHint string
SettingValue string
// builtins networks
builtins []string
// patterns for host names (with wildcard support)
patterns []string
// ipNets is the CIDR network list
ipNets []*net.IPNet
}
// MatchBuiltinAll all hosts are matched
const MatchBuiltinAll = "*"
// MatchBuiltinExternal A valid non-private unicast IP, all hosts on public internet are matched
const MatchBuiltinExternal = "external"
@ -31,9 +34,13 @@ const MatchBuiltinPrivate = "private"
// MatchBuiltinLoopback 127.0.0.0/8 for IPv4 and ::1/128 for IPv6, localhost is included.
const MatchBuiltinLoopback = "loopback"
func isBuiltin(s string) bool {
return s == MatchBuiltinExternal || s == MatchBuiltinPrivate || s == MatchBuiltinLoopback
}
// ParseHostMatchList parses the host list HostMatchList
func ParseHostMatchList(hostList string) *HostMatchList {
hl := &HostMatchList{}
func ParseHostMatchList(settingKeyHint string, hostList string) *HostMatchList {
hl := &HostMatchList{SettingKeyHint: settingKeyHint, SettingValue: hostList}
for _, s := range strings.Split(hostList, ",") {
s = strings.ToLower(strings.TrimSpace(s))
if s == "" {
@ -42,53 +49,106 @@ func ParseHostMatchList(hostList string) *HostMatchList {
_, ipNet, err := net.ParseCIDR(s)
if err == nil {
hl.ipNets = append(hl.ipNets, ipNet)
} else if isBuiltin(s) {
hl.builtins = append(hl.builtins, s)
} else {
hl.hosts = append(hl.hosts, s)
hl.patterns = append(hl.patterns, s)
}
}
return hl
}
// MatchesHostOrIP checks if the host or IP matches an allow/deny(block) list
func (hl *HostMatchList) MatchesHostOrIP(host string, ip net.IP) bool {
var matched bool
host = strings.ToLower(host)
ipStr := ip.String()
loop:
for _, hostInList := range hl.hosts {
switch hostInList {
case "":
// ParseSimpleMatchList parse a simple matchlist (no built-in networks, no CIDR support, only wildcard pattern match)
func ParseSimpleMatchList(settingKeyHint string, matchList string) *HostMatchList {
hl := &HostMatchList{
SettingKeyHint: settingKeyHint,
SettingValue: matchList,
}
for _, s := range strings.Split(matchList, ",") {
s = strings.ToLower(strings.TrimSpace(s))
if s == "" {
continue
case MatchBuiltinAll:
matched = true
break loop
}
// we keep the same result as old `matchlist`, so no builtin/CIDR support here, we only match wildcard patterns
hl.patterns = append(hl.patterns, s)
}
return hl
}
// AppendBuiltin appends more builtins to match
func (hl *HostMatchList) AppendBuiltin(builtin string) {
hl.builtins = append(hl.builtins, builtin)
}
// IsEmpty checks if the checklist is empty
func (hl *HostMatchList) IsEmpty() bool {
return hl == nil || (len(hl.builtins) == 0 && len(hl.patterns) == 0 && len(hl.ipNets) == 0)
}
func (hl *HostMatchList) checkPattern(host string) bool {
host = strings.ToLower(strings.TrimSpace(host))
for _, pattern := range hl.patterns {
if matched, _ := filepath.Match(pattern, host); matched {
return true
}
}
return false
}
func (hl *HostMatchList) checkIP(ip net.IP) bool {
for _, pattern := range hl.patterns {
if pattern == "*" {
return true
}
}
for _, builtin := range hl.builtins {
switch builtin {
case MatchBuiltinExternal:
if matched = ip.IsGlobalUnicast() && !util.IsIPPrivate(ip); matched {
break loop
if ip.IsGlobalUnicast() && !util.IsIPPrivate(ip) {
return true
}
case MatchBuiltinPrivate:
if matched = util.IsIPPrivate(ip); matched {
break loop
if util.IsIPPrivate(ip) {
return true
}
case MatchBuiltinLoopback:
if matched = ip.IsLoopback(); matched {
break loop
}
default:
if matched, _ = filepath.Match(hostInList, host); matched {
break loop
}
if matched, _ = filepath.Match(hostInList, ipStr); matched {
break loop
if ip.IsLoopback() {
return true
}
}
}
if !matched {
for _, ipNet := range hl.ipNets {
if matched = ipNet.Contains(ip); matched {
break
}
for _, ipNet := range hl.ipNets {
if ipNet.Contains(ip) {
return true
}
}
return matched
return false
}
// MatchHostName checks if the host matches an allow/deny(block) list
func (hl *HostMatchList) MatchHostName(host string) bool {
if hl == nil {
return false
}
if hl.checkPattern(host) {
return true
}
if ip := net.ParseIP(host); ip != nil {
return hl.checkIP(ip)
}
return false
}
// MatchIPAddr checks if the IP matches an allow/deny(block) list, it's safe to pass `nil` to `ip`
func (hl *HostMatchList) MatchIPAddr(ip net.IP) bool {
if hl == nil {
return false
}
host := ip.String() // nil-safe, we will get "<nil>" if ip is nil
return hl.checkPattern(host) || hl.checkIP(ip)
}
// MatchHostOrIP checks if the host or IP matches an allow/deny(block) list
func (hl *HostMatchList) MatchHostOrIP(host string, ip net.IP) bool {
return hl.MatchHostName(host) || hl.MatchIPAddr(ip)
}

79
modules/hostmatcher/hostmatcher_test.go
View file

@ -20,17 +20,28 @@ func TestHostOrIPMatchesList(t *testing.T) {
// for IPv6: "::1" is loopback, "fd00::/8" is private
hl := ParseHostMatchList("private, External, *.myDomain.com, 169.254.1.0/24")
hl := ParseHostMatchList("", "private, External, *.myDomain.com, 169.254.1.0/24")
test := func(cases []tc) {
for _, c := range cases {
assert.Equalf(t, c.expected, hl.MatchHostOrIP(c.host, c.ip), "case domain=%s, ip=%v, expected=%v", c.host, c.ip, c.expected)
}
}
cases := []tc{
{"", net.IPv4zero, false},
{"", net.IPv6zero, false},
{"", net.ParseIP("127.0.0.1"), false},
{"127.0.0.1", nil, false},
{"", net.ParseIP("::1"), false},
{"", net.ParseIP("10.0.1.1"), true},
{"10.0.1.1", nil, true},
{"", net.ParseIP("192.168.1.1"), true},
{"192.168.1.1", nil, true},
{"", net.ParseIP("fd00::1"), true},
{"fd00::1", nil, true},
{"", net.ParseIP("8.8.8.8"), true},
{"", net.ParseIP("1001::1"), true},
@ -39,13 +50,13 @@ func TestHostOrIPMatchesList(t *testing.T) {
{"sub.mydomain.com", net.IPv4zero, true},
{"", net.ParseIP("169.254.1.1"), true},
{"169.254.1.1", nil, true},
{"", net.ParseIP("169.254.2.2"), false},
{"169.254.2.2", nil, false},
}
for _, c := range cases {
assert.Equalf(t, c.expected, hl.MatchesHostOrIP(c.host, c.ip), "case %s(%v)", c.host, c.ip)
}
test(cases)
hl = ParseHostMatchList("loopback")
hl = ParseHostMatchList("", "loopback")
cases = []tc{
{"", net.IPv4zero, false},
{"", net.ParseIP("127.0.0.1"), true},
@ -59,11 +70,9 @@ func TestHostOrIPMatchesList(t *testing.T) {
{"mydomain.com", net.IPv4zero, false},
}
for _, c := range cases {
assert.Equalf(t, c.expected, hl.MatchesHostOrIP(c.host, c.ip), "case %s(%v)", c.host, c.ip)
}
test(cases)
hl = ParseHostMatchList("private")
hl = ParseHostMatchList("", "private")
cases = []tc{
{"", net.IPv4zero, false},
{"", net.ParseIP("127.0.0.1"), false},
@ -77,11 +86,9 @@ func TestHostOrIPMatchesList(t *testing.T) {
{"mydomain.com", net.IPv4zero, false},
}
for _, c := range cases {
assert.Equalf(t, c.expected, hl.MatchesHostOrIP(c.host, c.ip), "case %s(%v)", c.host, c.ip)
}
test(cases)
hl = ParseHostMatchList("external")
hl = ParseHostMatchList("", "external")
cases = []tc{
{"", net.IPv4zero, false},
{"", net.ParseIP("127.0.0.1"), false},
@ -95,11 +102,9 @@ func TestHostOrIPMatchesList(t *testing.T) {
{"mydomain.com", net.IPv4zero, false},
}
for _, c := range cases {
assert.Equalf(t, c.expected, hl.MatchesHostOrIP(c.host, c.ip), "case %s(%v)", c.host, c.ip)
}
test(cases)
hl = ParseHostMatchList("*")
hl = ParseHostMatchList("", "*")
cases = []tc{
{"", net.IPv4zero, true},
{"", net.ParseIP("127.0.0.1"), true},
@ -113,7 +118,43 @@ func TestHostOrIPMatchesList(t *testing.T) {
{"mydomain.com", net.IPv4zero, true},
}
for _, c := range cases {
assert.Equalf(t, c.expected, hl.MatchesHostOrIP(c.host, c.ip), "case %s(%v)", c.host, c.ip)
test(cases)
// built-in network names can be escaped (warping the first char with `[]`) to be used as a real host name
// this mechanism is reversed for internal usage only (maybe for some rare cases), it's not supposed to be used by end users
// a real user should never use loopback/private/external as their host names
hl = ParseHostMatchList("", "loopback, [p]rivate")
cases = []tc{
{"loopback", nil, false},
{"", net.ParseIP("127.0.0.1"), true},
{"private", nil, true},
{"", net.ParseIP("192.168.1.1"), false},
}
test(cases)
hl = ParseSimpleMatchList("", "loopback, *.domain.com")
cases = []tc{
{"loopback", nil, true},
{"", net.ParseIP("127.0.0.1"), false},
{"sub.domain.com", nil, true},
{"other.com", nil, false},
{"", net.ParseIP("1.1.1.1"), false},
}
test(cases)
hl = ParseSimpleMatchList("", "external")
cases = []tc{
{"", net.ParseIP("192.168.1.1"), false},
{"", net.ParseIP("1.1.1.1"), false},
{"external", nil, true},
}
test(cases)
hl = ParseSimpleMatchList("", "")
cases = []tc{
{"", net.ParseIP("192.168.1.1"), false},
{"", net.ParseIP("1.1.1.1"), false},
{"external", nil, false},
}
test(cases)
}

58
modules/hostmatcher/http.go Normal file
View file

@ -0,0 +1,58 @@
// Copyright 2021 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package hostmatcher
import (
"context"
"fmt"
"net"
"syscall"
"time"
)
// NewDialContext returns a DialContext for Transport, the DialContext will do allow/block list check
func NewDialContext(usage string, allowList *HostMatchList, blockList *HostMatchList) func(ctx context.Context, network, addr string) (net.Conn, error) {
// How Go HTTP Client works with redirection:
// transport.RoundTrip URL=http://domain.com, Host=domain.com
// transport.DialContext addrOrHost=domain.com:80
// dialer.Control tcp4:11.22.33.44:80
// transport.RoundTrip URL=http://www.domain.com/, Host=(empty here, in the direction, HTTP client doesn't fill the Host field)
// transport.DialContext addrOrHost=domain.com:80
// dialer.Control tcp4:11.22.33.44:80
return func(ctx context.Context, network, addrOrHost string) (net.Conn, error) {
dialer := net.Dialer{
// default values comes from http.DefaultTransport
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
Control: func(network, ipAddr string, c syscall.RawConn) (err error) {
var host string
if host, _, err = net.SplitHostPort(addrOrHost); err != nil {
return err
}
// in Control func, the addr was already resolved to IP:PORT format, there is no cost to do ResolveTCPAddr here
tcpAddr, err := net.ResolveTCPAddr(network, ipAddr)
if err != nil {
return fmt.Errorf("%s can only call HTTP servers via TCP, deny '%s(%s:%s)', err=%v", usage, host, network, ipAddr, err)
}
var blockedError error
if blockList.MatchHostOrIP(host, tcpAddr.IP) {
blockedError = fmt.Errorf("%s can not call blocked HTTP servers (check your %s setting), deny '%s(%s)'", usage, blockList.SettingKeyHint, host, ipAddr)
}
// if we have an allow-list, check the allow-list first
if !allowList.IsEmpty() {
if !allowList.MatchHostOrIP(host, tcpAddr.IP) {
return fmt.Errorf("%s can only call allowed HTTP servers (check your %s setting), deny '%s(%s)'", usage, allowList.SettingKeyHint, host, ipAddr)
}
}
// otherwise, we always follow the blocked list
return blockedError
},
}
return dialer.DialContext(ctx, network, addrOrHost)
}
}