summaryrefslogtreecommitdiff
path: root/modules/caddyhttp/matchers.go
blob: 6c5a23ee80c4472a48c1dd9273828dbb38a01480 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package caddyhttp

import (
	"encoding/json"
	"fmt"
	"log"
	"net"
	"net/http"
	"net/textproto"
	"net/url"
	"path"
	"path/filepath"
	"regexp"
	"strings"

	"github.com/caddyserver/caddy/v2"
	"github.com/caddyserver/caddy/v2/pkg/caddyscript"
	"go.starlark.net/starlark"
)

type (
	// MatchHost matches requests by the Host value.
	MatchHost []string

	// MatchPath matches requests by the URI's path.
	MatchPath []string

	// MatchPathRE matches requests by a regular expression on the URI's path.
	MatchPathRE struct{ MatchRegexp }

	// MatchMethod matches requests by the method.
	MatchMethod []string

	// MatchQuery matches requests by URI's query string.
	MatchQuery url.Values

	// MatchHeader matches requests by header fields.
	MatchHeader http.Header

	// MatchHeaderRE matches requests by a regular expression on header fields.
	MatchHeaderRE map[string]*MatchRegexp

	// MatchProtocol matches requests by protocol.
	MatchProtocol string

	// MatchRemoteIP matches requests by client IP (or CIDR range).
	MatchRemoteIP struct {
		Ranges []string `json:"ranges,omitempty"`

		cidrs []*net.IPNet
	}

	// MatchNegate matches requests by negating its matchers' results.
	MatchNegate struct {
		matchersRaw map[string]json.RawMessage

		matchers MatcherSet
	}

	// MatchStarlarkExpr matches requests by evaluating a Starlark expression.
	MatchStarlarkExpr string

	// MatchTable matches requests by values in the table.
	MatchTable string // TODO: finish implementing
)

func init() {
	caddy.RegisterModule(caddy.Module{
		Name: "http.matchers.host",
		New:  func() interface{} { return new(MatchHost) },
	})
	caddy.RegisterModule(caddy.Module{
		Name: "http.matchers.path",
		New:  func() interface{} { return new(MatchPath) },
	})
	caddy.RegisterModule(caddy.Module{
		Name: "http.matchers.path_regexp",
		New:  func() interface{} { return new(MatchPathRE) },
	})
	caddy.RegisterModule(caddy.Module{
		Name: "http.matchers.method",
		New:  func() interface{} { return new(MatchMethod) },
	})
	caddy.RegisterModule(caddy.Module{
		Name: "http.matchers.query",
		New:  func() interface{} { return new(MatchQuery) },
	})
	caddy.RegisterModule(caddy.Module{
		Name: "http.matchers.header",
		New:  func() interface{} { return new(MatchHeader) },
	})
	caddy.RegisterModule(caddy.Module{
		Name: "http.matchers.header_regexp",
		New:  func() interface{} { return new(MatchHeaderRE) },
	})
	caddy.RegisterModule(caddy.Module{
		Name: "http.matchers.protocol",
		New:  func() interface{} { return new(MatchProtocol) },
	})
	caddy.RegisterModule(caddy.Module{
		Name: "http.matchers.remote_ip",
		New:  func() interface{} { return new(MatchRemoteIP) },
	})
	caddy.RegisterModule(caddy.Module{
		Name: "http.matchers.not",
		New:  func() interface{} { return new(MatchNegate) },
	})
	caddy.RegisterModule(caddy.Module{
		Name: "http.matchers.starlark_expr",
		New:  func() interface{} { return new(MatchStarlarkExpr) },
	})
}

// Match returns true if r matches m.
func (m MatchHost) Match(r *http.Request) bool {
	reqHost, _, err := net.SplitHostPort(r.Host)
	if err != nil {
		// OK; probably didn't have a port
		reqHost = r.Host
	}

outer:
	for _, host := range m {
		if strings.Contains(host, "*") {
			patternParts := strings.Split(host, ".")
			incomingParts := strings.Split(reqHost, ".")
			if len(patternParts) != len(incomingParts) {
				continue
			}
			for i := range patternParts {
				if patternParts[i] == "*" {
					continue
				}
				if !strings.EqualFold(patternParts[i], incomingParts[i]) {
					continue outer
				}
			}
			return true
		} else if strings.EqualFold(reqHost, host) {
			return true
		}
	}

	return false
}

// Match returns true if r matches m.
func (m MatchPath) Match(r *http.Request) bool {
	for _, matchPath := range m {
		compare := r.URL.Path
		if strings.HasPrefix(matchPath, "*") {
			compare = path.Base(compare)
		}
		// can ignore error here because we can't handle it anyway
		matches, _ := filepath.Match(matchPath, compare)
		if matches {
			return true
		}
		if strings.HasPrefix(r.URL.Path, matchPath) {
			return true
		}
	}
	return false
}

// Match returns true if r matches m.
func (m MatchPathRE) Match(r *http.Request) bool {
	repl := r.Context().Value(caddy.ReplacerCtxKey).(caddy.Replacer)
	return m.MatchRegexp.Match(r.URL.Path, repl, "path_regexp")
}

// Match returns true if r matches m.
func (m MatchMethod) Match(r *http.Request) bool {
	for _, method := range m {
		if r.Method == method {
			return true
		}
	}
	return false
}

// Match returns true if r matches m.
func (m MatchQuery) Match(r *http.Request) bool {
	for param, vals := range m {
		paramVal := r.URL.Query().Get(param)
		for _, v := range vals {
			if paramVal == v {
				return true
			}
		}
	}
	return false
}

// Match returns true if r matches m.
func (m MatchHeader) Match(r *http.Request) bool {
	for field, allowedFieldVals := range m {
		var match bool
		actualFieldVals := r.Header[textproto.CanonicalMIMEHeaderKey(field)]
	fieldVals:
		for _, actualFieldVal := range actualFieldVals {
			for _, allowedFieldVal := range allowedFieldVals {
				if actualFieldVal == allowedFieldVal {
					match = true
					break fieldVals
				}
			}
		}
		if !match {
			return false
		}
	}
	return true
}

// Match returns true if r matches m.
func (m MatchHeaderRE) Match(r *http.Request) bool {
	for field, rm := range m {
		repl := r.Context().Value(caddy.ReplacerCtxKey).(caddy.Replacer)
		match := rm.Match(r.Header.Get(field), repl, "header_regexp")
		if !match {
			return false
		}
	}
	return true
}

// Provision compiles m's regular expressions.
func (m MatchHeaderRE) Provision(ctx caddy.Context) error {
	for _, rm := range m {
		err := rm.Provision(ctx)
		if err != nil {
			return err
		}
	}
	return nil
}

// Validate validates m's regular expressions.
func (m MatchHeaderRE) Validate() error {
	for _, rm := range m {
		err := rm.Validate()
		if err != nil {
			return err
		}
	}
	return nil
}

// Match returns true if r matches m.
func (m MatchProtocol) Match(r *http.Request) bool {
	switch string(m) {
	case "grpc":
		return r.Header.Get("content-type") == "application/grpc"
	case "https":
		return r.TLS != nil
	case "http":
		return r.TLS == nil
	}
	return false
}

// UnmarshalJSON unmarshals data into m's unexported map field.
// This is done because we cannot embed the map directly into
// the struct, but we need a struct because we need another
// field just for the provisioned modules.
func (m *MatchNegate) UnmarshalJSON(data []byte) error {
	return json.Unmarshal(data, &m.matchersRaw)
}

// Provision loads the matcher modules to be negated.
func (m *MatchNegate) Provision(ctx caddy.Context) error {
	for modName, rawMsg := range m.matchersRaw {
		val, err := ctx.LoadModule("http.matchers."+modName, rawMsg)
		if err != nil {
			return fmt.Errorf("loading matcher module '%s': %v", modName, err)
		}
		m.matchers = append(m.matchers, val.(RequestMatcher))
	}
	m.matchersRaw = nil // allow GC to deallocate - TODO: Does this help?
	return nil
}

// Match returns true if r matches m. Since this matcher negates the
// embedded matchers, false is returned if any of its matchers match.
func (m MatchNegate) Match(r *http.Request) bool {
	return !m.matchers.Match(r)
}

// Provision parses m's IP ranges, either from IP or CIDR expressions.
func (m *MatchRemoteIP) Provision(ctx caddy.Context) error {
	for _, str := range m.Ranges {
		if strings.Contains(str, "/") {
			_, ipNet, err := net.ParseCIDR(str)
			if err != nil {
				return fmt.Errorf("parsing CIDR expression: %v", err)
			}
			m.cidrs = append(m.cidrs, ipNet)
		} else {
			ip := net.ParseIP(str)
			if ip == nil {
				return fmt.Errorf("invalid IP address: %s", str)
			}
			mask := len(ip) * 8
			m.cidrs = append(m.cidrs, &net.IPNet{
				IP:   ip,
				Mask: net.CIDRMask(mask, mask),
			})
		}
	}
	return nil
}

func (m MatchRemoteIP) getClientIP(r *http.Request) (net.IP, error) {
	var remote string
	if fwdFor := r.Header.Get("X-Forwarded-For"); fwdFor != "" {
		remote = strings.TrimSpace(strings.Split(fwdFor, ",")[0])
	}
	if remote == "" {
		remote = r.RemoteAddr
	}

	ipStr, _, err := net.SplitHostPort(remote)
	if err != nil {
		ipStr = remote // OK; probably didn't have a port
	}

	ip := net.ParseIP(ipStr)
	if ip == nil {
		return nil, fmt.Errorf("invalid client IP address: %s", ipStr)
	}

	return ip, nil
}

// Match returns true if r matches m.
func (m MatchRemoteIP) Match(r *http.Request) bool {
	clientIP, err := m.getClientIP(r)
	if err != nil {
		log.Printf("[ERROR] remote_ip matcher: %v", err)
		return false
	}
	for _, ipRange := range m.cidrs {
		if ipRange.Contains(clientIP) {
			return true
		}
	}
	return false
}

// Match returns true if r matches m.
func (m MatchStarlarkExpr) Match(r *http.Request) bool {
	input := string(m)
	thread := new(starlark.Thread)
	env := caddyscript.MatcherEnv(r)
	val, err := starlark.Eval(thread, "", input, env)
	if err != nil {
		// TODO: Can we detect this in Provision or Validate instead?
		log.Printf("caddyscript for matcher is invalid: attempting to evaluate expression `%v` error `%v`", input, err)
		return false
	}
	return val.String() == "True"
}

// MatchRegexp is an embeddable type for matching
// using regular expressions.
type MatchRegexp struct {
	Name     string `json:"name"`
	Pattern  string `json:"pattern"`
	compiled *regexp.Regexp
}

// Provision compiles the regular expression.
func (mre *MatchRegexp) Provision(caddy.Context) error {
	re, err := regexp.Compile(mre.Pattern)
	if err != nil {
		return fmt.Errorf("compiling matcher regexp %s: %v", mre.Pattern, err)
	}
	mre.compiled = re
	return nil
}

// Validate ensures mre is set up correctly.
func (mre *MatchRegexp) Validate() error {
	if mre.Name != "" && !wordRE.MatchString(mre.Name) {
		return fmt.Errorf("invalid regexp name (must contain only word characters): %s", mre.Name)
	}
	return nil
}

// Match returns true if input matches the compiled regular
// expression in mre. It sets values on the replacer repl
// associated with capture groups, using the given scope
// (namespace). Capture groups stored to repl will take on
// the name "http.matchers.<scope>.<mre.Name>.<N>" where
// <N> is the name or number of the capture group.
func (mre *MatchRegexp) Match(input string, repl caddy.Replacer, scope string) bool {
	matches := mre.compiled.FindStringSubmatch(input)
	if matches == nil {
		return false
	}

	// save all capture groups, first by index
	for i, match := range matches {
		key := fmt.Sprintf("http.matchers.%s.%s.%d", scope, mre.Name, i)
		repl.Set(key, match)
	}

	// then by name
	for i, name := range mre.compiled.SubexpNames() {
		if i != 0 && name != "" {
			key := fmt.Sprintf("http.matchers.%s.%s.%s", scope, mre.Name, name)
			repl.Set(key, matches[i])
		}
	}

	return true
}

// ResponseMatcher is a type which can determine if a given response
// status code and its headers match some criteria.
type ResponseMatcher struct {
	// If set, one of these status codes would be required.
	// A one-digit status can be used to represent all codes
	// in that class (e.g. 3 for all 3xx codes).
	StatusCode []int `json:"status_code,omitempty"`

	// If set, each header specified must be one of the specified values.
	Headers http.Header `json:"headers,omitempty"`
}

// Match returns true if the given statusCode and hdr match rm.
func (rm ResponseMatcher) Match(statusCode int, hdr http.Header) bool {
	if !rm.matchStatusCode(statusCode) {
		return false
	}
	return rm.matchHeaders(hdr)
}

func (rm ResponseMatcher) matchStatusCode(statusCode int) bool {
	if rm.StatusCode == nil {
		return true
	}
	for _, code := range rm.StatusCode {
		if statusCode == code {
			return true
		}
		if code < 100 && statusCode >= code*100 && statusCode < (code+1)*100 {
			return true
		}
	}
	return false
}

func (rm ResponseMatcher) matchHeaders(hdr http.Header) bool {
	for field, allowedFieldVals := range rm.Headers {
		var match bool
		actualFieldVals := hdr[textproto.CanonicalMIMEHeaderKey(field)]
	fieldVals:
		for _, actualFieldVal := range actualFieldVals {
			for _, allowedFieldVal := range allowedFieldVals {
				if actualFieldVal == allowedFieldVal {
					match = true
					break fieldVals
				}
			}
		}
		if !match {
			return false
		}
	}
	return true
}

var wordRE = regexp.MustCompile(`\w+`)

// Interface guards
var (
	_ RequestMatcher    = (*MatchHost)(nil)
	_ RequestMatcher    = (*MatchPath)(nil)
	_ RequestMatcher    = (*MatchPathRE)(nil)
	_ caddy.Provisioner = (*MatchPathRE)(nil)
	_ RequestMatcher    = (*MatchMethod)(nil)
	_ RequestMatcher    = (*MatchQuery)(nil)
	_ RequestMatcher    = (*MatchHeader)(nil)
	_ RequestMatcher    = (*MatchHeaderRE)(nil)
	_ caddy.Provisioner = (*MatchHeaderRE)(nil)
	_ RequestMatcher    = (*MatchProtocol)(nil)
	_ RequestMatcher    = (*MatchRemoteIP)(nil)
	_ caddy.Provisioner = (*MatchRemoteIP)(nil)
	_ RequestMatcher    = (*MatchNegate)(nil)
	_ caddy.Provisioner = (*MatchNegate)(nil)
	_ RequestMatcher    = (*MatchStarlarkExpr)(nil)
	_ caddy.Provisioner = (*MatchRegexp)(nil)
)