Source file src/crypto/tls/ech_test.go

     1  // Copyright 2024 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package tls
     6  
     7  import (
     8  	"bytes"
     9  	"encoding/hex"
    10  	"strings"
    11  	"testing"
    12  
    13  	"golang.org/x/crypto/cryptobyte"
    14  )
    15  
    16  func TestDecodeECHConfigLists(t *testing.T) {
    17  	for _, tc := range []struct {
    18  		list       string
    19  		numConfigs int
    20  	}{
    21  		{"0045fe0d0041590020002092a01233db2218518ccbbbbc24df20686af417b37388de6460e94011974777090004000100010012636c6f7564666c6172652d6563682e636f6d0000", 1},
    22  		{"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", 3},
    23  	} {
    24  		b, err := hex.DecodeString(tc.list)
    25  		if err != nil {
    26  			t.Fatal(err)
    27  		}
    28  		configs, err := parseECHConfigList(b)
    29  		if err != nil {
    30  			t.Fatal(err)
    31  		}
    32  		if len(configs) != tc.numConfigs {
    33  			t.Fatalf("unexpected number of configs parsed: got %d want %d", len(configs), tc.numConfigs)
    34  		}
    35  	}
    36  
    37  }
    38  
    39  func TestSkipBadConfigs(t *testing.T) {
    40  	b, err := hex.DecodeString("00c8badd00050504030201fe0d0029006666000401020304000c000100010001000200010003400e7075626c69632e6578616d706c650000fe0d003d000020002072e8a23b7aef67832bcc89d652e3870a60f88ca684ec65d6eace6b61f136064c000411112222400e7075626c69632e6578616d706c650000fe0d004d00002000200ce95810a81d8023f41e83679bc92701b2acd46c75869f95c72bc61c6b12297c000c000100010001000200010003400e7075626c69632e6578616d706c650008aaaa000474657374")
    41  	if err != nil {
    42  		t.Fatal(err)
    43  	}
    44  	configs, err := parseECHConfigList(b)
    45  	if err != nil {
    46  		t.Fatal(err)
    47  	}
    48  	config, _, _, _ := pickECHConfig(configs)
    49  	if config != nil {
    50  		t.Fatal("pickECHConfig picked an invalid config")
    51  	}
    52  }
    53  
    54  func TestPickECHConfigWithInvalidAEADID(t *testing.T) {
    55  	b, err := hex.DecodeString("0045fe0d0041590020002092a01233db2218518ccbbbbc24df20686af417b37388de6460e94011974777090004000100010012636c6f7564666c6172652d6563682e636f6d0000")
    56  	if err != nil {
    57  		t.Fatal(err)
    58  	}
    59  	buf := bytes.Replace(b, []byte{0x00, 0x01, 0x00, 0x01}, []byte{0x00, 0x01, 0xFF, 0xFF}, 1)
    60  	configs, err := parseECHConfigList(buf)
    61  	if err != nil {
    62  		t.Fatal(err)
    63  	}
    64  	if config, _, _, _ := pickECHConfig(configs); config != nil {
    65  		t.Fatalf("got %v, want nil", config)
    66  	}
    67  }
    68  
    69  func TestECHPadding(t *testing.T) {
    70  	const maxNameLength = 64
    71  	for _, tc := range []struct {
    72  		name       string
    73  		serverName string
    74  	}{
    75  		{"Short", "a.test"},
    76  		{"Medium", strings.Repeat("a", 30) + ".test"},
    77  		{"MaxLength", strings.Repeat("a", maxNameLength) + ".test"},
    78  		{"NoSNI", ""},
    79  	} {
    80  		t.Run(tc.name, func(t *testing.T) {
    81  			inner := &clientHelloMsg{
    82  				vers:               VersionTLS13,
    83  				random:             make([]byte, 32),
    84  				serverName:         tc.serverName,
    85  				cipherSuites:       []uint16{TLS_AES_128_GCM_SHA256},
    86  				compressionMethods: []uint8{0},
    87  				supportedVersions:  []uint16{VersionTLS13},
    88  			}
    89  			encoded, err := encodeInnerClientHello(inner, maxNameLength)
    90  			if err != nil {
    91  				t.Fatal(err)
    92  			}
    93  			if len(encoded)%32 != 0 {
    94  				t.Errorf("got %d, want multiple of 32", len(encoded))
    95  			}
    96  		})
    97  	}
    98  
    99  	t.Run("SetSizeReduction", func(t *testing.T) {
   100  		sizes := make(map[int]struct{})
   101  		for sniLen := 1; sniLen <= maxNameLength; sniLen++ {
   102  			inner := &clientHelloMsg{
   103  				vers:               VersionTLS13,
   104  				random:             make([]byte, 32),
   105  				serverName:         strings.Repeat("a", sniLen) + ".test",
   106  				cipherSuites:       []uint16{TLS_AES_128_GCM_SHA256},
   107  				compressionMethods: []uint8{0},
   108  				supportedVersions:  []uint16{VersionTLS13},
   109  			}
   110  			encoded, err := encodeInnerClientHello(inner, maxNameLength)
   111  			if err != nil {
   112  				t.Fatal(err)
   113  			}
   114  			sizes[len(encoded)] = struct{}{}
   115  		}
   116  		if len(sizes) > 4 {
   117  			t.Errorf("got %d distinct encoded sizes for SNI lengths 1..%d, want <= 4", len(sizes), maxNameLength)
   118  		}
   119  	})
   120  }
   121  
   122  func TestDecodeInnerClientHelloOuterExtensions(t *testing.T) {
   123  	outer := &clientHelloMsg{
   124  		vers:                 VersionTLS12,
   125  		random:               make([]byte, 32),
   126  		cipherSuites:         []uint16{TLS_AES_128_GCM_SHA256},
   127  		compressionMethods:   []uint8{compressionNone},
   128  		ocspStapling:         true,
   129  		supportedCurves:      []CurveID{CurveP256},
   130  		encryptedClientHello: []byte{byte(innerECHExt)},
   131  	}
   132  	outer.original = mustMarshal(t, outer)
   133  
   134  	encodeInner := func(buildExts func(*cryptobyte.Builder)) []byte {
   135  		var b cryptobyte.Builder
   136  		b.AddUint16(VersionTLS12)
   137  		b.AddBytes(make([]byte, 32))
   138  		b.AddUint8(0)
   139  		b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
   140  			b.AddUint16(TLS_AES_128_GCM_SHA256)
   141  		})
   142  		b.AddUint8LengthPrefixed(func(b *cryptobyte.Builder) {
   143  			b.AddUint8(compressionNone)
   144  		})
   145  		b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
   146  			buildExts(b)
   147  			b.AddUint16(extensionEncryptedClientHello)
   148  			b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
   149  				b.AddUint8(uint8(innerECHExt))
   150  			})
   151  			b.AddUint16(extensionSupportedVersions)
   152  			b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
   153  				b.AddUint8LengthPrefixed(func(b *cryptobyte.Builder) {
   154  					b.AddUint16(VersionTLS13)
   155  				})
   156  			})
   157  		})
   158  		return b.BytesOrPanic()
   159  	}
   160  
   161  	outerExts := func(b *cryptobyte.Builder, extTypes ...uint16) {
   162  		b.AddUint16(extensionECHOuterExtensions)
   163  		b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
   164  			b.AddUint8LengthPrefixed(func(b *cryptobyte.Builder) {
   165  				for _, extType := range extTypes {
   166  					b.AddUint16(extType)
   167  				}
   168  			})
   169  		})
   170  	}
   171  
   172  	for _, tc := range []struct {
   173  		name      string
   174  		buildExts func(*cryptobyte.Builder)
   175  		wantErr   string
   176  	}{
   177  		{
   178  			name: "valid order",
   179  			buildExts: func(b *cryptobyte.Builder) {
   180  				outerExts(b, extensionStatusRequest, extensionSupportedCurves)
   181  			},
   182  		},
   183  		{
   184  			name: "duplicate reference",
   185  			buildExts: func(b *cryptobyte.Builder) {
   186  				outerExts(b, extensionStatusRequest, extensionStatusRequest)
   187  			},
   188  			wantErr: "tls: invalid outer extensions",
   189  		},
   190  		{
   191  			name: "references encrypted_client_hello",
   192  			buildExts: func(b *cryptobyte.Builder) {
   193  				outerExts(b, extensionEncryptedClientHello)
   194  			},
   195  			wantErr: "tls: invalid outer extensions",
   196  		},
   197  		{
   198  			name: "references ech_outer_extensions",
   199  			buildExts: func(b *cryptobyte.Builder) {
   200  				outerExts(b, extensionECHOuterExtensions)
   201  			},
   202  			wantErr: "tls: invalid outer extensions",
   203  		},
   204  		{
   205  			name: "multiple ech_outer_extensions",
   206  			buildExts: func(b *cryptobyte.Builder) {
   207  				outerExts(b, extensionStatusRequest)
   208  				outerExts(b, extensionSupportedCurves)
   209  			},
   210  			wantErr: "tls: invalid outer extensions",
   211  		},
   212  		{
   213  			name: "odd-length reference list",
   214  			buildExts: func(b *cryptobyte.Builder) {
   215  				b.AddUint16(extensionECHOuterExtensions)
   216  				b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
   217  					b.AddUint8LengthPrefixed(func(b *cryptobyte.Builder) {
   218  						b.AddUint8(0)
   219  					})
   220  				})
   221  			},
   222  			wantErr: "tls: invalid inner client hello",
   223  		},
   224  		{
   225  			name: "empty reference list",
   226  			buildExts: func(b *cryptobyte.Builder) {
   227  				b.AddUint16(extensionECHOuterExtensions)
   228  				b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
   229  					b.AddUint8(0)
   230  				})
   231  			},
   232  			wantErr: "tls: invalid inner client hello",
   233  		},
   234  	} {
   235  		t.Run(tc.name, func(t *testing.T) {
   236  			encoded := encodeInner(tc.buildExts)
   237  			_, err := decodeInnerClientHello(outer, encoded)
   238  			if tc.wantErr == "" {
   239  				if err != nil {
   240  					t.Fatalf("decodeInnerClientHello returned %v, want nil", err)
   241  				}
   242  			} else if err == nil || err.Error() != tc.wantErr {
   243  				t.Fatalf("decodeInnerClientHello returned %v, want %q", err, tc.wantErr)
   244  			}
   245  		})
   246  	}
   247  }
   248  

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