72 lines
2.3 KiB
Go
72 lines
2.3 KiB
Go
package handshake
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import (
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"crypto"
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"crypto/tls"
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"golang.org/x/crypto/hkdf"
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"github.com/quic-go/quic-go/internal/protocol"
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)
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var (
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quicSaltV1 = []byte{0x38, 0x76, 0x2c, 0xf7, 0xf5, 0x59, 0x34, 0xb3, 0x4d, 0x17, 0x9a, 0xe6, 0xa4, 0xc8, 0x0c, 0xad, 0xcc, 0xbb, 0x7f, 0x0a}
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quicSaltV2 = []byte{0x0d, 0xed, 0xe3, 0xde, 0xf7, 0x00, 0xa6, 0xdb, 0x81, 0x93, 0x81, 0xbe, 0x6e, 0x26, 0x9d, 0xcb, 0xf9, 0xbd, 0x2e, 0xd9}
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)
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const (
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hkdfLabelKeyV1 = "quic key"
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hkdfLabelKeyV2 = "quicv2 key"
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hkdfLabelIVV1 = "quic iv"
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hkdfLabelIVV2 = "quicv2 iv"
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)
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func getSalt(v protocol.Version) []byte {
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if v == protocol.Version2 {
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return quicSaltV2
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}
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return quicSaltV1
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}
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var initialSuite = getCipherSuite(tls.TLS_AES_128_GCM_SHA256)
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// NewInitialAEAD creates a new AEAD for Initial encryption / decryption.
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func NewInitialAEAD(connID protocol.ConnectionID, pers protocol.Perspective, v protocol.Version) (LongHeaderSealer, LongHeaderOpener) {
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clientSecret, serverSecret := computeSecrets(connID, v)
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var mySecret, otherSecret []byte
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if pers == protocol.PerspectiveClient {
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mySecret = clientSecret
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otherSecret = serverSecret
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} else {
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mySecret = serverSecret
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otherSecret = clientSecret
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}
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myKey, myIV := computeInitialKeyAndIV(mySecret, v)
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otherKey, otherIV := computeInitialKeyAndIV(otherSecret, v)
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encrypter := initialSuite.AEAD(myKey, myIV)
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decrypter := initialSuite.AEAD(otherKey, otherIV)
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return newLongHeaderSealer(encrypter, newHeaderProtector(initialSuite, mySecret, true, v)),
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newLongHeaderOpener(decrypter, newAESHeaderProtector(initialSuite, otherSecret, true, hkdfHeaderProtectionLabel(v)))
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}
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func computeSecrets(connID protocol.ConnectionID, v protocol.Version) (clientSecret, serverSecret []byte) {
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initialSecret := hkdf.Extract(crypto.SHA256.New, connID.Bytes(), getSalt(v))
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clientSecret = hkdfExpandLabel(crypto.SHA256, initialSecret, []byte{}, "client in", crypto.SHA256.Size())
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serverSecret = hkdfExpandLabel(crypto.SHA256, initialSecret, []byte{}, "server in", crypto.SHA256.Size())
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return
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}
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func computeInitialKeyAndIV(secret []byte, v protocol.Version) (key, iv []byte) {
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keyLabel := hkdfLabelKeyV1
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ivLabel := hkdfLabelIVV1
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if v == protocol.Version2 {
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keyLabel = hkdfLabelKeyV2
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ivLabel = hkdfLabelIVV2
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}
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key = hkdfExpandLabel(crypto.SHA256, secret, []byte{}, keyLabel, 16)
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iv = hkdfExpandLabel(crypto.SHA256, secret, []byte{}, ivLabel, 12)
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return
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}
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