65 lines
2.2 KiB
Go
65 lines
2.2 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/lucas-clemente/quic-go/internal/protocol"
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"github.com/lucas-clemente/quic-go/internal/qtls"
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)
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var (
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quicSaltOld = []byte{0xaf, 0xbf, 0xec, 0x28, 0x99, 0x93, 0xd2, 0x4c, 0x9e, 0x97, 0x86, 0xf1, 0x9c, 0x61, 0x11, 0xe0, 0x43, 0x90, 0xa8, 0x99}
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quicSaltDraft34 = []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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)
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func getSalt(v protocol.VersionNumber) []byte {
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if v == protocol.VersionDraft34 || v == protocol.Version1 {
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return quicSaltDraft34
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}
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return quicSaltOld
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}
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var initialSuite = &qtls.CipherSuiteTLS13{
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ID: tls.TLS_AES_128_GCM_SHA256,
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KeyLen: 16,
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AEAD: qtls.AEADAESGCMTLS13,
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Hash: crypto.SHA256,
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}
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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.VersionNumber) (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)
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otherKey, otherIV := computeInitialKeyAndIV(otherSecret)
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encrypter := qtls.AEADAESGCMTLS13(myKey, myIV)
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decrypter := qtls.AEADAESGCMTLS13(otherKey, otherIV)
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return newLongHeaderSealer(encrypter, newHeaderProtector(initialSuite, mySecret, true)),
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newLongHeaderOpener(decrypter, newAESHeaderProtector(initialSuite, otherSecret, true))
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}
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func computeSecrets(connID protocol.ConnectionID, v protocol.VersionNumber) (clientSecret, serverSecret []byte) {
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initialSecret := hkdf.Extract(crypto.SHA256.New, connID, 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) (key, iv []byte) {
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key = hkdfExpandLabel(crypto.SHA256, secret, []byte{}, "quic key", 16)
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iv = hkdfExpandLabel(crypto.SHA256, secret, []byte{}, "quic iv", 12)
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return
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}
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