vendor aes12, quic-go-certificates and golang-lru

vendor/github.com/lucas-clemente/aes12/aes_gcm.go

@@ -0,0 +1,148 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build amd64
+
+package aes12
+
+import "crypto/subtle"
+
+// The following functions are defined in gcm_amd64.s.
+func hasGCMAsm() bool
+
+//go:noescape
+func aesEncBlock(dst, src *[16]byte, ks []uint32)
+
+//go:noescape
+func gcmAesInit(productTable *[256]byte, ks []uint32)
+
+//go:noescape
+func gcmAesData(productTable *[256]byte, data []byte, T *[16]byte)
+
+//go:noescape
+func gcmAesEnc(productTable *[256]byte, dst, src []byte, ctr, T *[16]byte, ks []uint32)
+
+//go:noescape
+func gcmAesDec(productTable *[256]byte, dst, src []byte, ctr, T *[16]byte, ks []uint32)
+
+//go:noescape
+func gcmAesFinish(productTable *[256]byte, tagMask, T *[16]byte, pLen, dLen uint64)
+
+// aesCipherGCM implements crypto/cipher.gcmAble so that crypto/cipher.NewGCM
+// will use the optimised implementation in this file when possible. Instances
+// of this type only exist when hasGCMAsm returns true.
+type aesCipherGCM struct {
+	aesCipherAsm
+}
+
+// Assert that aesCipherGCM implements the gcmAble interface.
+var _ gcmAble = (*aesCipherGCM)(nil)
+
+// NewGCM returns the AES cipher wrapped in Galois Counter Mode. This is only
+// called by crypto/cipher.NewGCM via the gcmAble interface.
+func (c *aesCipherGCM) NewGCM(nonceSize int) (AEAD, error) {
+	g := &gcmAsm{ks: c.enc, nonceSize: nonceSize}
+	gcmAesInit(&g.productTable, g.ks)
+	return g, nil
+}
+
+type gcmAsm struct {
+	// ks is the key schedule, the length of which depends on the size of
+	// the AES key.
+	ks []uint32
+	// productTable contains pre-computed multiples of the binary-field
+	// element used in GHASH.
+	productTable [256]byte
+	// nonceSize contains the expected size of the nonce, in bytes.
+	nonceSize int
+}
+
+func (g *gcmAsm) NonceSize() int {
+	return g.nonceSize
+}
+
+func (*gcmAsm) Overhead() int {
+	return gcmTagSize
+}
+
+// Seal encrypts and authenticates plaintext. See the AEAD interface for
+// details.
+func (g *gcmAsm) Seal(dst, nonce, plaintext, data []byte) []byte {
+	if len(nonce) != g.nonceSize {
+		panic("cipher: incorrect nonce length given to GCM")
+	}
+
+	var counter, tagMask [gcmBlockSize]byte
+
+	if len(nonce) == gcmStandardNonceSize {
+		// Init counter to nonce||1
+		copy(counter[:], nonce)
+		counter[gcmBlockSize-1] = 1
+	} else {
+		// Otherwise counter = GHASH(nonce)
+		gcmAesData(&g.productTable, nonce, &counter)
+		gcmAesFinish(&g.productTable, &tagMask, &counter, uint64(len(nonce)), uint64(0))
+	}
+
+	aesEncBlock(&tagMask, &counter, g.ks)
+
+	var tagOut [16]byte
+	gcmAesData(&g.productTable, data, &tagOut)
+
+	ret, out := sliceForAppend(dst, len(plaintext)+gcmTagSize)
+	if len(plaintext) > 0 {
+		gcmAesEnc(&g.productTable, out, plaintext, &counter, &tagOut, g.ks)
+	}
+	gcmAesFinish(&g.productTable, &tagMask, &tagOut, uint64(len(plaintext)), uint64(len(data)))
+	copy(out[len(plaintext):], tagOut[:gcmTagSize])
+
+	return ret
+}
+
+// Open authenticates and decrypts ciphertext. See the AEAD interface
+// for details.
+func (g *gcmAsm) Open(dst, nonce, ciphertext, data []byte) ([]byte, error) {
+	if len(nonce) != g.nonceSize {
+		panic("cipher: incorrect nonce length given to GCM")
+	}
+
+	if len(ciphertext) < gcmTagSize {
+		return nil, errOpen
+	}
+	tag := ciphertext[len(ciphertext)-gcmTagSize:]
+	ciphertext = ciphertext[:len(ciphertext)-gcmTagSize]
+
+	// See GCM spec, section 7.1.
+	var counter, tagMask [gcmBlockSize]byte
+
+	if len(nonce) == gcmStandardNonceSize {
+		// Init counter to nonce||1
+		copy(counter[:], nonce)
+		counter[gcmBlockSize-1] = 1
+	} else {
+		// Otherwise counter = GHASH(nonce)
+		gcmAesData(&g.productTable, nonce, &counter)
+		gcmAesFinish(&g.productTable, &tagMask, &counter, uint64(len(nonce)), uint64(0))
+	}
+
+	aesEncBlock(&tagMask, &counter, g.ks)
+
+	var expectedTag [16]byte
+	gcmAesData(&g.productTable, data, &expectedTag)
+
+	ret, out := sliceForAppend(dst, len(ciphertext))
+	if len(ciphertext) > 0 {
+		gcmAesDec(&g.productTable, out, ciphertext, &counter, &expectedTag, g.ks)
+	}
+	gcmAesFinish(&g.productTable, &tagMask, &expectedTag, uint64(len(ciphertext)), uint64(len(data)))
+
+	if subtle.ConstantTimeCompare(expectedTag[:12], tag) != 1 {
+		for i := range out {
+			out[i] = 0
+		}
+		return nil, errOpen
+	}
+
+	return ret, nil
+}