blob: 504a841cd82719dbd66c516680c5c839c3d5fb86 [file] [log] [blame]
// Copyright 2017 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 linux,amd64
// +build !android
// +build !cmd_go_bootstrap
// +build !msan
package boring
/*
#include "goboringcrypto.h"
// These wrappers allocate out_len on the C stack, and check that it matches the expected
// value, to avoid having to pass a pointer from Go, which would escape to the heap.
int EVP_AEAD_CTX_seal_wrapper(const GO_EVP_AEAD_CTX *ctx, uint8_t *out,
size_t exp_out_len,
const uint8_t *nonce, size_t nonce_len,
const uint8_t *in, size_t in_len,
const uint8_t *ad, size_t ad_len) {
size_t out_len;
int ok = _goboringcrypto_EVP_AEAD_CTX_seal(ctx, out, &out_len, exp_out_len,
nonce, nonce_len, in, in_len, ad, ad_len);
if (out_len != exp_out_len) {
return 0;
}
return ok;
};
int EVP_AEAD_CTX_open_wrapper(const GO_EVP_AEAD_CTX *ctx, uint8_t *out,
size_t exp_out_len,
const uint8_t *nonce, size_t nonce_len,
const uint8_t *in, size_t in_len,
const uint8_t *ad, size_t ad_len) {
size_t out_len;
int ok = _goboringcrypto_EVP_AEAD_CTX_open(ctx, out, &out_len, exp_out_len,
nonce, nonce_len, in, in_len, ad, ad_len);
if (out_len != exp_out_len) {
return 0;
}
return ok;
};
*/
import "C"
import (
"crypto/cipher"
"errors"
"runtime"
"strconv"
"unsafe"
)
type aesKeySizeError int
func (k aesKeySizeError) Error() string {
return "crypto/aes: invalid key size " + strconv.Itoa(int(k))
}
const aesBlockSize = 16
type aesCipher struct {
key []byte
enc C.GO_AES_KEY
dec C.GO_AES_KEY
}
type extraModes interface {
// Copied out of crypto/aes/modes.go.
NewCBCEncrypter(iv []byte) cipher.BlockMode
NewCBCDecrypter(iv []byte) cipher.BlockMode
NewCTR(iv []byte) cipher.Stream
NewGCM(nonceSize, tagSize int) (cipher.AEAD, error)
// Invented for BoringCrypto.
NewGCMTLS() (cipher.AEAD, error)
}
var _ extraModes = (*aesCipher)(nil)
func NewAESCipher(key []byte) (cipher.Block, error) {
c := &aesCipher{key: make([]byte, len(key))}
copy(c.key, key)
// Note: 0 is success, contradicting the usual BoringCrypto convention.
if C._goboringcrypto_AES_set_decrypt_key((*C.uint8_t)(unsafe.Pointer(&c.key[0])), C.uint(8*len(c.key)), &c.dec) != 0 ||
C._goboringcrypto_AES_set_encrypt_key((*C.uint8_t)(unsafe.Pointer(&c.key[0])), C.uint(8*len(c.key)), &c.enc) != 0 {
return nil, aesKeySizeError(len(key))
}
return c, nil
}
func (c *aesCipher) BlockSize() int { return aesBlockSize }
func (c *aesCipher) Encrypt(dst, src []byte) {
if inexactOverlap(dst, src) {
panic("crypto/cipher: invalid buffer overlap")
}
if len(src) < aesBlockSize {
panic("crypto/aes: input not full block")
}
if len(dst) < aesBlockSize {
panic("crypto/aes: output not full block")
}
C._goboringcrypto_AES_encrypt(
(*C.uint8_t)(unsafe.Pointer(&src[0])),
(*C.uint8_t)(unsafe.Pointer(&dst[0])),
&c.enc)
}
func (c *aesCipher) Decrypt(dst, src []byte) {
if inexactOverlap(dst, src) {
panic("crypto/cipher: invalid buffer overlap")
}
if len(src) < aesBlockSize {
panic("crypto/aes: input not full block")
}
if len(dst) < aesBlockSize {
panic("crypto/aes: output not full block")
}
C._goboringcrypto_AES_decrypt(
(*C.uint8_t)(unsafe.Pointer(&src[0])),
(*C.uint8_t)(unsafe.Pointer(&dst[0])),
&c.dec)
}
type aesCBC struct {
key *C.GO_AES_KEY
mode C.int
iv [aesBlockSize]byte
}
func (x *aesCBC) BlockSize() int { return aesBlockSize }
func (x *aesCBC) CryptBlocks(dst, src []byte) {
if inexactOverlap(dst, src) {
panic("crypto/cipher: invalid buffer overlap")
}
if len(src)%aesBlockSize != 0 {
panic("crypto/cipher: input not full blocks")
}
if len(dst) < len(src) {
panic("crypto/cipher: output smaller than input")
}
if len(src) > 0 {
C._goboringcrypto_AES_cbc_encrypt(
(*C.uint8_t)(unsafe.Pointer(&src[0])),
(*C.uint8_t)(unsafe.Pointer(&dst[0])),
C.size_t(len(src)), x.key,
(*C.uint8_t)(unsafe.Pointer(&x.iv[0])), x.mode)
}
}
func (x *aesCBC) SetIV(iv []byte) {
if len(iv) != aesBlockSize {
panic("cipher: incorrect length IV")
}
copy(x.iv[:], iv)
}
func (c *aesCipher) NewCBCEncrypter(iv []byte) cipher.BlockMode {
x := &aesCBC{key: &c.enc, mode: C.GO_AES_ENCRYPT}
copy(x.iv[:], iv)
return x
}
func (c *aesCipher) NewCBCDecrypter(iv []byte) cipher.BlockMode {
x := &aesCBC{key: &c.dec, mode: C.GO_AES_DECRYPT}
copy(x.iv[:], iv)
return x
}
type aesCTR struct {
key *C.GO_AES_KEY
iv [aesBlockSize]byte
num C.uint
ecount_buf [16]C.uint8_t
}
func (x *aesCTR) XORKeyStream(dst, src []byte) {
if inexactOverlap(dst, src) {
panic("crypto/cipher: invalid buffer overlap")
}
if len(dst) < len(src) {
panic("crypto/cipher: output smaller than input")
}
if len(src) == 0 {
return
}
C._goboringcrypto_AES_ctr128_encrypt(
(*C.uint8_t)(unsafe.Pointer(&src[0])),
(*C.uint8_t)(unsafe.Pointer(&dst[0])),
C.size_t(len(src)), x.key, (*C.uint8_t)(unsafe.Pointer(&x.iv[0])),
&x.ecount_buf[0], &x.num)
}
func (c *aesCipher) NewCTR(iv []byte) cipher.Stream {
x := &aesCTR{key: &c.enc}
copy(x.iv[:], iv)
return x
}
type aesGCM struct {
ctx C.GO_EVP_AEAD_CTX
aead *C.GO_EVP_AEAD
}
const (
gcmBlockSize = 16
gcmTagSize = 16
gcmStandardNonceSize = 12
)
type aesNonceSizeError int
func (n aesNonceSizeError) Error() string {
return "crypto/aes: invalid GCM nonce size " + strconv.Itoa(int(n))
}
type noGCM struct {
cipher.Block
}
func (c *aesCipher) NewGCM(nonceSize, tagSize int) (cipher.AEAD, error) {
if nonceSize != gcmStandardNonceSize && tagSize != gcmTagSize {
return nil, errors.New("crypto/aes: GCM tag and nonce sizes can't be non-standard at the same time")
}
// Fall back to standard library for GCM with non-standard nonce or tag size.
if nonceSize != gcmStandardNonceSize {
return cipher.NewGCMWithNonceSize(&noGCM{c}, nonceSize)
}
if tagSize != gcmTagSize {
return cipher.NewGCMWithTagSize(&noGCM{c}, tagSize)
}
return c.newGCM(false)
}
func (c *aesCipher) NewGCMTLS() (cipher.AEAD, error) {
return c.newGCM(true)
}
func (c *aesCipher) newGCM(tls bool) (cipher.AEAD, error) {
var aead *C.GO_EVP_AEAD
switch len(c.key) * 8 {
case 128:
if tls {
aead = C._goboringcrypto_EVP_aead_aes_128_gcm_tls12()
} else {
aead = C._goboringcrypto_EVP_aead_aes_128_gcm()
}
case 256:
if tls {
aead = C._goboringcrypto_EVP_aead_aes_256_gcm_tls12()
} else {
aead = C._goboringcrypto_EVP_aead_aes_256_gcm()
}
default:
// Fall back to standard library for GCM with non-standard key size.
return cipher.NewGCMWithNonceSize(&noGCM{c}, gcmStandardNonceSize)
}
g := &aesGCM{aead: aead}
if C._goboringcrypto_EVP_AEAD_CTX_init(&g.ctx, aead, (*C.uint8_t)(unsafe.Pointer(&c.key[0])), C.size_t(len(c.key)), C.GO_EVP_AEAD_DEFAULT_TAG_LENGTH, nil) == 0 {
return nil, fail("EVP_AEAD_CTX_init")
}
// Note: Because of the finalizer, any time g.ctx is passed to cgo,
// that call must be followed by a call to runtime.KeepAlive(g),
// to make sure g is not collected (and finalized) before the cgo
// call returns.
runtime.SetFinalizer(g, (*aesGCM).finalize)
if g.NonceSize() != gcmStandardNonceSize {
panic("boringcrypto: internal confusion about nonce size")
}
if g.Overhead() != gcmTagSize {
panic("boringcrypto: internal confusion about tag size")
}
return g, nil
}
func (g *aesGCM) finalize() {
C._goboringcrypto_EVP_AEAD_CTX_cleanup(&g.ctx)
}
func (g *aesGCM) NonceSize() int {
return int(C._goboringcrypto_EVP_AEAD_nonce_length(g.aead))
}
func (g *aesGCM) Overhead() int {
return int(C._goboringcrypto_EVP_AEAD_max_overhead(g.aead))
}
// base returns the address of the underlying array in b,
// being careful not to panic when b has zero length.
func base(b []byte) *C.uint8_t {
if len(b) == 0 {
return nil
}
return (*C.uint8_t)(unsafe.Pointer(&b[0]))
}
func (g *aesGCM) Seal(dst, nonce, plaintext, additionalData []byte) []byte {
if len(nonce) != gcmStandardNonceSize {
panic("cipher: incorrect nonce length given to GCM")
}
if uint64(len(plaintext)) > ((1<<32)-2)*aesBlockSize || len(plaintext)+gcmTagSize < len(plaintext) {
panic("cipher: message too large for GCM")
}
if len(dst)+len(plaintext)+gcmTagSize < len(dst) {
panic("cipher: message too large for buffer")
}
// Make room in dst to append plaintext+overhead.
n := len(dst)
for cap(dst) < n+len(plaintext)+gcmTagSize {
dst = append(dst[:cap(dst)], 0)
}
dst = dst[:n+len(plaintext)+gcmTagSize]
// Check delayed until now to make sure len(dst) is accurate.
if inexactOverlap(dst[n:], plaintext) {
panic("cipher: invalid buffer overlap")
}
outLen := C.size_t(len(plaintext) + gcmTagSize)
ok := C.EVP_AEAD_CTX_seal_wrapper(
&g.ctx,
(*C.uint8_t)(unsafe.Pointer(&dst[n])), outLen,
base(nonce), C.size_t(len(nonce)),
base(plaintext), C.size_t(len(plaintext)),
base(additionalData), C.size_t(len(additionalData)))
runtime.KeepAlive(g)
if ok == 0 {
panic(fail("EVP_AEAD_CTX_seal"))
}
return dst[:n+int(outLen)]
}
var errOpen = errors.New("cipher: message authentication failed")
func (g *aesGCM) Open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error) {
if len(nonce) != gcmStandardNonceSize {
panic("cipher: incorrect nonce length given to GCM")
}
if len(ciphertext) < gcmTagSize {
return nil, errOpen
}
if uint64(len(ciphertext)) > ((1<<32)-2)*aesBlockSize+gcmTagSize {
return nil, errOpen
}
// Make room in dst to append ciphertext without tag.
n := len(dst)
for cap(dst) < n+len(ciphertext)-gcmTagSize {
dst = append(dst[:cap(dst)], 0)
}
dst = dst[:n+len(ciphertext)-gcmTagSize]
// Check delayed until now to make sure len(dst) is accurate.
if inexactOverlap(dst[n:], ciphertext) {
panic("cipher: invalid buffer overlap")
}
outLen := C.size_t(len(ciphertext) - gcmTagSize)
ok := C.EVP_AEAD_CTX_open_wrapper(
&g.ctx,
base(dst[n:]), outLen,
base(nonce), C.size_t(len(nonce)),
base(ciphertext), C.size_t(len(ciphertext)),
base(additionalData), C.size_t(len(additionalData)))
runtime.KeepAlive(g)
if ok == 0 {
return nil, errOpen
}
return dst[:n+int(outLen)], nil
}
func anyOverlap(x, y []byte) bool {
return len(x) > 0 && len(y) > 0 &&
uintptr(unsafe.Pointer(&x[0])) <= uintptr(unsafe.Pointer(&y[len(y)-1])) &&
uintptr(unsafe.Pointer(&y[0])) <= uintptr(unsafe.Pointer(&x[len(x)-1]))
}
func inexactOverlap(x, y []byte) bool {
if len(x) == 0 || len(y) == 0 || &x[0] == &y[0] {
return false
}
return anyOverlap(x, y)
}