github.com/guyezi/gofrontend@v0.0.0-20200228202240-7a62a49e62c0/libgo/go/crypto/aes/cipher_s390x.go (about)

     1  // Copyright 2016 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  // +build ignore
     6  
     7  package aes
     8  
     9  import (
    10  	"crypto/cipher"
    11  	"crypto/internal/subtle"
    12  	"internal/cpu"
    13  )
    14  
    15  type code int
    16  
    17  // Function codes for the cipher message family of instructions.
    18  const (
    19  	aes128 code = 18
    20  	aes192      = 19
    21  	aes256      = 20
    22  )
    23  
    24  type aesCipherAsm struct {
    25  	function code     // code for cipher message instruction
    26  	key      []byte   // key (128, 192 or 256 bits)
    27  	storage  [32]byte // array backing key slice
    28  }
    29  
    30  // cryptBlocks invokes the cipher message (KM) instruction with
    31  // the given function code. This is equivalent to AES in ECB
    32  // mode. The length must be a multiple of BlockSize (16).
    33  //go:noescape
    34  func cryptBlocks(c code, key, dst, src *byte, length int)
    35  
    36  func newCipher(key []byte) (cipher.Block, error) {
    37  	// The aesCipherAsm type implements the cbcEncAble, cbcDecAble,
    38  	// ctrAble and gcmAble interfaces. We therefore need to check
    39  	// for all the features required to implement these modes.
    40  	// Keep in sync with crypto/tls/common.go.
    41  	if !(cpu.S390X.HasAES && cpu.S390X.HasAESCBC && cpu.S390X.HasAESCTR && (cpu.S390X.HasGHASH || cpu.S390X.HasAESGCM)) {
    42  		return newCipherGeneric(key)
    43  	}
    44  
    45  	var function code
    46  	switch len(key) {
    47  	case 128 / 8:
    48  		function = aes128
    49  	case 192 / 8:
    50  		function = aes192
    51  	case 256 / 8:
    52  		function = aes256
    53  	default:
    54  		return nil, KeySizeError(len(key))
    55  	}
    56  
    57  	var c aesCipherAsm
    58  	c.function = function
    59  	c.key = c.storage[:len(key)]
    60  	copy(c.key, key)
    61  	return &c, nil
    62  }
    63  
    64  func (c *aesCipherAsm) BlockSize() int { return BlockSize }
    65  
    66  func (c *aesCipherAsm) Encrypt(dst, src []byte) {
    67  	if len(src) < BlockSize {
    68  		panic("crypto/aes: input not full block")
    69  	}
    70  	if len(dst) < BlockSize {
    71  		panic("crypto/aes: output not full block")
    72  	}
    73  	if subtle.InexactOverlap(dst[:BlockSize], src[:BlockSize]) {
    74  		panic("crypto/aes: invalid buffer overlap")
    75  	}
    76  	cryptBlocks(c.function, &c.key[0], &dst[0], &src[0], BlockSize)
    77  }
    78  
    79  func (c *aesCipherAsm) Decrypt(dst, src []byte) {
    80  	if len(src) < BlockSize {
    81  		panic("crypto/aes: input not full block")
    82  	}
    83  	if len(dst) < BlockSize {
    84  		panic("crypto/aes: output not full block")
    85  	}
    86  	if subtle.InexactOverlap(dst[:BlockSize], src[:BlockSize]) {
    87  		panic("crypto/aes: invalid buffer overlap")
    88  	}
    89  	// The decrypt function code is equal to the function code + 128.
    90  	cryptBlocks(c.function+128, &c.key[0], &dst[0], &src[0], BlockSize)
    91  }
    92  
    93  // expandKey is used by BenchmarkExpand. cipher message (KM) does not need key
    94  // expansion so there is no assembly equivalent.
    95  func expandKey(key []byte, enc, dec []uint32) {
    96  	expandKeyGo(key, enc, dec)
    97  }