cbc_s390x.go

     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  //go:build !purego
     6  
     7  package aes
     8  
     9  import (
    10  	"crypto/cipher"
    11  	"crypto/internal/alias"
    12  )
    13  
    14  // Assert that aesCipherAsm implements the cbcEncAble and cbcDecAble interfaces.
    15  var _ cbcEncAble = (*aesCipherAsm)(nil)
    16  var _ cbcDecAble = (*aesCipherAsm)(nil)
    17  
    18  type cbc struct {
    19  	b  *aesCipherAsm
    20  	c  code
    21  	iv [BlockSize]byte
    22  }
    23  
    24  func (b *aesCipherAsm) NewCBCEncrypter(iv []byte) cipher.BlockMode {
    25  	var c cbc
    26  	c.b = b
    27  	c.c = b.function
    28  	copy(c.iv[:], iv)
    29  	return &c
    30  }
    31  
    32  func (b *aesCipherAsm) NewCBCDecrypter(iv []byte) cipher.BlockMode {
    33  	var c cbc
    34  	c.b = b
    35  	c.c = b.function + 128 // decrypt function code is encrypt + 128
    36  	copy(c.iv[:], iv)
    37  	return &c
    38  }
    39  
    40  func (x *cbc) BlockSize() int { return BlockSize }
    41  
    42  // cryptBlocksChain invokes the cipher message with chaining (KMC) instruction
    43  // with the given function code. The length must be a multiple of BlockSize (16).
    44  //
    45  //go:noescape
    46  func cryptBlocksChain(c code, iv, key, dst, src *byte, length int)
    47  
    48  func (x *cbc) CryptBlocks(dst, src []byte) {
    49  	if len(src)%BlockSize != 0 {
    50  		panic("crypto/cipher: input not full blocks")
    51  	}
    52  	if len(dst) < len(src) {
    53  		panic("crypto/cipher: output smaller than input")
    54  	}
    55  	if alias.InexactOverlap(dst[:len(src)], src) {
    56  		panic("crypto/cipher: invalid buffer overlap")
    57  	}
    58  	if len(src) > 0 {
    59  		cryptBlocksChain(x.c, &x.iv[0], &x.b.key[0], &dst[0], &src[0], len(src))
    60  	}
    61  }
    62  
    63  func (x *cbc) SetIV(iv []byte) {
    64  	if len(iv) != BlockSize {
    65  		panic("cipher: incorrect length IV")
    66  	}
    67  	copy(x.iv[:], iv)
    68  }
    69
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