Files
GmSSL/go/cipher.go
2017-05-04 20:51:53 +08:00

122 lines
2.7 KiB
Go

/* +build cgo */
package gmssl
/*
#include <openssl/evp.h>
*/
import "C"
import (
"errors"
"fmt"
"runtime"
"unsafe"
)
func GetCiphers(aliases bool) []string {
return []string{"sms4-cbc", "aes-128-cbc", "aes-256-cbc"}
}
func GetCipherKeyLength(name string) (int, error) {
cname := C.CString(name)
defer C.free(unsafe.Pointer(cname))
cipher := C.EVP_get_cipherbyname(cname)
if cipher == nil {
return 0, errors.New("Invalid cipher name")
}
return int(C.EVP_CIPHER_key_length(cipher)), nil
}
func GetCipherBlockSize(name string) (int, error) {
cname := C.CString(name)
defer C.free(unsafe.Pointer(cname))
cipher := C.EVP_get_cipherbyname(cname)
if cipher == nil {
return 0, errors.New("Invalid cipher")
}
return int(C.EVP_CIPHER_block_size(cipher)), nil
}
func GetCipherIVLength(name string) (int, error) {
cname := C.CString(name)
defer C.free(unsafe.Pointer(cname))
cipher := C.EVP_get_cipherbyname(cname)
if cipher == nil {
return 0, errors.New("Invalid cipher")
}
return int(C.EVP_CIPHER_iv_length(cipher)), nil
}
type CipherContext struct {
ctx *C.EVP_CIPHER_CTX
}
func NewCipherContext(name string, args map[string]string, key, iv []byte, encrypt bool) (
*CipherContext, error) {
cname := C.CString(name)
defer C.free(unsafe.Pointer(cname))
cipher := C.EVP_get_cipherbyname(cname)
if cipher == nil {
return nil, fmt.Errorf("shit")
}
if key == nil {
return nil, errors.New("No key")
}
if len(key) != int(C.EVP_CIPHER_key_length(cipher)) {
return nil, errors.New("Invalid key length")
}
if 0 != int(C.EVP_CIPHER_iv_length(cipher)) {
if iv == nil {
return nil, errors.New("No IV")
}
if len(iv) != int(C.EVP_CIPHER_iv_length(cipher)) {
return nil, errors.New("Invalid IV")
}
}
ctx := C.EVP_CIPHER_CTX_new()
if ctx == nil {
return nil, fmt.Errorf("shit")
}
ret := &CipherContext{ctx}
runtime.SetFinalizer(ret, func(ret *CipherContext) {
C.EVP_CIPHER_CTX_free(ret.ctx)
})
enc := 1
if encrypt == false {
enc = 0
}
if 1 != C.EVP_CipherInit(ctx, cipher, (*C.uchar)(&key[0]),
(*C.uchar)(&iv[0]), C.int(enc)) {
return nil, fmt.Errorf("shit")
}
return ret, nil
}
func (ctx *CipherContext) Update(in []byte) ([]byte, error) {
outbuf := make([]byte, len(in)+int(C.EVP_CIPHER_CTX_block_size(ctx.ctx)))
outlen := C.int(len(outbuf))
if 1 != C.EVP_CipherUpdate(ctx.ctx, (*C.uchar)(&outbuf[0]), &outlen,
(*C.uchar)(&in[0]), C.int(len(in))) {
return nil, fmt.Errorf("failed to decrypt")
}
return outbuf[:outlen], nil
}
func (ctx *CipherContext) Final() ([]byte, error) {
outbuf := make([]byte, int(C.EVP_CIPHER_CTX_block_size(ctx.ctx)))
outlen := C.int(len(outbuf))
if 1 != C.EVP_CipherFinal(ctx.ctx, (*C.uchar)(&outbuf[0]), &outlen) {
return nil, fmt.Errorf("failed to decrypt")
}
return outbuf[:outlen], nil
}