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[crypto] Allow creation of arbitrary CBC cipher algorithms using CBC_CIPHER()

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Given any block cipher, a corresponding CBC mode of behaviour for the
cipher can be created using the CBC_CIPHER() macro.
This commit is contained in:
Michael Brown
2009-02-19 01:48:52 +00:00
parent e950dc04ba
commit 9937bf13c9
3 changed files with 66 additions and 106 deletions
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64
src/include/gpxe/cbc.h
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@@ -15,15 +15,15 @@
* @v ctx Context
* @v key Key
* @v keylen Key length
* @v cipher Underlying cipher algorithm
* @v raw_cipher Underlying cipher algorithm
* @v cbc_ctx CBC context
* @ret rc Return status code
*/
static inline int cbc_setkey ( void *ctx, const void *key, size_t keylen,
struct cipher_algorithm *cipher,
struct cipher_algorithm *raw_cipher,
void *cbc_ctx __unused ) {
return cipher_setkey ( cipher, ctx, key, keylen );
return cipher_setkey ( raw_cipher, ctx, key, keylen );
}
/**
@@ -31,20 +31,68 @@ static inline int cbc_setkey ( void *ctx, const void *key, size_t keylen,
*
* @v ctx Context
* @v iv Initialisation vector
* @v cipher Underlying cipher algorithm
* @v raw_cipher Underlying cipher algorithm
* @v cbc_ctx CBC context
*/
static inline void cbc_setiv ( void *ctx __unused, const void *iv,
struct cipher_algorithm *cipher,
struct cipher_algorithm *raw_cipher,
void *cbc_ctx ) {
memcpy ( cbc_ctx, iv, cipher->blocksize );
memcpy ( cbc_ctx, iv, raw_cipher->blocksize );
}
extern void cbc_encrypt ( void *ctx, const void *src, void *dst,
size_t len, struct cipher_algorithm *cipher,
size_t len, struct cipher_algorithm *raw_cipher,
void *cbc_ctx );
extern void cbc_decrypt ( void *ctx, const void *src, void *dst,
size_t len, struct cipher_algorithm *cipher,
size_t len, struct cipher_algorithm *raw_cipher,
void *cbc_ctx );
/**
* Create a cipher-block chaining mode of behaviour of an existing cipher
*
* @v _cbc_name Name for the new CBC cipher
* @v _cbc_cipher New cipher algorithm
* @v _raw_cipher Underlying cipher algorithm
* @v _raw_context Context structure for the underlying cipher
* @v _blocksize Cipher block size
*/
#define CBC_CIPHER( _cbc_name, _cbc_cipher, _raw_cipher, _raw_context, \
_blocksize ) \
struct _cbc_name ## _context { \
_raw_context raw_ctx; \
uint8_t cbc_ctx[_blocksize]; \
}; \
static int _cbc_name ## _setkey ( void *ctx, const void *key, \
size_t keylen ) { \
struct _cbc_name ## _context * _cbc_name ## _ctx = ctx; \
return cbc_setkey ( &_cbc_name ## _ctx->raw_ctx, key, keylen, \
&_raw_cipher, &_cbc_name ## _ctx->cbc_ctx );\
} \
static void _cbc_name ## _setiv ( void *ctx, const void *iv ) { \
struct _cbc_name ## _context * _cbc_name ## _ctx = ctx; \
cbc_setiv ( &_cbc_name ## _ctx->raw_ctx, iv, \
&_raw_cipher, &aes_cbc_ctx->cbc_ctx ); \
} \
static void _cbc_name ## _encrypt ( void *ctx, const void *src, \
void *dst, size_t len ) { \
struct _cbc_name ## _context * _cbc_name ## _ctx = ctx; \
cbc_encrypt ( &_cbc_name ## _ctx->raw_ctx, src, dst, len, \
&_raw_cipher, &aes_cbc_ctx->cbc_ctx ); \
} \
static void _cbc_name ## _decrypt ( void *ctx, const void *src, \
void *dst, size_t len ) { \
struct _cbc_name ## _context * _cbc_name ## _ctx = ctx; \
cbc_decrypt ( &_cbc_name ## _ctx->raw_ctx, src, dst, len, \
&_raw_cipher, &aes_cbc_ctx->cbc_ctx ); \
} \
struct cipher_algorithm _cbc_cipher = { \
.name = #_cbc_name, \
.ctxsize = sizeof ( struct _cbc_name ## _context ), \
.blocksize = _blocksize, \
.setkey = _cbc_name ## _setkey, \
.setiv = _cbc_name ## _setiv, \
.encrypt = _cbc_name ## _encrypt, \
.decrypt = _cbc_name ## _decrypt, \
};
#endif /* _GPXE_CBC_H */