cbc.c File Reference

Cipher-block chaining. More...

#include <string.h>
#include <assert.h>
#include <errno.h>
#include <ipxe/crypto.h>
#include <ipxe/cbc.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
	FILE_SECBOOT (PERMITTED)
int	cbc_setkey (struct cipher_algorithm *cipher, void *ctx, const void *key, size_t keylen)
	Set key.
int	cbc_setiv (struct cipher_algorithm *cipher, void *ctx, const void *iv, size_t ivlen)
	Set initialisation vector.
static void	cbc_xor (const void *src, void *dst, size_t len)
	XOR data blocks.
void	cbc_encrypt (struct cipher_algorithm *cipher, void *ctx, const void *src, void *dst, size_t len)
	Encrypt data.
void	cbc_decrypt (struct cipher_algorithm *cipher, void *ctx, const void *src, void *dst, size_t len)
	Decrypt data.

Detailed Description

Cipher-block chaining.

Definition in file cbc.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

cbc_setkey()

int cbc_setkey	(	struct cipher_algorithm *	cipher,
		void *	ctx,
		const void *	key,
		size_t	keylen )

Set key.

Parameters

cipher	Cipher algorithm
ctx	Context
key	Key
keylen	Key length

Return values

rc	Return status code

Definition at line 48 of file cbc.c.

                                                  {
        struct cipher_algorithm *raw_cipher = cipher->priv;
        size_t blocksize = cipher->blocksize;
        size_t ctxsize = cipher->ctxsize;
        cbc_context_t ( blocksize, ctxsize ) *context = ctx;
 
        return cipher_setkey ( raw_cipher, context->raw, key, keylen );
}

References cipher_algorithm::blocksize, cbc_context_t, cipher_setkey(), ctx, cipher_algorithm::ctxsize, key, and cipher_algorithm::priv.

cbc_setiv()

int cbc_setiv	(	struct cipher_algorithm *	cipher,
		void *	ctx,
		const void *	iv,
		size_t	ivlen )

Set initialisation vector.

Parameters

cipher	Cipher algorithm
ctx	Context
iv	Initialisation vector
ivlen	Initialisation vector length

Return values

rc	Return status code

Definition at line 67 of file cbc.c.

                                               {
        size_t blocksize = cipher->blocksize;
        size_t ctxsize = cipher->ctxsize;
        cbc_context_t ( blocksize, ctxsize ) *context = ctx;
 
        /* Check length */
        if ( ivlen != sizeof ( context->cbc ) )
                return -ENOTSUP;
 
        /* Record IV */
        memcpy ( context->cbc, iv, sizeof ( context->cbc ) );
 
        return 0;
}

References cipher_algorithm::blocksize, cbc_context_t, ctx, cipher_algorithm::ctxsize, ENOTSUP, iv, and memcpy().

cbc_xor()

void cbc_xor ( const void * src, void * dst, size_t len )

static

XOR data blocks.

Parameters

src	Input data
dst	Second input data and output data buffer
len	Length of data

Definition at line 90 of file cbc.c.

                                                               {
        const uint32_t *srcl = src;
        uint32_t *dstl = dst;
        unsigned int i;
 
        /* Assume that block sizes will always be dword-aligned, for speed */
        assert ( ( len % sizeof ( *srcl ) ) == 0 );
 
        for ( i = 0 ; i < ( len / sizeof ( *srcl ) ) ; i++ )
                dstl[i] ^= srcl[i];
}

References assert, len, and src.

Referenced by cbc_decrypt(), and cbc_encrypt().

cbc_encrypt()

void cbc_encrypt	(	struct cipher_algorithm *	cipher,
		void *	ctx,
		const void *	src,
		void *	dst,
		size_t	len )

Encrypt data.

Parameters

cipher	Cipher algorithm
ctx	Context
src	Data to encrypt
dst	Buffer for encrypted data
len	Length of data

Definition at line 111 of file cbc.c.

                                                            {
        struct cipher_algorithm *raw_cipher = cipher->priv;
        size_t blocksize = cipher->blocksize;
        size_t ctxsize = cipher->ctxsize;
        cbc_context_t ( blocksize, ctxsize ) *context = ctx;
 
        assert ( ( len % blocksize ) == 0 );
 
        while ( len ) {
                cbc_xor ( src, context->cbc, blocksize );
                cipher_encrypt ( raw_cipher, context->raw, context->cbc, dst,
                                 blocksize );
                memcpy ( context->cbc, dst, blocksize );
                dst += blocksize;
                src += blocksize;
                len -= blocksize;
        }
}

References assert, cipher_algorithm::blocksize, cbc_context_t, cbc_xor(), cipher_encrypt, ctx, cipher_algorithm::ctxsize, len, memcpy(), cipher_algorithm::priv, and src.

cbc_decrypt()

void cbc_decrypt	(	struct cipher_algorithm *	cipher,
		void *	ctx,
		const void *	src,
		void *	dst,
		size_t	len )

Decrypt data.

Parameters

cipher	Cipher algorithm
ctx	Context
src	Data to decrypt
dst	Buffer for decrypted data
len	Length of data

Definition at line 140 of file cbc.c.

                                                            {
        struct cipher_algorithm *raw_cipher = cipher->priv;
        size_t blocksize = cipher->blocksize;
        size_t ctxsize = cipher->ctxsize;
        cbc_context_t ( blocksize, ctxsize ) *context = ctx;
        uint8_t next_cbc_ctx[blocksize];
 
        assert ( ( len % blocksize ) == 0 );
 
        while ( len ) {
                memcpy ( next_cbc_ctx, src, blocksize );
                cipher_decrypt ( raw_cipher, context->raw, src, dst,
                                 blocksize );
                cbc_xor ( context->cbc, dst, blocksize );
                memcpy ( context->cbc, next_cbc_ctx, blocksize );
                dst += blocksize;
                src += blocksize;
                len -= blocksize;
        }
}

References assert, cipher_algorithm::blocksize, cbc_context_t, cbc_xor(), cipher_decrypt, ctx, cipher_algorithm::ctxsize, len, memcpy(), cipher_algorithm::priv, and src.