diff options
author | Herbert Xu <herbert@gondor.apana.org.au> | 2016-11-22 20:08:42 +0800 |
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committer | Herbert Xu <herbert@gondor.apana.org.au> | 2016-11-28 21:23:21 +0800 |
commit | cc868d82abca4a90a447bfd31b46b381ec144669 (patch) | |
tree | c793a9ad62175ba48ff5f5ce757fa5a6dce24987 /include/crypto/cbc.h | |
parent | 79c65d179a40e145287e59b33dc782a7c4bf0986 (diff) |
crypto: cbc - Export CBC implementation
This patch moves the core CBC implementation into a header file
so that it can be reused by drivers implementing CBC.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'include/crypto/cbc.h')
-rw-r--r-- | include/crypto/cbc.h | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/include/crypto/cbc.h b/include/crypto/cbc.h new file mode 100644 index 000000000000..f5b8bfc22e6d --- /dev/null +++ b/include/crypto/cbc.h @@ -0,0 +1,146 @@ +/* + * CBC: Cipher Block Chaining mode + * + * Copyright (c) 2016 Herbert Xu <herbert@gondor.apana.org.au> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + * + */ + +#ifndef _CRYPTO_CBC_H +#define _CRYPTO_CBC_H + +#include <crypto/internal/skcipher.h> +#include <linux/string.h> +#include <linux/types.h> + +static inline int crypto_cbc_encrypt_segment( + struct skcipher_walk *walk, struct crypto_skcipher *tfm, + void (*fn)(struct crypto_skcipher *, const u8 *, u8 *)) +{ + unsigned int bsize = crypto_skcipher_blocksize(tfm); + unsigned int nbytes = walk->nbytes; + u8 *src = walk->src.virt.addr; + u8 *dst = walk->dst.virt.addr; + u8 *iv = walk->iv; + + do { + crypto_xor(iv, src, bsize); + fn(tfm, iv, dst); + memcpy(iv, dst, bsize); + + src += bsize; + dst += bsize; + } while ((nbytes -= bsize) >= bsize); + + return nbytes; +} + +static inline int crypto_cbc_encrypt_inplace( + struct skcipher_walk *walk, struct crypto_skcipher *tfm, + void (*fn)(struct crypto_skcipher *, const u8 *, u8 *)) +{ + unsigned int bsize = crypto_skcipher_blocksize(tfm); + unsigned int nbytes = walk->nbytes; + u8 *src = walk->src.virt.addr; + u8 *iv = walk->iv; + + do { + crypto_xor(src, iv, bsize); + fn(tfm, src, src); + iv = src; + + src += bsize; + } while ((nbytes -= bsize) >= bsize); + + memcpy(walk->iv, iv, bsize); + + return nbytes; +} + +static inline int crypto_cbc_encrypt_walk(struct skcipher_request *req, + void (*fn)(struct crypto_skcipher *, + const u8 *, u8 *)) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + struct skcipher_walk walk; + int err; + + err = skcipher_walk_virt(&walk, req, false); + + while (walk.nbytes) { + if (walk.src.virt.addr == walk.dst.virt.addr) + err = crypto_cbc_encrypt_inplace(&walk, tfm, fn); + else + err = crypto_cbc_encrypt_segment(&walk, tfm, fn); + err = skcipher_walk_done(&walk, err); + } + + return err; +} + +static inline int crypto_cbc_decrypt_segment( + struct skcipher_walk *walk, struct crypto_skcipher *tfm, + void (*fn)(struct crypto_skcipher *, const u8 *, u8 *)) +{ + unsigned int bsize = crypto_skcipher_blocksize(tfm); + unsigned int nbytes = walk->nbytes; + u8 *src = walk->src.virt.addr; + u8 *dst = walk->dst.virt.addr; + u8 *iv = walk->iv; + + do { + fn(tfm, src, dst); + crypto_xor(dst, iv, bsize); + iv = src; + + src += bsize; + dst += bsize; + } while ((nbytes -= bsize) >= bsize); + + memcpy(walk->iv, iv, bsize); + + return nbytes; +} + +static inline int crypto_cbc_decrypt_inplace( + struct skcipher_walk *walk, struct crypto_skcipher *tfm, + void (*fn)(struct crypto_skcipher *, const u8 *, u8 *)) +{ + unsigned int bsize = crypto_skcipher_blocksize(tfm); + unsigned int nbytes = walk->nbytes; + u8 *src = walk->src.virt.addr; + u8 last_iv[bsize]; + + /* Start of the last block. */ + src += nbytes - (nbytes & (bsize - 1)) - bsize; + memcpy(last_iv, src, bsize); + + for (;;) { + fn(tfm, src, src); + if ((nbytes -= bsize) < bsize) + break; + crypto_xor(src, src - bsize, bsize); + src -= bsize; + } + + crypto_xor(src, walk->iv, bsize); + memcpy(walk->iv, last_iv, bsize); + + return nbytes; +} + +static inline int crypto_cbc_decrypt_blocks( + struct skcipher_walk *walk, struct crypto_skcipher *tfm, + void (*fn)(struct crypto_skcipher *, const u8 *, u8 *)) +{ + if (walk->src.virt.addr == walk->dst.virt.addr) + return crypto_cbc_decrypt_inplace(walk, tfm, fn); + else + return crypto_cbc_decrypt_segment(walk, tfm, fn); +} + +#endif /* _CRYPTO_CBC_H */ |