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f1c131b454
This patch converts xts over to the skcipher interface. It also optimises the implementation to be based on ECB instead of the underlying cipher. For compatibility the existing naming scheme of xts(aes) is maintained as opposed to the more obvious one of xts(ecb(aes)). Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
77 lines
1.8 KiB
C
77 lines
1.8 KiB
C
#ifndef _CRYPTO_XTS_H
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#define _CRYPTO_XTS_H
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#include <crypto/b128ops.h>
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#include <crypto/internal/skcipher.h>
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#include <linux/fips.h>
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struct scatterlist;
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struct blkcipher_desc;
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#define XTS_BLOCK_SIZE 16
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struct xts_crypt_req {
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be128 *tbuf;
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unsigned int tbuflen;
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void *tweak_ctx;
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void (*tweak_fn)(void *ctx, u8* dst, const u8* src);
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void *crypt_ctx;
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void (*crypt_fn)(void *ctx, u8 *blks, unsigned int nbytes);
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};
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#define XTS_TWEAK_CAST(x) ((void (*)(void *, u8*, const u8*))(x))
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int xts_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
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struct scatterlist *src, unsigned int nbytes,
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struct xts_crypt_req *req);
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static inline int xts_check_key(struct crypto_tfm *tfm,
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const u8 *key, unsigned int keylen)
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{
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u32 *flags = &tfm->crt_flags;
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/*
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* key consists of keys of equal size concatenated, therefore
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* the length must be even.
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*/
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if (keylen % 2) {
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*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
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return -EINVAL;
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}
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/* ensure that the AES and tweak key are not identical */
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if (fips_enabled &&
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!crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
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*flags |= CRYPTO_TFM_RES_WEAK_KEY;
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return -EINVAL;
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}
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return 0;
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}
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static inline int xts_verify_key(struct crypto_skcipher *tfm,
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const u8 *key, unsigned int keylen)
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{
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/*
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* key consists of keys of equal size concatenated, therefore
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* the length must be even.
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*/
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if (keylen % 2) {
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crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
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return -EINVAL;
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}
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/* ensure that the AES and tweak key are not identical */
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if ((fips_enabled || crypto_skcipher_get_flags(tfm) &
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CRYPTO_TFM_REQ_WEAK_KEY) &&
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!crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
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crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
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return -EINVAL;
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}
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return 0;
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}
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#endif /* _CRYPTO_XTS_H */
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