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ff3ab74623
Make the AES-XTS key verification code callable by the crypto library by splitting out a helper function that doesn't use crypto_skcipher. Reviewed-by: Thomas Huth <thuth@redhat.com> Link: https://patch.msgid.link/20260715221153.246410-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@kernel.org>
51 lines
1.2 KiB
C
51 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#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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#define XTS_BLOCK_SIZE 16
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#define XTS_FORBID_WEAK_KEYS (1 << 0)
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static inline int __xts_verify_key(const u8 *key, size_t keylen, int flags)
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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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return -EINVAL;
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/*
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* In FIPS mode only a combined key length of either 256 or
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* 512 bits is allowed, c.f. FIPS 140-3 IG C.I.
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*/
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if (fips_enabled && keylen != 32 && keylen != 64)
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return -EINVAL;
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/*
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* Ensure that the AES and tweak key are not identical when
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* in FIPS mode or the FORBID_WEAK_KEYS flag is set.
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*/
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if ((fips_enabled || (flags & XTS_FORBID_WEAK_KEYS)) &&
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!crypto_memneq(key, key + (keylen / 2), keylen / 2))
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return -EINVAL;
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return 0;
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}
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static inline int xts_verify_key(struct crypto_skcipher *tfm, const u8 *key,
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unsigned int keylen)
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{
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int flags = (crypto_skcipher_get_flags(tfm) &
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CRYPTO_TFM_REQ_FORBID_WEAK_KEYS) ?
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XTS_FORBID_WEAK_KEYS :
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0;
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return __xts_verify_key(key, keylen, flags);
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}
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#endif /* _CRYPTO_XTS_H */
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