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https://github.com/torvalds/linux
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28856a9e52
The patch centralizes the XTS key check logic into the service function xts_check_key which is invoked from the different XTS implementations. With this, the XTS implementations in ARM, ARM64, PPC and S390 have now a sanity check for the XTS keys similar to the other arches. In addition, this service function received a check to ensure that the key != the tweak key which is mandated by FIPS 140-2 IG A.9. As the check is not present in the standards defining XTS, it is only enforced in FIPS mode of the kernel. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
54 lines
1.2 KiB
C
54 lines
1.2 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 <linux/crypto.h>
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#include <crypto/algapi.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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#endif /* _CRYPTO_XTS_H */
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