/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* DES & Triple DES EDE key verification helpers
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*/
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#ifndef __CRYPTO_INTERNAL_DES_H
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#define __CRYPTO_INTERNAL_DES_H
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#include <linux/crypto.h>
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#include <linux/fips.h>
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#include <crypto/des.h>
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#include <crypto/aead.h>
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#include <crypto/skcipher.h>
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/**
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* crypto_des_verify_key - Check whether a DES key is weak
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* @tfm: the crypto algo
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* @key: the key buffer
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*
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* Returns -EINVAL if the key is weak and the crypto TFM does not permit weak
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* keys. Otherwise, 0 is returned.
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*
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* It is the job of the caller to ensure that the size of the key equals
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* DES_KEY_SIZE.
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*/
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static inline int crypto_des_verify_key(struct crypto_tfm *tfm, const u8 *key)
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{
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struct des_ctx tmp;
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int err;
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err = des_expand_key(&tmp, key, DES_KEY_SIZE);
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if (err == -ENOKEY) {
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if (crypto_tfm_get_flags(tfm) & CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)
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err = -EINVAL;
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else
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err = 0;
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}
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memzero_explicit(&tmp, sizeof(tmp));
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return err;
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}
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/*
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* RFC2451:
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*
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* For DES-EDE3, there is no known need to reject weak or
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* complementation keys. Any weakness is obviated by the use of
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* multiple keys.
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*
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* However, if the first two or last two independent 64-bit keys are
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* equal (k1 == k2 or k2 == k3), then the DES3 operation is simply the
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* same as DES. Implementers MUST reject keys that exhibit this
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* property.
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*
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*/
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static inline int des3_ede_verify_key(const u8 *key, unsigned int key_len,
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bool check_weak)
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{
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int ret = fips_enabled ? -EINVAL : -ENOKEY;
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u32 K[6];
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memcpy(K, key, DES3_EDE_KEY_SIZE);
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if ((!((K[0] ^ K[2]) | (K[1] ^ K[3])) ||
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!((K[2] ^ K[4]) | (K[3] ^ K[5]))) &&
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(fips_enabled || check_weak))
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goto bad;
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if ((!((K[0] ^ K[4]) | (K[1] ^ K[5]))) && fips_enabled)
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goto bad;
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ret = 0;
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bad:
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memzero_explicit(K, DES3_EDE_KEY_SIZE);
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return ret;
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}
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/**
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* crypto_des3_ede_verify_key - Check whether a DES3-EDE key is weak
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* @tfm: the crypto algo
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* @key: the key buffer
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*
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* Returns -EINVAL if the key is weak and the crypto TFM does not permit weak
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* keys or when running in FIPS mode. Otherwise, 0 is returned. Note that some
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* keys are rejected in FIPS mode even if weak keys are permitted by the TFM
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* flags.
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*
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* It is the job of the caller to ensure that the size of the key equals
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* DES3_EDE_KEY_SIZE.
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*/
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static inline int crypto_des3_ede_verify_key(struct crypto_tfm *tfm,
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const u8 *key)
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{
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return des3_ede_verify_key(key, DES3_EDE_KEY_SIZE,
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crypto_tfm_get_flags(tfm) &
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CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
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}
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static inline int verify_skcipher_des_key(struct crypto_skcipher *tfm,
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const u8 *key)
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{
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return crypto_des_verify_key(crypto_skcipher_tfm(tfm), key);
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}
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static inline int verify_skcipher_des3_key(struct crypto_skcipher *tfm,
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const u8 *key)
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{
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return crypto_des3_ede_verify_key(crypto_skcipher_tfm(tfm), key);
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}
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static inline int verify_aead_des_key(struct crypto_aead *tfm, const u8 *key,
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int keylen)
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{
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if (keylen != DES_KEY_SIZE)
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return -EINVAL;
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return crypto_des_verify_key(crypto_aead_tfm(tfm), key);
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}
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static inline int verify_aead_des3_key(struct crypto_aead *tfm, const u8 *key,
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int keylen)
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{
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if (keylen != DES3_EDE_KEY_SIZE)
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return -EINVAL;
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return crypto_des3_ede_verify_key(crypto_aead_tfm(tfm), key);
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}
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#endif /* __CRYPTO_INTERNAL_DES_H */
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