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c4c4db0d59
The CRYPTO_TFM_RES_WEAK_KEY flag was apparently meant as a way to make the ->setkey() functions provide more information about errors. However, no one actually checks for this flag, which makes it pointless. There are also no tests that verify that all algorithms actually set (or don't set) it correctly. This is also the last remaining CRYPTO_TFM_RES_* flag, which means that it's the only thing still needing all the boilerplate code which propagates these flags around from child => parent tfms. And if someone ever needs to distinguish this error in the future (which is somewhat unlikely, as it's been unneeded for a long time), it would be much better to just define a new return value like -EKEYREJECTED. That would be much simpler, less error-prone, and easier to test. So just remove this flag. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
128 lines
3.3 KiB
C
128 lines
3.3 KiB
C
/* 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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