| 1 |
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| 2 | |
| 3 | * DES & Triple DES EDE key verification helpers
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| 4 |
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| 5 |
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| 6 | #ifndef __CRYPTO_INTERNAL_DES_H
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| 7 | #define __CRYPTO_INTERNAL_DES_H
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| 8 |
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| 9 | #include <linux/crypto.h>
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| 10 | #include <linux/fips.h>
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| 11 | #include <crypto/des.h>
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| 12 | #include <crypto/aead.h>
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| 13 | #include <crypto/skcipher.h>
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| 14 |
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| 15 | |
| 16 | * crypto_des_verify_key - Check whether a DES key is weak
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| 17 | * @tfm: the crypto algo
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| 18 | * @key: the key buffer
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| 19 | *
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| 20 | * Returns -EINVAL if the key is weak and the crypto TFM does not permit weak
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| 21 | * keys. Otherwise, 0 is returned.
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| 22 | *
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| 23 | * It is the job of the caller to ensure that the size of the key equals
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| 24 | * DES_KEY_SIZE.
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| 25 |
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| 26 | static inline int crypto_des_verify_key(struct crypto_tfm *tfm, const u8 *key)
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| 27 | {
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| 28 | struct des_ctx tmp;
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| 29 | int err;
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| 30 |
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| 31 | err = des_expand_key(&tmp, key, DES_KEY_SIZE);
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| 32 | if (err == -ENOKEY) {
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| 33 | if (crypto_tfm_get_flags(tfm) & CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)
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| 34 | err = -EINVAL;
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| 35 | else
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| 36 | err = 0;
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| 37 | }
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| 38 | memzero_explicit(&tmp, sizeof(tmp));
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| 39 | return err;
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| 40 | }
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| 41 |
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| 42 | |
| 43 | * RFC2451:
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| 44 | *
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| 45 | * For DES-EDE3, there is no known need to reject weak or
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| 46 | * complementation keys. Any weakness is obviated by the use of
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| 47 | * multiple keys.
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| 48 | *
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| 49 | * However, if the first two or last two independent 64-bit keys are
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| 50 | * equal (k1 == k2 or k2 == k3), then the DES3 operation is simply the
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| 51 | * same as DES. Implementers MUST reject keys that exhibit this
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| 52 | * property.
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| 53 | *
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| 54 |
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| 55 | static inline int des3_ede_verify_key(const u8 *key, unsigned int key_len,
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| 56 | bool check_weak)
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| 57 | {
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| 58 | int ret = fips_enabled ? -EINVAL : -ENOKEY;
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| 59 | u32 K[6];
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| 60 |
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| 61 | memcpy(K, key, DES3_EDE_KEY_SIZE);
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| 62 |
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| 63 | if ((!((K[0] ^ K[2]) | (K[1] ^ K[3])) ||
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| 64 | !((K[2] ^ K[4]) | (K[3] ^ K[5]))) &&
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| 65 | (fips_enabled || check_weak))
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| 66 | goto bad;
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| 67 |
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| 68 | if ((!((K[0] ^ K[4]) | (K[1] ^ K[5]))) && fips_enabled)
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| 69 | goto bad;
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| 70 |
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| 71 | ret = 0;
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| 72 | bad:
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| 73 | memzero_explicit(K, DES3_EDE_KEY_SIZE);
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| 74 |
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| 75 | return ret;
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| 76 | }
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| 77 |
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| 78 | |
| 79 | * crypto_des3_ede_verify_key - Check whether a DES3-EDE key is weak
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| 80 | * @tfm: the crypto algo
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| 81 | * @key: the key buffer
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| 82 | *
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| 83 | * Returns -EINVAL if the key is weak and the crypto TFM does not permit weak
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| 84 | * keys or when running in FIPS mode. Otherwise, 0 is returned. Note that some
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| 85 | * keys are rejected in FIPS mode even if weak keys are permitted by the TFM
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| 86 | * flags.
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| 87 | *
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| 88 | * It is the job of the caller to ensure that the size of the key equals
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| 89 | * DES3_EDE_KEY_SIZE.
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| 90 |
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| 91 | static inline int crypto_des3_ede_verify_key(struct crypto_tfm *tfm,
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| 92 | const u8 *key)
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| 93 | {
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| 94 | return des3_ede_verify_key(key, DES3_EDE_KEY_SIZE,
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| 95 | crypto_tfm_get_flags(tfm) &
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| 96 | CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
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| 97 | }
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| 98 |
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| 99 | static inline int verify_skcipher_des_key(struct crypto_skcipher *tfm,
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| 100 | const u8 *key)
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| 101 | {
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| 102 | return crypto_des_verify_key(crypto_skcipher_tfm(tfm), key);
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| 103 | }
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| 104 |
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| 105 | static inline int verify_skcipher_des3_key(struct crypto_skcipher *tfm,
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| 106 | const u8 *key)
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| 107 | {
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| 108 | return crypto_des3_ede_verify_key(crypto_skcipher_tfm(tfm), key);
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| 109 | }
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| 110 |
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| 111 | static inline int verify_aead_des_key(struct crypto_aead *tfm, const u8 *key,
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| 112 | int keylen)
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| 113 | {
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| 114 | if (keylen != DES_KEY_SIZE)
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| 115 | return -EINVAL;
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| 116 | return crypto_des_verify_key(crypto_aead_tfm(tfm), key);
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| 117 | }
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| 118 |
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| 119 | static inline int verify_aead_des3_key(struct crypto_aead *tfm, const u8 *key,
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| 120 | int keylen)
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| 121 | {
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| 122 | if (keylen != DES3_EDE_KEY_SIZE)
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| 123 | return -EINVAL;
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| 124 | return crypto_des3_ede_verify_key(crypto_aead_tfm(tfm), key);
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| 125 | }
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| 126 |
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| 127 | #endif
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