128 lines · c
1/* SPDX-License-Identifier: GPL-2.0 */2/*3 * DES & Triple DES EDE key verification helpers4 */5 6#ifndef __CRYPTO_INTERNAL_DES_H7#define __CRYPTO_INTERNAL_DES_H8 9#include <linux/crypto.h>10#include <linux/fips.h>11#include <crypto/des.h>12#include <crypto/aead.h>13#include <crypto/skcipher.h>14 15/**16 * crypto_des_verify_key - Check whether a DES key is weak17 * @tfm: the crypto algo18 * @key: the key buffer19 *20 * Returns -EINVAL if the key is weak and the crypto TFM does not permit weak21 * keys. Otherwise, 0 is returned.22 *23 * It is the job of the caller to ensure that the size of the key equals24 * DES_KEY_SIZE.25 */26static inline int crypto_des_verify_key(struct crypto_tfm *tfm, const u8 *key)27{28 struct des_ctx tmp;29 int err;30 31 err = des_expand_key(&tmp, key, DES_KEY_SIZE);32 if (err == -ENOKEY) {33 if (crypto_tfm_get_flags(tfm) & CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)34 err = -EINVAL;35 else36 err = 0;37 }38 memzero_explicit(&tmp, sizeof(tmp));39 return err;40}41 42/*43 * RFC2451:44 *45 * For DES-EDE3, there is no known need to reject weak or46 * complementation keys. Any weakness is obviated by the use of47 * multiple keys.48 *49 * However, if the first two or last two independent 64-bit keys are50 * equal (k1 == k2 or k2 == k3), then the DES3 operation is simply the51 * same as DES. Implementers MUST reject keys that exhibit this52 * property.53 *54 */55static inline int des3_ede_verify_key(const u8 *key, unsigned int key_len,56 bool check_weak)57{58 int ret = fips_enabled ? -EINVAL : -ENOKEY;59 u32 K[6];60 61 memcpy(K, key, DES3_EDE_KEY_SIZE);62 63 if ((!((K[0] ^ K[2]) | (K[1] ^ K[3])) ||64 !((K[2] ^ K[4]) | (K[3] ^ K[5]))) &&65 (fips_enabled || check_weak))66 goto bad;67 68 if ((!((K[0] ^ K[4]) | (K[1] ^ K[5]))) && fips_enabled)69 goto bad;70 71 ret = 0;72bad:73 memzero_explicit(K, DES3_EDE_KEY_SIZE);74 75 return ret;76}77 78/**79 * crypto_des3_ede_verify_key - Check whether a DES3-EDE key is weak80 * @tfm: the crypto algo81 * @key: the key buffer82 *83 * Returns -EINVAL if the key is weak and the crypto TFM does not permit weak84 * keys or when running in FIPS mode. Otherwise, 0 is returned. Note that some85 * keys are rejected in FIPS mode even if weak keys are permitted by the TFM86 * flags.87 *88 * It is the job of the caller to ensure that the size of the key equals89 * DES3_EDE_KEY_SIZE.90 */91static inline int crypto_des3_ede_verify_key(struct crypto_tfm *tfm,92 const u8 *key)93{94 return des3_ede_verify_key(key, DES3_EDE_KEY_SIZE,95 crypto_tfm_get_flags(tfm) &96 CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);97}98 99static inline int verify_skcipher_des_key(struct crypto_skcipher *tfm,100 const u8 *key)101{102 return crypto_des_verify_key(crypto_skcipher_tfm(tfm), key);103}104 105static inline int verify_skcipher_des3_key(struct crypto_skcipher *tfm,106 const u8 *key)107{108 return crypto_des3_ede_verify_key(crypto_skcipher_tfm(tfm), key);109}110 111static inline int verify_aead_des_key(struct crypto_aead *tfm, const u8 *key,112 int keylen)113{114 if (keylen != DES_KEY_SIZE)115 return -EINVAL;116 return crypto_des_verify_key(crypto_aead_tfm(tfm), key);117}118 119static inline int verify_aead_des3_key(struct crypto_aead *tfm, const u8 *key,120 int keylen)121{122 if (keylen != DES3_EDE_KEY_SIZE)123 return -EINVAL;124 return crypto_des3_ede_verify_key(crypto_aead_tfm(tfm), key);125}126 127#endif /* __CRYPTO_INTERNAL_DES_H */128