1 /* 2 * Cryptographic API. 3 * 4 * Cipher operations. 5 * 6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> 7 * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au> 8 * 9 * This program is free software; you can redistribute it and/or modify it 10 * under the terms of the GNU General Public License as published by the Free 11 * Software Foundation; either version 2 of the License, or (at your option) 12 * any later version. 13 * 14 */ 15 16 #include <linux/kernel.h> 17 #include <linux/crypto.h> 18 #include <linux/errno.h> 19 #include <linux/slab.h> 20 #include <linux/string.h> 21 #include "internal.h" 22 23 static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key, 24 unsigned int keylen) 25 { 26 struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher; 27 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); 28 int ret; 29 u8 *buffer, *alignbuffer; 30 unsigned long absize; 31 32 absize = keylen + alignmask; 33 buffer = kmalloc(absize, GFP_ATOMIC); 34 if (!buffer) 35 return -ENOMEM; 36 37 alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); 38 memcpy(alignbuffer, key, keylen); 39 ret = cia->cia_setkey(tfm, alignbuffer, keylen); 40 memset(alignbuffer, 0, keylen); 41 kfree(buffer); 42 return ret; 43 44 } 45 46 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen) 47 { 48 struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher; 49 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); 50 51 tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK; 52 if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) { 53 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; 54 return -EINVAL; 55 } 56 57 if ((unsigned long)key & alignmask) 58 return setkey_unaligned(tfm, key, keylen); 59 60 return cia->cia_setkey(tfm, key, keylen); 61 } 62 63 static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *, 64 const u8 *), 65 struct crypto_tfm *tfm, 66 u8 *dst, const u8 *src) 67 { 68 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); 69 unsigned int size = crypto_tfm_alg_blocksize(tfm); 70 u8 buffer[size + alignmask]; 71 u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); 72 73 memcpy(tmp, src, size); 74 fn(tfm, tmp, tmp); 75 memcpy(dst, tmp, size); 76 } 77 78 static void cipher_encrypt_unaligned(struct crypto_tfm *tfm, 79 u8 *dst, const u8 *src) 80 { 81 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); 82 struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher; 83 84 if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) { 85 cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src); 86 return; 87 } 88 89 cipher->cia_encrypt(tfm, dst, src); 90 } 91 92 static void cipher_decrypt_unaligned(struct crypto_tfm *tfm, 93 u8 *dst, const u8 *src) 94 { 95 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); 96 struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher; 97 98 if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) { 99 cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src); 100 return; 101 } 102 103 cipher->cia_decrypt(tfm, dst, src); 104 } 105 106 int crypto_init_cipher_ops(struct crypto_tfm *tfm) 107 { 108 struct cipher_tfm *ops = &tfm->crt_cipher; 109 struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher; 110 111 ops->cit_setkey = setkey; 112 ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ? 113 cipher_encrypt_unaligned : cipher->cia_encrypt; 114 ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ? 115 cipher_decrypt_unaligned : cipher->cia_decrypt; 116 117 return 0; 118 } 119