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/scatterlist.h> 20 #include <linux/string.h> 21 #include "internal.h" 22 23 static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen) 24 { 25 struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher; 26 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); 27 int ret; 28 u8 *buffer, *alignbuffer; 29 unsigned long absize; 30 31 absize = keylen + alignmask; 32 buffer = kmalloc(absize, GFP_ATOMIC); 33 if (!buffer) 34 return -ENOMEM; 35 36 alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); 37 memcpy(alignbuffer, key, keylen); 38 ret = cia->cia_setkey(tfm, alignbuffer, keylen); 39 memset(alignbuffer, 0, absize); 40 kfree(buffer); 41 return ret; 42 43 } 44 45 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen) 46 { 47 struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher; 48 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); 49 50 tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK; 51 if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) { 52 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; 53 return -EINVAL; 54 } 55 56 if ((unsigned long)key & alignmask) 57 return setkey_unaligned(tfm, key, keylen); 58 59 return cia->cia_setkey(tfm, key, keylen); 60 } 61 62 static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *, 63 const u8 *), 64 struct crypto_tfm *tfm, 65 u8 *dst, const u8 *src) 66 { 67 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); 68 unsigned int size = crypto_tfm_alg_blocksize(tfm); 69 u8 buffer[size + alignmask]; 70 u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); 71 72 memcpy(tmp, src, size); 73 fn(tfm, tmp, tmp); 74 memcpy(dst, tmp, size); 75 } 76 77 static void cipher_encrypt_unaligned(struct crypto_tfm *tfm, 78 u8 *dst, const u8 *src) 79 { 80 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); 81 struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher; 82 83 if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) { 84 cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src); 85 return; 86 } 87 88 cipher->cia_encrypt(tfm, dst, src); 89 } 90 91 static void cipher_decrypt_unaligned(struct crypto_tfm *tfm, 92 u8 *dst, const u8 *src) 93 { 94 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); 95 struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher; 96 97 if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) { 98 cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src); 99 return; 100 } 101 102 cipher->cia_decrypt(tfm, dst, src); 103 } 104 105 int crypto_init_cipher_ops(struct crypto_tfm *tfm) 106 { 107 struct cipher_tfm *ops = &tfm->crt_cipher; 108 struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher; 109 110 ops->cit_setkey = setkey; 111 ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ? 112 cipher_encrypt_unaligned : cipher->cia_encrypt; 113 ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ? 114 cipher_decrypt_unaligned : cipher->cia_decrypt; 115 116 return 0; 117 } 118 119 void crypto_exit_cipher_ops(struct crypto_tfm *tfm) 120 { 121 } 122