1 /* 2 * Cryptographic API. 3 * 4 * HMAC: Keyed-Hashing for Message Authentication (RFC2104). 5 * 6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> 7 * 8 * The HMAC implementation is derived from USAGI. 9 * Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI 10 * 11 * This program is free software; you can redistribute it and/or modify it 12 * under the terms of the GNU General Public License as published by the Free 13 * Software Foundation; either version 2 of the License, or (at your option) 14 * any later version. 15 * 16 */ 17 #include <linux/crypto.h> 18 #include <linux/mm.h> 19 #include <linux/highmem.h> 20 #include <linux/slab.h> 21 #include <asm/scatterlist.h> 22 #include "internal.h" 23 24 static void hash_key(struct crypto_tfm *tfm, u8 *key, unsigned int keylen) 25 { 26 struct scatterlist tmp; 27 28 tmp.page = virt_to_page(key); 29 tmp.offset = offset_in_page(key); 30 tmp.length = keylen; 31 crypto_digest_digest(tfm, &tmp, 1, key); 32 33 } 34 35 int crypto_alloc_hmac_block(struct crypto_tfm *tfm) 36 { 37 int ret = 0; 38 39 BUG_ON(!crypto_tfm_alg_blocksize(tfm)); 40 41 tfm->crt_digest.dit_hmac_block = kmalloc(crypto_tfm_alg_blocksize(tfm), 42 GFP_KERNEL); 43 if (tfm->crt_digest.dit_hmac_block == NULL) 44 ret = -ENOMEM; 45 46 return ret; 47 48 } 49 50 void crypto_free_hmac_block(struct crypto_tfm *tfm) 51 { 52 kfree(tfm->crt_digest.dit_hmac_block); 53 } 54 55 void crypto_hmac_init(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen) 56 { 57 unsigned int i; 58 struct scatterlist tmp; 59 char *ipad = tfm->crt_digest.dit_hmac_block; 60 61 if (*keylen > crypto_tfm_alg_blocksize(tfm)) { 62 hash_key(tfm, key, *keylen); 63 *keylen = crypto_tfm_alg_digestsize(tfm); 64 } 65 66 memset(ipad, 0, crypto_tfm_alg_blocksize(tfm)); 67 memcpy(ipad, key, *keylen); 68 69 for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++) 70 ipad[i] ^= 0x36; 71 72 tmp.page = virt_to_page(ipad); 73 tmp.offset = offset_in_page(ipad); 74 tmp.length = crypto_tfm_alg_blocksize(tfm); 75 76 crypto_digest_init(tfm); 77 crypto_digest_update(tfm, &tmp, 1); 78 } 79 80 void crypto_hmac_update(struct crypto_tfm *tfm, 81 struct scatterlist *sg, unsigned int nsg) 82 { 83 crypto_digest_update(tfm, sg, nsg); 84 } 85 86 void crypto_hmac_final(struct crypto_tfm *tfm, u8 *key, 87 unsigned int *keylen, u8 *out) 88 { 89 unsigned int i; 90 struct scatterlist tmp; 91 char *opad = tfm->crt_digest.dit_hmac_block; 92 93 if (*keylen > crypto_tfm_alg_blocksize(tfm)) { 94 hash_key(tfm, key, *keylen); 95 *keylen = crypto_tfm_alg_digestsize(tfm); 96 } 97 98 crypto_digest_final(tfm, out); 99 100 memset(opad, 0, crypto_tfm_alg_blocksize(tfm)); 101 memcpy(opad, key, *keylen); 102 103 for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++) 104 opad[i] ^= 0x5c; 105 106 tmp.page = virt_to_page(opad); 107 tmp.offset = offset_in_page(opad); 108 tmp.length = crypto_tfm_alg_blocksize(tfm); 109 110 crypto_digest_init(tfm); 111 crypto_digest_update(tfm, &tmp, 1); 112 113 tmp.page = virt_to_page(out); 114 tmp.offset = offset_in_page(out); 115 tmp.length = crypto_tfm_alg_digestsize(tfm); 116 117 crypto_digest_update(tfm, &tmp, 1); 118 crypto_digest_final(tfm, out); 119 } 120 121 void crypto_hmac(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen, 122 struct scatterlist *sg, unsigned int nsg, u8 *out) 123 { 124 crypto_hmac_init(tfm, key, keylen); 125 crypto_hmac_update(tfm, sg, nsg); 126 crypto_hmac_final(tfm, key, keylen, out); 127 } 128 129 EXPORT_SYMBOL_GPL(crypto_hmac_init); 130 EXPORT_SYMBOL_GPL(crypto_hmac_update); 131 EXPORT_SYMBOL_GPL(crypto_hmac_final); 132 EXPORT_SYMBOL_GPL(crypto_hmac); 133 134