src/crypto/sha1.c

   1 /*
   2  * SHA1 hash implementation and interface functions
   3  * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
   4  *
   5  * This software may be distributed under the terms of the BSD license.
   6  * See README for more details.
   7  */
   8
   9 #include "includes.h"
  10
  11 #include "common.h"
  12 #include "sha1.h"
  13 #include "crypto.h"
  14
  15
  16 /**
  17  * hmac_sha1_vector - HMAC-SHA1 over data vector (RFC 2104)
  18  * @key: Key for HMAC operations
  19  * @key_len: Length of the key in bytes
  20  * @num_elem: Number of elements in the data vector
  21  * @addr: Pointers to the data areas
  22  * @len: Lengths of the data blocks
  23  * @mac: Buffer for the hash (20 bytes)
  24  * Returns: 0 on success, -1 on failure
  25  */
  26 int hmac_sha1_vector(const u8 *key, size_t key_len, size_t num_elem,
  27                      const u8 *addr[], const size_t *len, u8 *mac)
  28 {
  29         unsigned char k_pad[64]; /* padding - key XORd with ipad/opad */
  30         unsigned char tk[20];
  31         const u8 *_addr[6];
  32         size_t _len[6], i;
  33         int ret;
  34
  35         if (num_elem > 5) {
  36                 /*
  37                  * Fixed limit on the number of fragments to avoid having to
  38                  * allocate memory (which could fail).
  39                  */
  40                 return -1;
  41         }
  42
  43         /* if key is longer than 64 bytes reset it to key = SHA1(key) */
  44         if (key_len > 64) {
  45                 if (sha1_vector(1, &key, &key_len, tk))
  46                         return -1;
  47                 key = tk;
  48                 key_len = 20;
  49         }
  50
  51         /* the HMAC_SHA1 transform looks like:
  52          *
  53          * SHA1(K XOR opad, SHA1(K XOR ipad, text))
  54          *
  55          * where K is an n byte key
  56          * ipad is the byte 0x36 repeated 64 times
  57          * opad is the byte 0x5c repeated 64 times
  58          * and text is the data being protected */
  59
  60         /* start out by storing key in ipad */
  61         os_memset(k_pad, 0, sizeof(k_pad));
  62         os_memcpy(k_pad, key, key_len);
  63         /* XOR key with ipad values */
  64         for (i = 0; i < 64; i++)
  65                 k_pad[i] ^= 0x36;
  66
  67         /* perform inner SHA1 */
  68         _addr[0] = k_pad;
  69         _len[0] = 64;
  70         for (i = 0; i < num_elem; i++) {
  71                 _addr[i + 1] = addr[i];
  72                 _len[i + 1] = len[i];
  73         }
  74         if (sha1_vector(1 + num_elem, _addr, _len, mac))
  75                 return -1;
  76
  77         os_memset(k_pad, 0, sizeof(k_pad));
  78         os_memcpy(k_pad, key, key_len);
  79         /* XOR key with opad values */
  80         for (i = 0; i < 64; i++)
  81                 k_pad[i] ^= 0x5c;
  82
  83         /* perform outer SHA1 */
  84         _addr[0] = k_pad;
  85         _len[0] = 64;
  86         _addr[1] = mac;
  87         _len[1] = SHA1_MAC_LEN;
  88         ret = sha1_vector(2, _addr, _len, mac);
  89         forced_memzero(k_pad, sizeof(k_pad));
  90         forced_memzero(tk, sizeof(tk));
  91         return ret;
  92 }
  93
  94
  95 /**
  96  * hmac_sha1 - HMAC-SHA1 over data buffer (RFC 2104)
  97  * @key: Key for HMAC operations
  98  * @key_len: Length of the key in bytes
  99  * @data: Pointers to the data area
 100  * @data_len: Length of the data area
 101  * @mac: Buffer for the hash (20 bytes)
 102  * Returns: 0 on success, -1 of failure
 103  */
 104 int hmac_sha1(const u8 *key, size_t key_len, const u8 *data, size_t data_len,
 105                u8 *mac)
 106 {
 107         return hmac_sha1_vector(key, key_len, 1, &data, &data_len, mac);
 108 }