lib/sha1.c

   1 /*
   2  * SHA transform algorithm, originally taken from code written by
   3  * Peter Gutmann, and placed in the public domain.
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/cryptohash.h>
   9
  10 /* The SHA f()-functions.  */
  11
  12 #define f1(x,y,z)   (z ^ (x & (y ^ z)))         /* x ? y : z */
  13 #define f2(x,y,z)   (x ^ y ^ z)                 /* XOR */
  14 #define f3(x,y,z)   ((x & y) + (z & (x ^ y)))   /* majority */
  15
  16 /* The SHA Mysterious Constants */
  17
  18 #define K1  0x5A827999L                 /* Rounds  0-19: sqrt(2) * 2^30 */
  19 #define K2  0x6ED9EBA1L                 /* Rounds 20-39: sqrt(3) * 2^30 */
  20 #define K3  0x8F1BBCDCL                 /* Rounds 40-59: sqrt(5) * 2^30 */
  21 #define K4  0xCA62C1D6L                 /* Rounds 60-79: sqrt(10) * 2^30 */
  22
  23 /**
  24  * sha_transform - single block SHA1 transform
  25  *
  26  * @digest: 160 bit digest to update
  27  * @data:   512 bits of data to hash
  28  * @W:      80 words of workspace (see note)
  29  *
  30  * This function generates a SHA1 digest for a single 512-bit block.
  31  * Be warned, it does not handle padding and message digest, do not
  32  * confuse it with the full FIPS 180-1 digest algorithm for variable
  33  * length messages.
  34  *
  35  * Note: If the hash is security sensitive, the caller should be sure
  36  * to clear the workspace. This is left to the caller to avoid
  37  * unnecessary clears between chained hashing operations.
  38  */
  39 void sha_transform(__u32 *digest, const char *in, __u32 *W)
  40 {
  41         __u32 a, b, c, d, e, t, i;
  42
  43         for (i = 0; i < 16; i++)
  44                 W[i] = be32_to_cpu(((const __be32 *)in)[i]);
  45
  46         for (i = 0; i < 64; i++)
  47                 W[i+16] = rol32(W[i+13] ^ W[i+8] ^ W[i+2] ^ W[i], 1);
  48
  49         a = digest[0];
  50         b = digest[1];
  51         c = digest[2];
  52         d = digest[3];
  53         e = digest[4];
  54
  55         for (i = 0; i < 20; i++) {
  56                 t = f1(b, c, d) + K1 + rol32(a, 5) + e + W[i];
  57                 e = d; d = c; c = rol32(b, 30); b = a; a = t;
  58         }
  59
  60         for (; i < 40; i ++) {
  61                 t = f2(b, c, d) + K2 + rol32(a, 5) + e + W[i];
  62                 e = d; d = c; c = rol32(b, 30); b = a; a = t;
  63         }
  64
  65         for (; i < 60; i ++) {
  66                 t = f3(b, c, d) + K3 + rol32(a, 5) + e + W[i];
  67                 e = d; d = c; c = rol32(b, 30); b = a; a = t;
  68         }
  69
  70         for (; i < 80; i ++) {
  71                 t = f2(b, c, d) + K4 + rol32(a, 5) + e + W[i];
  72                 e = d; d = c; c = rol32(b, 30); b = a; a = t;
  73         }
  74
  75         digest[0] += a;
  76         digest[1] += b;
  77         digest[2] += c;
  78         digest[3] += d;
  79         digest[4] += e;
  80 }
  81 EXPORT_SYMBOL(sha_transform);
  82
  83 /**
  84  * sha_init - initialize the vectors for a SHA1 digest
  85  * @buf: vector to initialize
  86  */
  87 void sha_init(__u32 *buf)
  88 {
  89         buf[0] = 0x67452301;
  90         buf[1] = 0xefcdab89;
  91         buf[2] = 0x98badcfe;
  92         buf[3] = 0x10325476;
  93         buf[4] = 0xc3d2e1f0;
  94 }
  95