block-sha1/sha1.c

   1 /*
   2  * Based on the Mozilla SHA1 (see mozilla-sha1/sha1.c),
   3  * optimized to do word accesses rather than byte accesses,
   4  * and to avoid unnecessary copies into the context array.
   5  */
   6
   7 #include <string.h>
   8 #include <arpa/inet.h>
   9
  10 #include "sha1.h"
  11
  12 /* Hash one 64-byte block of data */
  13 static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data);
  14
  15 void blk_SHA1_Init(blk_SHA_CTX *ctx)
  16 {
  17         ctx->size = 0;
  18
  19         /* Initialize H with the magic constants (see FIPS180 for constants)
  20          */
  21         ctx->H[0] = 0x67452301;
  22         ctx->H[1] = 0xefcdab89;
  23         ctx->H[2] = 0x98badcfe;
  24         ctx->H[3] = 0x10325476;
  25         ctx->H[4] = 0xc3d2e1f0;
  26 }
  27
  28
  29 void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *data, unsigned long len)
  30 {
  31         int lenW = ctx->size & 63;
  32
  33         ctx->size += len;
  34
  35         /* Read the data into W and process blocks as they get full
  36          */
  37         if (lenW) {
  38                 int left = 64 - lenW;
  39                 if (len < left)
  40                         left = len;
  41                 memcpy(lenW + (char *)ctx->W, data, left);
  42                 lenW = (lenW + left) & 63;
  43                 len -= left;
  44                 data += left;
  45                 if (lenW)
  46                         return;
  47                 blk_SHA1Block(ctx, ctx->W);
  48         }
  49         while (len >= 64) {
  50                 blk_SHA1Block(ctx, data);
  51                 data += 64;
  52                 len -= 64;
  53         }
  54         if (len)
  55                 memcpy(ctx->W, data, len);
  56 }
  57
  58
  59 void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx)
  60 {
  61         static const unsigned char pad[64] = { 0x80 };
  62         unsigned int padlen[2];
  63         int i;
  64
  65         /* Pad with a binary 1 (ie 0x80), then zeroes, then length
  66          */
  67         padlen[0] = htonl(ctx->size >> 29);
  68         padlen[1] = htonl(ctx->size << 3);
  69
  70         i = ctx->size & 63;
  71         blk_SHA1_Update(ctx, pad, 1+ (63 & (55 - i)));
  72         blk_SHA1_Update(ctx, padlen, 8);
  73
  74         /* Output hash
  75          */
  76         for (i = 0; i < 5; i++)
  77                 ((unsigned int *)hashout)[i] = htonl(ctx->H[i]);
  78 }
  79
  80 #if defined(__i386__) || defined(__x86_64__)
  81
  82 #define SHA_ASM(op, x, n) ({ unsigned int __res; __asm__(op " %1,%0":"=r" (__res):"i" (n), "0" (x)); __res; })
  83 #define SHA_ROL(x,n)    SHA_ASM("rol", x, n)
  84 #define SHA_ROR(x,n)    SHA_ASM("ror", x, n)
  85 #define SMALL_REGISTER_SET
  86
  87 #else
  88
  89 #define SHA_ROT(X,l,r)  (((X) << (l)) | ((X) >> (r)))
  90 #define SHA_ROL(X,n)    SHA_ROT(X,n,32-(n))
  91 #define SHA_ROR(X,n)    SHA_ROT(X,32-(n),n)
  92
  93 #endif
  94
  95 /* This "rolls" over the 512-bit array */
  96 #define W(x) (array[(x)&15])
  97
  98 /*
  99  * If you have 32 registers or more, the compiler can (and should)
 100  * try to change the array[] accesses into registers. However, on
 101  * machines with less than ~25 registers, that won't really work,
 102  * and at least gcc will make an unholy mess of it.
 103  *
 104  * So to avoid that mess which just slows things down, we force
 105  * the stores to memory to actually happen (we might be better off
 106  * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as
 107  * suggested by Artur Skawina - that will also make gcc unable to
 108  * try to do the silly "optimize away loads" part because it won't
 109  * see what the value will be).
 110  *
 111  * Ben Herrenschmidt reports that on PPC, the C version comes close
 112  * to the optimized asm with this (ie on PPC you don't want that
 113  * 'volatile', since there are lots of registers).
 114  */
 115 #ifdef SMALL_REGISTER_SET
 116   #define setW(x, val) (*(volatile unsigned int *)&W(x) = (val))
 117 #else
 118   #define setW(x, val) (W(x) = (val))
 119 #endif
 120
 121 /*
 122  * Where do we get the source from? The first 16 iterations get it from
 123  * the input data, the next mix it from the 512-bit array.
 124  */
 125 #define SHA_SRC(t) htonl(data[t])
 126 #define SHA_MIX(t) SHA_ROL(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1)
 127
 128 #define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \
 129         unsigned int TEMP = input(t); setW(t, TEMP); \
 130         E += TEMP + SHA_ROL(A,5) + (fn) + (constant); \
 131         B = SHA_ROR(B, 2); } while (0)
 132
 133 #define T_0_15(t, A, B, C, D, E)  SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
 134 #define T_16_19(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
 135 #define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E )
 136 #define T_40_59(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc, A, B, C, D, E )
 137 #define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) ,  0xca62c1d6, A, B, C, D, E )
 138
 139 static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data)
 140 {
 141         unsigned int A,B,C,D,E;
 142         unsigned int array[16];
 143
 144         A = ctx->H[0];
 145         B = ctx->H[1];
 146         C = ctx->H[2];
 147         D = ctx->H[3];
 148         E = ctx->H[4];
 149
 150         /* Round 1 - iterations 0-16 take their input from 'data' */
 151         T_0_15( 0, A, B, C, D, E);
 152         T_0_15( 1, E, A, B, C, D);
 153         T_0_15( 2, D, E, A, B, C);
 154         T_0_15( 3, C, D, E, A, B);
 155         T_0_15( 4, B, C, D, E, A);
 156         T_0_15( 5, A, B, C, D, E);
 157         T_0_15( 6, E, A, B, C, D);
 158         T_0_15( 7, D, E, A, B, C);
 159         T_0_15( 8, C, D, E, A, B);
 160         T_0_15( 9, B, C, D, E, A);
 161         T_0_15(10, A, B, C, D, E);
 162         T_0_15(11, E, A, B, C, D);
 163         T_0_15(12, D, E, A, B, C);
 164         T_0_15(13, C, D, E, A, B);
 165         T_0_15(14, B, C, D, E, A);
 166         T_0_15(15, A, B, C, D, E);
 167
 168         /* Round 1 - tail. Input from 512-bit mixing array */
 169         T_16_19(16, E, A, B, C, D);
 170         T_16_19(17, D, E, A, B, C);
 171         T_16_19(18, C, D, E, A, B);
 172         T_16_19(19, B, C, D, E, A);
 173
 174         /* Round 2 */
 175         T_20_39(20, A, B, C, D, E);
 176         T_20_39(21, E, A, B, C, D);
 177         T_20_39(22, D, E, A, B, C);
 178         T_20_39(23, C, D, E, A, B);
 179         T_20_39(24, B, C, D, E, A);
 180         T_20_39(25, A, B, C, D, E);
 181         T_20_39(26, E, A, B, C, D);
 182         T_20_39(27, D, E, A, B, C);
 183         T_20_39(28, C, D, E, A, B);
 184         T_20_39(29, B, C, D, E, A);
 185         T_20_39(30, A, B, C, D, E);
 186         T_20_39(31, E, A, B, C, D);
 187         T_20_39(32, D, E, A, B, C);
 188         T_20_39(33, C, D, E, A, B);
 189         T_20_39(34, B, C, D, E, A);
 190         T_20_39(35, A, B, C, D, E);
 191         T_20_39(36, E, A, B, C, D);
 192         T_20_39(37, D, E, A, B, C);
 193         T_20_39(38, C, D, E, A, B);
 194         T_20_39(39, B, C, D, E, A);
 195
 196         /* Round 3 */
 197         T_40_59(40, A, B, C, D, E);
 198         T_40_59(41, E, A, B, C, D);
 199         T_40_59(42, D, E, A, B, C);
 200         T_40_59(43, C, D, E, A, B);
 201         T_40_59(44, B, C, D, E, A);
 202         T_40_59(45, A, B, C, D, E);
 203         T_40_59(46, E, A, B, C, D);
 204         T_40_59(47, D, E, A, B, C);
 205         T_40_59(48, C, D, E, A, B);
 206         T_40_59(49, B, C, D, E, A);
 207         T_40_59(50, A, B, C, D, E);
 208         T_40_59(51, E, A, B, C, D);
 209         T_40_59(52, D, E, A, B, C);
 210         T_40_59(53, C, D, E, A, B);
 211         T_40_59(54, B, C, D, E, A);
 212         T_40_59(55, A, B, C, D, E);
 213         T_40_59(56, E, A, B, C, D);
 214         T_40_59(57, D, E, A, B, C);
 215         T_40_59(58, C, D, E, A, B);
 216         T_40_59(59, B, C, D, E, A);
 217
 218         /* Round 4 */
 219         T_60_79(60, A, B, C, D, E);
 220         T_60_79(61, E, A, B, C, D);
 221         T_60_79(62, D, E, A, B, C);
 222         T_60_79(63, C, D, E, A, B);
 223         T_60_79(64, B, C, D, E, A);
 224         T_60_79(65, A, B, C, D, E);
 225         T_60_79(66, E, A, B, C, D);
 226         T_60_79(67, D, E, A, B, C);
 227         T_60_79(68, C, D, E, A, B);
 228         T_60_79(69, B, C, D, E, A);
 229         T_60_79(70, A, B, C, D, E);
 230         T_60_79(71, E, A, B, C, D);
 231         T_60_79(72, D, E, A, B, C);
 232         T_60_79(73, C, D, E, A, B);
 233         T_60_79(74, B, C, D, E, A);
 234         T_60_79(75, A, B, C, D, E);
 235         T_60_79(76, E, A, B, C, D);
 236         T_60_79(77, D, E, A, B, C);
 237         T_60_79(78, C, D, E, A, B);
 238         T_60_79(79, B, C, D, E, A);
 239
 240         ctx->H[0] += A;
 241         ctx->H[1] += B;
 242         ctx->H[2] += C;
 243         ctx->H[3] += D;
 244         ctx->H[4] += E;
 245 }