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 #if defined(__i386__) || defined(__x86_64__)
  13
  14 /*
  15  * Force usage of rol or ror by selecting the one with the smaller constant.
  16  * It _can_ generate slightly smaller code (a constant of 1 is special), but
  17  * perhaps more importantly it's possibly faster on any uarch that does a
  18  * rotate with a loop.
  19  */
  20
  21 #define SHA_ASM(op, x, n) ({ unsigned int __res; __asm__(op " %1,%0":"=r" (__res):"i" (n), "0" (x)); __res; })
  22 #define SHA_ROL(x,n)    SHA_ASM("rol", x, n)
  23 #define SHA_ROR(x,n)    SHA_ASM("ror", x, n)
  24
  25 #else
  26
  27 #define SHA_ROT(X,l,r)  (((X) << (l)) | ((X) >> (r)))
  28 #define SHA_ROL(X,n)    SHA_ROT(X,n,32-(n))
  29 #define SHA_ROR(X,n)    SHA_ROT(X,32-(n),n)
  30
  31 #endif
  32
  33 /*
  34  * If you have 32 registers or more, the compiler can (and should)
  35  * try to change the array[] accesses into registers. However, on
  36  * machines with less than ~25 registers, that won't really work,
  37  * and at least gcc will make an unholy mess of it.
  38  *
  39  * So to avoid that mess which just slows things down, we force
  40  * the stores to memory to actually happen (we might be better off
  41  * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as
  42  * suggested by Artur Skawina - that will also make gcc unable to
  43  * try to do the silly "optimize away loads" part because it won't
  44  * see what the value will be).
  45  *
  46  * Ben Herrenschmidt reports that on PPC, the C version comes close
  47  * to the optimized asm with this (ie on PPC you don't want that
  48  * 'volatile', since there are lots of registers).
  49  *
  50  * On ARM we get the best code generation by forcing a full memory barrier
  51  * between each SHA_ROUND, otherwise gcc happily get wild with spilling and
  52  * the stack frame size simply explode and performance goes down the drain.
  53  */
  54
  55 #if defined(__i386__) || defined(__x86_64__)
  56   #define setW(x, val) (*(volatile unsigned int *)&W(x) = (val))
  57 #elif defined(__arm__)
  58   #define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0)
  59 #else
  60   #define setW(x, val) (W(x) = (val))
  61 #endif
  62
  63 /* This "rolls" over the 512-bit array */
  64 #define W(x) (array[(x)&15])
  65
  66 /*
  67  * Where do we get the source from? The first 16 iterations get it from
  68  * the input data, the next mix it from the 512-bit array.
  69  */
  70 #define SHA_SRC(t) htonl(data[t])
  71 #define SHA_MIX(t) SHA_ROL(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1)
  72
  73 #define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \
  74         unsigned int TEMP = input(t); setW(t, TEMP); \
  75         E += TEMP + SHA_ROL(A,5) + (fn) + (constant); \
  76         B = SHA_ROR(B, 2); } while (0)
  77
  78 #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 )
  79 #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 )
  80 #define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E )
  81 #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 )
  82 #define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) ,  0xca62c1d6, A, B, C, D, E )
  83
  84 static void blk_SHA1_Block(blk_SHA_CTX *ctx, const unsigned int *data)
  85 {
  86         unsigned int A,B,C,D,E;
  87         unsigned int array[16];
  88
  89         A = ctx->H[0];
  90         B = ctx->H[1];
  91         C = ctx->H[2];
  92         D = ctx->H[3];
  93         E = ctx->H[4];
  94
  95         /* Round 1 - iterations 0-16 take their input from 'data' */
  96         T_0_15( 0, A, B, C, D, E);
  97         T_0_15( 1, E, A, B, C, D);
  98         T_0_15( 2, D, E, A, B, C);
  99         T_0_15( 3, C, D, E, A, B);
 100         T_0_15( 4, B, C, D, E, A);
 101         T_0_15( 5, A, B, C, D, E);
 102         T_0_15( 6, E, A, B, C, D);
 103         T_0_15( 7, D, E, A, B, C);
 104         T_0_15( 8, C, D, E, A, B);
 105         T_0_15( 9, B, C, D, E, A);
 106         T_0_15(10, A, B, C, D, E);
 107         T_0_15(11, E, A, B, C, D);
 108         T_0_15(12, D, E, A, B, C);
 109         T_0_15(13, C, D, E, A, B);
 110         T_0_15(14, B, C, D, E, A);
 111         T_0_15(15, A, B, C, D, E);
 112
 113         /* Round 1 - tail. Input from 512-bit mixing array */
 114         T_16_19(16, E, A, B, C, D);
 115         T_16_19(17, D, E, A, B, C);
 116         T_16_19(18, C, D, E, A, B);
 117         T_16_19(19, B, C, D, E, A);
 118
 119         /* Round 2 */
 120         T_20_39(20, A, B, C, D, E);
 121         T_20_39(21, E, A, B, C, D);
 122         T_20_39(22, D, E, A, B, C);
 123         T_20_39(23, C, D, E, A, B);
 124         T_20_39(24, B, C, D, E, A);
 125         T_20_39(25, A, B, C, D, E);
 126         T_20_39(26, E, A, B, C, D);
 127         T_20_39(27, D, E, A, B, C);
 128         T_20_39(28, C, D, E, A, B);
 129         T_20_39(29, B, C, D, E, A);
 130         T_20_39(30, A, B, C, D, E);
 131         T_20_39(31, E, A, B, C, D);
 132         T_20_39(32, D, E, A, B, C);
 133         T_20_39(33, C, D, E, A, B);
 134         T_20_39(34, B, C, D, E, A);
 135         T_20_39(35, A, B, C, D, E);
 136         T_20_39(36, E, A, B, C, D);
 137         T_20_39(37, D, E, A, B, C);
 138         T_20_39(38, C, D, E, A, B);
 139         T_20_39(39, B, C, D, E, A);
 140
 141         /* Round 3 */
 142         T_40_59(40, A, B, C, D, E);
 143         T_40_59(41, E, A, B, C, D);
 144         T_40_59(42, D, E, A, B, C);
 145         T_40_59(43, C, D, E, A, B);
 146         T_40_59(44, B, C, D, E, A);
 147         T_40_59(45, A, B, C, D, E);
 148         T_40_59(46, E, A, B, C, D);
 149         T_40_59(47, D, E, A, B, C);
 150         T_40_59(48, C, D, E, A, B);
 151         T_40_59(49, B, C, D, E, A);
 152         T_40_59(50, A, B, C, D, E);
 153         T_40_59(51, E, A, B, C, D);
 154         T_40_59(52, D, E, A, B, C);
 155         T_40_59(53, C, D, E, A, B);
 156         T_40_59(54, B, C, D, E, A);
 157         T_40_59(55, A, B, C, D, E);
 158         T_40_59(56, E, A, B, C, D);
 159         T_40_59(57, D, E, A, B, C);
 160         T_40_59(58, C, D, E, A, B);
 161         T_40_59(59, B, C, D, E, A);
 162
 163         /* Round 4 */
 164         T_60_79(60, A, B, C, D, E);
 165         T_60_79(61, E, A, B, C, D);
 166         T_60_79(62, D, E, A, B, C);
 167         T_60_79(63, C, D, E, A, B);
 168         T_60_79(64, B, C, D, E, A);
 169         T_60_79(65, A, B, C, D, E);
 170         T_60_79(66, E, A, B, C, D);
 171         T_60_79(67, D, E, A, B, C);
 172         T_60_79(68, C, D, E, A, B);
 173         T_60_79(69, B, C, D, E, A);
 174         T_60_79(70, A, B, C, D, E);
 175         T_60_79(71, E, A, B, C, D);
 176         T_60_79(72, D, E, A, B, C);
 177         T_60_79(73, C, D, E, A, B);
 178         T_60_79(74, B, C, D, E, A);
 179         T_60_79(75, A, B, C, D, E);
 180         T_60_79(76, E, A, B, C, D);
 181         T_60_79(77, D, E, A, B, C);
 182         T_60_79(78, C, D, E, A, B);
 183         T_60_79(79, B, C, D, E, A);
 184
 185         ctx->H[0] += A;
 186         ctx->H[1] += B;
 187         ctx->H[2] += C;
 188         ctx->H[3] += D;
 189         ctx->H[4] += E;
 190 }
 191
 192 void blk_SHA1_Init(blk_SHA_CTX *ctx)
 193 {
 194         ctx->size = 0;
 195
 196         /* Initialize H with the magic constants (see FIPS180 for constants) */
 197         ctx->H[0] = 0x67452301;
 198         ctx->H[1] = 0xefcdab89;
 199         ctx->H[2] = 0x98badcfe;
 200         ctx->H[3] = 0x10325476;
 201         ctx->H[4] = 0xc3d2e1f0;
 202 }
 203
 204 void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *data, unsigned long len)
 205 {
 206         int lenW = ctx->size & 63;
 207
 208         ctx->size += len;
 209
 210         /* Read the data into W and process blocks as they get full */
 211         if (lenW) {
 212                 int left = 64 - lenW;
 213                 if (len < left)
 214                         left = len;
 215                 memcpy(lenW + (char *)ctx->W, data, left);
 216                 lenW = (lenW + left) & 63;
 217                 len -= left;
 218                 data += left;
 219                 if (lenW)
 220                         return;
 221                 blk_SHA1_Block(ctx, ctx->W);
 222         }
 223         while (len >= 64) {
 224                 blk_SHA1_Block(ctx, data);
 225                 data += 64;
 226                 len -= 64;
 227         }
 228         if (len)
 229                 memcpy(ctx->W, data, len);
 230 }
 231
 232 void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx)
 233 {
 234         static const unsigned char pad[64] = { 0x80 };
 235         unsigned int padlen[2];
 236         int i;
 237
 238         /* Pad with a binary 1 (ie 0x80), then zeroes, then length */
 239         padlen[0] = htonl(ctx->size >> 29);
 240         padlen[1] = htonl(ctx->size << 3);
 241
 242         i = ctx->size & 63;
 243         blk_SHA1_Update(ctx, pad, 1+ (63 & (55 - i)));
 244         blk_SHA1_Update(ctx, padlen, 8);
 245
 246         /* Output hash */
 247         for (i = 0; i < 5; i++)
 248                 ((unsigned int *)hashout)[i] = htonl(ctx->H[i]);
 249 }