1/* 2 * SHA1 routine optimized to do word accesses rather than byte accesses, 3 * and to avoid unnecessary copies into the context array. 4 * 5 * This was based on the git SHA1 implementation. 6 */ 7 8#include <linux/kernel.h> 9#include <linux/export.h> 10#include <linux/bitops.h> 11#include <linux/cryptohash.h> 12#include <asm/unaligned.h> 13 14/* 15 * If you have 32 registers or more, the compiler can (and should) 16 * try to change the array[] accesses into registers. However, on 17 * machines with less than ~25 registers, that won't really work, 18 * and at least gcc will make an unholy mess of it. 19 * 20 * So to avoid that mess which just slows things down, we force 21 * the stores to memory to actually happen (we might be better off 22 * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as 23 * suggested by Artur Skawina - that will also make gcc unable to 24 * try to do the silly "optimize away loads" part because it won't 25 * see what the value will be). 26 * 27 * Ben Herrenschmidt reports that on PPC, the C version comes close 28 * to the optimized asm with this (ie on PPC you don't want that 29 * 'volatile', since there are lots of registers). 30 * 31 * On ARM we get the best code generation by forcing a full memory barrier 32 * between each SHA_ROUND, otherwise gcc happily get wild with spilling and 33 * the stack frame size simply explode and performance goes down the drain. 34 */ 35 36#ifdef CONFIG_X86 37 #define setW(x, val) (*(volatile __u32 *)&W(x) = (val)) 38#elif defined(CONFIG_ARM) 39 #define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0) 40#else 41 #define setW(x, val) (W(x) = (val)) 42#endif 43 44/* This "rolls" over the 512-bit array */ 45#define W(x) (array[(x)&15]) 46 47/* 48 * Where do we get the source from? The first 16 iterations get it from 49 * the input data, the next mix it from the 512-bit array. 50 */ 51#define SHA_SRC(t) get_unaligned_be32((__u32 *)data + t) 52#define SHA_MIX(t) rol32(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1) 53 54#define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \ 55 __u32 TEMP = input(t); setW(t, TEMP); \ 56 E += TEMP + rol32(A,5) + (fn) + (constant); \ 57 B = ror32(B, 2); } while (0) 58 59#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 ) 60#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 ) 61#define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E ) 62#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 ) 63#define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6, A, B, C, D, E ) 64 65/** 66 * sha_transform - single block SHA1 transform 67 * 68 * @digest: 160 bit digest to update 69 * @data: 512 bits of data to hash 70 * @array: 16 words of workspace (see note) 71 * 72 * This function generates a SHA1 digest for a single 512-bit block. 73 * Be warned, it does not handle padding and message digest, do not 74 * confuse it with the full FIPS 180-1 digest algorithm for variable 75 * length messages. 76 * 77 * Note: If the hash is security sensitive, the caller should be sure 78 * to clear the workspace. This is left to the caller to avoid 79 * unnecessary clears between chained hashing operations. 80 */ 81void sha_transform(__u32 *digest, const char *data, __u32 *array) 82{ 83 __u32 A, B, C, D, E; 84 85 A = digest[0]; 86 B = digest[1]; 87 C = digest[2]; 88 D = digest[3]; 89 E = digest[4]; 90 91 /* Round 1 - iterations 0-16 take their input from 'data' */ 92 T_0_15( 0, A, B, C, D, E); 93 T_0_15( 1, E, A, B, C, D); 94 T_0_15( 2, D, E, A, B, C); 95 T_0_15( 3, C, D, E, A, B); 96 T_0_15( 4, B, C, D, E, A); 97 T_0_15( 5, A, B, C, D, E); 98 T_0_15( 6, E, A, B, C, D); 99 T_0_15( 7, D, E, A, B, C); 100 T_0_15( 8, C, D, E, A, B); 101 T_0_15( 9, B, C, D, E, A); 102 T_0_15(10, A, B, C, D, E); 103 T_0_15(11, E, A, B, C, D); 104 T_0_15(12, D, E, A, B, C); 105 T_0_15(13, C, D, E, A, B); 106 T_0_15(14, B, C, D, E, A); 107 T_0_15(15, A, B, C, D, E); 108 109 /* Round 1 - tail. Input from 512-bit mixing array */ 110 T_16_19(16, E, A, B, C, D); 111 T_16_19(17, D, E, A, B, C); 112 T_16_19(18, C, D, E, A, B); 113 T_16_19(19, B, C, D, E, A); 114 115 /* Round 2 */ 116 T_20_39(20, A, B, C, D, E); 117 T_20_39(21, E, A, B, C, D); 118 T_20_39(22, D, E, A, B, C); 119 T_20_39(23, C, D, E, A, B); 120 T_20_39(24, B, C, D, E, A); 121 T_20_39(25, A, B, C, D, E); 122 T_20_39(26, E, A, B, C, D); 123 T_20_39(27, D, E, A, B, C); 124 T_20_39(28, C, D, E, A, B); 125 T_20_39(29, B, C, D, E, A); 126 T_20_39(30, A, B, C, D, E); 127 T_20_39(31, E, A, B, C, D); 128 T_20_39(32, D, E, A, B, C); 129 T_20_39(33, C, D, E, A, B); 130 T_20_39(34, B, C, D, E, A); 131 T_20_39(35, A, B, C, D, E); 132 T_20_39(36, E, A, B, C, D); 133 T_20_39(37, D, E, A, B, C); 134 T_20_39(38, C, D, E, A, B); 135 T_20_39(39, B, C, D, E, A); 136 137 /* Round 3 */ 138 T_40_59(40, A, B, C, D, E); 139 T_40_59(41, E, A, B, C, D); 140 T_40_59(42, D, E, A, B, C); 141 T_40_59(43, C, D, E, A, B); 142 T_40_59(44, B, C, D, E, A); 143 T_40_59(45, A, B, C, D, E); 144 T_40_59(46, E, A, B, C, D); 145 T_40_59(47, D, E, A, B, C); 146 T_40_59(48, C, D, E, A, B); 147 T_40_59(49, B, C, D, E, A); 148 T_40_59(50, A, B, C, D, E); 149 T_40_59(51, E, A, B, C, D); 150 T_40_59(52, D, E, A, B, C); 151 T_40_59(53, C, D, E, A, B); 152 T_40_59(54, B, C, D, E, A); 153 T_40_59(55, A, B, C, D, E); 154 T_40_59(56, E, A, B, C, D); 155 T_40_59(57, D, E, A, B, C); 156 T_40_59(58, C, D, E, A, B); 157 T_40_59(59, B, C, D, E, A); 158 159 /* Round 4 */ 160 T_60_79(60, A, B, C, D, E); 161 T_60_79(61, E, A, B, C, D); 162 T_60_79(62, D, E, A, B, C); 163 T_60_79(63, C, D, E, A, B); 164 T_60_79(64, B, C, D, E, A); 165 T_60_79(65, A, B, C, D, E); 166 T_60_79(66, E, A, B, C, D); 167 T_60_79(67, D, E, A, B, C); 168 T_60_79(68, C, D, E, A, B); 169 T_60_79(69, B, C, D, E, A); 170 T_60_79(70, A, B, C, D, E); 171 T_60_79(71, E, A, B, C, D); 172 T_60_79(72, D, E, A, B, C); 173 T_60_79(73, C, D, E, A, B); 174 T_60_79(74, B, C, D, E, A); 175 T_60_79(75, A, B, C, D, E); 176 T_60_79(76, E, A, B, C, D); 177 T_60_79(77, D, E, A, B, C); 178 T_60_79(78, C, D, E, A, B); 179 T_60_79(79, B, C, D, E, A); 180 181 digest[0] += A; 182 digest[1] += B; 183 digest[2] += C; 184 digest[3] += D; 185 digest[4] += E; 186} 187EXPORT_SYMBOL(sha_transform); 188 189/** 190 * sha_init - initialize the vectors for a SHA1 digest 191 * @buf: vector to initialize 192 */ 193void sha_init(__u32 *buf) 194{ 195 buf[0] = 0x67452301; 196 buf[1] = 0xefcdab89; 197 buf[2] = 0x98badcfe; 198 buf[3] = 0x10325476; 199 buf[4] = 0xc3d2e1f0; 200} 201EXPORT_SYMBOL(sha_init); 202