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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | /* |
1eb19a12 MSB |
3 | * SHA1 routine optimized to do word accesses rather than byte accesses, |
4 | * and to avoid unnecessary copies into the context array. | |
5 | * | |
6 | * This was based on the git SHA1 implementation. | |
1da177e4 LT |
7 | */ |
8 | ||
9 | #include <linux/kernel.h> | |
8bc3bcc9 | 10 | #include <linux/export.h> |
ed221835 | 11 | #include <linux/module.h> |
1eb19a12 | 12 | #include <linux/bitops.h> |
9a1536b0 | 13 | #include <linux/string.h> |
a24d22b2 | 14 | #include <crypto/sha1.h> |
1eb19a12 | 15 | #include <asm/unaligned.h> |
1da177e4 | 16 | |
1eb19a12 MSB |
17 | /* |
18 | * If you have 32 registers or more, the compiler can (and should) | |
19 | * try to change the array[] accesses into registers. However, on | |
20 | * machines with less than ~25 registers, that won't really work, | |
21 | * and at least gcc will make an unholy mess of it. | |
22 | * | |
23 | * So to avoid that mess which just slows things down, we force | |
24 | * the stores to memory to actually happen (we might be better off | |
25 | * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as | |
26 | * suggested by Artur Skawina - that will also make gcc unable to | |
27 | * try to do the silly "optimize away loads" part because it won't | |
28 | * see what the value will be). | |
29 | * | |
30 | * Ben Herrenschmidt reports that on PPC, the C version comes close | |
31 | * to the optimized asm with this (ie on PPC you don't want that | |
32 | * 'volatile', since there are lots of registers). | |
33 | * | |
34 | * On ARM we get the best code generation by forcing a full memory barrier | |
35 | * between each SHA_ROUND, otherwise gcc happily get wild with spilling and | |
36 | * the stack frame size simply explode and performance goes down the drain. | |
37 | */ | |
1da177e4 | 38 | |
1eb19a12 MSB |
39 | #ifdef CONFIG_X86 |
40 | #define setW(x, val) (*(volatile __u32 *)&W(x) = (val)) | |
41 | #elif defined(CONFIG_ARM) | |
42 | #define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0) | |
43 | #else | |
44 | #define setW(x, val) (W(x) = (val)) | |
45 | #endif | |
1da177e4 | 46 | |
1eb19a12 MSB |
47 | /* This "rolls" over the 512-bit array */ |
48 | #define W(x) (array[(x)&15]) | |
1da177e4 | 49 | |
1eb19a12 MSB |
50 | /* |
51 | * Where do we get the source from? The first 16 iterations get it from | |
52 | * the input data, the next mix it from the 512-bit array. | |
53 | */ | |
54 | #define SHA_SRC(t) get_unaligned_be32((__u32 *)data + t) | |
55 | #define SHA_MIX(t) rol32(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1) | |
56 | ||
57 | #define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \ | |
58 | __u32 TEMP = input(t); setW(t, TEMP); \ | |
59 | E += TEMP + rol32(A,5) + (fn) + (constant); \ | |
9a1536b0 JD |
60 | B = ror32(B, 2); \ |
61 | TEMP = E; E = D; D = C; C = B; B = A; A = TEMP; } while (0) | |
1eb19a12 MSB |
62 | |
63 | #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 ) | |
64 | #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 ) | |
65 | #define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E ) | |
66 | #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 ) | |
67 | #define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6, A, B, C, D, E ) | |
1da177e4 | 68 | |
72fd4a35 | 69 | /** |
6b0b0fa2 | 70 | * sha1_transform - single block SHA1 transform (deprecated) |
1da177e4 LT |
71 | * |
72 | * @digest: 160 bit digest to update | |
73 | * @data: 512 bits of data to hash | |
1eb19a12 | 74 | * @array: 16 words of workspace (see note) |
1da177e4 | 75 | * |
6b0b0fa2 EB |
76 | * This function executes SHA-1's internal compression function. It updates the |
77 | * 160-bit internal state (@digest) with a single 512-bit data block (@data). | |
78 | * | |
79 | * Don't use this function. SHA-1 is no longer considered secure. And even if | |
80 | * you do have to use SHA-1, this isn't the correct way to hash something with | |
81 | * SHA-1 as this doesn't handle padding and finalization. | |
1da177e4 LT |
82 | * |
83 | * Note: If the hash is security sensitive, the caller should be sure | |
84 | * to clear the workspace. This is left to the caller to avoid | |
85 | * unnecessary clears between chained hashing operations. | |
86 | */ | |
6b0b0fa2 | 87 | void sha1_transform(__u32 *digest, const char *data, __u32 *array) |
1da177e4 | 88 | { |
1eb19a12 | 89 | __u32 A, B, C, D, E; |
9a1536b0 | 90 | unsigned int i = 0; |
1eb19a12 MSB |
91 | |
92 | A = digest[0]; | |
93 | B = digest[1]; | |
94 | C = digest[2]; | |
95 | D = digest[3]; | |
96 | E = digest[4]; | |
97 | ||
98 | /* Round 1 - iterations 0-16 take their input from 'data' */ | |
9a1536b0 JD |
99 | for (; i < 16; ++i) |
100 | T_0_15(i, A, B, C, D, E); | |
1eb19a12 MSB |
101 | |
102 | /* Round 1 - tail. Input from 512-bit mixing array */ | |
9a1536b0 JD |
103 | for (; i < 20; ++i) |
104 | T_16_19(i, A, B, C, D, E); | |
1eb19a12 MSB |
105 | |
106 | /* Round 2 */ | |
9a1536b0 JD |
107 | for (; i < 40; ++i) |
108 | T_20_39(i, A, B, C, D, E); | |
1eb19a12 MSB |
109 | |
110 | /* Round 3 */ | |
9a1536b0 JD |
111 | for (; i < 60; ++i) |
112 | T_40_59(i, A, B, C, D, E); | |
1eb19a12 MSB |
113 | |
114 | /* Round 4 */ | |
9a1536b0 JD |
115 | for (; i < 80; ++i) |
116 | T_60_79(i, A, B, C, D, E); | |
1eb19a12 MSB |
117 | |
118 | digest[0] += A; | |
119 | digest[1] += B; | |
120 | digest[2] += C; | |
121 | digest[3] += D; | |
122 | digest[4] += E; | |
1da177e4 | 123 | } |
6b0b0fa2 | 124 | EXPORT_SYMBOL(sha1_transform); |
1da177e4 | 125 | |
72fd4a35 | 126 | /** |
6b0b0fa2 | 127 | * sha1_init - initialize the vectors for a SHA1 digest |
1da177e4 LT |
128 | * @buf: vector to initialize |
129 | */ | |
6b0b0fa2 | 130 | void sha1_init(__u32 *buf) |
1da177e4 LT |
131 | { |
132 | buf[0] = 0x67452301; | |
133 | buf[1] = 0xefcdab89; | |
134 | buf[2] = 0x98badcfe; | |
135 | buf[3] = 0x10325476; | |
136 | buf[4] = 0xc3d2e1f0; | |
137 | } | |
6b0b0fa2 | 138 | EXPORT_SYMBOL(sha1_init); |
ed221835 EB |
139 | |
140 | MODULE_LICENSE("GPL"); |