Line data Source code
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 : */
81 19154 : void sha_transform(__u32 *digest, const char *data, __u32 *array)
82 : {
83 : __u32 A, B, C, D, E;
84 :
85 19154 : A = digest[0];
86 19154 : B = digest[1];
87 19154 : C = digest[2];
88 19154 : D = digest[3];
89 19154 : E = digest[4];
90 :
91 : /* Round 1 - iterations 0-16 take their input from 'data' */
92 38308 : T_0_15( 0, A, B, C, D, E);
93 38308 : T_0_15( 1, E, A, B, C, D);
94 38308 : T_0_15( 2, D, E, A, B, C);
95 38308 : T_0_15( 3, C, D, E, A, B);
96 38308 : T_0_15( 4, B, C, D, E, A);
97 38308 : T_0_15( 5, A, B, C, D, E);
98 38308 : T_0_15( 6, E, A, B, C, D);
99 38308 : T_0_15( 7, D, E, A, B, C);
100 38308 : T_0_15( 8, C, D, E, A, B);
101 38308 : T_0_15( 9, B, C, D, E, A);
102 38308 : T_0_15(10, A, B, C, D, E);
103 38308 : T_0_15(11, E, A, B, C, D);
104 38308 : T_0_15(12, D, E, A, B, C);
105 38308 : T_0_15(13, C, D, E, A, B);
106 38308 : T_0_15(14, B, C, D, E, A);
107 38308 : T_0_15(15, A, B, C, D, E);
108 :
109 : /* Round 1 - tail. Input from 512-bit mixing array */
110 19154 : T_16_19(16, E, A, B, C, D);
111 57462 : T_16_19(17, D, E, A, B, C);
112 57462 : T_16_19(18, C, D, E, A, B);
113 57462 : T_16_19(19, B, C, D, E, A);
114 :
115 : /* Round 2 */
116 57462 : T_20_39(20, A, B, C, D, E);
117 57462 : T_20_39(21, E, A, B, C, D);
118 57462 : T_20_39(22, D, E, A, B, C);
119 57462 : T_20_39(23, C, D, E, A, B);
120 38308 : T_20_39(24, B, C, D, E, A);
121 57462 : T_20_39(25, A, B, C, D, E);
122 57462 : T_20_39(26, E, A, B, C, D);
123 57462 : T_20_39(27, D, E, A, B, C);
124 57462 : T_20_39(28, C, D, E, A, B);
125 57462 : T_20_39(29, B, C, D, E, A);
126 57462 : T_20_39(30, A, B, C, D, E);
127 57462 : T_20_39(31, E, A, B, C, D);
128 57462 : T_20_39(32, D, E, A, B, C);
129 57462 : T_20_39(33, C, D, E, A, B);
130 57462 : T_20_39(34, B, C, D, E, A);
131 57462 : T_20_39(35, A, B, C, D, E);
132 57462 : T_20_39(36, E, A, B, C, D);
133 57462 : T_20_39(37, D, E, A, B, C);
134 57462 : T_20_39(38, C, D, E, A, B);
135 57462 : T_20_39(39, B, C, D, E, A);
136 :
137 : /* Round 3 */
138 57462 : T_40_59(40, A, B, C, D, E);
139 57462 : T_40_59(41, E, A, B, C, D);
140 57462 : T_40_59(42, D, E, A, B, C);
141 57462 : T_40_59(43, C, D, E, A, B);
142 57462 : T_40_59(44, B, C, D, E, A);
143 57462 : T_40_59(45, A, B, C, D, E);
144 57462 : T_40_59(46, E, A, B, C, D);
145 57462 : T_40_59(47, D, E, A, B, C);
146 57462 : T_40_59(48, C, D, E, A, B);
147 57462 : T_40_59(49, B, C, D, E, A);
148 57462 : T_40_59(50, A, B, C, D, E);
149 57462 : T_40_59(51, E, A, B, C, D);
150 57462 : T_40_59(52, D, E, A, B, C);
151 57462 : T_40_59(53, C, D, E, A, B);
152 57462 : T_40_59(54, B, C, D, E, A);
153 57462 : T_40_59(55, A, B, C, D, E);
154 57462 : T_40_59(56, E, A, B, C, D);
155 57462 : T_40_59(57, D, E, A, B, C);
156 57462 : T_40_59(58, C, D, E, A, B);
157 57462 : T_40_59(59, B, C, D, E, A);
158 :
159 : /* Round 4 */
160 57462 : T_60_79(60, A, B, C, D, E);
161 57462 : T_60_79(61, E, A, B, C, D);
162 57462 : T_60_79(62, D, E, A, B, C);
163 57462 : T_60_79(63, C, D, E, A, B);
164 57462 : T_60_79(64, B, C, D, E, A);
165 57462 : T_60_79(65, A, B, C, D, E);
166 57462 : T_60_79(66, E, A, B, C, D);
167 57462 : T_60_79(67, D, E, A, B, C);
168 57462 : T_60_79(68, C, D, E, A, B);
169 57462 : T_60_79(69, B, C, D, E, A);
170 57462 : T_60_79(70, A, B, C, D, E);
171 57462 : T_60_79(71, E, A, B, C, D);
172 57462 : T_60_79(72, D, E, A, B, C);
173 57462 : T_60_79(73, C, D, E, A, B);
174 57462 : T_60_79(74, B, C, D, E, A);
175 57462 : T_60_79(75, A, B, C, D, E);
176 57462 : T_60_79(76, E, A, B, C, D);
177 57462 : T_60_79(77, D, E, A, B, C);
178 57462 : T_60_79(78, C, D, E, A, B);
179 57462 : T_60_79(79, B, C, D, E, A);
180 :
181 19154 : digest[0] += A;
182 19154 : digest[1] += B;
183 19154 : digest[2] += C;
184 19154 : digest[3] += D;
185 19154 : digest[4] += E;
186 19154 : }
187 : EXPORT_SYMBOL(sha_transform);
188 :
189 : /**
190 : * sha_init - initialize the vectors for a SHA1 digest
191 : * @buf: vector to initialize
192 : */
193 6916 : void sha_init(__u32 *buf)
194 : {
195 6916 : buf[0] = 0x67452301;
196 6916 : buf[1] = 0xefcdab89;
197 6916 : buf[2] = 0x98badcfe;
198 6916 : buf[3] = 0x10325476;
199 6916 : buf[4] = 0xc3d2e1f0;
200 6916 : }
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