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Annotation of /trunk/mkinitrd-magellan/busybox/libbb/sha1.c

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Sat Sep 1 22:45:15 2007 UTC (16 years, 9 months ago) by niro
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-import if magellan mkinitrd; it is a fork of redhats mkinitrd-5.0.8 with all magellan patches and features; deprecates magellan-src/mkinitrd

1 niro 532 /* vi: set sw=4 ts=4: */
2     /*
3     * Based on shasum from http://www.netsw.org/crypto/hash/
4     * Majorly hacked up to use Dr Brian Gladman's sha1 code
5     *
6     * Copyright (C) 2002 Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK.
7     * Copyright (C) 2003 Glenn L. McGrath
8     * Copyright (C) 2003 Erik Andersen
9     *
10     * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
11     *
12     * ---------------------------------------------------------------------------
13     * Issue Date: 10/11/2002
14     *
15     * This is a byte oriented version of SHA1 that operates on arrays of bytes
16     * stored in memory. It runs at 22 cycles per byte on a Pentium P4 processor
17     */
18    
19     #include <fcntl.h>
20     #include <limits.h>
21     #include <stdio.h>
22     #include <stdint.h>
23     #include <stdlib.h>
24     #include <string.h>
25     #include <unistd.h>
26    
27     #include "libbb.h"
28    
29     #define SHA1_BLOCK_SIZE 64
30     #define SHA1_DIGEST_SIZE 20
31     #define SHA1_HASH_SIZE SHA1_DIGEST_SIZE
32     #define SHA2_GOOD 0
33     #define SHA2_BAD 1
34    
35     #define rotl32(x,n) (((x) << n) | ((x) >> (32 - n)))
36    
37     #define SHA1_MASK (SHA1_BLOCK_SIZE - 1)
38    
39     /* reverse byte order in 32-bit words */
40     #define ch(x,y,z) ((z) ^ ((x) & ((y) ^ (z))))
41     #define parity(x,y,z) ((x) ^ (y) ^ (z))
42     #define maj(x,y,z) (((x) & (y)) | ((z) & ((x) | (y))))
43    
44     /* A normal version as set out in the FIPS. This version uses */
45     /* partial loop unrolling and is optimised for the Pentium 4 */
46     #define rnd(f,k) \
47     do { \
48     t = a; a = rotl32(a,5) + f(b,c,d) + e + k + w[i]; \
49     e = d; d = c; c = rotl32(b, 30); b = t; \
50     } while (0)
51    
52     static void sha1_compile(sha1_ctx_t *ctx)
53     {
54     uint32_t w[80], i, a, b, c, d, e, t;
55    
56     /* note that words are compiled from the buffer into 32-bit */
57     /* words in big-endian order so an order reversal is needed */
58     /* here on little endian machines */
59     for (i = 0; i < SHA1_BLOCK_SIZE / 4; ++i)
60     w[i] = htonl(ctx->wbuf[i]);
61    
62     for (i = SHA1_BLOCK_SIZE / 4; i < 80; ++i)
63     w[i] = rotl32(w[i - 3] ^ w[i - 8] ^ w[i - 14] ^ w[i - 16], 1);
64    
65     a = ctx->hash[0];
66     b = ctx->hash[1];
67     c = ctx->hash[2];
68     d = ctx->hash[3];
69     e = ctx->hash[4];
70    
71     for (i = 0; i < 20; ++i) {
72     rnd(ch, 0x5a827999);
73     }
74    
75     for (i = 20; i < 40; ++i) {
76     rnd(parity, 0x6ed9eba1);
77     }
78    
79     for (i = 40; i < 60; ++i) {
80     rnd(maj, 0x8f1bbcdc);
81     }
82    
83     for (i = 60; i < 80; ++i) {
84     rnd(parity, 0xca62c1d6);
85     }
86    
87     ctx->hash[0] += a;
88     ctx->hash[1] += b;
89     ctx->hash[2] += c;
90     ctx->hash[3] += d;
91     ctx->hash[4] += e;
92     }
93    
94     void sha1_begin(sha1_ctx_t *ctx)
95     {
96     ctx->count[0] = ctx->count[1] = 0;
97     ctx->hash[0] = 0x67452301;
98     ctx->hash[1] = 0xefcdab89;
99     ctx->hash[2] = 0x98badcfe;
100     ctx->hash[3] = 0x10325476;
101     ctx->hash[4] = 0xc3d2e1f0;
102     }
103    
104     /* SHA1 hash data in an array of bytes into hash buffer and call the */
105     /* hash_compile function as required. */
106     void sha1_hash(const void *data, size_t length, sha1_ctx_t *ctx)
107     {
108     uint32_t pos = (uint32_t) (ctx->count[0] & SHA1_MASK);
109     uint32_t freeb = SHA1_BLOCK_SIZE - pos;
110     const unsigned char *sp = data;
111    
112     if ((ctx->count[0] += length) < length)
113     ++(ctx->count[1]);
114    
115     while (length >= freeb) { /* tranfer whole blocks while possible */
116     memcpy(((unsigned char *) ctx->wbuf) + pos, sp, freeb);
117     sp += freeb;
118     length -= freeb;
119     freeb = SHA1_BLOCK_SIZE;
120     pos = 0;
121     sha1_compile(ctx);
122     }
123    
124     memcpy(((unsigned char *) ctx->wbuf) + pos, sp, length);
125     }
126    
127     void *sha1_end(void *resbuf, sha1_ctx_t *ctx)
128     {
129     /* SHA1 Final padding and digest calculation */
130     #if BB_BIG_ENDIAN
131     static uint32_t mask[4] = { 0x00000000, 0xff000000, 0xffff0000, 0xffffff00 };
132     static uint32_t bits[4] = { 0x80000000, 0x00800000, 0x00008000, 0x00000080 };
133     #else
134     static uint32_t mask[4] = { 0x00000000, 0x000000ff, 0x0000ffff, 0x00ffffff };
135     static uint32_t bits[4] = { 0x00000080, 0x00008000, 0x00800000, 0x80000000 };
136     #endif
137    
138     uint8_t *hval = resbuf;
139     uint32_t i, cnt = (uint32_t) (ctx->count[0] & SHA1_MASK);
140    
141     /* mask out the rest of any partial 32-bit word and then set */
142     /* the next byte to 0x80. On big-endian machines any bytes in */
143     /* the buffer will be at the top end of 32 bit words, on little */
144     /* endian machines they will be at the bottom. Hence the AND */
145     /* and OR masks above are reversed for little endian systems */
146     ctx->wbuf[cnt >> 2] =
147     (ctx->wbuf[cnt >> 2] & mask[cnt & 3]) | bits[cnt & 3];
148    
149     /* we need 9 or more empty positions, one for the padding byte */
150     /* (above) and eight for the length count. If there is not */
151     /* enough space pad and empty the buffer */
152     if (cnt > SHA1_BLOCK_SIZE - 9) {
153     if (cnt < 60)
154     ctx->wbuf[15] = 0;
155     sha1_compile(ctx);
156     cnt = 0;
157     } else /* compute a word index for the empty buffer positions */
158     cnt = (cnt >> 2) + 1;
159    
160     while (cnt < 14) /* and zero pad all but last two positions */
161     ctx->wbuf[cnt++] = 0;
162    
163     /* assemble the eight byte counter in the buffer in big-endian */
164     /* format */
165    
166     ctx->wbuf[14] = htonl((ctx->count[1] << 3) | (ctx->count[0] >> 29));
167     ctx->wbuf[15] = htonl(ctx->count[0] << 3);
168    
169     sha1_compile(ctx);
170    
171     /* extract the hash value as bytes in case the hash buffer is */
172     /* misaligned for 32-bit words */
173    
174     for (i = 0; i < SHA1_DIGEST_SIZE; ++i)
175     hval[i] = (unsigned char) (ctx->hash[i >> 2] >> 8 * (~i & 3));
176    
177     return resbuf;
178     }