1 /* sha.c
2 **
3 ** Copyright 2013, The Android Open Source Project
4 **
5 ** Redistribution and use in source and binary forms, with or without
6 ** modification, are permitted provided that the following conditions are met:
7 **     * Redistributions of source code must retain the above copyright
8 **       notice, this list of conditions and the following disclaimer.
9 **     * Redistributions in binary form must reproduce the above copyright
10 **       notice, this list of conditions and the following disclaimer in the
11 **       documentation and/or other materials provided with the distribution.
12 **     * Neither the name of Google Inc. nor the names of its contributors may
13 **       be used to endorse or promote products derived from this software
14 **       without specific prior written permission.
15 **
16 ** THIS SOFTWARE IS PROVIDED BY Google Inc. ``AS IS'' AND ANY EXPRESS OR
17 ** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 ** MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 ** EVENT SHALL Google Inc. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 ** PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 ** OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 ** WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 ** OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 ** ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27 
28 // Optimized for minimal code size.
29 
30 #include "constrainedcrypto/sha.h"
31 
32 #include <stdio.h>
33 #include <string.h>
34 #include <stdint.h>
35 
36 #define rol(bits, value) (((value) << (bits)) | ((value) >> (32 - (bits))))
37 
SHA1_Transform(SHA_CTX * ctx)38 static void SHA1_Transform(SHA_CTX* ctx) {
39     uint32_t W[80];
40     uint32_t A, B, C, D, E;
41     uint8_t* p = ctx->buf;
42     int t;
43 
44     for(t = 0; t < 16; ++t) {
45         uint32_t tmp =  *p++ << 24;
46         tmp |= *p++ << 16;
47         tmp |= *p++ << 8;
48         tmp |= *p++;
49         W[t] = tmp;
50     }
51 
52     for(; t < 80; t++) {
53         W[t] = rol(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]);
54     }
55 
56     A = ctx->state[0];
57     B = ctx->state[1];
58     C = ctx->state[2];
59     D = ctx->state[3];
60     E = ctx->state[4];
61 
62     for(t = 0; t < 80; t++) {
63         uint32_t tmp = rol(5,A) + E + W[t];
64 
65         if (t < 20)
66             tmp += (D^(B&(C^D))) + 0x5A827999;
67         else if ( t < 40)
68             tmp += (B^C^D) + 0x6ED9EBA1;
69         else if ( t < 60)
70             tmp += ((B&C)|(D&(B|C))) + 0x8F1BBCDC;
71         else
72             tmp += (B^C^D) + 0xCA62C1D6;
73 
74         E = D;
75         D = C;
76         C = rol(30,B);
77         B = A;
78         A = tmp;
79     }
80 
81     ctx->state[0] += A;
82     ctx->state[1] += B;
83     ctx->state[2] += C;
84     ctx->state[3] += D;
85     ctx->state[4] += E;
86 }
87 
88 static const HASH_VTAB SHA_VTAB = {
89     SHA_init,
90     SHA_update,
91     SHA_final,
92     SHA_hash,
93     SHA_DIGEST_SIZE
94 };
95 
SHA_init(SHA_CTX * ctx)96 void SHA_init(SHA_CTX* ctx) {
97     ctx->f = &SHA_VTAB;
98     ctx->state[0] = 0x67452301;
99     ctx->state[1] = 0xEFCDAB89;
100     ctx->state[2] = 0x98BADCFE;
101     ctx->state[3] = 0x10325476;
102     ctx->state[4] = 0xC3D2E1F0;
103     ctx->count = 0;
104 }
105 
106 
SHA_update(SHA_CTX * ctx,const void * data,int len)107 void SHA_update(SHA_CTX* ctx, const void* data, int len) {
108     int i = (int) (ctx->count & 63);
109     const uint8_t* p = (const uint8_t*)data;
110 
111     ctx->count += len;
112 
113     while (len--) {
114         ctx->buf[i++] = *p++;
115         if (i == 64) {
116             SHA1_Transform(ctx);
117             i = 0;
118         }
119     }
120 }
121 
122 
SHA_final(SHA_CTX * ctx)123 const uint8_t* SHA_final(SHA_CTX* ctx) {
124     uint8_t *p = ctx->buf;
125     uint64_t cnt = ctx->count * 8;
126     int i;
127 
128     SHA_update(ctx, (uint8_t*)"\x80", 1);
129     while ((ctx->count & 63) != 56) {
130         SHA_update(ctx, (uint8_t*)"\0", 1);
131     }
132     for (i = 0; i < 8; ++i) {
133         uint8_t tmp = (uint8_t) (cnt >> ((7 - i) * 8));
134         SHA_update(ctx, &tmp, 1);
135     }
136 
137     for (i = 0; i < 5; i++) {
138         uint32_t tmp = ctx->state[i];
139         *p++ = tmp >> 24;
140         *p++ = tmp >> 16;
141         *p++ = tmp >> 8;
142         *p++ = tmp >> 0;
143     }
144 
145     return ctx->buf;
146 }
147 
148 /* Convenience function */
SHA_hash(const void * data,int len,uint8_t * digest)149 const uint8_t* SHA_hash(const void* data, int len, uint8_t* digest) {
150     SHA_CTX ctx;
151     SHA_init(&ctx);
152     SHA_update(&ctx, data, len);
153     memcpy(digest, SHA_final(&ctx), SHA_DIGEST_SIZE);
154     return digest;
155 }
156