1 //======- SHA1.h - Private copy of the SHA1 implementation ---*- C++ -* ======//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 // This code is taken from public domain
10 // (http://oauth.googlecode.com/svn/code/c/liboauth/src/sha1.c)
11 // and modified by wrapping it in a C++ interface for LLVM,
12 // and removing unnecessary code.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "llvm/Support/Host.h"
17 #include "llvm/Support/SHA1.h"
18 #include "llvm/ADT/ArrayRef.h"
19 using namespace llvm;
20 
21 #include <stdint.h>
22 #include <string.h>
23 
24 #if defined(BYTE_ORDER) && defined(BIG_ENDIAN) && BYTE_ORDER == BIG_ENDIAN
25 #define SHA_BIG_ENDIAN
26 #endif
27 
28 /* code */
29 #define SHA1_K0 0x5a827999
30 #define SHA1_K20 0x6ed9eba1
31 #define SHA1_K40 0x8f1bbcdc
32 #define SHA1_K60 0xca62c1d6
33 
34 #define SEED_0 0x67452301
35 #define SEED_1 0xefcdab89
36 #define SEED_2 0x98badcfe
37 #define SEED_3 0x10325476
38 #define SEED_4 0xc3d2e1f0
39 
40 void SHA1::init() {
41   InternalState.State[0] = SEED_0;
42   InternalState.State[1] = SEED_1;
43   InternalState.State[2] = SEED_2;
44   InternalState.State[3] = SEED_3;
45   InternalState.State[4] = SEED_4;
46   InternalState.ByteCount = 0;
47   InternalState.BufferOffset = 0;
48 }
49 
50 static uint32_t rol32(uint32_t number, uint8_t bits) {
51   return ((number << bits) | (number >> (32 - bits)));
52 }
53 
54 void SHA1::hashBlock() {
55   uint8_t i;
56   uint32_t a, b, c, d, e, t;
57 
58   a = InternalState.State[0];
59   b = InternalState.State[1];
60   c = InternalState.State[2];
61   d = InternalState.State[3];
62   e = InternalState.State[4];
63   for (i = 0; i < 80; i++) {
64     if (i >= 16) {
65       t = InternalState.Buffer[(i + 13) & 15] ^
66           InternalState.Buffer[(i + 8) & 15] ^
67           InternalState.Buffer[(i + 2) & 15] ^ InternalState.Buffer[i & 15];
68       InternalState.Buffer[i & 15] = rol32(t, 1);
69     }
70     if (i < 20) {
71       t = (d ^ (b & (c ^ d))) + SHA1_K0;
72     } else if (i < 40) {
73       t = (b ^ c ^ d) + SHA1_K20;
74     } else if (i < 60) {
75       t = ((b & c) | (d & (b | c))) + SHA1_K40;
76     } else {
77       t = (b ^ c ^ d) + SHA1_K60;
78     }
79     t += rol32(a, 5) + e + InternalState.Buffer[i & 15];
80     e = d;
81     d = c;
82     c = rol32(b, 30);
83     b = a;
84     a = t;
85   }
86   InternalState.State[0] += a;
87   InternalState.State[1] += b;
88   InternalState.State[2] += c;
89   InternalState.State[3] += d;
90   InternalState.State[4] += e;
91 }
92 
93 void SHA1::addUncounted(uint8_t data) {
94   uint8_t *const b = (uint8_t *)InternalState.Buffer;
95 #ifdef SHA_BIG_ENDIAN
96   b[InternalState.BufferOffset] = data;
97 #else
98   b[InternalState.BufferOffset ^ 3] = data;
99 #endif
100   InternalState.BufferOffset++;
101   if (InternalState.BufferOffset == BLOCK_LENGTH) {
102     hashBlock();
103     InternalState.BufferOffset = 0;
104   }
105 }
106 
107 void SHA1::writebyte(uint8_t data) {
108   ++InternalState.ByteCount;
109   addUncounted(data);
110 }
111 
112 void SHA1::update(ArrayRef<uint8_t> Data) {
113   for (auto &C : Data)
114     writebyte(C);
115 }
116 
117 void SHA1::pad() {
118   // Implement SHA-1 padding (fips180-2 5.1.1)
119 
120   // Pad with 0x80 followed by 0x00 until the end of the block
121   addUncounted(0x80);
122   while (InternalState.BufferOffset != 56)
123     addUncounted(0x00);
124 
125   // Append length in the last 8 bytes
126   addUncounted(0); // We're only using 32 bit lengths
127   addUncounted(0); // But SHA-1 supports 64 bit lengths
128   addUncounted(0); // So zero pad the top bits
129   addUncounted(InternalState.ByteCount >> 29); // Shifting to multiply by 8
130   addUncounted(InternalState.ByteCount >>
131                21); // as SHA-1 supports bitstreams as well as
132   addUncounted(InternalState.ByteCount >> 13); // byte.
133   addUncounted(InternalState.ByteCount >> 5);
134   addUncounted(InternalState.ByteCount << 3);
135 }
136 
137 StringRef SHA1::final() {
138   // Pad to complete the last block
139   pad();
140 
141 #ifdef SHA_BIG_ENDIAN
142   // Just copy the current state
143   for (int i = 0; i < 5; i++) {
144     HashResult[i] = InternalState.State[i];
145   }
146 #else
147   // Swap byte order back
148   for (int i = 0; i < 5; i++) {
149     HashResult[i] = (((InternalState.State[i]) << 24) & 0xff000000) |
150                     (((InternalState.State[i]) << 8) & 0x00ff0000) |
151                     (((InternalState.State[i]) >> 8) & 0x0000ff00) |
152                     (((InternalState.State[i]) >> 24) & 0x000000ff);
153   }
154 #endif
155 
156   // Return pointer to hash (20 characters)
157   return StringRef((char *)HashResult, HASH_LENGTH);
158 }
159 
160 StringRef SHA1::result() {
161   auto StateToRestore = InternalState;
162 
163   auto Hash = final();
164 
165   // Restore the state
166   InternalState = StateToRestore;
167 
168   // Return pointer to hash (20 characters)
169   return Hash;
170 }
171