Line data Source code
1 : /*
2 : * This code implements the MD5 message-digest algorithm.
3 : * The algorithm is due to Ron Rivest. This code was
4 : * written by Colin Plumb in 1993, no copyright is claimed.
5 : * This code is in the public domain; do with it what you wish.
6 : *
7 : * Equivalent code is available from RSA Data Security, Inc.
8 : * This code has been tested against that, and is equivalent,
9 : * except that you don't need to include two pages of legalese
10 : * with every copy.
11 : *
12 : * To compute the message digest of a chunk of bytes, declare an
13 : * MD5Context structure, pass it to MD5Init, call MD5Update as
14 : * needed on buffers full of bytes, and then call MD5Final, which
15 : * will fill a supplied 16-byte array with the digest.
16 : */
17 :
18 : // Changes from original C code:
19 : // Ported to C++, type casting, Google code style.
20 :
21 : #include "webrtc/base/md5.h"
22 :
23 : // TODO: Avoid memcmpy - hash directly from memory.
24 : #include <string.h> // for memcpy().
25 :
26 : #include "webrtc/base/byteorder.h" // for RTC_ARCH_CPU_LITTLE_ENDIAN.
27 :
28 : namespace rtc {
29 :
30 : #ifdef RTC_ARCH_CPU_LITTLE_ENDIAN
31 : #define ByteReverse(buf, len) // Nothing.
32 : #else // RTC_ARCH_CPU_BIG_ENDIAN
33 : static void ByteReverse(uint32_t* buf, int len) {
34 : for (int i = 0; i < len; ++i) {
35 : buf[i] = rtc::GetLE32(&buf[i]);
36 : }
37 : }
38 : #endif
39 :
40 : // Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
41 : // initialization constants.
42 0 : void MD5Init(MD5Context* ctx) {
43 0 : ctx->buf[0] = 0x67452301;
44 0 : ctx->buf[1] = 0xefcdab89;
45 0 : ctx->buf[2] = 0x98badcfe;
46 0 : ctx->buf[3] = 0x10325476;
47 0 : ctx->bits[0] = 0;
48 0 : ctx->bits[1] = 0;
49 0 : }
50 :
51 : // Update context to reflect the concatenation of another buffer full of bytes.
52 0 : void MD5Update(MD5Context* ctx, const uint8_t* buf, size_t len) {
53 : // Update bitcount.
54 0 : uint32_t t = ctx->bits[0];
55 0 : if ((ctx->bits[0] = t + (static_cast<uint32_t>(len) << 3)) < t) {
56 0 : ctx->bits[1]++; // Carry from low to high.
57 : }
58 0 : ctx->bits[1] += static_cast<uint32_t>(len >> 29);
59 0 : t = (t >> 3) & 0x3f; // Bytes already in shsInfo->data.
60 :
61 : // Handle any leading odd-sized chunks.
62 0 : if (t) {
63 0 : uint8_t* p = reinterpret_cast<uint8_t*>(ctx->in) + t;
64 :
65 0 : t = 64-t;
66 0 : if (len < t) {
67 0 : memcpy(p, buf, len);
68 0 : return;
69 : }
70 0 : memcpy(p, buf, t);
71 : ByteReverse(ctx->in, 16);
72 0 : MD5Transform(ctx->buf, ctx->in);
73 0 : buf += t;
74 0 : len -= t;
75 : }
76 :
77 : // Process data in 64-byte chunks.
78 0 : while (len >= 64) {
79 0 : memcpy(ctx->in, buf, 64);
80 : ByteReverse(ctx->in, 16);
81 0 : MD5Transform(ctx->buf, ctx->in);
82 0 : buf += 64;
83 0 : len -= 64;
84 : }
85 :
86 : // Handle any remaining bytes of data.
87 0 : memcpy(ctx->in, buf, len);
88 : }
89 :
90 : // Final wrapup - pad to 64-byte boundary with the bit pattern.
91 : // 1 0* (64-bit count of bits processed, MSB-first)
92 0 : void MD5Final(MD5Context* ctx, uint8_t digest[16]) {
93 : // Compute number of bytes mod 64.
94 0 : uint32_t count = (ctx->bits[0] >> 3) & 0x3F;
95 :
96 : // Set the first char of padding to 0x80. This is safe since there is
97 : // always at least one byte free.
98 0 : uint8_t* p = reinterpret_cast<uint8_t*>(ctx->in) + count;
99 0 : *p++ = 0x80;
100 :
101 : // Bytes of padding needed to make 64 bytes.
102 0 : count = 64 - 1 - count;
103 :
104 : // Pad out to 56 mod 64.
105 0 : if (count < 8) {
106 : // Two lots of padding: Pad the first block to 64 bytes.
107 0 : memset(p, 0, count);
108 : ByteReverse(ctx->in, 16);
109 0 : MD5Transform(ctx->buf, ctx->in);
110 :
111 : // Now fill the next block with 56 bytes.
112 0 : memset(ctx->in, 0, 56);
113 : } else {
114 : // Pad block to 56 bytes.
115 0 : memset(p, 0, count - 8);
116 : }
117 : ByteReverse(ctx->in, 14);
118 :
119 : // Append length in bits and transform.
120 0 : ctx->in[14] = ctx->bits[0];
121 0 : ctx->in[15] = ctx->bits[1];
122 :
123 0 : MD5Transform(ctx->buf, ctx->in);
124 : ByteReverse(ctx->buf, 4);
125 0 : memcpy(digest, ctx->buf, 16);
126 0 : memset(ctx, 0, sizeof(*ctx)); // In case it's sensitive.
127 0 : }
128 :
129 : // The four core functions - F1 is optimized somewhat.
130 : // #define F1(x, y, z) (x & y | ~x & z)
131 : #define F1(x, y, z) (z ^ (x & (y ^ z)))
132 : #define F2(x, y, z) F1(z, x, y)
133 : #define F3(x, y, z) (x ^ y ^ z)
134 : #define F4(x, y, z) (y ^ (x | ~z))
135 :
136 : // This is the central step in the MD5 algorithm.
137 : #define MD5STEP(f, w, x, y, z, data, s) \
138 : (w += f(x, y, z) + data, w = w << s | w >> (32 - s), w += x)
139 :
140 : // The core of the MD5 algorithm, this alters an existing MD5 hash to
141 : // reflect the addition of 16 longwords of new data. MD5Update blocks
142 : // the data and converts bytes into longwords for this routine.
143 0 : void MD5Transform(uint32_t buf[4], const uint32_t in[16]) {
144 0 : uint32_t a = buf[0];
145 0 : uint32_t b = buf[1];
146 0 : uint32_t c = buf[2];
147 0 : uint32_t d = buf[3];
148 :
149 0 : MD5STEP(F1, a, b, c, d, in[ 0] + 0xd76aa478, 7);
150 0 : MD5STEP(F1, d, a, b, c, in[ 1] + 0xe8c7b756, 12);
151 0 : MD5STEP(F1, c, d, a, b, in[ 2] + 0x242070db, 17);
152 0 : MD5STEP(F1, b, c, d, a, in[ 3] + 0xc1bdceee, 22);
153 0 : MD5STEP(F1, a, b, c, d, in[ 4] + 0xf57c0faf, 7);
154 0 : MD5STEP(F1, d, a, b, c, in[ 5] + 0x4787c62a, 12);
155 0 : MD5STEP(F1, c, d, a, b, in[ 6] + 0xa8304613, 17);
156 0 : MD5STEP(F1, b, c, d, a, in[ 7] + 0xfd469501, 22);
157 0 : MD5STEP(F1, a, b, c, d, in[ 8] + 0x698098d8, 7);
158 0 : MD5STEP(F1, d, a, b, c, in[ 9] + 0x8b44f7af, 12);
159 0 : MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
160 0 : MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
161 0 : MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
162 0 : MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
163 0 : MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
164 0 : MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
165 :
166 0 : MD5STEP(F2, a, b, c, d, in[ 1] + 0xf61e2562, 5);
167 0 : MD5STEP(F2, d, a, b, c, in[ 6] + 0xc040b340, 9);
168 0 : MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
169 0 : MD5STEP(F2, b, c, d, a, in[ 0] + 0xe9b6c7aa, 20);
170 0 : MD5STEP(F2, a, b, c, d, in[ 5] + 0xd62f105d, 5);
171 0 : MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
172 0 : MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
173 0 : MD5STEP(F2, b, c, d, a, in[ 4] + 0xe7d3fbc8, 20);
174 0 : MD5STEP(F2, a, b, c, d, in[ 9] + 0x21e1cde6, 5);
175 0 : MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
176 0 : MD5STEP(F2, c, d, a, b, in[ 3] + 0xf4d50d87, 14);
177 0 : MD5STEP(F2, b, c, d, a, in[ 8] + 0x455a14ed, 20);
178 0 : MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
179 0 : MD5STEP(F2, d, a, b, c, in[ 2] + 0xfcefa3f8, 9);
180 0 : MD5STEP(F2, c, d, a, b, in[ 7] + 0x676f02d9, 14);
181 0 : MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
182 :
183 0 : MD5STEP(F3, a, b, c, d, in[ 5] + 0xfffa3942, 4);
184 0 : MD5STEP(F3, d, a, b, c, in[ 8] + 0x8771f681, 11);
185 0 : MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
186 0 : MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
187 0 : MD5STEP(F3, a, b, c, d, in[ 1] + 0xa4beea44, 4);
188 0 : MD5STEP(F3, d, a, b, c, in[ 4] + 0x4bdecfa9, 11);
189 0 : MD5STEP(F3, c, d, a, b, in[ 7] + 0xf6bb4b60, 16);
190 0 : MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
191 0 : MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
192 0 : MD5STEP(F3, d, a, b, c, in[ 0] + 0xeaa127fa, 11);
193 0 : MD5STEP(F3, c, d, a, b, in[ 3] + 0xd4ef3085, 16);
194 0 : MD5STEP(F3, b, c, d, a, in[ 6] + 0x04881d05, 23);
195 0 : MD5STEP(F3, a, b, c, d, in[ 9] + 0xd9d4d039, 4);
196 0 : MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
197 0 : MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
198 0 : MD5STEP(F3, b, c, d, a, in[ 2] + 0xc4ac5665, 23);
199 :
200 0 : MD5STEP(F4, a, b, c, d, in[ 0] + 0xf4292244, 6);
201 0 : MD5STEP(F4, d, a, b, c, in[ 7] + 0x432aff97, 10);
202 0 : MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
203 0 : MD5STEP(F4, b, c, d, a, in[ 5] + 0xfc93a039, 21);
204 0 : MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
205 0 : MD5STEP(F4, d, a, b, c, in[ 3] + 0x8f0ccc92, 10);
206 0 : MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
207 0 : MD5STEP(F4, b, c, d, a, in[ 1] + 0x85845dd1, 21);
208 0 : MD5STEP(F4, a, b, c, d, in[ 8] + 0x6fa87e4f, 6);
209 0 : MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
210 0 : MD5STEP(F4, c, d, a, b, in[ 6] + 0xa3014314, 15);
211 0 : MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
212 0 : MD5STEP(F4, a, b, c, d, in[ 4] + 0xf7537e82, 6);
213 0 : MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
214 0 : MD5STEP(F4, c, d, a, b, in[ 2] + 0x2ad7d2bb, 15);
215 0 : MD5STEP(F4, b, c, d, a, in[ 9] + 0xeb86d391, 21);
216 0 : buf[0] += a;
217 0 : buf[1] += b;
218 0 : buf[2] += c;
219 0 : buf[3] += d;
220 0 : }
221 :
222 9 : } // namespace rtc
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