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1 #include "xmpmeta/md5.h"
2 
3 #include <string.h>  // for memcpy().
4 
5 #include <vector>
6 
7 #include "base/integral_types.h"
8 #include "strings/escaping.h"
9 
10 namespace dynamic_depth {
11 namespace xmpmeta {
12 namespace {
13 
14 const int kMd5DigestSize = 16;
15 
16 typedef struct MD5Context MD5_CTX;
17 
18 struct MD5Context {
19   uint32 buf[4];
20   uint32 bits[2];
21   uint32 in[16];
22 };
23 
24 void MD5Init(struct MD5Context* context);
25 void MD5Update(struct MD5Context* context, const uint8* data, size_t len);
26 void MD5Final(unsigned char digest[16], struct MD5Context* ctx);
27 void MD5Transform(uint32 buf[4], const uint32 in[16]);
28 
29 // Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
30 // initialization constants.
MD5Init(MD5Context * context)31 void MD5Init(MD5Context* context) {
32   context->buf[0] = 0x67452301;
33   context->buf[1] = 0xefcdab89;
34   context->buf[2] = 0x98badcfe;
35   context->buf[3] = 0x10325476;
36   context->bits[0] = 0;
37   context->bits[1] = 0;
38 }
39 
40 // Update context to reflect the concatenation of another buffer full of bytes.
MD5Update(MD5Context * context,const uint8 * data,size_t len)41 void MD5Update(MD5Context* context, const uint8* data, size_t len) {
42   // Update bitcount.
43   uint32 t = context->bits[0];
44   if ((context->bits[0] = t + (static_cast<uint32>(len) << 3)) < t) {
45     context->bits[1]++;  // Carry from low to high.
46   }
47   context->bits[1] += len >> 29;
48   t = (t >> 3) & 0x3f;  // Bytes already in shsInfo->data.
49 
50   // Handle any leading odd-sized chunks.
51   if (t) {
52     uint8* p = reinterpret_cast<uint8*>(context->in) + t;
53 
54     t = 64 - t;
55     if (len < t) {
56       memcpy(p, data, len);
57       return;
58     }
59     memcpy(p, data, t);
60     MD5Transform(context->buf, context->in);
61     data += t;
62     len -= t;
63   }
64 
65   // Process data in 64-byte chunks.
66   while (len >= 64) {
67     memcpy(context->in, data, 64);
68     MD5Transform(context->buf, context->in);
69     data += 64;
70     len -= 64;
71   }
72 
73   // Handle any remaining bytes of data.
74   memcpy(context->in, data, len);
75 }
76 
77 // Final wrapup - pad to 64-byte boundary with the bit pattern.
78 // 1 0* (64-bit count of bits processed, MSB-first)
MD5Final(uint8 digest[16],MD5Context * ctx)79 void MD5Final(uint8 digest[16], MD5Context* ctx) {
80   // Compute number of bytes mod 64.
81   uint32 count = (ctx->bits[0] >> 3) & 0x3F;
82 
83   // Set the first char of padding to 0x80.  This is safe since there is
84   // always at least one byte free.
85   uint8* p = reinterpret_cast<uint8*>(ctx->in) + count;
86   *p++ = 0x80;
87 
88   // Bytes of padding needed to make 64 bytes.
89   count = 64 - 1 - count;
90 
91   // Pad out to 56 mod 64.
92   if (count < 8) {
93     // Two lots of padding:  Pad the first block to 64 bytes.
94     memset(p, 0, count);
95     MD5Transform(ctx->buf, ctx->in);
96 
97     // Now fill the next block with 56 bytes.
98     memset(ctx->in, 0, 56);
99   } else {
100     // Pad block to 56 bytes.
101     memset(p, 0, count - 8);
102   }
103 
104   // Append length in bits and transform.
105   ctx->in[14] = ctx->bits[0];
106   ctx->in[15] = ctx->bits[1];
107 
108   MD5Transform(ctx->buf, ctx->in);
109   memcpy(digest, ctx->buf, 16);
110   memset(ctx, 0, sizeof(*ctx));  // In case it's sensitive.
111 }
112 
113 // The four core functions - F1 is optimized somewhat.
114 // #define F1(x, y, z) (x & y | ~x & z)
115 #define F1(x, y, z) (z ^ (x & (y ^ z)))
116 #define F2(x, y, z) F1(z, x, y)
117 #define F3(x, y, z) (x ^ y ^ z)
118 #define F4(x, y, z) (y ^ (x | ~z))
119 
120 // This is the central step in the MD5 algorithm.
121 #define MD5STEP(f, w, x, y, z, data, s) \
122   (w += f(x, y, z) + data, w = w << s | w >> (32 - s), w += x)
123 
124 #if defined(__clang__) && defined(__has_attribute)
125 #if __has_attribute(no_sanitize)
126 #define DDEPTH_NO_UNSIGNED_OVERFLOW_CHECK \
127   __attribute__((no_sanitize("unsigned-integer-overflow")))
128 #endif
129 #endif
130 
131 #ifndef DDEPTH_NO_UNSIGNED_OVERFLOW_CHECK
132 #define DDEPTH_NO_UNSIGNED_OVERFLOW_CHECK
133 #endif
134 
135 // The core of the MD5 algorithm, this alters an existing MD5 hash to
136 // reflect the addition of 16 longwords of new data.  MD5Update blocks
137 // the data and converts bytes into longwords for this routine.
MD5Transform(uint32 buf[4],const uint32 in[16])138 DDEPTH_NO_UNSIGNED_OVERFLOW_CHECK void MD5Transform(uint32 buf[4],
139                                                     const uint32 in[16]) {
140   uint32 a = buf[0];
141   uint32 b = buf[1];
142   uint32 c = buf[2];
143   uint32 d = buf[3];
144 
145   MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
146   MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
147   MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
148   MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
149   MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
150   MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
151   MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
152   MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
153   MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
154   MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
155   MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
156   MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
157   MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
158   MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
159   MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
160   MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
161 
162   MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
163   MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
164   MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
165   MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
166   MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
167   MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
168   MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
169   MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
170   MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
171   MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
172   MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
173   MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
174   MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
175   MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
176   MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
177   MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
178 
179   MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
180   MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
181   MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
182   MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
183   MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
184   MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
185   MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
186   MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
187   MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
188   MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
189   MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
190   MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
191   MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
192   MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
193   MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
194   MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
195 
196   MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
197   MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
198   MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
199   MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
200   MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
201   MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
202   MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
203   MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
204   MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
205   MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
206   MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
207   MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
208   MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
209   MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
210   MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
211   MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
212   buf[0] += a;
213   buf[1] += b;
214   buf[2] += c;
215   buf[3] += d;
216 }
217 
MD5(const uint8_t * to_hash,size_t to_hash_length,uint8_t * output)218 void MD5(const uint8_t* to_hash, size_t to_hash_length, uint8_t* output) {
219   MD5Context md5_context;
220   MD5Init(&md5_context);
221   MD5Update(&md5_context, to_hash, to_hash_length);
222   MD5Final(output, &md5_context);
223 }
224 
225 }  // namespace
226 
MD5Hash(const string & to_hash)227 string MD5Hash(const string& to_hash) {
228   std::vector<uint8_t> buffer;
229   buffer.resize(kMd5DigestSize);
230   MD5(reinterpret_cast<const uint8_t*>(to_hash.data()), to_hash.length(),
231       &buffer[0]);
232   return dynamic_depth::b2a_hex(reinterpret_cast<const char*>(&buffer[0]),
233                                 kMd5DigestSize);
234 }
235 
236 }  // namespace xmpmeta
237 }  // namespace dynamic_depth
238