NeoMutt  2020-06-26-89-g172cd3
Teaching an old dog new tricks
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md5.c
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1 
30 #include "config.h"
31 #include <stddef.h> // IWYU pragma: keep
32 #include <stdbool.h>
33 #include <stdio.h>
34 #include <string.h>
35 #include "md5.h"
36 
37 #ifdef WORDS_BIGENDIAN
38 #define SWAP(n) \
39  (((n) << 24) | (((n) &0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
40 #else
41 #define SWAP(n) (n)
42 #endif
43 
44 /* This array contains the bytes used to pad the buffer to the next
45  * 64-byte boundary. (RFC1321, 3.1: Step 1) */
46 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
47 
48 /* These are the four functions used in the four steps of the MD5 algorithm
49  * and defined in the RFC1321. The first function is a little bit optimized
50  * (as found in Colin Plumbs public domain implementation). */
51 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
52 #define FF(b, c, d) (d ^ (b & (c ^ d)))
53 #define FG(b, c, d) FF(d, b, c)
54 #define FH(b, c, d) (b ^ c ^ d)
55 #define FI(b, c, d) (c ^ (b | ~d))
56 
66 static void mutt_md5_process_block(const void *buffer, size_t len, struct Md5Ctx *md5ctx)
67 {
68  md5_uint32 correct_words[16];
69  const md5_uint32 *words = buffer;
70  size_t nwords = len / sizeof(md5_uint32);
71  const md5_uint32 *endp = words + nwords;
72  md5_uint32 A = md5ctx->A;
73  md5_uint32 B = md5ctx->B;
74  md5_uint32 C = md5ctx->C;
75  md5_uint32 D = md5ctx->D;
76 
77  /* First increment the byte count. RFC1321 specifies the possible length of
78  * the file up to 2^64 bits. Here we only compute the number of bytes. Do a
79  * double word increment. */
80  md5ctx->total[0] += len;
81  if (md5ctx->total[0] < len)
82  md5ctx->total[1]++;
83 
84  /* Process all bytes in the buffer with 64 bytes in each round of the loop. */
85  while (words < endp)
86  {
87  md5_uint32 *cwp = correct_words;
88  md5_uint32 save_A = A;
89  md5_uint32 save_B = B;
90  md5_uint32 save_C = C;
91  md5_uint32 save_D = D;
92 
93  /* First round: using the given function, the context and a constant the
94  * next context is computed. Because the algorithms processing unit is a
95  * 32-bit word and it is determined to work on words in little endian byte
96  * order we perhaps have to change the byte order before the computation.
97  * To reduce the work for the next steps we store the swapped words in the
98  * array CORRECT_WORDS. */
99 
100 #define OP(a, b, c, d, s, T) \
101  do \
102  { \
103  a += FF(b, c, d) + (*cwp++ = SWAP(*words)) + T; \
104  words++; \
105  CYCLIC(a, s); \
106  a += b; \
107  } while (false)
108 
109 /* It is unfortunate that C does not provide an operator for
110  * cyclic rotation. Hope the C compiler is smart enough. */
111 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
112 
113  /* Before we start, one word to the strange constants.
114  * They are defined in RFC1321 as
115  * T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
116  * Here is an equivalent invocation using Perl:
117  * perl -e 'foreach(1..64){printf "0x%08x\n", int (4294967296 * abs (sin $_))}'
118  */
119 
120  /* Round 1. */
121  OP(A, B, C, D, 7, 0xd76aa478);
122  OP(D, A, B, C, 12, 0xe8c7b756);
123  OP(C, D, A, B, 17, 0x242070db);
124  OP(B, C, D, A, 22, 0xc1bdceee);
125  OP(A, B, C, D, 7, 0xf57c0faf);
126  OP(D, A, B, C, 12, 0x4787c62a);
127  OP(C, D, A, B, 17, 0xa8304613);
128  OP(B, C, D, A, 22, 0xfd469501);
129  OP(A, B, C, D, 7, 0x698098d8);
130  OP(D, A, B, C, 12, 0x8b44f7af);
131  OP(C, D, A, B, 17, 0xffff5bb1);
132  OP(B, C, D, A, 22, 0x895cd7be);
133  OP(A, B, C, D, 7, 0x6b901122);
134  OP(D, A, B, C, 12, 0xfd987193);
135  OP(C, D, A, B, 17, 0xa679438e);
136  OP(B, C, D, A, 22, 0x49b40821);
137 
138 /* For the second to fourth round we have the possibly swapped words
139  * in CORRECT_WORDS. Redefine the macro to take an additional first
140  * argument specifying the function to use. */
141 #undef OP
142 #define OP(f, a, b, c, d, k, s, T) \
143  do \
144  { \
145  a += f(b, c, d) + correct_words[k] + T; \
146  CYCLIC(a, s); \
147  a += b; \
148  } while (false)
149 
150  /* Round 2. */
151  OP(FG, A, B, C, D, 1, 5, 0xf61e2562);
152  OP(FG, D, A, B, C, 6, 9, 0xc040b340);
153  OP(FG, C, D, A, B, 11, 14, 0x265e5a51);
154  OP(FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
155  OP(FG, A, B, C, D, 5, 5, 0xd62f105d);
156  OP(FG, D, A, B, C, 10, 9, 0x02441453);
157  OP(FG, C, D, A, B, 15, 14, 0xd8a1e681);
158  OP(FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
159  OP(FG, A, B, C, D, 9, 5, 0x21e1cde6);
160  OP(FG, D, A, B, C, 14, 9, 0xc33707d6);
161  OP(FG, C, D, A, B, 3, 14, 0xf4d50d87);
162  OP(FG, B, C, D, A, 8, 20, 0x455a14ed);
163  OP(FG, A, B, C, D, 13, 5, 0xa9e3e905);
164  OP(FG, D, A, B, C, 2, 9, 0xfcefa3f8);
165  OP(FG, C, D, A, B, 7, 14, 0x676f02d9);
166  OP(FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
167 
168  /* Round 3. */
169  OP(FH, A, B, C, D, 5, 4, 0xfffa3942);
170  OP(FH, D, A, B, C, 8, 11, 0x8771f681);
171  OP(FH, C, D, A, B, 11, 16, 0x6d9d6122);
172  OP(FH, B, C, D, A, 14, 23, 0xfde5380c);
173  OP(FH, A, B, C, D, 1, 4, 0xa4beea44);
174  OP(FH, D, A, B, C, 4, 11, 0x4bdecfa9);
175  OP(FH, C, D, A, B, 7, 16, 0xf6bb4b60);
176  OP(FH, B, C, D, A, 10, 23, 0xbebfbc70);
177  OP(FH, A, B, C, D, 13, 4, 0x289b7ec6);
178  OP(FH, D, A, B, C, 0, 11, 0xeaa127fa);
179  OP(FH, C, D, A, B, 3, 16, 0xd4ef3085);
180  OP(FH, B, C, D, A, 6, 23, 0x04881d05);
181  OP(FH, A, B, C, D, 9, 4, 0xd9d4d039);
182  OP(FH, D, A, B, C, 12, 11, 0xe6db99e5);
183  OP(FH, C, D, A, B, 15, 16, 0x1fa27cf8);
184  OP(FH, B, C, D, A, 2, 23, 0xc4ac5665);
185 
186  /* Round 4. */
187  OP(FI, A, B, C, D, 0, 6, 0xf4292244);
188  OP(FI, D, A, B, C, 7, 10, 0x432aff97);
189  OP(FI, C, D, A, B, 14, 15, 0xab9423a7);
190  OP(FI, B, C, D, A, 5, 21, 0xfc93a039);
191  OP(FI, A, B, C, D, 12, 6, 0x655b59c3);
192  OP(FI, D, A, B, C, 3, 10, 0x8f0ccc92);
193  OP(FI, C, D, A, B, 10, 15, 0xffeff47d);
194  OP(FI, B, C, D, A, 1, 21, 0x85845dd1);
195  OP(FI, A, B, C, D, 8, 6, 0x6fa87e4f);
196  OP(FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
197  OP(FI, C, D, A, B, 6, 15, 0xa3014314);
198  OP(FI, B, C, D, A, 13, 21, 0x4e0811a1);
199  OP(FI, A, B, C, D, 4, 6, 0xf7537e82);
200  OP(FI, D, A, B, C, 11, 10, 0xbd3af235);
201  OP(FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
202  OP(FI, B, C, D, A, 9, 21, 0xeb86d391);
203 
204  /* Add the starting values of the context. */
205  A += save_A;
206  B += save_B;
207  C += save_C;
208  D += save_D;
209  }
210 
211  /* Put checksum in context given as argument. */
212  md5ctx->A = A;
213  md5ctx->B = B;
214  md5ctx->C = C;
215  md5ctx->D = D;
216 }
217 
227 static inline void set_uint32(char *cp, md5_uint32 v)
228 {
229  memcpy(cp, &v, sizeof(v));
230 }
231 
241 static void *mutt_md5_read_ctx(const struct Md5Ctx *md5ctx, void *resbuf)
242 {
243  if (!md5ctx || !resbuf)
244  return NULL;
245 
246  char *r = resbuf;
247 
248  set_uint32(r + 0 * sizeof(md5ctx->A), SWAP(md5ctx->A));
249  set_uint32(r + 1 * sizeof(md5ctx->B), SWAP(md5ctx->B));
250  set_uint32(r + 2 * sizeof(md5ctx->C), SWAP(md5ctx->C));
251  set_uint32(r + 3 * sizeof(md5ctx->D), SWAP(md5ctx->D));
252 
253  return resbuf;
254 }
255 
262 void mutt_md5_init_ctx(struct Md5Ctx *md5ctx)
263 {
264  if (!md5ctx)
265  return;
266 
267  md5ctx->A = 0x67452301;
268  md5ctx->B = 0xefcdab89;
269  md5ctx->C = 0x98badcfe;
270  md5ctx->D = 0x10325476;
271 
272  md5ctx->total[0] = 0;
273  md5ctx->total[1] = 0;
274  md5ctx->buflen = 0;
275 }
276 
286 void *mutt_md5_finish_ctx(struct Md5Ctx *md5ctx, void *resbuf)
287 {
288  if (!md5ctx)
289  return NULL;
290 
291  /* Take yet unprocessed bytes into account. */
292  md5_uint32 bytes = md5ctx->buflen;
293  size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
294 
295  /* Now count remaining bytes. */
296  md5ctx->total[0] += bytes;
297  if (md5ctx->total[0] < bytes)
298  md5ctx->total[1]++;
299 
300  /* Put the 64-bit file length in *bits* at the end of the buffer. */
301  md5ctx->buffer[size - 2] = SWAP(md5ctx->total[0] << 3);
302  md5ctx->buffer[size - 1] = SWAP((md5ctx->total[1] << 3) | (md5ctx->total[0] >> 29));
303 
304  memcpy(&((char *) md5ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
305 
306  /* Process last bytes. */
307  mutt_md5_process_block(md5ctx->buffer, size * 4, md5ctx);
308 
309  return mutt_md5_read_ctx(md5ctx, resbuf);
310 }
311 
317 void *mutt_md5(const char *str, void *buf)
318 {
319  if (!str)
320  return NULL;
321 
322  return mutt_md5_bytes(str, strlen(str), buf);
323 }
324 
336 void *mutt_md5_bytes(const void *buffer, size_t len, void *resbuf)
337 {
338  struct Md5Ctx md5ctx;
339 
340  /* Initialize the computation context. */
341  mutt_md5_init_ctx(&md5ctx);
342 
343  /* Process whole buffer but last len % 64 bytes. */
344  mutt_md5_process_bytes(buffer, len, &md5ctx);
345 
346  /* Put result in desired memory area. */
347  return mutt_md5_finish_ctx(&md5ctx, resbuf);
348 }
349 
355 void mutt_md5_process(const char *str, struct Md5Ctx *md5ctx)
356 {
357  if (!str)
358  return;
359 
360  mutt_md5_process_bytes(str, strlen(str), md5ctx);
361 }
362 
373 void mutt_md5_process_bytes(const void *buf, size_t buflen, struct Md5Ctx *md5ctx)
374 {
375  if (!buf || !md5ctx)
376  return;
377 
378  /* When we already have some bits in our internal buffer concatenate both
379  * inputs first. */
380  if (md5ctx->buflen != 0)
381  {
382  size_t left_over = md5ctx->buflen;
383  size_t add = ((128 - left_over) > buflen) ? buflen : (128 - left_over);
384 
385  memcpy(&((char *) md5ctx->buffer)[left_over], buf, add);
386  md5ctx->buflen += add;
387 
388  if (md5ctx->buflen > 64)
389  {
390  mutt_md5_process_block(md5ctx->buffer, md5ctx->buflen & ~63, md5ctx);
391 
392  md5ctx->buflen &= 63;
393  /* The regions in the following copy operation can't overlap. */
394  memcpy(md5ctx->buffer, &((char *) md5ctx->buffer)[(left_over + add) & ~63],
395  md5ctx->buflen);
396  }
397 
398  buf = (const char *) buf + add;
399  buflen -= add;
400  }
401 
402  /* Process available complete blocks. */
403  if (buflen >= 64)
404  {
405 #if !defined(_STRING_ARCH_unaligned)
406 #define alignof(type) \
407  offsetof( \
408  struct { \
409  char c; \
410  type x; \
411  }, \
412  x)
413 #define UNALIGNED_P(p) (((size_t) p) % alignof(md5_uint32) != 0)
414  if (UNALIGNED_P(buf))
415  {
416  while (buflen > 64)
417  {
418  mutt_md5_process_block(memcpy(md5ctx->buffer, buf, 64), 64, md5ctx);
419  buf = (const char *) buf + 64;
420  buflen -= 64;
421  }
422  }
423  else
424 #endif
425  {
426  mutt_md5_process_block(buf, buflen & ~63, md5ctx);
427  buf = (const char *) buf + (buflen & ~63);
428  buflen &= 63;
429  }
430  }
431 
432  /* Move remaining bytes in internal buffer. */
433  if (buflen > 0)
434  {
435  size_t left_over = md5ctx->buflen;
436 
437  memcpy(&((char *) md5ctx->buffer)[left_over], buf, buflen);
438  left_over += buflen;
439  if (left_over >= 64)
440  {
441  mutt_md5_process_block(md5ctx->buffer, 64, md5ctx);
442  left_over -= 64;
443  memmove(md5ctx->buffer, &md5ctx->buffer[16], left_over);
444  }
445  md5ctx->buflen = left_over;
446  }
447 }
448 
456 void mutt_md5_toascii(const void *digest, char *resbuf)
457 {
458  if (!digest || !resbuf)
459  return;
460 
461  const unsigned char *c = digest;
462  sprintf(resbuf, "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
463  c[0], c[1], c[2], c[3], c[4], c[5], c[6], c[7], c[8], c[9], c[10],
464  c[11], c[12], c[13], c[14], c[15]);
465 }
#define C
#define FG(b, c, d)
Definition: md5.c:53
Cursor for the MD5 hashing.
Definition: md5.h:36
void * mutt_md5_bytes(const void *buffer, size_t len, void *resbuf)
Calculate the MD5 hash of a buffer.
Definition: md5.c:336
#define UNALIGNED_P(p)
#define SWAP(n)
Definition: md5.c:41
void mutt_md5_process(const char *str, struct Md5Ctx *md5ctx)
Process a NULL-terminated string.
Definition: md5.c:355
md5_uint32 A
Definition: md5.h:38
void mutt_md5_init_ctx(struct Md5Ctx *md5ctx)
Initialise the MD5 computation.
Definition: md5.c:262
#define FI(b, c, d)
Definition: md5.c:55
#define OP(a, b, c, d, s, T)
#define FH(b, c, d)
Definition: md5.c:54
void mutt_md5_toascii(const void *digest, char *resbuf)
Convert a binary MD5 digest into ASCII Hexadecimal.
Definition: md5.c:456
static const unsigned char fillbuf[64]
Definition: md5.c:46
void * mutt_md5_finish_ctx(struct Md5Ctx *md5ctx, void *resbuf)
Process the remaining bytes in the buffer.
Definition: md5.c:286
md5_uint32 D
Definition: md5.h:41
uint32_t md5_uint32
Definition: md5.h:29
static int const char char buffer[256]
Definition: acutest.h:489
md5_uint32 total[2]
Definition: md5.h:43
md5_uint32 buflen
Definition: md5.h:44
md5_uint32 C
Definition: md5.h:40
md5_uint32 buffer[32]
Definition: md5.h:45
void mutt_md5_process_bytes(const void *buf, size_t buflen, struct Md5Ctx *md5ctx)
Process a block of data.
Definition: md5.c:373
void * mutt_md5(const char *str, void *buf)
Calculate the MD5 hash of a NULL-terminated string.
Definition: md5.c:317
md5_uint32 B
Definition: md5.h:39
static void set_uint32(char *cp, md5_uint32 v)
Write a 32 bit number.
Definition: md5.c:227
static void * mutt_md5_read_ctx(const struct Md5Ctx *md5ctx, void *resbuf)
Read from the context into a buffer.
Definition: md5.c:241
Calculate the MD5 checksum of a buffer.
static void mutt_md5_process_block(const void *buffer, size_t len, struct Md5Ctx *md5ctx)
Process a block with MD5.
Definition: md5.c:66