1 /* SHA256-based Unix crypt implementation.
2 Released into the Public Domain by Ulrich Drepper <drepper@redhat.com>. */
3
4 #include "sha256crypt.h"
5
6 #ifdef __linux__
7 #include <endian.h>
8 #elif __hpux
9 /* Nothing to do in HP-UX */
10 #elif _AIX
11 /* Nothing to do in AIX */
12 #else
13 #if defined(ZBX_OLD_SOLARIS)
14 #include <sys/isa_defs.h>
15 #else
16 #include <machine/endian.h>
17 #endif
18 #endif
19 #include <errno.h>
20 #include <limits.h>
21 #include <stdint.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <sys/param.h>
26 #include <sys/types.h>
27
28
29 /* Structure to save state of computation between the single steps. */
30 struct sha256_ctx
31 {
32 uint32_t H[8];
33
34 uint32_t total[2];
35 uint32_t buflen;
36 char buffer[128]; /* NB: always correctly aligned for uint32_t. */
37 };
38
39
40 #if __BYTE_ORDER == __LITTLE_ENDIAN
41 # define SWAP(n) \
42 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
43 #else
44 # define SWAP(n) (n)
45 #endif
46
47
48 /* This array contains the bytes used to pad the buffer to the next
49 64-byte boundary. (FIPS 180-2:5.1.1) */
50 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
51
52
53 /* Constants for SHA256 from FIPS 180-2:4.2.2. */
54 static const uint32_t K[64] =
55 {
56 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
57 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
58 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
59 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
60 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
61 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
62 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
63 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
64 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
65 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
66 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
67 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
68 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
69 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
70 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
71 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
72 };
73
74
75 /* Process LEN bytes of BUFFER, accumulating context into CTX.
76 It is assumed that LEN % 64 == 0. */
77 static void
sha256_process_block(const void * buffer,size_t len,struct sha256_ctx * ctx)78 sha256_process_block (const void *buffer, size_t len, struct sha256_ctx *ctx)
79 {
80 const uint32_t *words = buffer;
81 size_t nwords = len / sizeof (uint32_t);
82 uint32_t a = ctx->H[0];
83 uint32_t b = ctx->H[1];
84 uint32_t c = ctx->H[2];
85 uint32_t d = ctx->H[3];
86 uint32_t e = ctx->H[4];
87 uint32_t f = ctx->H[5];
88 uint32_t g = ctx->H[6];
89 uint32_t h = ctx->H[7];
90
91 /* First increment the byte count. FIPS 180-2 specifies the possible
92 length of the file up to 2^64 bits. Here we only compute the
93 number of bytes. Do a double word increment. */
94 ctx->total[0] += len;
95 if (ctx->total[0] < len)
96 ++ctx->total[1];
97
98 /* Process all bytes in the buffer with 64 bytes in each round of
99 the loop. */
100 while (nwords > 0)
101 {
102 uint32_t W[64];
103 uint32_t a_save = a;
104 uint32_t b_save = b;
105 uint32_t c_save = c;
106 uint32_t d_save = d;
107 uint32_t e_save = e;
108 uint32_t f_save = f;
109 uint32_t g_save = g;
110 uint32_t h_save = h;
111
112 /* Operators defined in FIPS 180-2:4.1.2. */
113 #define Ch(x, y, z) ((x & y) ^ (~x & z))
114 #define Maj(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
115 #define S0(x) (CYCLIC (x, 2) ^ CYCLIC (x, 13) ^ CYCLIC (x, 22))
116 #define S1(x) (CYCLIC (x, 6) ^ CYCLIC (x, 11) ^ CYCLIC (x, 25))
117 #define R0(x) (CYCLIC (x, 7) ^ CYCLIC (x, 18) ^ (x >> 3))
118 #define R1(x) (CYCLIC (x, 17) ^ CYCLIC (x, 19) ^ (x >> 10))
119
120 /* It is unfortunate that C does not provide an operator for
121 cyclic rotation. Hope the C compiler is smart enough. */
122 #define CYCLIC(w, s) ((w >> s) | (w << (32 - s)))
123
124 unsigned int t = 0;
125
126 /* Compute the message schedule according to FIPS 180-2:6.2.2 step 2. */
127 for (t = 0; t < 16; ++t)
128 {
129 W[t] = SWAP (*words);
130 ++words;
131 }
132
133 for (t = 16; t < 64; ++t)
134 W[t] = R1 (W[t - 2]) + W[t - 7] + R0 (W[t - 15]) + W[t - 16];
135
136 /* The actual computation according to FIPS 180-2:6.2.2 step 3. */
137 for (t = 0; t < 64; ++t)
138 {
139 uint32_t T1 = h + S1 (e) + Ch (e, f, g) + K[t] + W[t];
140 uint32_t T2 = S0 (a) + Maj (a, b, c);
141 h = g;
142 g = f;
143 f = e;
144 e = d + T1;
145 d = c;
146 c = b;
147 b = a;
148 a = T1 + T2;
149 }
150
151 /* Add the starting values of the context according to FIPS 180-2:6.2.2
152 * step 4. */
153 a += a_save;
154 b += b_save;
155 c += c_save;
156 d += d_save;
157 e += e_save;
158 f += f_save;
159 g += g_save;
160 h += h_save;
161
162 /* Prepare for the next round. */
163 nwords -= 16;
164 }
165
166 /* Put checksum in context given as argument. */
167 ctx->H[0] = a;
168 ctx->H[1] = b;
169 ctx->H[2] = c;
170 ctx->H[3] = d;
171 ctx->H[4] = e;
172 ctx->H[5] = f;
173 ctx->H[6] = g;
174 ctx->H[7] = h;
175 }
176
177
178 /* Initialize structure containing state of computation.
179 (FIPS 180-2:5.3.2) */
180 static void
sha256_init_ctx(struct sha256_ctx * ctx)181 sha256_init_ctx (struct sha256_ctx *ctx)
182 {
183 ctx->H[0] = 0x6a09e667;
184 ctx->H[1] = 0xbb67ae85;
185 ctx->H[2] = 0x3c6ef372;
186 ctx->H[3] = 0xa54ff53a;
187 ctx->H[4] = 0x510e527f;
188 ctx->H[5] = 0x9b05688c;
189 ctx->H[6] = 0x1f83d9ab;
190 ctx->H[7] = 0x5be0cd19;
191
192 ctx->total[0] = ctx->total[1] = 0;
193 ctx->buflen = 0;
194 }
195
196
197 /* Process the remaining bytes in the internal buffer and the usual
198 prolog according to the standard and write the result to RESBUF.
199
200 IMPORTANT: On some systems it is required that RESBUF is correctly
201 aligned for a 32 bits value. */
202 static void *
sha256_finish_ctx(struct sha256_ctx * ctx,void * resbuf)203 sha256_finish_ctx (struct sha256_ctx *ctx, void *resbuf)
204 {
205 /* Take yet unprocessed bytes into account. */
206 uint32_t bytes = ctx->buflen;
207 size_t pad;
208 unsigned int i = 0;
209
210 /* Now count remaining bytes. */
211 ctx->total[0] += bytes;
212 if (ctx->total[0] < bytes)
213 ++ctx->total[1];
214
215 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
216 memcpy (&ctx->buffer[bytes], fillbuf, pad);
217
218 /* Put the 64-bit file length in *bits* at the end of the buffer. */
219 *(uint32_t *) &ctx->buffer[bytes + pad + 4] = SWAP (ctx->total[0] << 3);
220 *(uint32_t *) &ctx->buffer[bytes + pad] = SWAP ((ctx->total[1] << 3) |
221 (ctx->total[0] >> 29));
222
223 /* Process last bytes. */
224 sha256_process_block (ctx->buffer, bytes + pad + 8, ctx);
225
226 /* Put result from CTX in first 32 bytes following RESBUF. */
227 for (i = 0; i < 8; ++i)
228 ((uint32_t *) resbuf)[i] = SWAP (ctx->H[i]);
229
230 return resbuf;
231 }
232
233
234 static void
sha256_process_bytes(const void * buffer,size_t len,struct sha256_ctx * ctx)235 sha256_process_bytes (const void *buffer, size_t len, struct sha256_ctx *ctx)
236 {
237 /* When we already have some bits in our internal buffer concatenate
238 both inputs first. */
239 if (ctx->buflen != 0)
240 {
241 size_t left_over = ctx->buflen;
242 size_t add = 128 - left_over > len ? len : 128 - left_over;
243
244 memcpy (&ctx->buffer[left_over], buffer, add);
245 ctx->buflen += add;
246
247 if (ctx->buflen > 64)
248 {
249 sha256_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
250
251 ctx->buflen &= 63;
252 /* The regions in the following copy operation cannot overlap. */
253 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
254 ctx->buflen);
255 }
256
257 buffer = (const char *) buffer + add;
258 len -= add;
259 }
260
261 /* Process available complete blocks. */
262 if (len >= 64)
263 {
264 /* To check alignment gcc has an appropriate operator. Other
265 compilers don't. */
266 #if __GNUC__ >= 2
267 # define UNALIGNED_P(p) (((uintptr_t) p) % __alignof__ (uint32_t) != 0)
268 #else
269 # define UNALIGNED_P(p) (((uintptr_t) p) % sizeof (uint32_t) != 0)
270 #endif
271 if (UNALIGNED_P (buffer))
272 while (len > 64)
273 {
274 sha256_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
275 buffer = (const char *) buffer + 64;
276 len -= 64;
277 }
278 else
279 {
280 sha256_process_block (buffer, len & ~63, ctx);
281 buffer = (const char *) buffer + (len & ~63);
282 len &= 63;
283 }
284 }
285
286 /* Move remaining bytes into internal buffer. */
287 if (len > 0)
288 {
289 size_t left_over = ctx->buflen;
290
291 memcpy (&ctx->buffer[left_over], buffer, len);
292 left_over += len;
293 if (left_over >= 64)
294 {
295 sha256_process_block (ctx->buffer, 64, ctx);
296 left_over -= 64;
297 memcpy (ctx->buffer, &ctx->buffer[64], left_over);
298 }
299 ctx->buflen = left_over;
300 }
301 }
302
zbx_sha256_hash(const char * in,char * out)303 void zbx_sha256_hash(const char *in, char *out)
304 {
305 struct sha256_ctx ctx;
306 sha256_init_ctx (&ctx);
307 sha256_process_bytes (in, strlen (in), &ctx);
308 sha256_finish_ctx (&ctx, out);
309 }
310
311