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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 | /* SHA256 and SHA512-based Unix crypt implementation.
* Released into the Public Domain by Ulrich Drepper <drepper@redhat.com>.
*/
/* Prefix for optional rounds specification. */
static const char str_rounds[] = "rounds=%u$";
/* Maximum salt string length. */
#define SALT_LEN_MAX 16
/* Default number of rounds if not explicitly specified. */
#define ROUNDS_DEFAULT 5000
/* Minimum number of rounds. */
#define ROUNDS_MIN 1000
/* Maximum number of rounds. */
#define ROUNDS_MAX 999999999
static char *
NOINLINE
sha_crypt(/*const*/ char *key_data, /*const*/ char *salt_data)
{
void (*sha_begin)(void *ctx) FAST_FUNC;
void (*sha_hash)(const void *buffer, size_t len, void *ctx) FAST_FUNC;
void (*sha_end)(void *resbuf, void *ctx) FAST_FUNC;
int _32or64;
char *result, *resptr;
/* btw, sha256 needs [32] and uint32_t only */
struct {
unsigned char alt_result[64];
unsigned char temp_result[64];
union {
sha256_ctx_t x;
sha512_ctx_t y;
} ctx;
union {
sha256_ctx_t x;
sha512_ctx_t y;
} alt_ctx;
} L __attribute__((__aligned__(__alignof__(uint64_t))));
#define alt_result (L.alt_result )
#define temp_result (L.temp_result)
#define ctx (L.ctx )
#define alt_ctx (L.alt_ctx )
unsigned salt_len;
unsigned key_len;
unsigned cnt;
unsigned rounds;
char *cp;
char is_sha512;
/* Analyze salt, construct already known part of result */
cnt = strlen(salt_data) + 1 + 43 + 1;
is_sha512 = salt_data[1];
if (is_sha512 == '6')
cnt += 43;
result = resptr = xzalloc(cnt); /* will provide NUL terminator */
*resptr++ = '$';
*resptr++ = is_sha512;
*resptr++ = '$';
rounds = ROUNDS_DEFAULT;
salt_data += 3;
if (strncmp(salt_data, str_rounds, 7) == 0) {
/* 7 == strlen("rounds=") */
char *endp;
cnt = bb_strtou(salt_data + 7, &endp, 10);
if (*endp == '$') {
salt_data = endp + 1;
rounds = cnt;
if (rounds < ROUNDS_MIN)
rounds = ROUNDS_MIN;
if (rounds > ROUNDS_MAX)
rounds = ROUNDS_MAX;
/* add "rounds=NNNNN$" to result */
resptr += sprintf(resptr, str_rounds, rounds);
}
}
salt_len = strchrnul(salt_data, '$') - salt_data;
if (salt_len > SALT_LEN_MAX)
salt_len = SALT_LEN_MAX;
/* xstrdup assures suitable alignment; also we will use it
as a scratch space later. */
salt_data = xstrndup(salt_data, salt_len);
/* add "salt$" to result */
strcpy(resptr, salt_data);
resptr += salt_len;
*resptr++ = '$';
/* key data doesn't need much processing */
key_len = strlen(key_data);
key_data = xstrdup(key_data);
/* Which flavor of SHAnnn ops to use? */
sha_begin = (void*)sha256_begin;
sha_hash = (void*)sha256_hash;
sha_end = (void*)sha256_end;
_32or64 = 32;
if (is_sha512 == '6') {
sha_begin = (void*)sha512_begin;
sha_hash = (void*)sha512_hash;
sha_end = (void*)sha512_end;
_32or64 = 64;
}
/* Add KEY, SALT. */
sha_begin(&ctx);
sha_hash(key_data, key_len, &ctx);
sha_hash(salt_data, salt_len, &ctx);
/* Compute alternate SHA sum with input KEY, SALT, and KEY.
The final result will be added to the first context. */
sha_begin(&alt_ctx);
sha_hash(key_data, key_len, &alt_ctx);
sha_hash(salt_data, salt_len, &alt_ctx);
sha_hash(key_data, key_len, &alt_ctx);
sha_end(alt_result, &alt_ctx);
/* Add result of this to the other context. */
/* Add for any character in the key one byte of the alternate sum. */
for (cnt = key_len; cnt > _32or64; cnt -= _32or64)
sha_hash(alt_result, _32or64, &ctx);
sha_hash(alt_result, cnt, &ctx);
/* Take the binary representation of the length of the key and for every
1 add the alternate sum, for every 0 the key. */
for (cnt = key_len; cnt != 0; cnt >>= 1)
if ((cnt & 1) != 0)
sha_hash(alt_result, _32or64, &ctx);
else
sha_hash(key_data, key_len, &ctx);
/* Create intermediate result. */
sha_end(alt_result, &ctx);
/* Start computation of P byte sequence. */
/* For every character in the password add the entire password. */
sha_begin(&alt_ctx);
for (cnt = 0; cnt < key_len; ++cnt)
sha_hash(key_data, key_len, &alt_ctx);
sha_end(temp_result, &alt_ctx);
/* NB: past this point, raw key_data is not used anymore */
/* Create byte sequence P. */
#define p_bytes key_data /* reuse the buffer as it is of the key_len size */
cp = p_bytes; /* was: ... = alloca(key_len); */
for (cnt = key_len; cnt >= _32or64; cnt -= _32or64) {
cp = memcpy(cp, temp_result, _32or64);
cp += _32or64;
}
memcpy(cp, temp_result, cnt);
/* Start computation of S byte sequence. */
/* For every character in the password add the entire password. */
sha_begin(&alt_ctx);
for (cnt = 0; cnt < 16 + alt_result[0]; ++cnt)
sha_hash(salt_data, salt_len, &alt_ctx);
sha_end(temp_result, &alt_ctx);
/* NB: past this point, raw salt_data is not used anymore */
/* Create byte sequence S. */
#define s_bytes salt_data /* reuse the buffer as it is of the salt_len size */
cp = s_bytes; /* was: ... = alloca(salt_len); */
for (cnt = salt_len; cnt >= _32or64; cnt -= _32or64) {
cp = memcpy(cp, temp_result, _32or64);
cp += _32or64;
}
memcpy(cp, temp_result, cnt);
/* Repeatedly run the collected hash value through SHA to burn
CPU cycles. */
for (cnt = 0; cnt < rounds; ++cnt) {
sha_begin(&ctx);
/* Add key or last result. */
if ((cnt & 1) != 0)
sha_hash(p_bytes, key_len, &ctx);
else
sha_hash(alt_result, _32or64, &ctx);
/* Add salt for numbers not divisible by 3. */
if (cnt % 3 != 0)
sha_hash(s_bytes, salt_len, &ctx);
/* Add key for numbers not divisible by 7. */
if (cnt % 7 != 0)
sha_hash(p_bytes, key_len, &ctx);
/* Add key or last result. */
if ((cnt & 1) != 0)
sha_hash(alt_result, _32or64, &ctx);
else
sha_hash(p_bytes, key_len, &ctx);
sha_end(alt_result, &ctx);
}
/* Append encrypted password to result buffer */
//TODO: replace with something like
// bb_uuencode(cp, src, length, bb_uuenc_tbl_XXXbase64);
#define b64_from_24bit(B2, B1, B0, N) \
do { \
unsigned w = ((B2) << 16) | ((B1) << 8) | (B0); \
resptr = to64(resptr, w, N); \
} while (0)
if (is_sha512 == '5') {
unsigned i = 0;
while (1) {
unsigned j = i + 10;
unsigned k = i + 20;
if (j >= 30) j -= 30;
if (k >= 30) k -= 30;
b64_from_24bit(alt_result[i], alt_result[j], alt_result[k], 4);
if (k == 29)
break;
i = k + 1;
}
b64_from_24bit(0, alt_result[31], alt_result[30], 3);
/* was:
b64_from_24bit(alt_result[0], alt_result[10], alt_result[20], 4);
b64_from_24bit(alt_result[21], alt_result[1], alt_result[11], 4);
b64_from_24bit(alt_result[12], alt_result[22], alt_result[2], 4);
b64_from_24bit(alt_result[3], alt_result[13], alt_result[23], 4);
b64_from_24bit(alt_result[24], alt_result[4], alt_result[14], 4);
b64_from_24bit(alt_result[15], alt_result[25], alt_result[5], 4);
b64_from_24bit(alt_result[6], alt_result[16], alt_result[26], 4);
b64_from_24bit(alt_result[27], alt_result[7], alt_result[17], 4);
b64_from_24bit(alt_result[18], alt_result[28], alt_result[8], 4);
b64_from_24bit(alt_result[9], alt_result[19], alt_result[29], 4);
b64_from_24bit(0, alt_result[31], alt_result[30], 3);
*/
} else {
unsigned i = 0;
while (1) {
unsigned j = i + 21;
unsigned k = i + 42;
if (j >= 63) j -= 63;
if (k >= 63) k -= 63;
b64_from_24bit(alt_result[i], alt_result[j], alt_result[k], 4);
if (j == 20)
break;
i = j + 1;
}
b64_from_24bit(0, 0, alt_result[63], 2);
/* was:
b64_from_24bit(alt_result[0], alt_result[21], alt_result[42], 4);
b64_from_24bit(alt_result[22], alt_result[43], alt_result[1], 4);
b64_from_24bit(alt_result[44], alt_result[2], alt_result[23], 4);
b64_from_24bit(alt_result[3], alt_result[24], alt_result[45], 4);
b64_from_24bit(alt_result[25], alt_result[46], alt_result[4], 4);
b64_from_24bit(alt_result[47], alt_result[5], alt_result[26], 4);
b64_from_24bit(alt_result[6], alt_result[27], alt_result[48], 4);
b64_from_24bit(alt_result[28], alt_result[49], alt_result[7], 4);
b64_from_24bit(alt_result[50], alt_result[8], alt_result[29], 4);
b64_from_24bit(alt_result[9], alt_result[30], alt_result[51], 4);
b64_from_24bit(alt_result[31], alt_result[52], alt_result[10], 4);
b64_from_24bit(alt_result[53], alt_result[11], alt_result[32], 4);
b64_from_24bit(alt_result[12], alt_result[33], alt_result[54], 4);
b64_from_24bit(alt_result[34], alt_result[55], alt_result[13], 4);
b64_from_24bit(alt_result[56], alt_result[14], alt_result[35], 4);
b64_from_24bit(alt_result[15], alt_result[36], alt_result[57], 4);
b64_from_24bit(alt_result[37], alt_result[58], alt_result[16], 4);
b64_from_24bit(alt_result[59], alt_result[17], alt_result[38], 4);
b64_from_24bit(alt_result[18], alt_result[39], alt_result[60], 4);
b64_from_24bit(alt_result[40], alt_result[61], alt_result[19], 4);
b64_from_24bit(alt_result[62], alt_result[20], alt_result[41], 4);
b64_from_24bit(0, 0, alt_result[63], 2);
*/
}
/* *resptr = '\0'; - xzalloc did it */
#undef b64_from_24bit
/* Clear the buffer for the intermediate result so that people
attaching to processes or reading core dumps cannot get any
information. */
memset(&L, 0, sizeof(L)); /* [alt]_ctx and XXX_result buffers */
memset(key_data, 0, key_len); /* also p_bytes */
memset(salt_data, 0, salt_len); /* also s_bytes */
free(key_data);
free(salt_data);
#undef p_bytes
#undef s_bytes
return result;
#undef alt_result
#undef temp_result
#undef ctx
#undef alt_ctx
}
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