mirror of
https://github.com/ilyakooo0/urbit.git
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66 lines
1.3 KiB
C
66 lines
1.3 KiB
C
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#include <stdlib.h>
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#include <stdio.h>
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#include <stdint.h>
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#include "libscrypt.h"
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/* ilog2 for powers of two */
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static uint32_t scrypt_ilog2(uint32_t n)
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{
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#ifndef S_SPLINT_S
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/* Check for a valid power of two */
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if (n < 2 || (n & (n - 1)))
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return -1;
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#endif
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uint32_t t = 1;
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while (((uint32_t)1 << t) < n)
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{
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if(t > SCRYPT_SAFE_N)
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return (uint32_t) -1; /* Check for insanity */
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t++;
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}
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return t;
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}
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#ifdef _MSC_VER
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#define SNPRINTF _snprintf
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#else
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#define SNPRINTF snprintf
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#endif
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int libscrypt_mcf(uint32_t N, uint32_t r, uint32_t p, const char *salt,
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const char *hash, char *mcf)
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{
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uint32_t t, params;
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int s;
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if(!mcf || !hash)
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return 0;
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/* Although larger values of r, p are valid in scrypt, this mcf format
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* limits to 8 bits. If your number is larger, current computers will
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* struggle
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*/
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if(r > (uint8_t)(-1) || p > (uint8_t)(-1))
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return 0;
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t = scrypt_ilog2(N);
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if (t < 1)
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return 0;
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params = (r << 8) + p;
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params += (uint32_t)t << 16;
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/* Using snprintf - not checking for overflows. We've already
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* determined that mcf should be defined as at least SCRYPT_MCF_LEN
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* in length
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*/
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s = SNPRINTF(mcf, SCRYPT_MCF_LEN, SCRYPT_MCF_ID "$%06x$%s$%s", (unsigned int)params, salt, hash);
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if (s >= SCRYPT_MCF_LEN)
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return 0;
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return 1;
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}
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