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bcrypt.c
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bcrypt.c
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/*
* bcrypt wrapper library
*
* Written in 2011, 2013, 2014, 2015 by Ricardo Garcia <r@rg3.name>
*
* To the extent possible under law, the author(s) have dedicated all copyright
* and related and neighboring rights to this software to the public domain
* worldwide. This software is distributed without any warranty.
*
* You should have received a copy of the CC0 Public Domain Dedication along
* with this software. If not, see
* <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
/*
* 21FEB2018 - Gregory A Lundberg
*
* Deleted all unneeded code. This converts this source file from POSIX-only
* to fully portable, strictly compliant ISO Standard C.
*/
#include <stddef.h>
#include <string.h>
#include "bcrypt.h"
#include "crypt_blowfish/ow-crypt.h"
/*
* This is a best effort implementation. Nothing prevents a compiler from
* optimizing this function and making it vulnerable to timing attacks, but
* this method is commonly used in crypto libraries like NaCl.
*
* Return value is zero if both strings are equal and nonzero otherwise.
*/
static int timing_safe_strcmp(const char *str1, const char *str2)
{
const unsigned char *u1;
const unsigned char *u2;
int ret;
int i;
int len1 = strlen(str1);
int len2 = strlen(str2);
/* In our context both strings should always have the same length
* because they will be hashed passwords. */
if (len1 != len2)
return 1;
/* Force unsigned for bitwise operations. */
u1 = (const unsigned char *)str1;
u2 = (const unsigned char *)str2;
ret = 0;
for (i = 0; i < len1; ++i)
ret |= (u1[i] ^ u2[i]);
return ret;
}
int bcrypt_hashpw(const char *passwd, const char salt[BCRYPT_HASHSIZE], char hash[BCRYPT_HASHSIZE])
{
char *aux;
aux = crypt_rn(passwd, salt, hash, BCRYPT_HASHSIZE);
return (aux == NULL)?1:0;
}
int bcrypt_checkpw(const char *passwd, const char hash[BCRYPT_HASHSIZE])
{
int ret;
char outhash[BCRYPT_HASHSIZE];
ret = bcrypt_hashpw(passwd, hash, outhash);
if (ret != 0)
return -1;
return timing_safe_strcmp(hash, outhash);
}