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Provide a safer salting method that does not turn invalid salts to '.'. 

Be more sensitive to bad salts and counts. From:
http://cvsweb.openwall.com/cgi/cvsweb.cgi/Owl/packages/glibc/crypt_freesec.c
From Solar Designer
This commit is contained in:
christos 2011-12-26 22:58:45 +00:00
parent f5b35cecad
commit aeeea54d2f
1 changed files with 46 additions and 20 deletions
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66
lib/libcrypt/crypt.c
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@ -1,4 +1,4 @@
/* $NetBSD: crypt.c,v 1.29 2011/12/26 16:03:42 christos Exp $ */
/* $NetBSD: crypt.c,v 1.30 2011/12/26 22:58:45 christos Exp $ */
/*
* Copyright (c) 1989, 1993
@ -37,7 +37,7 @@
#if 0
static char sccsid[] = "@(#)crypt.c 8.1.1.1 (Berkeley) 8/18/93";
#else
__RCSID("$NetBSD: crypt.c,v 1.29 2011/12/26 16:03:42 christos Exp $");
__RCSID("$NetBSD: crypt.c,v 1.30 2011/12/26 22:58:45 christos Exp $");
#endif
#endif /* not lint */
@ -445,8 +445,6 @@ static const unsigned char itoa64[] = /* 0..63 => ascii-64 */
/* ===== Tables that are initialized at run time ==================== */
static unsigned char a64toi[128]; /* ascii-64 => 0..63 */
/* Initial key schedule permutation */
static C_block PC1ROT[64/CHUNKBITS][1<<CHUNKBITS];
@ -469,6 +467,35 @@ static C_block CF6464[64/CHUNKBITS][1<<CHUNKBITS];
static C_block constdatablock; /* encryption constant */
static char cryptresult[1+4+4+11+1]; /* encrypted result */
/*
* We match the behavior of UFC-crypt on systems where "char" is signed by
* default (the majority), regardless of char's signedness on our system.
*/
static inline int
ascii_to_bin(char ch)
{
signed char sch = ch;
int retval;
if (sch >= 'a')
retval = sch - ('a' - 38);
else if (sch >= 'A')
retval = sch - ('A' - 12);
else
retval = sch - '.';
return retval & 0x3f;
}
#include <stdio.h>
/*
* When we choose to "support" invalid salts, nevertheless disallow those
* containing characters that would violate the passwd file format.
*/
static inline int
ascii_is_unsafe(char ch)
{
return !ch || ch == '\n' || ch == ':';
}
/*
* Return a pointer to static data consisting of the "setting"
@ -502,7 +529,7 @@ crypt(const char *key, const char *setting)
key++;
keyblock.b[i] = t;
}
if (des_setkey((char *)keyblock.b)) /* also initializes "a64toi" */
if (des_setkey((char *)keyblock.b))
return (NULL);
encp = &cryptresult[0];
@ -529,12 +556,14 @@ crypt(const char *key, const char *setting)
/* get iteration count */
num_iter = 0;
for (i = 4; --i >= 0; ) {
if ((t = (unsigned char)setting[i]) == '\0')
t = '.';
encp[i] = t;
num_iter = (num_iter << 6) |
a64toi[t & (sizeof(a64toi) - 1)];
int value = ascii_to_bin(setting[i]);
if (itoa64[value] != setting[i])
return NULL;
encp[i] = setting[i];
num_iter = (num_iter << 6) | value;
}
if (num_iter == 0)
return NULL;
setting += 4;
encp += 4;
salt_size = 4;
@ -542,14 +571,17 @@ crypt(const char *key, const char *setting)
default:
num_iter = 25;
salt_size = 2;
if (ascii_is_unsafe(setting[0]) || ascii_is_unsafe(setting[1]))
return NULL;
}
salt = 0;
for (i = salt_size; --i >= 0; ) {
if ((t = (unsigned char)setting[i]) == '\0')
t = '.';
encp[i] = t;
salt = (salt<<6) | a64toi[t & (sizeof(a64toi) - 1)];
int value = ascii_to_bin(setting[i]);
if (salt_size == 4 && itoa64[value] != setting[i])
return NULL;
encp[i] = setting[i];
salt = (salt << 6) | value;
}
encp += salt_size;
if (des_cipher((char *)(void *)&constdatablock,
@ -751,12 +783,6 @@ init_des(void)
int tableno;
static unsigned char perm[64], tmp32[32]; /* "static" for speed */
/*
* table that converts chars "./0-9A-Za-z"to integers 0-63.
*/
for (i = 0; i < 64; i++)
a64toi[itoa64[i]] = i;
/*
* PC1ROT - bit reverse, then PC1, then Rotate, then PC2.
*/