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Make use of gcry_kdf_derive.

Factoring common code out is always a Good Thing.  Also added a
configure test to print an error if gcry_kdf_derive is missing in
Libgcrypt.
This commit is contained in:
Werner Koch 2011-03-10 18:39:34 +01:00
parent 35c731d889
commit b9bcc77d6c
5 changed files with 59 additions and 140 deletions

View file

@ -1023,70 +1023,13 @@ hash_passphrase (const char *passphrase, int hashalgo,
unsigned long s2kcount,
unsigned char *key, size_t keylen)
{
int rc;
gcry_md_hd_t md;
int pass, i;
int used = 0;
int pwlen = strlen (passphrase);
if ( (s2kmode != 0 && s2kmode != 1 && s2kmode != 3)
|| !hashalgo || !keylen || !key || !passphrase)
return gpg_error (GPG_ERR_INV_VALUE);
if ((s2kmode == 1 ||s2kmode == 3) && !s2ksalt)
return gpg_error (GPG_ERR_INV_VALUE);
rc = gcry_md_open (&md, hashalgo, GCRY_MD_FLAG_SECURE);
if (rc)
return rc;
for (pass=0; used < keylen; pass++)
{
if (pass)
{
gcry_md_reset (md);
for (i=0; i < pass; i++) /* preset the hash context */
gcry_md_putc (md, 0);
}
if (s2kmode == 1 || s2kmode == 3)
{
int len2 = pwlen + 8;
unsigned long count = len2;
if (s2kmode == 3)
{
count = s2kcount;
if (count < len2)
count = len2;
}
while (count > len2)
{
gcry_md_write (md, s2ksalt, 8);
gcry_md_write (md, passphrase, pwlen);
count -= len2;
}
if (count < 8)
gcry_md_write (md, s2ksalt, count);
else
{
gcry_md_write (md, s2ksalt, 8);
count -= 8;
gcry_md_write (md, passphrase, count);
}
}
else
gcry_md_write (md, passphrase, pwlen);
gcry_md_final (md);
i = gcry_md_get_algo_dlen (hashalgo);
if (i > keylen - used)
i = keylen - used;
memcpy (key+used, gcry_md_read (md, hashalgo), i);
used += i;
}
gcry_md_close(md);
return 0;
return gcry_kdf_derive (passphrase, strlen (passphrase),
s2kmode == 3? GCRY_KDF_ITERSALTED_S2K :
s2kmode == 1? GCRY_KDF_SALTED_S2K :
s2kmode == 0? GCRY_KDF_SIMPLE_S2K : GCRY_KDF_NONE,
hashalgo, s2ksalt, 8, s2kcount,
keylen, key);
}