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g10,scd: Support single salt for KDF data object.

Browse source 
* g10/card-util.c (gen_kdf_data): Support single salt.
(kdf_setup): Can have argument for single salt.
* scd/app-openpgp.c (pin2hash_if_kdf): Support single salt.

--

Gnuk has "admin-less" mode.  To support "admin-less" mode with KDF
feature, salt should be same for user and admin.  Thus, I introduce a
valid use of single salt.

Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
This commit is contained in:
NIIBE Yutaka 2018-03-30 12:48:04 +09:00
parent 820380335a
commit 0c097575a9
2 changed files with 54 additions and 23 deletions
Download patch file Download diff file Expand all files Collapse all files

29
scd/app-openpgp.c
View file

@ -2061,6 +2061,9 @@ get_prompt_info (app_t app, int chvno, unsigned long sigcount, int remaining)
return result;
}
#define KDF_DATA_LENGTH_MIN 90
#define KDF_DATA_LENGTH_MAX 110
/* Compute hash if KDF-DO is available. CHVNO must be 0 for reset
code, 1 or 2 for user pin and 3 for admin pin.
*/
@ -2068,21 +2071,33 @@ static gpg_error_t
pin2hash_if_kdf (app_t app, int chvno, char *pinvalue, int *r_pinlen)
{
gpg_error_t err = 0;
void *relptr;
void *relptr = NULL;
unsigned char *buffer;
size_t buflen;
if (app->app_local->extcap.kdf_do
&& (relptr = get_one_do (app, 0x00F9, &buffer, &buflen, NULL))
&& buflen == 110 && (buffer[2] == 0x03))
&& buflen >= KDF_DATA_LENGTH_MIN && (buffer[2] == 0x03))
{
char *salt;
const char *salt;
unsigned long s2k_count;
char dek[32];
int salt_index;
salt = &buffer[(chvno==3 ? 34 : (chvno==0 ? 24 : 14))];
s2k_count = (((unsigned int)buffer[8] << 24)
| (buffer[9] << 16) | (buffer[10] << 8) | buffer[11]);
if (buflen == KDF_DATA_LENGTH_MIN)
salt_index =14;
else if (buflen == KDF_DATA_LENGTH_MAX)
salt_index = (chvno==3 ? 34 : (chvno==0 ? 24 : 14));
else
{
err = gpg_error (GPG_ERR_INV_DATA);
goto leave;
}
salt = &buffer[salt_index];
err = gcry_kdf_derive (pinvalue, strlen (pinvalue),
GCRY_KDF_ITERSALTED_S2K,
DIGEST_ALGO_SHA256, salt, 8,
@ -2094,12 +2109,12 @@ pin2hash_if_kdf (app_t app, int chvno, char *pinvalue, int *r_pinlen)
memcpy (pinvalue, dek, *r_pinlen);
wipememory (dek, *r_pinlen);
}
xfree (relptr);
}
}
else
*r_pinlen = strlen (pinvalue);
leave:
xfree (relptr);
return err;
}