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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

48
g10/card-util.c
View file

@ -1978,11 +1978,12 @@ factory_reset (void)
#define USER_PIN_DEFAULT "123456"
#define ADMIN_PIN_DEFAULT "12345678"
#define KDF_DATA_LENGTH 110
#define KDF_DATA_LENGTH_MIN 90
#define KDF_DATA_LENGTH_MAX 110
/* Generate KDF data. */
static gpg_error_t
gen_kdf_data (unsigned char *data)
gen_kdf_data (unsigned char *data, int single_salt)
{
const unsigned char h0[] = { 0x81, 0x01, 0x03,
0x82, 0x01, 0x08,
@ -2015,14 +2016,19 @@ gen_kdf_data (unsigned char *data)
salt_user = (p += sizeof h1);
gcry_randomize (p, 8, GCRY_STRONG_RANDOM);
p += 8;
memcpy (p, h2, sizeof h2);
p += sizeof h2;
gcry_randomize (p, 8, GCRY_STRONG_RANDOM);
p += 8;
memcpy (p, h3, sizeof h3);
salt_admin = (p += sizeof h3);
gcry_randomize (p, 8, GCRY_STRONG_RANDOM);
p += 8;
if (!single_salt)
{
memcpy (p, h2, sizeof h2);
p += sizeof h2;
gcry_randomize (p, 8, GCRY_STRONG_RANDOM);
p += 8;
memcpy (p, h3, sizeof h3);
salt_admin = (p += sizeof h3);
gcry_randomize (p, 8, GCRY_STRONG_RANDOM);
p += 8;
}
memcpy (p, h4, sizeof h4);
p += sizeof h4;
err = gcry_kdf_derive (USER_PIN_DEFAULT, strlen (USER_PIN_DEFAULT),
@ -2043,11 +2049,12 @@ gen_kdf_data (unsigned char *data)
/* Setup KDF data object which is used for PIN authentication. */
static void
kdf_setup (void)
kdf_setup (const char *args)
{
struct agent_card_info_s info;
gpg_error_t err;
unsigned char kdf_data[KDF_DATA_LENGTH];
unsigned char kdf_data[KDF_DATA_LENGTH_MAX];
int single = (*args != 0);
memset (&info, 0, sizeof info);
@ -2064,10 +2071,19 @@ kdf_setup (void)
goto leave;
}
if (!(err = gen_kdf_data (kdf_data))
&& !(err = agent_scd_setattr ("KDF", kdf_data, KDF_DATA_LENGTH, NULL)))
err = agent_scd_getattr ("KDF", &info);
err = gen_kdf_data (kdf_data, single);
if (err)
goto leave_error;
err = agent_scd_setattr ("KDF", kdf_data,
single ? KDF_DATA_LENGTH_MIN : KDF_DATA_LENGTH_MAX,
NULL);
if (err)
goto leave_error;
err = agent_scd_getattr ("KDF", &info);
leave_error:
if (err)
log_error (_("error for setup KDF: %s\n"), gpg_strerror (err));
@ -2403,7 +2419,7 @@ card_edit (ctrl_t ctrl, strlist_t commands)
break;
case cmdKDFSETUP:
kdf_setup ();
kdf_setup (arg_string);
break;
case cmdKEYATTR: