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scd: Make the PIN cache robust against wrongdoing of gpg-agent.

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* scd/app-openpgp.c (struct app_local_s): New field pincache.
(cache_pin): Set it.
(pin_from_cache): Consult it.
* scd/app-piv.c (struct app_local_s): New field pincache.
(cache_pin): Set it.
(pin_from_cache): Consult it.
--

Signed-off-by: Werner Koch <wk@gnupg.org>
This commit is contained in:
Werner Koch 2020-01-13 18:24:01 +01:00
parent 60502c3606
commit 2dd6b4b998
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
2 changed files with 81 additions and 4 deletions
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37
scd/app-openpgp.c
View File

@ -215,6 +215,18 @@ struct app_local_s {
unsigned int def_chv2:1; /* Use 123456 for CHV2. */
} flags;
/* Keep track on whether we cache a certain PIN so that we get it
* from the cache only if we know we cached it. This inhibits the
* use of the same cache entry for a card plugged in and out without
* gpg-agent having noticed that due to a bug. */
struct
{
unsigned int maybe_chv1:1;
unsigned int maybe_chv2:1;
unsigned int maybe_chv3:1;
} pincache;
/* Pinpad request specified on card. */
struct
{
@ -223,8 +235,8 @@ struct app_local_s {
int fixedlen_admin;
} pinpad;
struct
{
struct
{
key_type_t key_type;
union {
struct {
@ -240,6 +252,7 @@ struct app_local_s {
} ecc;
};
} keyattr[3];
};
#define ECC_FLAG_DJB_TWEAK (1 << 0)
@ -2227,6 +2240,13 @@ cache_pin (app_t app, ctrl_t ctrl, int chvno, const char *pin)
pincache_put (ctrl, app_get_slot (app), "openpgp", keyref,
pin, pin? strlen (pin):0);
switch (chvno)
{
case 1: app->app_local->pincache.maybe_chv1 = !!pin; break;
case 2: app->app_local->pincache.maybe_chv2 = !!pin; break;
case 3: app->app_local->pincache.maybe_chv3 = !!pin; break;
}
}
@ -2237,6 +2257,7 @@ static int
pin_from_cache (app_t app, ctrl_t ctrl, int chvno, char **r_pin)
{
const char *keyref = chvno_to_keyref (chvno);
int maybe_cached;
*r_pin = NULL;
@ -2248,6 +2269,17 @@ pin_from_cache (app_t app, ctrl_t ctrl, int chvno, char **r_pin)
default: return 0;
}
switch (chvno)
{
case 1: maybe_cached = app->app_local->pincache.maybe_chv1; break;
case 2: maybe_cached = app->app_local->pincache.maybe_chv2; break;
case 3: maybe_cached = app->app_local->pincache.maybe_chv3; break;
default: maybe_cached = 0; break;
}
if (!maybe_cached)
return 0;
if (pincache_get (ctrl, app_get_slot (app), "openpgp", keyref, r_pin))
return 0;
@ -2255,7 +2287,6 @@ pin_from_cache (app_t app, ctrl_t ctrl, int chvno, char **r_pin)
}
/* Verify a CHV either using the pinentry or if possible by
using a pinpad. PINCB and PINCB_ARG describe the usual callback
for the pinentry. CHVNO must be either 1 or 2. SIGCOUNT is only

48
scd/app-piv.c
View File

@ -213,6 +213,21 @@ struct app_local_s {
unsigned int yubikey:1; /* This is on a Yubikey. */
} flags;
/* Keep track on whether we cache a certain PIN so that we get it
* from the cache only if we know we cached it. This inhibits the
* use of the same cache entry for a card plugged in and out without
* gpg-agent having noticed that due to a bug. */
struct
{
unsigned int maybe_00:1;
unsigned int maybe_80:1;
unsigned int maybe_81:1;
unsigned int maybe_96:1;
unsigned int maybe_97:1;
unsigned int maybe_98:1;
unsigned int maybe_9B:1;
} pincache;
};
@ -1726,8 +1741,22 @@ cache_pin (app_t app, ctrl_t ctrl, int pinno,
default: return;
}
snprintf (pinref, sizeof pinref, "%02x", pinno);
pincache_put (ctrl, app_get_slot (app), "piv", pinref, pin, pinlen);
switch (pinno)
{
case 0x00: app->app_local->pincache.maybe_00 = !!pin; break;
case 0x80: app->app_local->pincache.maybe_80 = !!pin; break;
case 0x81: app->app_local->pincache.maybe_81 = !!pin; break;
case 0x96: app->app_local->pincache.maybe_96 = !!pin; break;
case 0x97: app->app_local->pincache.maybe_97 = !!pin; break;
case 0x98: app->app_local->pincache.maybe_98 = !!pin; break;
case 0x9B: app->app_local->pincache.maybe_9B = !!pin; break;
}
}
@ -1738,6 +1767,7 @@ static int
pin_from_cache (app_t app, ctrl_t ctrl, int pinno, char **r_pin)
{
char pinref[20];
int maybe_cached;
*r_pin = NULL;
@ -1749,6 +1779,21 @@ pin_from_cache (app_t app, ctrl_t ctrl, int pinno, char **r_pin)
default: return 0;
}
switch (pinno)
{
case 0x00: maybe_cached = app->app_local->pincache.maybe_00; break;
case 0x80: maybe_cached = app->app_local->pincache.maybe_80; break;
case 0x81: maybe_cached = app->app_local->pincache.maybe_81; break;
case 0x96: maybe_cached = app->app_local->pincache.maybe_96; break;
case 0x97: maybe_cached = app->app_local->pincache.maybe_97; break;
case 0x98: maybe_cached = app->app_local->pincache.maybe_98; break;
case 0x9B: maybe_cached = app->app_local->pincache.maybe_9B; break;
default: maybe_cached = 0;
}
if (!maybe_cached)
return 0;
snprintf (pinref, sizeof pinref, "%02x", pinno);
if (pincache_get (ctrl, app_get_slot (app), "piv", pinref, r_pin))
return 0;
@ -1875,7 +1920,8 @@ ask_and_prepare_chv (app_t app, ctrl_t ctrl,
default:
return gpg_error (GPG_ERR_INV_ID);
}
#warning debug...
no_cache =0;
/* Ask for the PIN. */
if (!no_cache && remaining >= 3
&& pin_from_cache (app, ctrl, keyref, &pinvalue))