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gpg: Allow decryption using non-OpenPGP cards. 

* g10/call-agent.c (struct getattr_one_parm_s): New.
(getattr_one_status_cb): New.
(agent_scd_getattr_one): New.
* g10/pubkey-enc.c (get_it): Allow the standard leading zero byte from
pkcs#1.
* g10/getkey.c (enum_secret_keys): Move to...
* g10/skclist.c (enum_secret_keys): here and handle non-OpenPGP cards.
--

Signed-off-by: Werner Koch <wk@gnupg.org>
(cherry picked from commit ec6a677923)

This commit also incorporates "g10: Move enum_secret_keys to
skclist.c."  Which was started with
commit 03a8de7def
on master about a year ago.

Signed-off-by: Werner Koch <wk@gnupg.org>
GnuPG-bug-id: 4681
This commit is contained in:
Werner Koch 2019-04-03 15:30:10 +02:00
parent 23784f8bf0
commit 9a317557c5
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
5 changed files with 400 additions and 174 deletions
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80
g10/call-agent.c
View File

@ -925,6 +925,86 @@ agent_keytocard (const char *hexgrip, int keyno, int force,
return rc;
}
/* Object used with the agent_scd_getattr_one. */
struct getattr_one_parm_s {
const char *keyword; /* Keyword to look for. */
char *data; /* Malloced and unescaped data. */
gpg_error_t err; /* Error code or 0 on success. */
};
/* Callback for agent_scd_getattr_one. */
static gpg_error_t
getattr_one_status_cb (void *opaque, const char *line)
{
struct getattr_one_parm_s *parm = opaque;
const char *s;
if (parm->data)
return 0; /* We want only the first occurrence. */
if ((s=has_leading_keyword (line, parm->keyword)))
{
parm->data = percent_plus_unescape (s, 0xff);
if (!parm->data)
parm->err = gpg_error_from_syserror ();
}
return 0;
}
/* Simplified version of agent_scd_getattr. This function returns
* only the first occurance of the attribute NAME and stores it at
* R_VALUE. A nul in the result is silennly replaced by 0xff. On
* error NULL is stored at R_VALUE. */
gpg_error_t
agent_scd_getattr_one (const char *name, char **r_value)
{
gpg_error_t err;
char line[ASSUAN_LINELENGTH];
struct default_inq_parm_s inqparm;
struct getattr_one_parm_s parm;
*r_value = NULL;
if (!*name)
return gpg_error (GPG_ERR_INV_VALUE);
memset (&inqparm, 0, sizeof inqparm);
inqparm.ctx = agent_ctx;
memset (&parm, 0, sizeof parm);
parm.keyword = name;
/* We assume that NAME does not need escaping. */
if (12 + strlen (name) > DIM(line)-1)
return gpg_error (GPG_ERR_TOO_LARGE);
stpcpy (stpcpy (line, "SCD GETATTR "), name);
err = start_agent (NULL, 1);
if (err)
return err;
err = assuan_transact (agent_ctx, line,
NULL, NULL,
default_inq_cb, &inqparm,
getattr_one_status_cb, &parm);
if (!err && parm.err)
err = parm.err;
else if (!err && !parm.data)
err = gpg_error (GPG_ERR_NO_DATA);
if (!err)
*r_value = parm.data;
else
xfree (parm.data);
return err;
}
/* Call the agent to retrieve a data object. This function returns
* the data in the same structure as used by the learn command. It is

3
g10/call-agent.h
View File

@ -94,6 +94,9 @@ int agent_scd_serialno (char **r_serialno, const char *demand);
/* Send an APDU to the card. */
gpg_error_t agent_scd_apdu (const char *hexapdu, unsigned int *r_sw);
/* Get attribute NAME from the card and store at R_VALUE. */
gpg_error_t agent_scd_getattr_one (const char *name, char **r_value);
/* Update INFO with the attribute NAME. */
int agent_scd_getattr (const char *name, struct agent_card_info_s *info);

174
g10/getkey.c
View File

@ -3774,180 +3774,6 @@ lookup (ctrl_t ctrl, getkey_ctx_t ctx, int want_secret,
}
/* Enumerate some secret keys (specifically, those specified with
* --default-key and --try-secret-key). Use the following procedure:
*
* 1) Initialize a void pointer to NULL
* 2) Pass a reference to this pointer to this function (content)
* and provide space for the secret key (sk)
* 3) Call this function as long as it does not return an error (or
* until you are done). The error code GPG_ERR_EOF indicates the
* end of the listing.
* 4) Call this function a last time with SK set to NULL,
* so that can free it's context.
*
* In pseudo-code:
*
* void *ctx = NULL;
* PKT_public_key *sk = xmalloc_clear (sizeof (*sk));
*
* while ((err = enum_secret_keys (&ctx, sk)))
* { // Process SK.
* if (done)
* break;
* free_public_key (sk);
* sk = xmalloc_clear (sizeof (*sk));
* }
*
* // Release any resources used by CTX.
* enum_secret_keys (&ctx, NULL);
* free_public_key (sk);
*
* if (gpg_err_code (err) != GPG_ERR_EOF)
* ; // An error occurred.
*/
gpg_error_t
enum_secret_keys (ctrl_t ctrl, void **context, PKT_public_key *sk)
{
gpg_error_t err = 0;
const char *name;
kbnode_t keyblock;
struct
{
int eof;
int state;
strlist_t sl;
kbnode_t keyblock;
kbnode_t node;
getkey_ctx_t ctx;
} *c = *context;
if (!c)
{
/* Make a new context. */
c = xtrycalloc (1, sizeof *c);
if (!c)
return gpg_error_from_syserror ();
*context = c;
}
if (!sk)
{
/* Free the context. */
release_kbnode (c->keyblock);
getkey_end (ctrl, c->ctx);
xfree (c);
*context = NULL;
return 0;
}
if (c->eof)
return gpg_error (GPG_ERR_EOF);
for (;;)
{
/* Loop until we have a keyblock. */
while (!c->keyblock)
{
/* Loop over the list of secret keys. */
do
{
name = NULL;
keyblock = NULL;
switch (c->state)
{
case 0: /* First try to use the --default-key. */
name = parse_def_secret_key (ctrl);
c->state = 1;
break;
case 1: /* Init list of keys to try. */
c->sl = opt.secret_keys_to_try;
c->state++;
break;
case 2: /* Get next item from list. */
if (c->sl)
{
name = c->sl->d;
c->sl = c->sl->next;
}
else
c->state++;
break;
case 3: /* Init search context to enum all secret keys. */
err = getkey_bynames (ctrl, &c->ctx, NULL, NULL, 1,
&keyblock);
if (err)
{
release_kbnode (keyblock);
keyblock = NULL;
getkey_end (ctrl, c->ctx);
c->ctx = NULL;
}
c->state++;
break;
case 4: /* Get next item from the context. */
if (c->ctx)
{
err = getkey_next (ctrl, c->ctx, NULL, &keyblock);
if (err)
{
release_kbnode (keyblock);
keyblock = NULL;
getkey_end (ctrl, c->ctx);
c->ctx = NULL;
}
}
else
c->state++;
break;
default: /* No more names to check - stop. */
c->eof = 1;
return gpg_error (GPG_ERR_EOF);
}
}
while ((!name || !*name) && !keyblock);
if (keyblock)
c->node = c->keyblock = keyblock;
else
{
err = getkey_byname (ctrl, NULL, NULL, name, 1, &c->keyblock);
if (err)
{
/* getkey_byname might return a keyblock even in the
error case - I have not checked. Thus better release
it. */
release_kbnode (c->keyblock);
c->keyblock = NULL;
}
else
c->node = c->keyblock;
}
}
/* Get the next key from the current keyblock. */
for (; c->node; c->node = c->node->next)
{
if (c->node->pkt->pkttype == PKT_PUBLIC_KEY
|| c->node->pkt->pkttype == PKT_PUBLIC_SUBKEY)
{
copy_public_key (sk, c->node->pkt->pkt.public_key);
c->node = c->node->next;
return 0; /* Found. */
}
}
/* Dispose the keyblock and continue. */
release_kbnode (c->keyblock);
c->keyblock = NULL;
}
}
gpg_error_t
get_seckey_default_or_card (ctrl_t ctrl, PKT_public_key *pk,
const byte *fpr_card, size_t fpr_len)

10
g10/pubkey-enc.c
View File

@ -305,6 +305,16 @@ get_it (ctrl_t ctrl,
err = gpg_error (GPG_ERR_WRONG_SECKEY);
goto leave;
}
/* FIXME: Actually the leading zero is required but due to
* the way we encode the output in libgcrypt as an MPI we
* are not able to encode that leading zero. However, when
* using a Smartcard we are doing it the right way and
* therefore we have to skip the zero. This should be fixed
* in gpg-agent of course. */
if (!frame[n])
n++;
if (frame[n] == 1 && frame[nframe - 1] == 2)
{
log_info (_("old encoding of the DEK is not supported\n"));

307
g10/skclist.c
View File

@ -286,3 +286,310 @@ build_sk_list (ctrl_t ctrl,
*ret_sk_list = sk_list;
return err;
}
/* Enumerate some secret keys (specifically, those specified with
* --default-key and --try-secret-key). Use the following procedure:
*
* 1) Initialize a void pointer to NULL
* 2) Pass a reference to this pointer to this function (content)
* and provide space for the secret key (sk)
* 3) Call this function as long as it does not return an error (or
* until you are done). The error code GPG_ERR_EOF indicates the
* end of the listing.
* 4) Call this function a last time with SK set to NULL,
* so that can free it's context.
*
* In pseudo-code:
*
* void *ctx = NULL;
* PKT_public_key *sk = xmalloc_clear (sizeof (*sk));
*
* while ((err = enum_secret_keys (&ctx, sk)))
* { // Process SK.
* if (done)
* break;
* sk = xmalloc_clear (sizeof (*sk));
* }
*
* // Release any resources used by CTX.
* enum_secret_keys (&ctx, NULL);
*
* if (gpg_err_code (err) != GPG_ERR_EOF)
* ; // An error occurred.
*/
gpg_error_t
enum_secret_keys (ctrl_t ctrl, void **context, PKT_public_key *sk)
{
gpg_error_t err = 0;
const char *name;
kbnode_t keyblock;
struct
{
int eof;
int state;
strlist_t sl;
strlist_t card_list;
char *serialno;
char fpr2[2 * MAX_FINGERPRINT_LEN + 3 ];
struct agent_card_info_s info;
kbnode_t keyblock;
kbnode_t node;
getkey_ctx_t ctx;
SK_LIST results;
} *c = *context;
#if MAX_FINGERPRINT_LEN < KEYGRIP_LEN
# error buffer too short for this configuration
#endif
if (!c)
{
/* Make a new context. */
c = xtrycalloc (1, sizeof *c);
if (!c)
{
err = gpg_error_from_syserror ();
free_public_key (sk);
return err;
}
*context = c;
}
if (!sk)
{
/* Free the context. */
xfree (c->serialno);
free_strlist (c->card_list);
release_sk_list (c->results);
release_kbnode (c->keyblock);
getkey_end (ctrl, c->ctx);
xfree (c);
*context = NULL;
return 0;
}
if (c->eof)
{
free_public_key (sk);
return gpg_error (GPG_ERR_EOF);
}
for (;;)
{
/* Loop until we have a keyblock. */
while (!c->keyblock)
{
/* Loop over the list of secret keys. */
do
{
char *serialno;
name = NULL;
keyblock = NULL;
switch (c->state)
{
case 0: /* First try to use the --default-key. */
name = parse_def_secret_key (ctrl);
c->state = 1;
break;
case 1: /* Init list of keys to try. */
c->sl = opt.secret_keys_to_try;
c->state++;
break;
case 2: /* Get next item from list. */
if (c->sl)
{
name = c->sl->d;
c->sl = c->sl->next;
}
else
c->state++;
break;
case 3: /* Init list of card keys to try. */
err = agent_scd_cardlist (&c->card_list);
if (!err)
agent_scd_serialno (&c->serialno, NULL);
c->sl = c->card_list;
c->state++;
break;
case 4: /* Get next item from card list. */
if (c->sl)
{
err = agent_scd_serialno (&serialno, c->sl->d);
if (err)
{
if (opt.verbose)
log_info (_("error getting serial number of card: %s\n"),
gpg_strerror (err));
c->sl = c->sl->next;
continue;
}
xfree (serialno);
err = agent_scd_getattr ("KEY-FPR", &c->info);
if (!err)
{
if (c->info.fpr2valid)
{
c->fpr2[0] = '0';
c->fpr2[1] = 'x';
bin2hex (c->info.fpr2, sizeof c->info.fpr2,
c->fpr2 + 2);
name = c->fpr2;
}
}
else if (gpg_err_code (err) == GPG_ERR_INV_NAME)
{
/* KEY-FPR not supported by the card - get
* the key using the keygrip. */
char *keyref;
strlist_t kplist, sl;
const char *s;
int i;
err = agent_scd_getattr_one ("$ENCRKEYID", &keyref);
if (!err)
{
err = agent_scd_keypairinfo (ctrl, &kplist);
if (!err)
{
for (sl = kplist; sl; sl = sl->next)
if ((s = strchr (sl->d, ' '))
&& !strcmp (s+1, keyref))
break;
if (sl)
{
c->fpr2[0] = '&';
for (i=1, s=sl->d;
(*s && *s != ' '
&& i < sizeof c->fpr2 - 3);
s++, i++)
c->fpr2[i] = *s;
c->fpr2[i] = 0;
name = c->fpr2;
}
else /* Restore error. */
err = gpg_error (GPG_ERR_INV_NAME);
free_strlist (kplist);
}
}
xfree (keyref);
}
if (err)
log_error ("error retrieving key from card: %s\n",
gpg_strerror (err));
c->sl = c->sl->next;
}
else
{
serialno = c->serialno;
if (serialno)
{
/* Select the original card again. */
agent_scd_serialno (&c->serialno, serialno);
xfree (serialno);
}
c->state++;
}
break;
case 5: /* Init search context to enum all secret keys. */
err = getkey_bynames (ctrl, &c->ctx, NULL, NULL, 1,
&keyblock);
if (err)
{
release_kbnode (keyblock);
keyblock = NULL;
getkey_end (ctrl, c->ctx);
c->ctx = NULL;
}
c->state++;
break;
case 6: /* Get next item from the context. */
if (c->ctx)
{
err = getkey_next (ctrl, c->ctx, NULL, &keyblock);
if (err)
{
release_kbnode (keyblock);
keyblock = NULL;
getkey_end (ctrl, c->ctx);
c->ctx = NULL;
}
}
else
c->state++;
break;
default: /* No more names to check - stop. */
c->eof = 1;
free_public_key (sk);
return gpg_error (GPG_ERR_EOF);
}
}
while ((!name || !*name) && !keyblock);
if (keyblock)
c->node = c->keyblock = keyblock;
else
{
err = getkey_byname (ctrl, NULL, NULL, name, 1, &c->keyblock);
if (err)
{
/* getkey_byname might return a keyblock even in the
error case - I have not checked. Thus better release
it. */
release_kbnode (c->keyblock);
c->keyblock = NULL;
}
else
c->node = c->keyblock;
}
}
/* Get the next key from the current keyblock. */
for (; c->node; c->node = c->node->next)
{
if (c->node->pkt->pkttype == PKT_PUBLIC_KEY
|| c->node->pkt->pkttype == PKT_PUBLIC_SUBKEY)
{
SK_LIST r;
/* Skip this candidate if it's already enumerated. */
for (r = c->results; r; r = r->next)
if (!cmp_public_keys (r->pk, c->node->pkt->pkt.public_key))
break;
if (r)
continue;
copy_public_key (sk, c->node->pkt->pkt.public_key);
c->node = c->node->next;
r = xtrycalloc (1, sizeof (*r));
if (!r)
{
err = gpg_error_from_syserror ();
free_public_key (sk);
return err;
}
r->pk = sk;
r->next = c->results;
c->results = r;
return 0; /* Found. */
}
}
/* Dispose the keyblock and continue. */
release_kbnode (c->keyblock);
c->keyblock = NULL;
}
}