/* Return the secret key as an S-Exp in RESULT after locating it using
the GRIP. Stores NULL at RESULT if the operation shall be diverted
to a token; in this case an allocated S-expression with the
shadow_info part from the file is stored at SHADOW_INFO.
CACHE_MODE defines now the cache shall be used. DESC_TEXT may be
set to present a custom description for the pinentry. LOOKUP_TTL
is an optional function to convey a TTL to the cache manager; we do
not simply pass the TTL value because the value is only needed if an
unprotect action was needed and looking up the TTL may have some
overhead (e.g. scanning the sshcontrol file). */
gpg_error_t
agent_key_from_file (ctrl_t ctrl, const char *desc_text,
const unsigned char *grip, unsigned char **shadow_info,
cache_mode_t cache_mode, lookup_ttl_t lookup_ttl,
gcry_sexp_t *result)
{
int rc;
unsigned char *buf;
size_t len, buflen, erroff;
gcry_sexp_t s_skey;
int got_shadow_info = 0;
*result = NULL;
if (shadow_info)
*shadow_info = NULL;
rc = read_key_file (grip, &s_skey);
if (rc)
return rc;
/* For use with the protection functions we also need the key as an
canonical encoded S-expression in a buffer. Create this buffer
now. */
rc = make_canon_sexp (s_skey, &buf, &len);
if (rc)
return rc;
switch (agent_private_key_type (buf))
{
case PRIVATE_KEY_CLEAR:
break; /* no unprotection needed */
case PRIVATE_KEY_PROTECTED:
{
char *desc_text_final;
char *comment = NULL;
/* Note, that we will take the comment as a C string for
display purposes; i.e. all stuff beyond a Nul character is
ignored. */
{
gcry_sexp_t comment_sexp;
comment_sexp = gcry_sexp_find_token (s_skey, "comment", 0);
if (comment_sexp)
comment = gcry_sexp_nth_string (comment_sexp, 1);
gcry_sexp_release (comment_sexp);
}
desc_text_final = NULL;
if (desc_text)
rc = modify_description (desc_text, comment? comment:"", s_skey,
&desc_text_final);
gcry_free (comment);
if (!rc)
{
rc = unprotect (ctrl, desc_text_final, &buf, grip,
cache_mode, lookup_ttl);
if (rc)
log_error ("failed to unprotect the secret key: %s\n",
gpg_strerror (rc));
}
xfree (desc_text_final);
}
break;
case PRIVATE_KEY_SHADOWED:
if (shadow_info)
{
const unsigned char *s;
size_t n;
rc = agent_get_shadow_info (buf, &s);
if (!rc)
{
n = gcry_sexp_canon_len (s, 0, NULL,NULL);
assert (n);
*shadow_info = xtrymalloc (n);
if (!*shadow_info)
rc = out_of_core ();
else
{
memcpy (*shadow_info, s, n);
rc = 0;
got_shadow_info = 1;
}
}
if (rc)
log_error ("get_shadow_info failed: %s\n", gpg_strerror (rc));
}
else
rc = gpg_error (GPG_ERR_UNUSABLE_SECKEY);
break;
default:
log_error ("invalid private key format\n");
rc = gpg_error (GPG_ERR_BAD_SECKEY);
break;
}
gcry_sexp_release (s_skey);
s_skey = NULL;
if (rc || got_shadow_info)
{
xfree (buf);
return rc;
}
buflen = gcry_sexp_canon_len (buf, 0, NULL, NULL);
rc = gcry_sexp_sscan (&s_skey, &erroff, (char*)buf, buflen);
wipememory (buf, buflen);
xfree (buf);
if (rc)
{
log_error ("failed to build S-Exp (off=%u): %s\n",
(unsigned int)erroff, gpg_strerror (rc));
return rc;
}
*result = s_skey;
return 0;
}
/* Delete the key with GRIP from the disk after having asked for
confirmation using DESC_TEXT. If FORCE is set the function won't
require a confirmation via Pinentry or warns if the key is also
used by ssh.
Common error codes are:
GPG_ERR_NO_SECKEY
GPG_ERR_KEY_ON_CARD
GPG_ERR_NOT_CONFIRMED
*/
gpg_error_t
agent_delete_key (ctrl_t ctrl, const char *desc_text,
const unsigned char *grip, int force)
{
gpg_error_t err;
gcry_sexp_t s_skey = NULL;
unsigned char *buf = NULL;
size_t len;
char *desc_text_final = NULL;
char *comment = NULL;
ssh_control_file_t cf = NULL;
char hexgrip[40+4+1];
char *default_desc = NULL;
err = read_key_file (grip, &s_skey);
if (gpg_err_code (err) == GPG_ERR_ENOENT)
err = gpg_error (GPG_ERR_NO_SECKEY);
if (err)
goto leave;
err = make_canon_sexp (s_skey, &buf, &len);
if (err)
goto leave;
switch (agent_private_key_type (buf))
{
case PRIVATE_KEY_CLEAR:
case PRIVATE_KEY_OPENPGP_NONE:
case PRIVATE_KEY_PROTECTED:
bin2hex (grip, 20, hexgrip);
if (!force)
{
if (!desc_text)
{
default_desc = xtryasprintf
(L_("Do you really want to delete the key identified by keygrip%%0A"
" %s%%0A %%C%%0A?"), hexgrip);
desc_text = default_desc;
}
/* Note, that we will take the comment as a C string for
display purposes; i.e. all stuff beyond a Nul character is
ignored. */
{
gcry_sexp_t comment_sexp;
comment_sexp = gcry_sexp_find_token (s_skey, "comment", 0);
if (comment_sexp)
comment = gcry_sexp_nth_string (comment_sexp, 1);
gcry_sexp_release (comment_sexp);
}
if (desc_text)
err = modify_description (desc_text, comment? comment:"", s_skey,
&desc_text_final);
if (err)
goto leave;
err = agent_get_confirmation (ctrl, desc_text_final,
L_("Delete key"), L_("No"), 0);
if (err)
goto leave;
cf = ssh_open_control_file ();
if (cf)
{
if (!ssh_search_control_file (cf, hexgrip, NULL, NULL, NULL))
{
err = agent_get_confirmation
(ctrl,
L_("Warning: This key is also listed for use with SSH!\n"
"Deleting the key might remove your ability to "
"access remote machines."),
L_("Delete key"), L_("No"), 0);
if (err)
goto leave;
}
}
}
err = remove_key_file (grip);
break;
case PRIVATE_KEY_SHADOWED:
err = remove_key_file (grip);
break;
default:
log_error ("invalid private key format\n");
err = gpg_error (GPG_ERR_BAD_SECKEY);
break;
}
leave:
ssh_close_control_file (cf);
gcry_free (comment);
xfree (desc_text_final);
xfree (default_desc);
xfree (buf);
gcry_sexp_release (s_skey);
return err;
}
