/* command.c - TPM2daemon command handler
* Copyright (C) 2001, 2002, 2003, 2004, 2005,
* 2007, 2008, 2009, 2011 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* GnuPG is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses/>.
* SPDX-License-Identifier: GPL-3.0-or-later
*/
#include <config.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <signal.h>
#ifdef USE_NPTH
# include <npth.h>
#endif
#include "tpm2daemon.h"
#include "tpm2.h"
#include <assuan.h>
#include <ksba.h>
#include "../common/asshelp.h"
#include "../common/server-help.h"
/* Maximum length allowed as a PIN; used for INQUIRE NEEDPIN */
#define MAXLEN_PIN 100
/* Maximum allowed size of key data as used in inquiries. */
#define MAXLEN_KEYDATA 4096
/* Maximum allowed total data size for SETDATA. */
#define MAXLEN_SETDATA 4096
/* Maximum allowed size of certificate data as used in inquiries. */
#define MAXLEN_CERTDATA 16384
#define set_error(e,t) assuan_set_error (ctx, gpg_error (e), (t))
/* Data used to associate an Assuan context with local server data.
This object describes the local properties of one session. */
struct server_local_s
{
/* We keep a list of all active sessions with the anchor at
SESSION_LIST (see below). This field is used for linking. */
struct server_local_s *next_session;
/* This object is usually assigned to a CTRL object (which is
globally visible). While enumerating all sessions we sometimes
need to access data of the CTRL object; thus we keep a
backpointer here. */
ctrl_t ctrl_backlink;
/* The Assuan context used by this session/server. */
assuan_context_t assuan_ctx;
#ifdef HAVE_W32_SYSTEM
unsigned long event_signal; /* Or 0 if not used. */
#else
int event_signal; /* Or 0 if not used. */
#endif
/* True if the card has been removed and a reset is required to
continue operation. */
int card_removed;
/* If set to true we will be terminate ourself at the end of the
this session. */
int stopme;
};
/* To keep track of all running sessions, we link all active server
contexts and the anchor in this variable. */
static struct server_local_s *session_list;
static gpg_error_t
reset_notify (assuan_context_t ctx, char *line)
{
(void) ctx;
(void) line;
return 0;
}
static gpg_error_t
option_handler (assuan_context_t ctx, const char *key, const char *value)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
if (!strcmp (key, "event-signal"))
{
/* A value of 0 is allowed to reset the event signal. */
#ifdef HAVE_W32_SYSTEM
if (!*value)
return gpg_error (GPG_ERR_ASS_PARAMETER);
ctrl->server_local->event_signal = strtoul (value, NULL, 16);
#else
int i = *value? atoi (value) : -1;
if (i < 0)
return gpg_error (GPG_ERR_ASS_PARAMETER);
ctrl->server_local->event_signal = i;
#endif
}
return 0;
}
static gpg_error_t
pin_cb (ctrl_t ctrl, const char *info, char **retstr)
{
assuan_context_t ctx = ctrl->ctx;
char *command;
int rc;
unsigned char *value;
size_t valuelen;
*retstr = NULL;
log_debug ("asking for PIN '%s'\n", info);
rc = gpgrt_asprintf (&command, "NEEDPIN %s", info);
if (rc < 0)
return gpg_error (gpg_err_code_from_errno (errno));
/* Fixme: Write an inquire function which returns the result in
secure memory and check all further handling of the PIN. */
rc = assuan_inquire (ctx, command, &value, &valuelen, MAXLEN_PIN);
xfree (command);
if (rc)
return rc;
if (!valuelen)
{
/* We require that the returned value is an UTF-8 string */
xfree (value);
return gpg_error (GPG_ERR_INV_RESPONSE);
}
*retstr = (char*)value;
return 0;
}
static const char hlp_import[] =
"IMPORT\n"
"\n"
"This command is used to convert a public and secret key to tpm format.\n"
"keydata is communicated via an inquire KEYDATA command\n"
"The keydata is expected to be the usual canonical encoded\n"
"S-expression. The return will be a TPM format S-expression\n"
"\n"
"A PIN will be requested.";
static gpg_error_t
cmd_import (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
int rc;
unsigned char *keydata;
size_t keydatalen;
TSS_CONTEXT *tssc;
gcry_sexp_t s_key;
unsigned char *shadow_info = NULL;
size_t shadow_len;
line = skip_options (line);
if (*line)
return set_error (GPG_ERR_ASS_PARAMETER, "additional parameters given");
/* Now get the actual keydata. */
assuan_begin_confidential (ctx);
rc = assuan_inquire (ctx, "KEYDATA", &keydata, &keydatalen, MAXLEN_KEYDATA);
assuan_end_confidential (ctx);
if (rc)
return rc;
if ((rc = tpm2_start (&tssc)))
goto out;
gcry_sexp_new (&s_key, keydata, keydatalen, 0);
rc = tpm2_import_key (ctrl, tssc, pin_cb, &shadow_info, &shadow_len,
s_key, opt.parent);
gcry_sexp_release (s_key);
tpm2_end (tssc);
if (rc)
goto out;
rc = assuan_send_data (ctx, shadow_info, shadow_len);
out:
xfree (shadow_info);
xfree (keydata);
return rc;
}
static const char hlp_pksign[] =
"PKSIGN\n"
"\n"
"Get the TPM to produce a signature. KEYDATA will request the TPM\n"
"form S-expression (returned by IMPORT) and EXTRA will be the hash\n"
"to sign. The TPM currently deduces hash type from length.\n"
"\n"
"A PIN will be requested.";
static gpg_error_t
cmd_pksign (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
int rc;
unsigned char *shadow_info;
size_t len;
TSS_CONTEXT *tssc;
TPM_HANDLE key;
TPMI_ALG_PUBLIC type;
unsigned char *digest;
size_t digestlen;
unsigned char *sig;
size_t siglen;
line = skip_options (line);
if (*line)
return set_error (GPG_ERR_ASS_PARAMETER, "additional parameters given");
/* Now get the actual keydata. */
rc = assuan_inquire (ctx, "KEYDATA", &shadow_info, &len, MAXLEN_KEYDATA);
if (rc)
return rc;
rc = assuan_inquire (ctx, "EXTRA", &digest, &digestlen, MAXLEN_KEYDATA);
if (rc)
goto out_freeshadow;
rc = tpm2_start (&tssc);
if (rc)
goto out;
rc = tpm2_load_key (tssc, shadow_info, &key, &type);
if (rc)
goto end_out;
rc = tpm2_sign (ctrl, tssc, key, pin_cb, type, digest, digestlen,
&sig, &siglen);
tpm2_flush_handle (tssc, key);
end_out:
tpm2_end (tssc);
if (rc)
goto out;
rc = assuan_send_data (ctx, sig, siglen);
xfree (sig);
out:
xfree (digest);
out_freeshadow:
xfree (shadow_info);
return rc;
}
static const char hlp_pkdecrypt[] =
"PKDECRYPT\n"
"Get the TPM to recover a symmetric key. KEYDATA will request the TPM\n"
"form S-expression (returned by IMPORT) and EXTRA will be the input\n"
"to derive or decrypt. The return will be the symmetric key\n"
"\n"
"\n"
"A PIN will be requested.";
static gpg_error_t
cmd_pkdecrypt (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
int rc;
unsigned char *shadow_info;
size_t len;
TSS_CONTEXT *tssc;
TPM_HANDLE key;
TPMI_ALG_PUBLIC type;
unsigned char *crypto;
size_t cryptolen;
char *buf;
size_t buflen;
line = skip_options (line);
if (*line)
return set_error (GPG_ERR_ASS_PARAMETER, "additional parameters given");
/* Now get the actual keydata. */
rc = assuan_inquire (ctx, "KEYDATA", &shadow_info, &len, MAXLEN_KEYDATA);
if (rc)
return rc;
rc = assuan_inquire (ctx, "EXTRA", &crypto, &cryptolen, MAXLEN_KEYDATA);
if (rc)
goto out_freeshadow;
rc = tpm2_start (&tssc);
if (rc)
goto out;
rc = tpm2_load_key (tssc, shadow_info, &key, &type);
if (rc)
goto end_out;
if (type == TPM_ALG_RSA)
rc = tpm2_rsa_decrypt (ctrl, tssc, key, pin_cb, crypto,
cryptolen, &buf, &buflen);
else if (type == TPM_ALG_ECC)
rc = tpm2_ecc_decrypt (ctrl, tssc, key, pin_cb, crypto,
cryptolen, &buf, &buflen);
tpm2_flush_handle (tssc, key);
end_out:
tpm2_end (tssc);
if (rc)
goto out;
rc = assuan_send_data (ctx, buf, buflen);
xfree (buf);
out:
xfree (crypto);
out_freeshadow:
xfree (shadow_info);
return rc;
}
static const char hlp_killtpm2d[] =
"KILLTPM2D\n"
"\n"
"Commit suicide.";
static gpg_error_t
cmd_killtpm2d (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
(void)line;
ctrl->server_local->stopme = 1;
assuan_set_flag (ctx, ASSUAN_FORCE_CLOSE, 1);
return 0;
}
/* Tell the assuan library about our commands */
static int
register_commands (assuan_context_t ctx)
{
static struct {
const char *name;
assuan_handler_t handler;
const char * const help;
} table[] = {
{ "IMPORT", cmd_import, hlp_import },
{ "PKSIGN", cmd_pksign, hlp_pksign },
{ "PKDECRYPT", cmd_pkdecrypt, hlp_pkdecrypt },
{ "KILLTPM2D", cmd_killtpm2d, hlp_killtpm2d },
{ NULL }
};
int i, rc;
for (i=0; table[i].name; i++)
{
rc = assuan_register_command (ctx, table[i].name, table[i].handler,
table[i].help);
if (rc)
return rc;
}
assuan_set_hello_line (ctx, "GNU Privacy Guard's TPM2 server ready");
assuan_register_reset_notify (ctx, reset_notify);
assuan_register_option_handler (ctx, option_handler);
return 0;
}
/* Startup the server. If FD is given as -1 this is simple pipe
server, otherwise it is a regular server. Returns true if there
are no more active asessions. */
int
tpm2d_command_handler (ctrl_t ctrl, int fd)
{
int rc;
assuan_context_t ctx = NULL;
int stopme;
rc = assuan_new (&ctx);
if (rc)
{
log_error ("failed to allocate assuan context: %s\n",
gpg_strerror (rc));
tpm2d_exit (2);
}
if (fd == -1)
{
assuan_fd_t filedes[2];
filedes[0] = assuan_fdopen (0);
filedes[1] = assuan_fdopen (1);
rc = assuan_init_pipe_server (ctx, filedes);
}
else
{
rc = assuan_init_socket_server (ctx, INT2FD (fd),
ASSUAN_SOCKET_SERVER_ACCEPTED);
}
if (rc)
{
log_error ("failed to initialize the server: %s\n",
gpg_strerror (rc));
tpm2d_exit (2);
}
rc = register_commands (ctx);
if (rc)
{
log_error ("failed to register commands with Assuan: %s\n",
gpg_strerror (rc));
tpm2d_exit (2);
}
assuan_set_pointer (ctx, ctrl);
ctrl->ctx = ctx;
/* Allocate and initialize the server object. Put it into the list
of active sessions. */
ctrl->server_local = xcalloc (1, sizeof *ctrl->server_local);
ctrl->server_local->next_session = session_list;
session_list = ctrl->server_local;
ctrl->server_local->ctrl_backlink = ctrl;
ctrl->server_local->assuan_ctx = ctx;
/* Command processing loop. */
for (;;)
{
rc = assuan_accept (ctx);
if (rc == -1)
{
break;
}
else if (rc)
{
log_info ("Assuan accept problem: %s\n", gpg_strerror (rc));
break;
}
rc = assuan_process (ctx);
if (rc)
{
log_info ("Assuan processing failed: %s\n", gpg_strerror (rc));
continue;
}
}
/* Release the server object. */
if (session_list == ctrl->server_local)
session_list = ctrl->server_local->next_session;
else
{
struct server_local_s *sl;
for (sl=session_list; sl->next_session; sl = sl->next_session)
if (sl->next_session == ctrl->server_local)
break;
if (!sl->next_session)
BUG ();
sl->next_session = ctrl->server_local->next_session;
}
stopme = ctrl->server_local->stopme;
xfree (ctrl->server_local);
ctrl->server_local = NULL;
/* Release the Assuan context. */
assuan_release (ctx);
if (stopme)
tpm2d_exit (0);
/* If there are no more sessions return true. */
return !session_list;
}