fips.c
No OneTemporary
Actions

Size

16 KB

Subscribers

None

fips.c
View Options

	/* fips.c - FIPS mode management
	* Copyright (C) 2008 Free Software Foundation, Inc.
	*
	* This file is part of Libgcrypt.
	*
	* Libgcrypt is free software; you can redistribute it and/or modify
	* it under the terms of the GNU Lesser General Public License as
	* published by the Free Software Foundation; either version 2.1 of
	* the License, or (at your option) any later version.
	*
	* Libgcrypt 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 Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this program; if not, see <http://www.gnu.org/licenses/>.
	*/

	#include <config.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <errno.h>
	#include <unistd.h>
	#ifdef ENABLE_HMAC_BINARY_CHECK
	# include <dlfcn.h>
	#endif

	#include "g10lib.h"
	#include "ath.h"
	#include "cipher-proto.h"
	#include "hmac256.h"

	/* The states of the finite state machine used in fips mode. */
	enum module_states
	{
	/* POWEROFF cannot be represented. */
	STATE_POWERON = 0,
	STATE_INIT,
	STATE_SELFTEST,
	STATE_OPERATIONAL,
	STATE_ERROR,
	STATE_FATALERROR,
	STATE_SHUTDOWN
	};


	/* Flag telling whether we are in fips mode. It uses inverse logic so
	that fips mode is the default unless changed by the intialization
	code. To check whether fips mode is enabled, use the function
	fips_mode()! */
	static int no_fips_mode_required;

	/* This is the lock we use to protect the FSM. */
	static ath_mutex_t fsm_lock = ATH_MUTEX_INITIALIZER;

	/* The current state of the FSM. The whole state machinery is only
	used while in fips mode. Change this only while holding fsm_lock. */
	static enum module_states current_state;




	static void fips_new_state (enum module_states new_state);




	/* Check whether the OS is in FIPS mode and record that in a module
	local variable. If FORCE is passed as true, fips mode will be
	enabled anyway. Note: This function is not thread-safe and should
	be called before any threads are created. This function may only
	be called once. */
	void
	_gcry_initialize_fips_mode (int force)
	{
	static int done;
	gpg_error_t err;

	/* Make sure we are not accidently called twice. */
	if (done)
	{
	if ( fips_mode () )
	{
	fips_new_state (STATE_FATALERROR);
	fips_noreturn ();
	}
	/* If not in fips mode an assert is sufficient. */
	gcry_assert (!done);
	}
	done = 1;

	/* If the calling applicatione explicitly requested fipsmode, do so. */
	if (force)
	{
	gcry_assert (!no_fips_mode_required);
	goto leave;
	}

	/* For testing the system it is useful to override the system
	provided detection of the FIPS mode and force FIPS mode using a
	file. The filename is hardwired so that there won't be any
	confusion on whether /etc/gcrypt/ or /usr/local/etc/gcrypt/ is
	actually used. The file itself may be empty. A comment may be
	included in the file, but comment lines need to be prefixed with
	a hash mark; only such comment lines and empty lines are
	allowed. */
	if ( !access ("/etc/gcrypt/fips140.force", F_OK) )
	{
	gcry_assert (!no_fips_mode_required);
	goto leave;
	}

	/* Checking based on /proc file properties. */
	{
	FILE *fp;
	int saved_errno;

	fp = fopen ("/proc/fips140", "r");
	if (fp)
	{
	char line[256];

	if (fgets (line, sizeof line, fp) && atoi (line) == 1)
	{
	/* System is in fips mode. */
	fclose (fp);
	gcry_assert (!no_fips_mode_required);
	goto leave;
	}
	fclose (fp);
	}
	else if ((saved_errno = errno) != ENOENT
	&& !access ("/proc/version", F_OK) )
	{
	/* Problem reading the fips file despite that we have the proc
	file system. We better stop right away. */
	log_info ("FATAL: error reading `%s' in libgcrypt: %s\n",
	"/proc/fips140", strerror (saved_errno));
	abort ();
	}
	}

	/* Fips not not requested, set flag. */
	no_fips_mode_required = 1;

	leave:
	if (!no_fips_mode_required)
	{
	/* Yes, we are in FIPS mode. */

	/* Intitialize the lock to protect the FSM. */
	err = ath_mutex_init (&fsm_lock);
	if (err)
	{
	/* If that fails we can't do anything but abort the
	process. We need to use log_info so that the FSM won't
	get involved. */
	log_info ("FATAL: failed to create the FSM lock in libgcrypt: %s\n",
	strerror (err));
	abort ();
	}

	/* Now get us into the INIT state. */
	fips_new_state (STATE_INIT);

	}
	return;
	}

	static void
	lock_fsm (void)
	{
	gpg_error_t err;

	err = ath_mutex_lock (&fsm_lock);
	if (err)
	{
	log_info ("FATAL: failed to acquire the FSM lock in libgrypt: %s\n",
	strerror (err));
	abort ();
	}
	}

	static void
	unlock_fsm (void)
	{
	gpg_error_t err;

	err = ath_mutex_unlock (&fsm_lock);
	if (err)
	{
	log_info ("FATAL: failed to release the FSM lock in libgrypt: %s\n",
	strerror (err));
	abort ();
	}
	}


	/* This function returns true if fips mode is enabled. This is
	independent of the fips required finite state machine and only used
	to enable run fips specific code. Please use the fips_mode macro
	instead of calling this fucntion directly. */
	int
	_gcry_fips_mode (void)
	{
	/* No locking is required becuase we have the requirement that this
	variable is only intialized once with no other threads
	exiisting. */
	return !no_fips_mode_required;
	}


	static const char *
	state2str (enum module_states state)
	{
	const char *s;

	switch (state)
	{
	case STATE_POWERON: s = "Power-On"; break;
	case STATE_INIT: s = "Init"; break;
	case STATE_SELFTEST: s = "Self-Test"; break;
	case STATE_OPERATIONAL: s = "Operational"; break;
	case STATE_ERROR: s = "Error"; break;
	case STATE_FATALERROR: s = "Fatal-Error"; break;
	case STATE_SHUTDOWN: s = "Shutdown"; break;
	default: s = "?"; break;
	}
	return s;
	}


	/* Return true if the library is in the operational state. */
	int
	_gcry_fips_is_operational (void)
	{
	int result;

	if (!fips_mode ())
	result = 1;
	else
	{
	lock_fsm ();
	if (current_state == STATE_INIT)
	{
	/* If we are still in the INIT state, we need to run the
	selftests so that the FSM can eventually get into
	operational state. Given that we would need a 2-phase
	initialization of libgcrypt, but that has traditionally
	not been enforced, we use this on demand self-test
	checking. Note that Proper applications would do the
	application specific libgcrypt initialization between a
	gcry_check_version() and gcry_control
	(GCRYCTL_INITIALIZATION_FINISHED) where the latter will
	run the selftests. The drawback of these on-demand
	self-tests are a small chance that self-tests are
	performed by severeal threads; that is no problem because
	our FSM make sure that we won't oversee any error. */
	unlock_fsm ();
	_gcry_fips_run_selftests ();
	lock_fsm ();
	}

	result = (current_state == STATE_OPERATIONAL);
	unlock_fsm ();
	}
	return result;
	}


	/* This is test on wether the library is in the operational state. In
	contrast to _gcry_fips_is_operational this function won't do a
	state transition on the fly. */
	int
	_gcry_fips_test_operational (void)
	{
	int result;

	if (!fips_mode ())
	result = 1;
	else
	{
	lock_fsm ();
	result = (current_state == STATE_OPERATIONAL);
	unlock_fsm ();
	}
	return result;
	}


	/* This is a test on whether the library is in the error or
	operational state. */
	int
	_gcry_fips_test_error_or_operational (void)
	{
	int result;

	if (!fips_mode ())
	result = 1;
	else
	{
	lock_fsm ();
	result = (current_state == STATE_OPERATIONAL
	\|\| current_state == STATE_ERROR);
	unlock_fsm ();
	}
	return result;
	}


	static void
	reporter (const char domain, int algo, const char what, const char *errtxt)
	{
	if (!errtxt && !_gcry_log_verbosity (2))
	return;

	log_info ("libgcrypt selftest: %s %s%s (%d): %s%s%s%s\n",
	!strcmp (domain, "hmac")? "digest":domain,
	!strcmp (domain, "hmac")? "HMAC-":"",
	!strcmp (domain, "cipher")? _gcry_cipher_algo_name (algo) :
	!strcmp (domain, "digest")? _gcry_md_algo_name (algo) :
	!strcmp (domain, "hmac")? _gcry_md_algo_name (algo) :
	!strcmp (domain, "pubkey")? _gcry_pk_algo_name (algo) : "",
	algo, errtxt? errtxt:"Okay",
	what?" (":"", what? what:"", what?")":"");
	}

	/* Run self-tests for all required cipher algorithms. Return 0 on
	success. */
	static int
	run_cipher_selftests (void)
	{
	static int algos[] =
	{
	GCRY_CIPHER_3DES,
	GCRY_CIPHER_AES128,
	GCRY_CIPHER_AES192,
	GCRY_CIPHER_AES256,
	0
	};
	int idx;
	gpg_error_t err;
	int anyerr = 0;

	for (idx=0; algos[idx]; idx++)
	{
	err = _gcry_cipher_selftest (algos[idx], reporter);
	reporter ("cipher", algos[idx], NULL,
	err? gpg_strerror (err):NULL);
	if (err)
	anyerr = 1;
	}
	return anyerr;
	}


	/* Run self-tests for all required hash algorithms. Return 0 on
	success. */
	static int
	run_digest_selftests (void)
	{
	static int algos[] =
	{
	GCRY_MD_SHA1,
	GCRY_MD_SHA224,
	GCRY_MD_SHA256,
	GCRY_MD_SHA384,
	GCRY_MD_SHA512,
	0
	};
	int idx;
	gpg_error_t err;
	int anyerr = 0;

	for (idx=0; algos[idx]; idx++)
	{
	err = _gcry_md_selftest (algos[idx], reporter);
	reporter ("digest", algos[idx], NULL,
	err? gpg_strerror (err):NULL);
	if (err)
	anyerr = 1;
	}
	return anyerr;
	}


	/* Run self-tests for all HMAC algorithms. Return 0 on success. */
	static int
	run_hmac_selftests (void)
	{
	static int algos[] =
	{
	GCRY_MD_SHA1,
	GCRY_MD_SHA224,
	GCRY_MD_SHA256,
	GCRY_MD_SHA384,
	GCRY_MD_SHA512,
	0
	};
	int idx;
	gpg_error_t err;
	int anyerr = 0;

	for (idx=0; algos[idx]; idx++)
	{
	err = _gcry_hmac_selftest (algos[idx], reporter);
	reporter ("hmac", algos[idx], NULL,
	err? gpg_strerror (err):NULL);
	if (err)
	anyerr = 1;
	}
	return anyerr;
	}


	/* Run self-tests for all required public key algorithms. Return 0 on
	success. */
	static int
	run_pubkey_selftests (void)
	{
	static int algos[] =
	{
	GCRY_PK_RSA,
	GCRY_PK_DSA,
	/* GCRY_PK_ECDSA is not enabled in fips mode. */
	0
	};
	int idx;
	gpg_error_t err;
	int anyerr = 0;

	for (idx=0; algos[idx]; idx++)
	{
	err = _gcry_pk_selftest (algos[idx], reporter);
	reporter ("pubkey", algos[idx], NULL,
	err? gpg_strerror (err):NULL);
	if (err)
	anyerr = 1;
	}
	return anyerr;
	}


	/* Run self-tests for the random number generator. Returns 0 on
	success. */
	static int
	run_random_selftests (void)
	{
	gpg_error_t err;

	err = _gcry_random_selftest (reporter);
	reporter ("random", 0, NULL, err? gpg_strerror (err):NULL);

	return !!err;
	}

	/* Run an integrity check on the binary. Returns 0 on success. */
	static int
	check_binary_integrity (void)
	{
	#ifdef ENABLE_HMAC_BINARY_CHECK
	gpg_error_t err;
	Dl_info info;
	unsigned char digest[32];
	int dlen;
	char *fname = NULL;
	const char key[] = "What am I, a doctor or a moonshuttle conductor?";

	if (!dladdr ("gcry_check_version", &info))
	err = gpg_error_from_syserror ();
	else
	{
	dlen = _gcry_hmac256_file (digest, sizeof digest, info.dli_fname,
	key, strlen (key));
	if (dlen < 0)
	err = gpg_error_from_syserror ();
	else if (dlen != 32)
	err = gpg_error (GPG_ERR_INTERNAL);
	else
	{
	FILE *fp;

	fname = gcry_malloc (strlen (info.dli_fname) + 5 + 1 );
	if (!fname)
	err = gpg_error_from_syserror ();
	else
	{
	strcpy (stpcpy (fname, info.dli_fname), ".hmac");
	fp = fopen (fname, "rb");
	if (!fp)
	err = gpg_error_from_syserror ();
	else
	{
	char buffer[33];
	int n;

	/* We expect a file of exactly 32 bytes. Consider
	the self-test failed if this is not the case or
	if it does not match the just computed HMAC. */
	if ((n=fread (buffer, 1, 33, fp)) != 32
	\|\| memcmp (digest, buffer, 32) )
	err = gpg_error (GPG_ERR_SELFTEST_FAILED);
	else
	err = 0;

	fclose (fp);
	}
	}
	}
	}
	reporter ("binary", 0, fname, err? gpg_strerror (err):NULL);
	gcry_free (fname);
	return !!err;
	#else
	return 0;
	#endif
	}


	/* Run the self-tests. */
	void
	_gcry_fips_run_selftests (void)
	{
	enum module_states result = STATE_ERROR;

	fips_new_state (STATE_SELFTEST);

	if (run_cipher_selftests ())
	goto leave;

	if (run_digest_selftests ())
	goto leave;

	if (run_hmac_selftests ())
	goto leave;

	if (run_pubkey_selftests ())
	goto leave;

	if (run_random_selftests ())
	goto leave;

	/* Now check the integrity of the binary. We do this this after
	having checked the HMAC code. */
	if (check_binary_integrity ())
	goto leave;

	/* All selftests passed. */
	result = STATE_OPERATIONAL;

	leave:
	fips_new_state (result);
	}


	/* This function is used to tell the FSM about errors in the library.
	The FSM will be put into an error state. This function should not
	be called directly but by one of the macros

	fips_signal_error (description)
	fips_signal_fatal_error (description)

	where DESCRIPTION is a string describing the error. */
	void
	_gcry_fips_signal_error (const char srcfile, int srcline, const char srcfunc,
	int is_fatal, const char *description)
	{
	if (!fips_mode ())
	return; /* Not required. */

	/* Set new state before printing an error. */
	fips_new_state (is_fatal? STATE_FATALERROR : STATE_ERROR);

	/* Print error. */
	log_info ("%serror in libgcrypt, file %s, line %d%s%s: %s\n",
	is_fatal? "fatal ":"",
	srcfile, srcline,
	srcfunc? ", function ":"", srcfunc? srcfunc:"",
	description? description : "no description available");
	}


	/* Perform a state transition to NEW_STATE. If this is an invalid
	transition, the module will go into a fatal error state. */
	static void
	fips_new_state (enum module_states new_state)
	{
	int ok = 0;
	enum module_states last_state;

	lock_fsm ();

	last_state = current_state;
	switch (current_state)
	{
	case STATE_POWERON:
	if (new_state == STATE_INIT
	\|\| new_state == STATE_ERROR
	\|\| new_state == STATE_FATALERROR)
	ok = 1;
	break;

	case STATE_INIT:
	if (new_state == STATE_SELFTEST )
	ok = 1;
	break;

	case STATE_SELFTEST:
	if (new_state == STATE_OPERATIONAL
	\|\| new_state == STATE_ERROR
	\|\| new_state == STATE_FATALERROR)
	ok = 1;
	break;

	case STATE_OPERATIONAL:
	if (new_state == STATE_SHUTDOWN
	\|\| new_state == STATE_SELFTEST
	\|\| new_state == STATE_ERROR
	\|\| new_state == STATE_FATALERROR)
	ok = 1;
	break;

	case STATE_ERROR:
	if (new_state == STATE_SHUTDOWN
	\|\| new_state == STATE_FATALERROR
	\|\| new_state == STATE_SELFTEST)
	ok = 1;
	break;

	case STATE_FATALERROR:
	if (new_state == STATE_SHUTDOWN )
	ok = 1;
	break;

	case STATE_SHUTDOWN:
	/* We won't see any transition from Shutdown because the only
	allowed new state is Power-Off and that one can't be
	represented. */
	break;

	}

	if (ok)
	{
	current_state = new_state;
	}

	unlock_fsm ();

	if (!ok \|\| _gcry_log_verbosity (2))
	log_info ("libgcrypt state transition %s => %s %s\n",
	state2str (last_state), state2str (new_state),
	ok? "granted":"denied");

	if (!ok)
	{
	/* Invalid state transition. Halting library. */
	fips_noreturn ();
	}
	}




	/* This function should be called to ensure that the execution shall
	not continue. */
	void
	_gcry_fips_noreturn (void)
	{
	fflush (NULL);
	abort ();
	/NOTREACHED/
	}

File Metadata

Mime Type: text/x-c
Expires: Mon, Dec 23, 5:22 PM (2 h, 40 m)
Storage Engine: local-disk
Storage Format: Raw Data
Storage Handle: 6a/88/6911512761a2ba96330ce10b9067

fips.cNo OneTemporaryActions

fips.cView Options

File Metadata

Event Timeline

fips.c
No OneTemporary
Actions

fips.c
View Options