md.c
No OneTemporary
Actions

Size

29 KB

Subscribers

None

md.c
View Options

	/* md.c - message digest dispatcher
	* Copyright (C) 1998, 1999, 2002, 2003 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, write to the Free Software
	* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
	*/

	#include <config.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <errno.h>
	#include <assert.h>

	#include "g10lib.h"
	#include "cipher.h"
	#include "ath.h"

	#include "rmd.h"

	static struct digest_table_entry
	{
	gcry_md_spec_t *digest;
	unsigned int algorithm;
	} digest_table[] =
	{
	#if USE_CRC
	{ &_gcry_digest_spec_crc32, GCRY_MD_CRC32 },
	{ &_gcry_digest_spec_crc32_rfc1510, GCRY_MD_CRC32_RFC1510 },
	{ &_gcry_digest_spec_crc24_rfc2440, GCRY_MD_CRC24_RFC2440 },
	#endif
	#if USE_MD4
	{ &_gcry_digest_spec_md4, GCRY_MD_MD4 },
	#endif
	#if USE_MD5
	{ &_gcry_digest_spec_md5, GCRY_MD_MD5 },
	#endif
	#if USE_RMD160
	{ &_gcry_digest_spec_rmd160, GCRY_MD_RMD160 },
	#endif
	#if USE_SHA1
	{ &_gcry_digest_spec_sha1, GCRY_MD_SHA1 },
	#endif
	#if USE_SHA256
	{ &_gcry_digest_spec_sha256, GCRY_MD_SHA256 },
	#endif
	#if USE_SHA512
	{ &_gcry_digest_spec_sha512, GCRY_MD_SHA512 },
	{ &_gcry_digest_spec_sha384, GCRY_MD_SHA384 },
	#endif
	#if USE_TIGER
	{ &_gcry_digest_spec_tiger, GCRY_MD_TIGER },
	#endif
	{ NULL },
	};

	/* List of registered digests. */
	static gcry_module_t digests_registered;

	/* This is the lock protecting DIGESTS_REGISTERED. */
	static ath_mutex_t digests_registered_lock = ATH_MUTEX_INITIALIZER;

	/* Flag to check wether the default ciphers have already been
	registered. */
	static int default_digests_registered;

	typedef struct gcry_md_list
	{
	gcry_md_spec_t *digest;
	gcry_module_t module;
	struct gcry_md_list *next;
	size_t actual_struct_size; /* Allocated size of this structure. */
	PROPERLY_ALIGNED_TYPE context;
	} GcryDigestEntry;

	/* this structure is put right after the gcry_md_hd_t buffer, so that
	* only one memory block is needed. */
	struct gcry_md_context
	{
	int magic;
	size_t actual_handle_size; /* Allocated size of this handle. */
	int secure;
	FILE *debug;
	int finalized;
	GcryDigestEntry *list;
	byte *macpads;
	};


	#define CTX_MAGIC_NORMAL 0x11071961
	#define CTX_MAGIC_SECURE 0x16917011

	/* Convenient macro for registering the default digests. */
	#define REGISTER_DEFAULT_DIGESTS \
	do \
	{ \
	ath_mutex_lock (&digests_registered_lock); \
	if (! default_digests_registered) \
	{ \
	gcry_md_register_default (); \
	default_digests_registered = 1; \
	} \
	ath_mutex_unlock (&digests_registered_lock); \
	} \
	while (0)


	static const char * digest_algo_to_string( int algo );
	static gcry_err_code_t check_digest_algo (int algo);
	static gcry_err_code_t md_open (gcry_md_hd_t *h, int algo,
	int secure, int hmac);
	static gcry_err_code_t md_enable (gcry_md_hd_t hd, int algo);
	static gcry_err_code_t md_copy (gcry_md_hd_t a, gcry_md_hd_t *b);
	static void md_close (gcry_md_hd_t a);
	static void md_write (gcry_md_hd_t a, byte *inbuf, size_t inlen);
	static void md_final(gcry_md_hd_t a);
	static byte *md_read( gcry_md_hd_t a, int algo );
	static int md_get_algo( gcry_md_hd_t a );
	static int md_digest_length( int algo );
	static const byte md_asn_oid( int algo, size_t asnlen, size_t *mdlen );
	static void md_start_debug( gcry_md_hd_t a, char *suffix );
	static void md_stop_debug( gcry_md_hd_t a );




	/* Internal function. Register all the ciphers included in
	CIPHER_TABLE. Returns zero on success or an error code. */
	static void
	gcry_md_register_default (void)
	{
	gcry_err_code_t err = 0;
	int i;

	for (i = 0; (! err) && digest_table[i].digest; i++)
	err = _gcry_module_add (&digests_registered,
	digest_table[i].algorithm,
	(void *) digest_table[i].digest,
	NULL);

	if (err)
	BUG ();
	}

	/* Internal callback function. */
	static int
	gcry_md_lookup_func_name (void spec, void data)
	{
	gcry_md_spec_t digest = (gcry_md_spec_t ) spec;
	char name = (char ) data;

	return (! stricmp (digest->name, name));
	}

	/* Internal callback function. Used via _gcry_module_lookup. */
	static int
	gcry_md_lookup_func_oid (void spec, void data)
	{
	gcry_md_spec_t digest = (gcry_md_spec_t ) spec;
	char oid = (char ) data;
	gcry_md_oid_spec_t *oid_specs = digest->oids;
	int ret = 0, i;

	if (oid_specs)
	{
	for (i = 0; oid_specs[i].oidstring && (! ret); i++)
	if (! stricmp (oid, oid_specs[i].oidstring))
	ret = 1;
	}

	return ret;
	}

	/* Internal function. Lookup a digest entry by it's name. */
	static gcry_module_t
	gcry_md_lookup_name (const char *name)
	{
	gcry_module_t digest;

	digest = _gcry_module_lookup (digests_registered, (void *) name,
	gcry_md_lookup_func_name);

	return digest;
	}

	/* Internal function. Lookup a cipher entry by it's oid. */
	static gcry_module_t
	gcry_md_lookup_oid (const char *oid)
	{
	gcry_module_t digest;

	digest = _gcry_module_lookup (digests_registered, (void *) oid,
	gcry_md_lookup_func_oid);

	return digest;
	}

	/* Register a new digest module whose specification can be found in
	DIGEST. On success, a new algorithm ID is stored in ALGORITHM_ID
	and a pointer representhing this module is stored in MODULE. */
	gcry_error_t
	gcry_md_register (gcry_md_spec_t *digest,
	unsigned int *algorithm_id,
	gcry_module_t *module)
	{
	gcry_err_code_t err = 0;
	gcry_module_t mod;

	ath_mutex_lock (&digests_registered_lock);
	err = _gcry_module_add (&digests_registered, 0,
	(void *) digest, &mod);
	ath_mutex_unlock (&digests_registered_lock);

	if (! err)
	{
	*module = mod;
	*algorithm_id = mod->mod_id;
	}

	return gcry_error (err);
	}

	/* Unregister the digest identified by ID, which must have been
	registered with gcry_digest_register. */
	void
	gcry_md_unregister (gcry_module_t module)
	{
	ath_mutex_lock (&digests_registered_lock);
	_gcry_module_release (module);
	ath_mutex_unlock (&digests_registered_lock);
	}


	static int
	search_oid (const char oid, int algorithm, gcry_md_oid_spec_t *oid_spec)
	{
	gcry_module_t module;
	int ret = 0;

	if (oid && ((! strncmp (oid, "oid.", 4))
	\|\| (! strncmp (oid, "OID.", 4))))
	oid += 4;

	module = gcry_md_lookup_oid (oid);
	if (module)
	{
	gcry_md_spec_t *digest = module->spec;
	int i;

	for (i = 0; digest->oids[i].oidstring && !ret; i++)
	if (! stricmp (oid, digest->oids[i].oidstring))
	{
	if (algorithm)
	*algorithm = module->mod_id;
	if (oid_spec)
	*oid_spec = digest->oids[i];
	ret = 1;
	}
	_gcry_module_release (module);
	}

	return ret;
	}

	/****************
	* Map a string to the digest algo
	*/
	int
	gcry_md_map_name (const char *string)
	{
	gcry_module_t digest;
	int ret, algorithm = 0;

	if (! string)
	return 0;

	REGISTER_DEFAULT_DIGESTS;

	/* If the string starts with a digit (optionally prefixed with
	either "OID." or "oid."), we first look into our table of ASN.1
	object identifiers to figure out the algorithm */

	ath_mutex_lock (&digests_registered_lock);

	ret = search_oid (string, &algorithm, NULL);
	if (! ret)
	{
	/* Not found, search for an acording diget name. */
	digest = gcry_md_lookup_name (string);
	if (digest)
	{
	algorithm = digest->mod_id;
	_gcry_module_release (digest);
	}
	}
	ath_mutex_unlock (&digests_registered_lock);

	return algorithm;
	}


	/****************
	* Map a digest algo to a string
	*/
	static const char *
	digest_algo_to_string (int algorithm)
	{
	const char *name = NULL;
	gcry_module_t digest;

	REGISTER_DEFAULT_DIGESTS;

	ath_mutex_lock (&digests_registered_lock);
	digest = _gcry_module_lookup_id (digests_registered, algorithm);
	if (digest)
	{
	name = ((gcry_md_spec_t *) digest->spec)->name;
	_gcry_module_release (digest);
	}
	ath_mutex_unlock (&digests_registered_lock);

	return name;
	}

	/****************
	* This function simply returns the name of the algorithm or some constant
	* string when there is no algo. It will never return NULL.
	* Use the macro gcry_md_test_algo() to check whether the algorithm
	* is valid.
	*/
	const char *
	gcry_md_algo_name (int algorithm)
	{
	const char *s = digest_algo_to_string (algorithm);
	return s ? s : "?";
	}


	static gcry_err_code_t
	check_digest_algo (int algorithm)
	{
	gcry_err_code_t rc = 0;
	gcry_module_t digest;

	REGISTER_DEFAULT_DIGESTS;

	ath_mutex_lock (&digests_registered_lock);
	digest = _gcry_module_lookup_id (digests_registered, algorithm);
	if (digest)
	_gcry_module_release (digest);
	else
	rc = GPG_ERR_DIGEST_ALGO;
	ath_mutex_unlock (&digests_registered_lock);

	return rc;
	}



	/****************
	* Open a message digest handle for use with algorithm ALGO.
	* More algorithms may be added by md_enable(). The initial algorithm
	* may be 0.
	*/
	static gcry_err_code_t
	md_open (gcry_md_hd_t *h, int algo, int secure, int hmac)
	{
	gcry_err_code_t err = GPG_ERR_NO_ERROR;
	int bufsize = secure ? 512 : 1024;
	struct gcry_md_context *ctx;
	gcry_md_hd_t hd;
	size_t n;

	/* Allocate a memory area to hold the caller visible buffer with it's
	* control information and the data required by this module. Set the
	* context pointer at the beginning to this area.
	* We have to use this strange scheme because we want to hide the
	* internal data but have a variable sized buffer.
	*
	* +---+------+---........------+-------------+
	* !ctx! bctl ! buffer ! private !
	* +---+------+---........------+-------------+
	* ! ^
	* !---------------------------!
	*
	* We have to make sure that private is well aligned.
	*/
	n = sizeof (struct gcry_md_handle) + bufsize;
	n = ((n + sizeof (PROPERLY_ALIGNED_TYPE) - 1)
	/ sizeof (PROPERLY_ALIGNED_TYPE)) * sizeof (PROPERLY_ALIGNED_TYPE);

	/* Allocate and set the Context pointer to the private data */
	if (secure)
	hd = gcry_malloc_secure (n + sizeof (struct gcry_md_context));
	else
	hd = gcry_malloc (n + sizeof (struct gcry_md_context));

	if (! hd)
	err = gpg_err_code_from_errno (errno);

	if (! err)
	{
	hd->ctx = ctx = (struct gcry_md_context ) ((char ) hd + n);
	/* Setup the globally visible data (bctl in the diagram).*/
	hd->bufsize = n - sizeof (struct gcry_md_handle) + 1;
	hd->bufpos = 0;

	/* Initialize the private data. */
	memset (hd->ctx, 0, sizeof *hd->ctx);
	ctx->magic = secure ? CTX_MAGIC_SECURE : CTX_MAGIC_NORMAL;
	ctx->actual_handle_size = n + sizeof (struct gcry_md_context);
	ctx->secure = secure;

	if (hmac)
	{
	ctx->macpads = gcry_malloc_secure (128);
	if (! ctx->macpads)
	{
	md_close (hd);
	err = gpg_err_code_from_errno (errno);
	}
	}
	}

	if (! err)
	{
	/* FIXME: should we really do that? - yes [-wk] */
	_gcry_fast_random_poll ();

	if (algo)
	{
	err = md_enable (hd, algo);
	if (err)
	md_close (hd);
	}
	}

	if (! err)
	*h = hd;

	return err;
	}

	/* Create a message digest object for algorithm ALGO. FLAGS may be
	given as an bitwise OR of the gcry_md_flags values. ALGO may be
	given as 0 if the algorithms to be used are later set using
	gcry_md_enable. H is guaranteed to be a valid handle or NULL on
	error. */
	gcry_error_t
	gcry_md_open (gcry_md_hd_t *h, int algo, unsigned int flags)
	{
	gcry_err_code_t err = GPG_ERR_NO_ERROR;
	gcry_md_hd_t hd;

	if ((flags & ~(GCRY_MD_FLAG_SECURE \| GCRY_MD_FLAG_HMAC)))
	err = GPG_ERR_INV_ARG;
	else
	{
	err = md_open (&hd, algo, (flags & GCRY_MD_FLAG_SECURE),
	(flags & GCRY_MD_FLAG_HMAC));
	}

	*h = err? NULL : hd;
	return gcry_error (err);
	}



	static gcry_err_code_t
	md_enable (gcry_md_hd_t hd, int algorithm)
	{
	struct gcry_md_context *h = hd->ctx;
	gcry_md_spec_t *digest = NULL;
	GcryDigestEntry *entry;
	gcry_module_t module;
	gcry_err_code_t err = 0;

	for (entry = h->list; entry; entry = entry->next)
	if (entry->module->mod_id == algorithm)
	return err; /* already enabled */

	REGISTER_DEFAULT_DIGESTS;

	ath_mutex_lock (&digests_registered_lock);
	module = _gcry_module_lookup_id (digests_registered, algorithm);
	ath_mutex_unlock (&digests_registered_lock);
	if (! module)
	{
	log_debug ("md_enable: algorithm %d not available\n", algorithm);
	err = GPG_ERR_DIGEST_ALGO;
	}
	else
	digest = (gcry_md_spec_t *) module->spec;

	if (! err)
	{
	size_t size = (sizeof (*entry)
	+ digest->contextsize
	- sizeof (entry->context));

	/* And allocate a new list entry. */
	if (h->secure)
	entry = gcry_malloc_secure (size);
	else
	entry = gcry_malloc (size);

	if (! entry)
	err = gpg_err_code_from_errno (errno);
	else
	{
	entry->digest = digest;
	entry->module = module;
	entry->next = h->list;
	entry->actual_struct_size = size;
	h->list = entry;

	/* And init this instance. */
	entry->digest->init (&entry->context.c);
	}
	}

	if (err)
	{
	if (module)
	{
	ath_mutex_lock (&digests_registered_lock);
	_gcry_module_release (module);
	ath_mutex_unlock (&digests_registered_lock);
	}
	}

	return err;
	}


	gcry_error_t
	gcry_md_enable (gcry_md_hd_t hd, int algorithm)
	{
	gcry_err_code_t err = md_enable (hd, algorithm);
	return gcry_error (err);
	}

	static gcry_err_code_t
	md_copy (gcry_md_hd_t ahd, gcry_md_hd_t *b_hd)
	{
	gcry_err_code_t err = GPG_ERR_NO_ERROR;
	struct gcry_md_context *a = ahd->ctx;
	struct gcry_md_context *b;
	GcryDigestEntry ar, br;
	gcry_md_hd_t bhd;
	size_t n;

	if (ahd->bufpos)
	md_write (ahd, NULL, 0);

	n = (char ) ahd->ctx - (char ) ahd;
	if (a->secure)
	bhd = gcry_malloc_secure (n + sizeof (struct gcry_md_context));
	else
	bhd = gcry_malloc (n + sizeof (struct gcry_md_context));

	if (! bhd)
	err = gpg_err_code_from_errno (errno);

	if (! err)
	{
	bhd->ctx = b = (struct gcry_md_context ) ((char ) bhd + n);
	/* No need to copy the buffer due to the write above. */
	assert (ahd->bufsize == (n - sizeof (struct gcry_md_handle) + 1));
	bhd->bufsize = ahd->bufsize;
	bhd->bufpos = 0;
	assert (! ahd->bufpos);
	memcpy (b, a, sizeof *a);
	b->list = NULL;
	b->debug = NULL;
	if (a->macpads)
	{
	b->macpads = gcry_malloc_secure (128);
	if (! b->macpads)
	{
	md_close (bhd);
	err = gpg_err_code_from_errno (errno);
	}
	else
	memcpy (b->macpads, a->macpads, 128);
	}
	}

	/* Copy the complete list of algorithms. The copied list is
	reversed, but that doesn't matter. */
	if (! err)
	for (ar = a->list; ar; ar = ar->next)
	{
	if (a->secure)
	br = gcry_xmalloc_secure (sizeof *br
	+ ar->digest->contextsize
	- sizeof(ar->context));
	else
	br = gcry_xmalloc (sizeof *br
	+ ar->digest->contextsize
	- sizeof (ar->context));
	memcpy (br, ar,
	sizeof (*br) + ar->digest->contextsize - sizeof (ar->context));
	br->next = b->list;
	b->list = br;

	/* Add a reference to the module. */
	ath_mutex_lock (&digests_registered_lock);
	_gcry_module_use (br->module);
	ath_mutex_unlock (&digests_registered_lock);
	}

	if (a->debug)
	md_start_debug (bhd, "unknown");

	if (! err)
	*b_hd = bhd;

	return err;
	}

	gcry_error_t
	gcry_md_copy (gcry_md_hd_t *handle, gcry_md_hd_t hd)
	{
	gcry_err_code_t err = md_copy (hd, handle);
	if (err)
	*handle = NULL;
	return gcry_error (err);
	}

	/*
	* Reset all contexts and discard any buffered stuff. This may be used
	* instead of a md_close(); md_open().
	*/
	void
	gcry_md_reset (gcry_md_hd_t a)
	{
	GcryDigestEntry *r;

	a->bufpos = a->ctx->finalized = 0;

	for (r = a->ctx->list; r; r = r->next)
	{
	memset (r->context.c, 0, r->digest->contextsize);
	(*r->digest->init) (&r->context.c);
	}
	if (a->ctx->macpads)
	md_write (a, a->ctx->macpads, 64); /* inner pad */
	}

	static void
	md_close (gcry_md_hd_t a)
	{
	GcryDigestEntry r, r2;

	if (! a)
	return;
	if (a->ctx->debug)
	md_stop_debug (a);
	for (r = a->ctx->list; r; r = r2)
	{
	r2 = r->next;
	ath_mutex_lock (&digests_registered_lock);
	_gcry_module_release (r->module);
	ath_mutex_unlock (&digests_registered_lock);
	wipememory (r, r->actual_struct_size);
	gcry_free (r);
	}

	if (a->ctx->macpads)
	{
	wipememory (a->ctx->macpads, 128);
	gcry_free(a->ctx->macpads);
	}

	wipememory (a, a->ctx->actual_handle_size);
	gcry_free(a);
	}

	void
	gcry_md_close (gcry_md_hd_t hd)
	{
	md_close (hd);
	}

	static void
	md_write (gcry_md_hd_t a, byte *inbuf, size_t inlen)
	{
	GcryDigestEntry *r;

	if (a->ctx->debug)
	{
	if (a->bufpos && fwrite (a->buf, a->bufpos, 1, a->ctx->debug) != 1)
	BUG();
	if (inlen && fwrite (inbuf, inlen, 1, a->ctx->debug) != 1)
	BUG();
	}

	for (r = a->ctx->list; r; r = r->next)
	{
	if (a->bufpos)
	(*r->digest->write) (&r->context.c, a->buf, a->bufpos);
	(*r->digest->write) (&r->context.c, inbuf, inlen);
	}
	a->bufpos = 0;
	}

	void
	gcry_md_write (gcry_md_hd_t hd, const void *inbuf, size_t inlen)
	{
	md_write (hd, (unsigned char *) inbuf, inlen);
	}

	static void
	md_final (gcry_md_hd_t a)
	{
	GcryDigestEntry *r;

	if (a->ctx->finalized)
	return;

	if (a->bufpos)
	md_write (a, NULL, 0);

	for (r = a->ctx->list; r; r = r->next)
	(*r->digest->final) (&r->context.c);

	a->ctx->finalized = 1;

	if (a->ctx->macpads)
	{
	/* Finish the hmac. */
	int algo = md_get_algo (a);
	byte *p = md_read (a, algo);
	size_t dlen = md_digest_length (algo);
	gcry_md_hd_t om;
	gcry_err_code_t err = md_open (&om, algo, a->ctx->secure, 0);

	if (err)
	_gcry_fatal_error (err, NULL);
	md_write (om, a->ctx->macpads+64, 64);
	md_write (om, p, dlen);
	md_final (om);
	/* Replace our digest with the mac (they have the same size). */
	memcpy (p, md_read (om, algo), dlen);
	md_close (om);
	}
	}

	static gcry_err_code_t
	prepare_macpads( gcry_md_hd_t hd, const byte *key, size_t keylen)
	{
	int i;
	int algo = md_get_algo( hd );
	byte *helpkey = NULL;
	byte ipad, opad;

	if ( !algo )
	return GPG_ERR_DIGEST_ALGO; /* i.e. no algo enabled */

	if ( keylen > 64 )
	{
	helpkey = gcry_malloc_secure ( md_digest_length( algo ) );
	if ( !helpkey )
	return gpg_err_code_from_errno (errno);
	gcry_md_hash_buffer ( algo, helpkey, key, keylen );
	key = helpkey;
	keylen = md_digest_length( algo );
	assert ( keylen <= 64 );
	}

	memset ( hd->ctx->macpads, 0, 128 );
	ipad = hd->ctx->macpads;
	opad = hd->ctx->macpads+64;
	memcpy ( ipad, key, keylen );
	memcpy ( opad, key, keylen );
	for (i=0; i < 64; i++ )
	{
	ipad[i] ^= 0x36;
	opad[i] ^= 0x5c;
	}
	gcry_free( helpkey );

	return GPG_ERR_NO_ERROR;
	}

	gcry_error_t
	gcry_md_ctl (gcry_md_hd_t hd, int cmd, byte *buffer, size_t buflen)
	{
	gcry_err_code_t rc = 0;

	switch (cmd)
	{
	case GCRYCTL_FINALIZE:
	md_final (hd);
	break;
	case GCRYCTL_SET_KEY:
	rc = gcry_err_code (gcry_md_setkey (hd, buffer, buflen));
	break;
	case GCRYCTL_START_DUMP:
	md_start_debug (hd, buffer);
	break;
	case GCRYCTL_STOP_DUMP:
	md_stop_debug( hd );
	break;
	default:
	rc = GPG_ERR_INV_OP;
	}
	return gcry_error (rc);
	}

	gcry_error_t
	gcry_md_setkey (gcry_md_hd_t hd, const void *key, size_t keylen)
	{
	gcry_err_code_t rc = GPG_ERR_NO_ERROR;

	if (! hd->ctx->macpads)
	rc = GPG_ERR_CONFLICT;
	else
	{
	rc = prepare_macpads (hd, key, keylen);
	if (! rc)
	gcry_md_reset (hd);
	}

	return gcry_error (rc);
	}


	/****************
	* if ALGO is null get the digest for the used algo (which should be only one)
	*/
	static byte *
	md_read( gcry_md_hd_t a, int algo )
	{
	GcryDigestEntry *r = a->ctx->list;

	if (! algo)
	{
	/* return the first algorithm */
	if (r && r->next)
	log_debug("more than algorithm in md_read(0)\n");
	return r->digest->read( &r->context.c );
	}
	else
	{
	for (r = a->ctx->list; r; r = r->next)
	if (r->module->mod_id == algo)
	return r->digest->read (&r->context.c);
	}
	BUG();
	return NULL;
	}

	/*
	* Read out the complete digest, this function implictly finalizes
	* the hash.
	*/
	byte *
	gcry_md_read (gcry_md_hd_t hd, int algo)
	{
	gcry_md_ctl (hd, GCRYCTL_FINALIZE, NULL, 0);
	return md_read (hd, algo);
	}

	/****************
	* This function combines md_final and md_read but keeps the context
	* intact. This function can be used to calculate intermediate
	* digests. The digest is copied into buffer and the digestlength is
	* returned. If buffer is NULL only the needed size for buffer is returned.
	* buflen gives the max size of buffer. If the buffer is too shourt to
	* hold the complete digest, the buffer is filled with as many bytes are
	* possible and this value is returned.
	*/
	#if 0
	static int
	md_digest( gcry_md_hd_t a, int algo, byte *buffer, int buflen )
	{
	struct md_digest_list_s *r = NULL;
	char *context;
	char *digest;

	if( a->bufpos )
	md_write( a, NULL, 0 );

	if( !algo ) { /* return digest for the first algorithm */
	if( (r=a->ctx->list) && r->next )
	log_debug("more than algorithm in md_digest(0)\n");
	}
	else {
	for(r=a->ctx->list; r; r = r->next )
	if( r->algo == algo )
	break;
	}
	if( !r )
	BUG();

	if( !buffer )
	return r->mdlen;

	/* I don't want to change the interface, so I simply work on a copy
	* of the context (extra overhead - should be fixed)*/
	context = a->ctx->secure ? gcry_xmalloc_secure( r->contextsize )
	: gcry_xmalloc( r->contextsize );
	memcpy( context, r->context.c, r->contextsize );
	(*r->digest->final)( context );
	digest = (*r->digest->read)( context );

	if( buflen > r->mdlen )
	buflen = r->mdlen;
	memcpy( buffer, digest, buflen );

	gcry_free(context);
	return buflen;
	}
	#endif

	/*
	* Read out an intermediate digest. Not yet fucntional.
	*/
	gcry_err_code_t
	gcry_md_get (gcry_md_hd_t hd, int algo, byte *buffer, int buflen)
	{
	/md_digest ... /
	return GPG_ERR_INTERNAL;
	}


	/*
	* Shortcut function to hash a buffer with a given algo. The only
	* guaranteed supported algorithms are RIPE-MD160 and SHA-1. The
	* supplied digest buffer must be large enough to store the resulting
	* hash. No error is returned, the function will abort on an invalid
	* algo. DISABLED_ALGOS are ignored here. */
	void
	gcry_md_hash_buffer (int algo, void *digest,
	const void *buffer, size_t length)
	{
	if (algo == GCRY_MD_SHA1)
	_gcry_sha1_hash_buffer (digest, buffer, length);
	else if (algo == GCRY_MD_RMD160)
	_gcry_rmd160_hash_buffer (digest, buffer, length);
	else
	{
	/* For the others we do not have a fast function, so we use the
	normal functions. */
	gcry_md_hd_t h;
	gpg_err_code_t err = md_open (&h, algo, 0, 0);
	if (err)
	log_bug ("gcry_md_open failed for algo %d: %s",
	algo, gpg_strerror (gcry_error(err)));
	md_write (h, (byte *) buffer, length);
	md_final (h);
	memcpy (digest, md_read (h, algo), md_digest_length (algo));
	md_close (h);
	}
	}

	static int
	md_get_algo (gcry_md_hd_t a)
	{
	GcryDigestEntry *r = a->ctx->list;

	if (r && r->next)
	log_error("WARNING: more than algorithm in md_get_algo()\n");
	return r ? r->module->mod_id : 0;
	}

	int
	gcry_md_get_algo (gcry_md_hd_t hd)
	{
	return md_get_algo (hd);
	}


	/****************
	* Return the length of the digest
	*/
	static int
	md_digest_length (int algorithm)
	{
	gcry_module_t digest;
	int mdlen = 0;

	REGISTER_DEFAULT_DIGESTS;

	ath_mutex_lock (&digests_registered_lock);
	digest = _gcry_module_lookup_id (digests_registered, algorithm);
	if (digest)
	{
	mdlen = ((gcry_md_spec_t *) digest->spec)->mdlen;
	_gcry_module_release (digest);
	}
	ath_mutex_unlock (&digests_registered_lock);

	return mdlen;
	}

	/****************
	* Return the length of the digest in bytes.
	* This function will return 0 in case of errors.
	*/
	unsigned int
	gcry_md_get_algo_dlen (int algorithm)
	{
	return md_digest_length (algorithm);
	}


	/* Hmmm: add a mode to enumerate the OIDs
	* to make g10/sig-check.c more portable */
	static const byte *
	md_asn_oid (int algorithm, size_t asnlen, size_t mdlen)
	{
	const byte *asnoid = NULL;
	gcry_module_t digest;

	REGISTER_DEFAULT_DIGESTS;

	ath_mutex_lock (&digests_registered_lock);
	digest = _gcry_module_lookup_id (digests_registered, algorithm);
	if (digest)
	{
	if (asnlen)
	asnlen = ((gcry_md_spec_t ) digest->spec)->asnlen;
	if (mdlen)
	mdlen = ((gcry_md_spec_t ) digest->spec)->mdlen;
	asnoid = ((gcry_md_spec_t *) digest->spec)->asnoid;
	_gcry_module_release (digest);
	}
	else
	log_bug ("no ASN.1 OID for md algo %d\n", algorithm);
	ath_mutex_unlock (&digests_registered_lock);

	return asnoid;
	}



	/****************
	* Return information about the given cipher algorithm
	* WHAT select the kind of information returned:
	* GCRYCTL_TEST_ALGO:
	* Returns 0 when the specified algorithm is available for use.
	* buffer and nbytes must be zero.
	* GCRYCTL_GET_ASNOID:
	* Return the ASNOID of the algorithm in buffer. if buffer is NULL, only
	* the required length is returned.
	*
	* Note: Because this function is in most cases used to return an
	* integer value, we can make it easier for the caller to just look at
	* the return value. The caller will in all cases consult the value
	* and thereby detecting whether a error occured or not (i.e. while checking
	* the block size)
	*/
	gcry_error_t
	gcry_md_algo_info (int algo, int what, void buffer, size_t nbytes)
	{
	gcry_err_code_t err = GPG_ERR_NO_ERROR;

	switch (what)
	{
	case GCRYCTL_TEST_ALGO:
	if (buffer \|\| nbytes)
	err = GPG_ERR_INV_ARG;
	else
	err = check_digest_algo (algo);
	break;

	case GCRYCTL_GET_ASNOID:
	{
	const char unsigned *asn;
	size_t asnlen;

	asn = md_asn_oid (algo, &asnlen, NULL);
	if (buffer && (*nbytes >= asnlen))
	{
	memcpy (buffer, asn, asnlen);
	*nbytes = asnlen;
	}
	else if ((! buffer) && nbytes)
	*nbytes = asnlen;
	else
	{
	if (buffer)
	err = GPG_ERR_TOO_SHORT;
	else
	err = GPG_ERR_INV_ARG;
	}
	break;
	}

	default:
	err = GPG_ERR_INV_OP;
	}

	return gcry_error (err);
	}


	static void
	md_start_debug( gcry_md_hd_t md, char *suffix )
	{
	static int idx=0;
	char buf[50];

	if( md->ctx->debug ) {
	log_debug("Oops: md debug already started\n");
	return;
	}
	idx++;
	sprintf(buf, "dbgmd-%05d.%.10s", idx, suffix );
	md->ctx->debug = fopen(buf, "w");
	if( !md->ctx->debug )
	log_debug("md debug: can't open %s\n", buf );
	}

	static void
	md_stop_debug( gcry_md_hd_t md )
	{
	if( md->ctx->debug ) {
	if( md->bufpos )
	md_write( md, NULL, 0 );
	fclose(md->ctx->debug);
	md->ctx->debug = NULL;
	}
	#ifdef HAVE_U64_TYPEDEF
	{ /* a kludge to pull in the __muldi3 for Solaris */
	volatile u32 a = (u32)(ulong)md;
	volatile u64 b = 42;
	volatile u64 c;
	c = a * b;
	}
	#endif
	}



	/*
	* Return information about the digest handle.
	* GCRYCTL_IS_SECURE:
	* Returns 1 when the handle works on secured memory
	* otherwise 0 is returned. There is no error return.
	* GCRYCTL_IS_ALGO_ENABLED:
	* Returns 1 if the algo is enanled for that handle.
	* The algo must be passed as the address of an int.
	*/
	gcry_error_t
	gcry_md_info (gcry_md_hd_t h, int cmd, void buffer, size_t nbytes)
	{
	gcry_err_code_t err = GPG_ERR_NO_ERROR;

	switch (cmd)
	{
	case GCRYCTL_IS_SECURE:
	*nbytes = h->ctx->secure;
	break;

	case GCRYCTL_IS_ALGO_ENABLED:
	{
	GcryDigestEntry *r;
	int algo;

	if ( !buffer \|\| (nbytes && (*nbytes != sizeof (int))))
	err = GPG_ERR_INV_ARG;
	else
	{
	algo = (int)buffer;

	*nbytes = 0;
	for(r=h->ctx->list; r; r = r->next ) {
	if (r->module->mod_id == algo)
	{
	*nbytes = 1;
	break;
	}
	}
	}
	break;
	}

	default:
	err = GPG_ERR_INV_OP;
	}

	return gcry_error (err);
	}

	gcry_err_code_t
	_gcry_md_init (void)
	{
	gcry_err_code_t err = GPG_ERR_NO_ERROR;

	REGISTER_DEFAULT_DIGESTS;

	return err;
	}


	int
	gcry_md_is_secure (gcry_md_hd_t a)
	{
	size_t value;

	if (gcry_md_info (a, GCRYCTL_IS_SECURE, NULL, &value))
	value = 1; /* It seems to be better to assume secure memory on
	error. */
	return value;
	}


	int
	gcry_md_is_enabled (gcry_md_hd_t a, int algo)
	{
	size_t value;

	value = sizeof algo;
	if (gcry_md_info (a, GCRYCTL_IS_ALGO_ENABLED, &algo, &value))
	value = 0;
	return value;
	}

	/* Get a list consisting of the IDs of the loaded message digest
	modules. If LIST is zero, write the number of loaded message
	digest modules to LIST_LENGTH and return. If LIST is non-zero, the
	first *LIST_LENGTH algorithm IDs are stored in LIST, which must be
	of according size. In case there are less message digest modules
	than LIST_LENGTH, LIST_LENGTH is updated to the correct
	number. */
	gcry_error_t
	gcry_md_list (int list, int list_length)
	{
	gcry_err_code_t err = GPG_ERR_NO_ERROR;

	ath_mutex_lock (&digests_registered_lock);
	err = _gcry_module_list (digests_registered, list, list_length);
	ath_mutex_unlock (&digests_registered_lock);

	return err;
	}

File Metadata

Mime Type: text/x-c
Expires: Sat, Nov 29, 7:14 AM (2 h, 54 m)
Storage Engine: local-disk
Storage Format: Raw Data
Storage Handle: 37/45/d754a22ca71e960811f8f7868ddc

md.cNo OneTemporaryActions

md.cView Options

File Metadata

Event Timeline

md.c
No OneTemporary
Actions

md.c
View Options