[u/mdw/catacomb] / key-binary.c

/* -*-c-*-
 *
 * $Id$
 *
 * Key binary encoding
 *
 * (c) 1999 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * Catacomb 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 Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with Catacomb; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Header files ------------------------------------------------------*/

#include <stdlib.h>
#include <string.h>

#include <mLib/bits.h>
#include <mLib/dstr.h>
#include <mLib/sub.h>
#include <mLib/sym.h>

#include "key-data.h"
#include "mp.h"
#include "mptext.h"

/*----- Main code ---------------------------------------------------------*/

/* --- @key_decode@ --- *
 *
 * Arguments:	@const void *p@ = pointer to buffer to read
 *		@size_t sz@ = size of the buffer
 *
 * Returns:	The newly-read key data, or null if it failed.
 *
 * Use:		Decodes a binary representation of a key.
 */

key_data *key_decode(const void *p, size_t sz)
{
  const octet *q = p;
  size_t psz;
  key_data *kd;
  unsigned e;

  /* --- Parse the header information --- *
   *
   * Make sure the size matches external reality.  Security holes have been
   * known to creep in without this sort of check.  (No, this isn't an after-
   * the-fact patch-up.)
   */

  e = LOAD16(q);
  psz = LOAD16(q + 2);
  if (psz + 4 > sz)
    return (0);

  /* --- Now decide what to do --- */

  switch (e & KF_ENCMASK) {

    /* --- Plain binary data --- */

    case KENC_BINARY:
    case KENC_ENCRYPT:
      kd = key_newbinary(e, q + 4, psz);
      break;

    /* --- Multiprecision integer data --- */

    case KENC_MP:
      kd = key_newmp(e, mp_loadb(e & KF_BURN ? MP_NEWSEC : MP_NEW,
				 q + 4, psz));
      break;

    /* --- String data --- */

    case KENC_STRING:
      kd = key_newraw(e);
      kd->u.p = xmalloc(sz + 1);
      memcpy(kd->u.p, q + 4, sz);
      kd->u.p[sz] = 0;
      break;

    /* --- Elliptic curve point data --- */

    case KENC_EC: {
      size_t xsz, ysz;
      kd = key_newraw(e);
      EC_CREATE(&kd->u.e);
      if (!sz) break;
      if (sz < 2) return (0);
      xsz = LOAD16(q + 4);
      if (sz < xsz + 4) return (0);
      ysz = LOAD16(q + 6 + xsz);
      if (sz < xsz + ysz + 4) return (0);
      kd->u.e.x = mp_loadb(MP_NEW, q + 6, xsz);
      kd->u.e.y = mp_loadb(MP_NEW, q + 8 + xsz, ysz);
    } break;

    /* --- Structured key data --- */

    case KENC_STRUCT: {
      dstr d = DSTR_INIT;
      key_data *nkd;

      if ((e & ~KF_ENCMASK) || (psz & 3))
	return (0);
      q += 4;
      kd = key_newstruct();

      while (psz) {

	/* --- Read the tag string --- */

	DRESET(&d);
	sz = LOAD8(q);
	if (sz >= psz)
	  goto fail;
	DPUTM(&d, q + 1, sz);
	DPUTZ(&d);
	sz = (sz + 4) & ~3;
	q += sz; psz -= sz;

	/* --- Read the encoding and size --- */

	sz = (LOAD16(q + 2) + 7) & ~3;
	if (sz > psz)
	  goto fail;

	/* --- Create a table node and fill it in --- */

	if ((nkd = key_decode(q, sz)) == 0)
	  goto fail;
	key_structsteal(kd, d.buf, nkd);
	psz -= sz;
	q += sz;
      }
      dstr_destroy(&d);
      break;

      /* --- Tidy up after a failure --- */

    fail:
      dstr_destroy(&d);
      key_drop(kd);
      return (0);
    } break;

    /* --- Everything else --- */

    default:
      return (0);
  }

  /* --- OK, that was good --- */

  kd->e = e;
  return (kd);
}

/* --- @key_encode@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data block
 *		@dstr *d@ = pointer to destination string
 *		@const key_filter *kf@ = pointer to key selection block
 *
 * Returns:	Nonzero if an item was actually written.
 *
 * Use:		Encodes a key block as binary data.
 */

static int ksbyname(const void *a, const void *b) {
  key_struct *const *x = a, *const *y = b;
  return (strcmp(SYM_NAME(*x), SYM_NAME(*y)));
}

int key_encode(key_data *k, dstr *d, const key_filter *kf)
{
  int rc = 0;
  if (!KEY_MATCH(k, kf))
    return (0);
  switch (k->e & KF_ENCMASK) {
    case KENC_BINARY:
    case KENC_ENCRYPT: {
      char *p;

      DENSURE(d, (k->u.k.sz + 7) & ~3);
      p = d->buf + d->len;
      STORE16(p, k->e);
      STORE16(p + 2, k->u.k.sz);
      d->len += 4;
      DPUTM(d, k->u.k.k, k->u.k.sz);
      rc = 1;
    } break;

    case KENC_MP: {
      char *p;
      size_t sz = mp_octets(k->u.m);

      DENSURE(d, (sz + 7) & ~3);
      p = d->buf + d->len;
      STORE16(p, k->e);
      STORE16(p + 2, sz);
      mp_storeb(k->u.m, p + 4, sz);
      d->len += sz + 4;
      rc = 1;
    } break;

    case KENC_STRING: {
      char *p;
      size_t sz = strlen(k->u.p);

      DENSURE(d, (sz + 7) & ~3);
      p = d->buf + d->len;
      STORE16(p, k->e);
      STORE16(p + 2, sz);
      memcpy(p + 4, k->u.p, sz);
      d->len += sz + 4;
      rc = 1;
    } break;

    case KENC_EC: {
      char *p;
      size_t xsz = 0, ysz = 0;
      size_t sz;

      if (EC_ATINF(&k->u.e))
	sz = 0;
      else {
	xsz = mp_octets(k->u.e.x);
	ysz = mp_octets(k->u.e.y);
	sz = xsz + ysz + 4;
      }
      DENSURE(d, (sz + 7) & ~3);
      p = d->buf + d->len;
      STORE16(p, k->e);
      STORE16(p + 2, sz);
      if (!EC_ATINF(&k->u.e)) {
	STORE16(p + 4, xsz);
	mp_storeb(k->u.e.x, p + 6, xsz);
	STORE16(p + 6 + xsz, ysz);
	mp_storeb(k->u.e.y, p + 8 + xsz, ysz);
      }
      d->len += sz + 4;
      rc = 1;
    } break;

    case KENC_STRUCT: {
      size_t n;
      char *p;
      key_struct *ks, **ksv;
      size_t nks, j;
      sym_iter i;

      n = d->len;
      DENSURE(d, 4);
      p = d->buf + n;
      STORE16(p, k->e & KF_ENCMASK);
      d->len += 4;

      for (nks = 0, sym_mkiter(&i, &k->u.s);
	   (ks = sym_next(&i)) != 0;
	   nks++);
      if (nks) {
	ksv = xmalloc(nks * sizeof(*ksv));
	for (j = 0, sym_mkiter(&i, &k->u.s); (ks = sym_next(&i)) != 0; j++)
	  ksv[j] = ks;
	qsort(ksv, nks, sizeof(*ksv), ksbyname);
	for (j = 0; j < nks; j++) {
	  size_t o = d->len;
	  ks = ksv[j];
	  DENSURE(d, 1);
	  *(octet *)(d->buf + d->len++) = strlen(SYM_NAME(ks));
	  DPUTS(d, SYM_NAME(ks));
	  while (d->len & 3)
	    DPUTC(d, 0);
	  if (key_encode(ks->k, d, kf))
	    rc = 1;
	  else
	    d->len = o;
	}
	xfree(ksv);
      }
      if (!rc)
	d->len = n;
      else {
	p = d->buf + n + 2;
	n = d->len - n - 4;
	STORE16(p,  n);
      }
    } break;
  }
  while (d->len & 3)
    DPUTC(d, 0);
  return (rc);
}

/*----- That's all, folks -------------------------------------------------*/
Commit	Line	Data
052b36d0	1	/* --c--
052b36d0	2	*
21aac40c	3	* $Id$
052b36d0	4	*
	5	* Key binary encoding
	6	*
	7	* (c) 1999 Straylight/Edgeware
	8	*/
	9
45c0fd36	10	/----- Licensing notice --------------------------------------------------
052b36d0	11	*
	12	* This file is part of Catacomb.
	13	*
	14	* Catacomb is free software; you can redistribute it and/or modify
	15	* it under the terms of the GNU Library General Public License as
	16	* published by the Free Software Foundation; either version 2 of the
	17	* License, or (at your option) any later version.
45c0fd36	18	*
052b36d0	19	* Catacomb is distributed in the hope that it will be useful,
	20	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	21	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	22	* GNU Library General Public License for more details.
45c0fd36	23	*
052b36d0	24	* You should have received a copy of the GNU Library General Public
	25	* License along with Catacomb; if not, write to the Free
	26	* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
	27	* MA 02111-1307, USA.
	28	*/
	29
052b36d0	30	/----- Header files ------------------------------------------------------/
	31
	32	#include <stdlib.h>
	33	#include <string.h>
	34
	35	#include <mLib/bits.h>
	36	#include <mLib/dstr.h>
	37	#include <mLib/sub.h>
	38	#include <mLib/sym.h>
	39
	40	#include "key-data.h"
	41	#include "mp.h"
	42	#include "mptext.h"
	43
	44	/----- Main code ---------------------------------------------------------/
	45
	46	/* --- @key_decode@ --- *
	47	*
	48	* Arguments: @const void *p@ = pointer to buffer to read
	49	* @size_t sz@ = size of the buffer
052b36d0	50	*
ef13e9a4	51	* Returns: The newly-read key data, or null if it failed.
052b36d0	52	*
	53	* Use: Decodes a binary representation of a key.
	54	*/
	55
ef13e9a4	56	key_data key_decode(const void p, size_t sz)
052b36d0	57	{
	58	const octet *q = p;
	59	size_t psz;
ef13e9a4	60	key_data *kd;
052b36d0	61	unsigned e;
	62
	63	/* --- Parse the header information --- *
	64	*
	65	* Make sure the size matches external reality. Security holes have been
	66	* known to creep in without this sort of check. (No, this isn't an after-
	67	* the-fact patch-up.)
	68	*/
	69
	70	e = LOAD16(q);
	71	psz = LOAD16(q + 2);
	72	if (psz + 4 > sz)
ef13e9a4	73	return (0);
052b36d0	74
	75	/* --- Now decide what to do --- */
	76
	77	switch (e & KF_ENCMASK) {
	78
	79	/* --- Plain binary data --- */
	80
	81	case KENC_BINARY:
	82	case KENC_ENCRYPT:
ef13e9a4	83	kd = key_newbinary(e, q + 4, psz);
052b36d0	84	break;
	85
	86	/* --- Multiprecision integer data --- */
	87
	88	case KENC_MP:
ef13e9a4	89	kd = key_newmp(e, mp_loadb(e & KF_BURN ? MP_NEWSEC : MP_NEW,
ef13e9a4	90	q + 4, psz));
052b36d0	91	break;
052b36d0	92
1ba83484	93	/* --- String data --- */
	94
	95	case KENC_STRING:
ef13e9a4	96	kd = key_newraw(e);
	97	kd->u.p = xmalloc(sz + 1);
	98	memcpy(kd->u.p, q + 4, sz);
	99	kd->u.p[sz] = 0;
1ba83484	100	break;
	101
	102	/* --- Elliptic curve point data --- */
	103
	104	case KENC_EC: {
	105	size_t xsz, ysz;
ef13e9a4	106	kd = key_newraw(e);
ef13e9a4	107	EC_CREATE(&kd->u.e);
34e4f738	108	if (!sz) break;
ef13e9a4	109	if (sz < 2) return (0);
1ba83484	110	xsz = LOAD16(q + 4);
ef13e9a4	111	if (sz < xsz + 4) return (0);
1ba83484	112	ysz = LOAD16(q + 6 + xsz);
ef13e9a4	113	if (sz < xsz + ysz + 4) return (0);
	114	kd->u.e.x = mp_loadb(MP_NEW, q + 6, xsz);
	115	kd->u.e.y = mp_loadb(MP_NEW, q + 8 + xsz, ysz);
1ba83484	116	} break;
1ba83484	117
052b36d0	118	/* --- Structured key data --- */
	119
	120	case KENC_STRUCT: {
	121	dstr d = DSTR_INIT;
ef13e9a4	122	key_data *nkd;
052b36d0	123
ef13e9a4	124	if ((e & ~KF_ENCMASK) \|\| (psz & 3))
ef13e9a4	125	return (0);
052b36d0	126	q += 4;
ef13e9a4	127	kd = key_newstruct();
052b36d0	128
	129	while (psz) {
	130
	131	/* --- Read the tag string --- */
	132
	133	DRESET(&d);
	134	sz = LOAD8(q);
	135	if (sz >= psz)
	136	goto fail;
	137	DPUTM(&d, q + 1, sz);
	138	DPUTZ(&d);
	139	sz = (sz + 4) & ~3;
	140	q += sz; psz -= sz;
	141
	142	/* --- Read the encoding and size --- */
	143
052b36d0	144	sz = (LOAD16(q + 2) + 7) & ~3;
	145	if (sz > psz)
	146	goto fail;
	147
	148	/* --- Create a table node and fill it in --- */
	149
ef13e9a4	150	if ((nkd = key_decode(q, sz)) == 0)
052b36d0	151	goto fail;
ef13e9a4	152	key_structsteal(kd, d.buf, nkd);
052b36d0	153	psz -= sz;
	154	q += sz;
	155	}
	156	dstr_destroy(&d);
	157	break;
	158
	159	/* --- Tidy up after a failure --- */
	160
	161	fail:
	162	dstr_destroy(&d);
ef13e9a4	163	key_drop(kd);
ef13e9a4	164	return (0);
052b36d0	165	} break;
	166
	167	/* --- Everything else --- */
	168
	169	default:
ef13e9a4	170	return (0);
052b36d0	171	}
	172
	173	/* --- OK, that was good --- */
	174
ef13e9a4	175	kd->e = e;
ef13e9a4	176	return (kd);
052b36d0	177	}
	178
	179	/* --- @key_encode@ --- *
	180	*
	181	* Arguments: @key_data *k@ = pointer to key data block
	182	* @dstr *d@ = pointer to destination string
	183	* @const key_filter *kf@ = pointer to key selection block
	184	*
	185	* Returns: Nonzero if an item was actually written.
	186	*
	187	* Use: Encodes a key block as binary data.
	188	*/
	189
898a4e25	190	static int ksbyname(const void a, const void b) {
	191	key_struct const x = a, const y = b;
	192	return (strcmp(SYM_NAME(x), SYM_NAME(y)));
	193	}
	194
052b36d0	195	int key_encode(key_data k, dstr d, const key_filter *kf)
	196	{
	197	int rc = 0;
	198	if (!KEY_MATCH(k, kf))
	199	return (0);
	200	switch (k->e & KF_ENCMASK) {
	201	case KENC_BINARY:
	202	case KENC_ENCRYPT: {
	203	char *p;
	204
	205	DENSURE(d, (k->u.k.sz + 7) & ~3);
	206	p = d->buf + d->len;
	207	STORE16(p, k->e);
	208	STORE16(p + 2, k->u.k.sz);
	209	d->len += 4;
	210	DPUTM(d, k->u.k.k, k->u.k.sz);
	211	rc = 1;
	212	} break;
	213
	214	case KENC_MP: {
	215	char *p;
	216	size_t sz = mp_octets(k->u.m);
	217
	218	DENSURE(d, (sz + 7) & ~3);
	219	p = d->buf + d->len;
	220	STORE16(p, k->e);
	221	STORE16(p + 2, sz);
	222	mp_storeb(k->u.m, p + 4, sz);
	223	d->len += sz + 4;
	224	rc = 1;
	225	} break;
	226
1ba83484	227	case KENC_STRING: {
	228	char *p;
	229	size_t sz = strlen(k->u.p);
	230
	231	DENSURE(d, (sz + 7) & ~3);
	232	p = d->buf + d->len;
	233	STORE16(p, k->e);
	234	STORE16(p + 2, sz);
	235	memcpy(p + 4, k->u.p, sz);
	236	d->len += sz + 4;
	237	rc = 1;
	238	} break;
	239
	240	case KENC_EC: {
	241	char *p;
898a4e25	242	size_t xsz = 0, ysz = 0;
34e4f738	243	size_t sz;
1ba83484	244
34e4f738	245	if (EC_ATINF(&k->u.e))
	246	sz = 0;
	247	else {
	248	xsz = mp_octets(k->u.e.x);
	249	ysz = mp_octets(k->u.e.y);
	250	sz = xsz + ysz + 4;
	251	}
1ba83484	252	DENSURE(d, (sz + 7) & ~3);
	253	p = d->buf + d->len;
	254	STORE16(p, k->e);
	255	STORE16(p + 2, sz);
34e4f738	256	if (!EC_ATINF(&k->u.e)) {
	257	STORE16(p + 4, xsz);
	258	mp_storeb(k->u.e.x, p + 6, xsz);
	259	STORE16(p + 6 + xsz, ysz);
	260	mp_storeb(k->u.e.y, p + 8 + xsz, ysz);
	261	}
1ba83484	262	d->len += sz + 4;
	263	rc = 1;
	264	} break;
	265
052b36d0	266	case KENC_STRUCT: {
	267	size_t n;
	268	char *p;
898a4e25	269	key_struct ks, *ksv;
898a4e25	270	size_t nks, j;
052b36d0	271	sym_iter i;
	272
	273	n = d->len;
	274	DENSURE(d, 4);
	275	p = d->buf + n;
	276	STORE16(p, k->e & KF_ENCMASK);
	277	d->len += 4;
45c0fd36	278
898a4e25	279	for (nks = 0, sym_mkiter(&i, &k->u.s);
	280	(ks = sym_next(&i)) != 0;
	281	nks++);
	282	if (nks) {
	283	ksv = xmalloc(nks * sizeof(*ksv));
	284	for (j = 0, sym_mkiter(&i, &k->u.s); (ks = sym_next(&i)) != 0; j++)
	285	ksv[j] = ks;
	286	qsort(ksv, nks, sizeof(*ksv), ksbyname);
	287	for (j = 0; j < nks; j++) {
	288	size_t o = d->len;
	289	ks = ksv[j];
	290	DENSURE(d, 1);
	291	(octet )(d->buf + d->len++) = strlen(SYM_NAME(ks));
	292	DPUTS(d, SYM_NAME(ks));
	293	while (d->len & 3)
	294	DPUTC(d, 0);
ef13e9a4	295	if (key_encode(ks->k, d, kf))
898a4e25	296	rc = 1;
	297	else
	298	d->len = o;
	299	}
	300	xfree(ksv);
052b36d0	301	}
052b36d0	302	if (!rc)
45c0fd36	303	d->len = n;
052b36d0	304	else {
	305	p = d->buf + n + 2;
	306	n = d->len - n - 4;
	307	STORE16(p, n);
	308	}
	309	} break;
	310	}
	311	while (d->len & 3)
	312	DPUTC(d, 0);
	313	return (rc);
	314	}
	315
	316	/----- That's all, folks -------------------------------------------------/