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

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