tasn_dec.c

开源的ssl算法openssl,版本0.9.8H

/* tasn_dec.c */
/* Written by Dr Stephen N Henson ([e-mail]) for the OpenSSL
 * project 2000.
 */
/* ====================================================================
 * Copyright (c) 2000-2005 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    [e-mail].
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * ([e-mail]).  This product includes software written by Tim
 * Hudson ([e-mail]).
 *
 */


#include <stddef.h>
#include <string.h>
#include <openssl/asn1.h>
#include <openssl/asn1t.h>
#include <openssl/objects.h>
#include <openssl/buffer.h>
#include <openssl/err.h>

static int asn1_check_eoc(const unsigned char **in, long len);
static int asn1_find_end(const unsigned char **in, long len, char inf);

static int asn1_collect(BUF_MEM *buf, const unsigned char **in, long len,
				char inf, int tag, int aclass);

static int collect_data(BUF_MEM *buf, const unsigned char **p, long plen);

static int asn1_check_tlen(long *olen, int *otag, unsigned char *oclass,
				char *inf, char *cst,
				const unsigned char **in, long len,
				int exptag, int expclass, char opt,
				ASN1_TLC *ctx);

static int asn1_template_ex_d2i(ASN1_VALUE **pval,
				const unsigned char **in, long len,
				const ASN1_TEMPLATE *tt, char opt,
				ASN1_TLC *ctx);
static int asn1_template_noexp_d2i(ASN1_VALUE **val,
				const unsigned char **in, long len,
				const ASN1_TEMPLATE *tt, char opt,
				ASN1_TLC *ctx);
static int asn1_d2i_ex_primitive(ASN1_VALUE **pval,
				const unsigned char **in, long len,
				const ASN1_ITEM *it,
				int tag, int aclass, char opt, ASN1_TLC *ctx);

/* Table to convert tags to bit values, used for MSTRING type */
static const unsigned long tag2bit[32] = {
0,	0,	0,	B_ASN1_BIT_STRING,	/* tags  0 -  3 */
B_ASN1_OCTET_STRING,	0,	0,		B_ASN1_UNKNOWN,/* tags  4- 7 */
B_ASN1_UNKNOWN,	B_ASN1_UNKNOWN,	B_ASN1_UNKNOWN,	B_ASN1_UNKNOWN,/* tags  8-11 */
B_ASN1_UTF8STRING,B_ASN1_UNKNOWN,B_ASN1_UNKNOWN,B_ASN1_UNKNOWN,/* tags 12-15 */
B_ASN1_SEQUENCE,0,B_ASN1_NUMERICSTRING,B_ASN1_PRINTABLESTRING, /* tags 16-19 */
B_ASN1_T61STRING,B_ASN1_VIDEOTEXSTRING,B_ASN1_IA5STRING,       /* tags 20-22 */
B_ASN1_UTCTIME, B_ASN1_GENERALIZEDTIME,			       /* tags 23-24 */	
B_ASN1_GRAPHICSTRING,B_ASN1_ISO64STRING,B_ASN1_GENERALSTRING,  /* tags 25-27 */
B_ASN1_UNIVERSALSTRING,B_ASN1_UNKNOWN,B_ASN1_BMPSTRING,B_ASN1_UNKNOWN, /* tags 28-31 */
	};

unsigned long ASN1_tag2bit(int tag)
	{
	if ((tag < 0) || (tag > 30)) return 0;
	return tag2bit[tag];
	}

/* Macro to initialize and invalidate the cache */

#define asn1_tlc_clear(c)	if (c) (c)->valid = 0

/* Decode an ASN1 item, this currently behaves just 
 * like a standard 'd2i' function. 'in' points to 
 * a buffer to read the data from, in future we will
 * have more advanced versions that can input data
 * a piece at a time and this will simply be a special
 * case.
 */

ASN1_VALUE *ASN1_item_d2i(ASN1_VALUE **pval,
		const unsigned char **in, long len, const ASN1_ITEM *it)
	{
	ASN1_TLC c;
	ASN1_VALUE *ptmpval = NULL;
	if (!pval)
		pval = &ptmpval;
	c.valid = 0;
	if (ASN1_item_ex_d2i(pval, in, len, it, -1, 0, 0, &c) > 0) 
		return *pval;
	return NULL;
	}

int ASN1_template_d2i(ASN1_VALUE **pval,
		const unsigned char **in, long len, const ASN1_TEMPLATE *tt)
	{
	ASN1_TLC c;
	c.valid = 0;
	return asn1_template_ex_d2i(pval, in, len, tt, 0, &c);
	}


/* Decode an item, taking care of IMPLICIT tagging, if any.
 * If 'opt' set and tag mismatch return -1 to handle OPTIONAL
 */

int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
			const ASN1_ITEM *it,
			int tag, int aclass, char opt, ASN1_TLC *ctx)
	{
	const ASN1_TEMPLATE *tt, *errtt = NULL;
	const ASN1_COMPAT_FUNCS *cf;
	const ASN1_EXTERN_FUNCS *ef;
	const ASN1_AUX *aux = it->funcs;
	ASN1_aux_cb *asn1_cb;
	const unsigned char *p = NULL, *q;
	unsigned char *wp=NULL;	/* BIG FAT WARNING!  BREAKS CONST WHERE USED */
	unsigned char imphack = 0, oclass;
	char seq_eoc, seq_nolen, cst, isopt;
	long tmplen;
	int i;
	int otag;
	int ret = 0;
	ASN1_VALUE *pchval, **pchptr, *ptmpval;
	if (!pval)
		return 0;
	if (aux && aux->asn1_cb)
		asn1_cb = aux->asn1_cb;
	else asn1_cb = 0;

	switch(it->itype)
		{
		case ASN1_ITYPE_PRIMITIVE:
		if (it->templates)
			{
			/* tagging or OPTIONAL is currently illegal on an item
			 * template because the flags can't get passed down.
			 * In practice this isn't a problem: we include the
			 * relevant flags from the item template in the
			 * template itself.
			 */
			if ((tag != -1) || opt)
				{
				ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
				ASN1_R_ILLEGAL_OPTIONS_ON_ITEM_TEMPLATE);
				goto err;
				}
			return asn1_template_ex_d2i(pval, in, len,
					it->templates, opt, ctx);
		}
		return asn1_d2i_ex_primitive(pval, in, len, it,
						tag, aclass, opt, ctx);
		break;

		case ASN1_ITYPE_MSTRING:
		p = *in;
		/* Just read in tag and class */
		ret = asn1_check_tlen(NULL, &otag, &oclass, NULL, NULL,
						&p, len, -1, 0, 1, ctx);
		if (!ret)
			{
			ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
					ERR_R_NESTED_ASN1_ERROR);
			goto err;
			}

		/* Must be UNIVERSAL class */
		if (oclass != V_ASN1_UNIVERSAL)
			{
			/* If OPTIONAL, assume this is OK */
			if (opt) return -1;
			ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
					ASN1_R_MSTRING_NOT_UNIVERSAL);
			goto err;
			}
		/* Check tag matches bit map */
		if (!(ASN1_tag2bit(otag) & it->utype))
			{
			/* If OPTIONAL, assume this is OK */
			if (opt)
				return -1;
			ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
					ASN1_R_MSTRING_WRONG_TAG);
			goto err;
			}
		return asn1_d2i_ex_primitive(pval, in, len,
						it, otag, 0, 0, ctx);

		case ASN1_ITYPE_EXTERN:
		/* Use new style d2i */
		ef = it->funcs;
		return ef->asn1_ex_d2i(pval, in, len,
						it, tag, aclass, opt, ctx);

		case ASN1_ITYPE_COMPAT:
		/* we must resort to old style evil hackery */
		cf = it->funcs;

		/* If OPTIONAL see if it is there */
		if (opt)
			{
			int exptag;
			p = *in;
			if (tag == -1)
				exptag = it->utype;
			else exptag = tag;
			/* Don't care about anything other than presence
			 * of expected tag */

			ret = asn1_check_tlen(NULL, NULL, NULL, NULL, NULL,
					&p, len, exptag, aclass, 1, ctx);
			if (!ret)
				{
				ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
					ERR_R_NESTED_ASN1_ERROR);
				goto err;
				}
			if (ret == -1)
				return -1;
			}

		/* This is the old style evil hack IMPLICIT handling:
		 * since the underlying code is expecting a tag and
		 * class other than the one present we change the
		 * buffer temporarily then change it back afterwards.
		 * This doesn't and never did work for tags > 30.
		 *
		 * Yes this is *horrible* but it is only needed for
		 * old style d2i which will hopefully not be around
		 * for much longer.
		 * FIXME: should copy the buffer then modify it so
		 * the input buffer can be const: we should *always*
		 * copy because the old style d2i might modify the
		 * buffer.
		 */

		if (tag != -1)
			{
			wp = *(unsigned char **)in;
			imphack = *wp;
			if (p == NULL)
				{
				ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
					ERR_R_NESTED_ASN1_ERROR);
				goto err;
				}
			*wp = (unsigned char)((*p & V_ASN1_CONSTRUCTED)
								| it->utype);
			}

		ptmpval = cf->asn1_d2i(pval, in, len);

		if (tag != -1)
			*wp = imphack;

		if (ptmpval)
			return 1;

		ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ERR_R_NESTED_ASN1_ERROR);
		goto err;


		case ASN1_ITYPE_CHOICE:
		if (asn1_cb && !asn1_cb(ASN1_OP_D2I_PRE, pval, it))
				goto auxerr;

		/* Allocate structure */
		if (!*pval && !ASN1_item_ex_new(pval, it))
			{
			ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
						ERR_R_NESTED_ASN1_ERROR);
			goto err;
			}
		/* CHOICE type, try each possibility in turn */
		pchval = NULL;
		p = *in;
		for (i = 0, tt=it->templates; i < it->tcount; i++, tt++)
			{
			pchptr = asn1_get_field_ptr(pval, tt);
			/* We mark field as OPTIONAL so its absence
			 * can be recognised.
			 */
			ret = asn1_template_ex_d2i(pchptr, &p, len, tt, 1, ctx);
			/* If field not present, try the next one */
			if (ret == -1)
				continue;
			/* If positive return, read OK, break loop */
			if (ret > 0)
				break;
			/* Otherwise must be an ASN1 parsing error */
			errtt = tt;
			ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
						ERR_R_NESTED_ASN1_ERROR);
			goto err;
			}

		/* Did we fall off the end without reading anything? */
		if (i == it->tcount)
			{
			/* If OPTIONAL, this is OK */
			if (opt)
				{
				/* Free and zero it */
				ASN1_item_ex_free(pval, it);
				return -1;
				}
			ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
					ASN1_R_NO_MATCHING_CHOICE_TYPE);
			goto err;
			}

		asn1_set_choice_selector(pval, i, it);
		*in = p;
		if (asn1_cb && !asn1_cb(ASN1_OP_D2I_POST, pval, it))
				goto auxerr;
		return 1;

		case ASN1_ITYPE_NDEF_SEQUENCE:
		case ASN1_ITYPE_SEQUENCE:
		p = *in;
		tmplen = len;

		/* If no IMPLICIT tagging set to SEQUENCE, UNIVERSAL */
		if (tag == -1)
			{
			tag = V_ASN1_SEQUENCE;
			aclass = V_ASN1_UNIVERSAL;
			}
		/* Get SEQUENCE length and update len, p */
		ret = asn1_check_tlen(&len, NULL, NULL, &seq_eoc, &cst,
					&p, len, tag, aclass, opt, ctx);
		if (!ret)
			{
			ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
					ERR_R_NESTED_ASN1_ERROR);
			goto err;
			}
		else if (ret == -1)
			return -1;
		if (aux && (aux->flags & ASN1_AFLG_BROKEN))
			{
			len = tmplen - (p - *in);
			seq_nolen = 1;
			}
		/* If indefinite we don't do a length check */
		else seq_nolen = seq_eoc;
		if (!cst)
			{
			ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
				ASN1_R_SEQUENCE_NOT_CONSTRUCTED);
			goto err;
			}

		if (!*pval && !ASN1_item_ex_new(pval, it))
			{
			ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
				ERR_R_NESTED_ASN1_ERROR);
			goto err;
			}

		if (asn1_cb && !asn1_cb(ASN1_OP_D2I_PRE, pval, it))
				goto auxerr;

		/* Get each field entry */
		for (i = 0, tt = it->templates; i < it->tcount; i++, tt++)
			{
			const ASN1_TEMPLATE *seqtt;
			ASN1_VALUE **pseqval;
			seqtt = asn1_do_adb(pval, tt, 1);
			if (!seqtt)
				goto err;
			pseqval = asn1_get_field_ptr(pval, seqtt);
			/* Have we ran out of data? */
			if (!len)
				break;
			q = p;
			if (asn1_check_eoc(&p, len))
				{
				if (!seq_eoc)
					{
					ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
							ASN1_R_UNEXPECTED_EOC);
					goto err;
					}
				len -= p - q;
				seq_eoc = 0;
				q = p;
				break;
				}
			/* This determines the OPTIONAL flag value. The field
			 * cannot be omitted if it is the last of a SEQUENCE
			 * and there is still data to be read. This isn't
			 * strictly necessary but it increases efficiency in
			 * some cases.
			 */
			if (i == (it->tcount - 1))