tasn_dec.c

开源的ssl算法openssl,版本0.9.8H

				isopt = 0;
			else isopt = (char)(seqtt->flags & ASN1_TFLG_OPTIONAL);
			/* attempt to read in field, allowing each to be
			 * OPTIONAL */

			ret = asn1_template_ex_d2i(pseqval, &p, len,
							seqtt, isopt, ctx);
			if (!ret)
				{
				errtt = seqtt;
				goto err;
				}
			else if (ret == -1)
				{
				/* OPTIONAL component absent.
				 * Free and zero the field.
				 */
				ASN1_template_free(pseqval, seqtt);
				continue;
				}
			/* Update length */
			len -= p - q;
			}

		/* Check for EOC if expecting one */
		if (seq_eoc && !asn1_check_eoc(&p, len))
			{
			ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_MISSING_EOC);
			goto err;
			}
		/* Check all data read */
		if (!seq_nolen && len)
			{
			ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
					ASN1_R_SEQUENCE_LENGTH_MISMATCH);
			goto err;
			}

		/* If we get here we've got no more data in the SEQUENCE,
		 * however we may not have read all fields so check all
		 * remaining are OPTIONAL and clear any that are.
		 */
		for (; i < it->tcount; tt++, i++)
			{
			const ASN1_TEMPLATE *seqtt;
			seqtt = asn1_do_adb(pval, tt, 1);
			if (!seqtt)
				goto err;
			if (seqtt->flags & ASN1_TFLG_OPTIONAL)
				{
				ASN1_VALUE **pseqval;
				pseqval = asn1_get_field_ptr(pval, seqtt);
				ASN1_template_free(pseqval, seqtt);
				}
			else
				{
				errtt = seqtt;
				ASN1err(ASN1_F_ASN1_ITEM_EX_D2I,
							ASN1_R_FIELD_MISSING);
				goto err;
				}
			}
		/* Save encoding */
		if (!asn1_enc_save(pval, *in, p - *in, it))
			goto auxerr;
		*in = p;
		if (asn1_cb && !asn1_cb(ASN1_OP_D2I_POST, pval, it))
				goto auxerr;
		return 1;

		default:
		return 0;
		}
	auxerr:
	ASN1err(ASN1_F_ASN1_ITEM_EX_D2I, ASN1_R_AUX_ERROR);
	err:
	ASN1_item_ex_free(pval, it);
	if (errtt)
		ERR_add_error_data(4, "Field=", errtt->field_name,
					", Type=", it->sname);
	else
		ERR_add_error_data(2, "Type=", it->sname);
	return 0;
	}

/* Templates are handled with two separate functions.
 * One handles any EXPLICIT tag and the other handles the rest.
 */

static int asn1_template_ex_d2i(ASN1_VALUE **val,
				const unsigned char **in, long inlen,
				const ASN1_TEMPLATE *tt, char opt,
							ASN1_TLC *ctx)
	{
	int flags, aclass;
	int ret;
	long len;
	const unsigned char *p, *q;
	char exp_eoc;
	if (!val)
		return 0;
	flags = tt->flags;
	aclass = flags & ASN1_TFLG_TAG_CLASS;

	p = *in;

	/* Check if EXPLICIT tag expected */
	if (flags & ASN1_TFLG_EXPTAG)
		{
		char cst;
		/* Need to work out amount of data available to the inner
		 * content and where it starts: so read in EXPLICIT header to
		 * get the info.
		 */
		ret = asn1_check_tlen(&len, NULL, NULL, &exp_eoc, &cst,
					&p, inlen, tt->tag, aclass, opt, ctx);
		q = p;
		if (!ret)
			{
			ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
					ERR_R_NESTED_ASN1_ERROR);
			return 0;
			}
		else if (ret == -1)
			return -1;
		if (!cst)
			{
			ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
					ASN1_R_EXPLICIT_TAG_NOT_CONSTRUCTED);
			return 0;
			}
		/* We've found the field so it can't be OPTIONAL now */
		ret = asn1_template_noexp_d2i(val, &p, len, tt, 0, ctx);
		if (!ret)
			{
			ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
					ERR_R_NESTED_ASN1_ERROR);
			return 0;
			}
		/* We read the field in OK so update length */
		len -= p - q;
		if (exp_eoc)
			{
			/* If NDEF we must have an EOC here */
			if (!asn1_check_eoc(&p, len))
				{
				ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
						ASN1_R_MISSING_EOC);
				goto err;
				}
			}
		else
			{
			/* Otherwise we must hit the EXPLICIT tag end or its
			 * an error */
			if (len)
				{
				ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
					ASN1_R_EXPLICIT_LENGTH_MISMATCH);
				goto err;
				}
			}
		}
		else 
			return asn1_template_noexp_d2i(val, in, inlen,
								tt, opt, ctx);

	*in = p;
	return 1;

	err:
	ASN1_template_free(val, tt);
	*val = NULL;
	return 0;
	}

static int asn1_template_noexp_d2i(ASN1_VALUE **val,
				const unsigned char **in, long len,
				const ASN1_TEMPLATE *tt, char opt,
				ASN1_TLC *ctx)
	{
	int flags, aclass;
	int ret;
	const unsigned char *p, *q;
	if (!val)
		return 0;
	flags = tt->flags;
	aclass = flags & ASN1_TFLG_TAG_CLASS;

	p = *in;
	q = p;

	if (flags & ASN1_TFLG_SK_MASK)
		{
		/* SET OF, SEQUENCE OF */
		int sktag, skaclass;
		char sk_eoc;
		/* First work out expected inner tag value */
		if (flags & ASN1_TFLG_IMPTAG)
			{
			sktag = tt->tag;
			skaclass = aclass;
			}
		else
			{
			skaclass = V_ASN1_UNIVERSAL;
			if (flags & ASN1_TFLG_SET_OF)
				sktag = V_ASN1_SET;
			else
				sktag = V_ASN1_SEQUENCE;
			}
		/* Get the tag */
		ret = asn1_check_tlen(&len, NULL, NULL, &sk_eoc, NULL,
					&p, len, sktag, skaclass, opt, ctx);
		if (!ret)
			{
			ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
						ERR_R_NESTED_ASN1_ERROR);
			return 0;
			}
		else if (ret == -1)
			return -1;
		if (!*val)
			*val = (ASN1_VALUE *)sk_new_null();
		else
			{
			/* We've got a valid STACK: free up any items present */
			STACK *sktmp = (STACK *)*val;
			ASN1_VALUE *vtmp;
			while(sk_num(sktmp) > 0)
				{
				vtmp = (ASN1_VALUE *)sk_pop(sktmp);
				ASN1_item_ex_free(&vtmp,
						ASN1_ITEM_ptr(tt->item));
				}
			}
				
		if (!*val)
			{
			ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
						ERR_R_MALLOC_FAILURE);
			goto err;
			}

		/* Read as many items as we can */
		while(len > 0)
			{
			ASN1_VALUE *skfield;
			q = p;
			/* See if EOC found */
			if (asn1_check_eoc(&p, len))
				{
				if (!sk_eoc)
					{
					ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
							ASN1_R_UNEXPECTED_EOC);
					goto err;
					}
				len -= p - q;
				sk_eoc = 0;
				break;
				}
			skfield = NULL;
			if (!ASN1_item_ex_d2i(&skfield, &p, len,
						ASN1_ITEM_ptr(tt->item),
						-1, 0, 0, ctx))
				{
				ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
					ERR_R_NESTED_ASN1_ERROR);
				goto err;
				}
			len -= p - q;
			if (!sk_push((STACK *)*val, (char *)skfield))
				{
				ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
						ERR_R_MALLOC_FAILURE);
				goto err;
				}
			}
		if (sk_eoc)
			{
			ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I, ASN1_R_MISSING_EOC);
			goto err;
			}
		}
	else if (flags & ASN1_TFLG_IMPTAG)
		{
		/* IMPLICIT tagging */
		ret = ASN1_item_ex_d2i(val, &p, len,
			ASN1_ITEM_ptr(tt->item), tt->tag, aclass, opt, ctx);
		if (!ret)
			{
			ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
						ERR_R_NESTED_ASN1_ERROR);
			goto err;
			}
		else if (ret == -1)
			return -1;
		}
	else
		{
		/* Nothing special */
		ret = ASN1_item_ex_d2i(val, &p, len, ASN1_ITEM_ptr(tt->item),
							-1, 0, opt, ctx);
		if (!ret)
			{
			ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
					ERR_R_NESTED_ASN1_ERROR);
			goto err;
			}
		else if (ret == -1)
			return -1;
		}

	*in = p;
	return 1;

	err:
	ASN1_template_free(val, tt);
	*val = NULL;
	return 0;
	}

static int asn1_d2i_ex_primitive(ASN1_VALUE **pval,
				const unsigned char **in, long inlen, 
				const ASN1_ITEM *it,
				int tag, int aclass, char opt, ASN1_TLC *ctx)
	{
	int ret = 0, utype;
	long plen;
	char cst, inf, free_cont = 0;
	const unsigned char *p;
	BUF_MEM buf;
	const unsigned char *cont = NULL;
	long len; 
	if (!pval)
		{
		ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ASN1_R_ILLEGAL_NULL);
		return 0; /* Should never happen */
		}

	if (it->itype == ASN1_ITYPE_MSTRING)
		{
		utype = tag;
		tag = -1;
		}
	else
		utype = it->utype;

	if (utype == V_ASN1_ANY)
		{
		/* If type is ANY need to figure out type from tag */
		unsigned char oclass;
		if (tag >= 0)
			{
			ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
					ASN1_R_ILLEGAL_TAGGED_ANY);
			return 0;
			}
		if (opt)
			{
			ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
					ASN1_R_ILLEGAL_OPTIONAL_ANY);
			return 0;
			}
		p = *in;
		ret = asn1_check_tlen(NULL, &utype, &oclass, NULL, NULL,
					&p, inlen, -1, 0, 0, ctx);
		if (!ret)
			{
			ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
					ERR_R_NESTED_ASN1_ERROR);
			return 0;
			}
		if (oclass != V_ASN1_UNIVERSAL)
			utype = V_ASN1_OTHER;
		}
	if (tag == -1)
		{
		tag = utype;
		aclass = V_ASN1_UNIVERSAL;
		}
	p = *in;
	/* Check header */
	ret = asn1_check_tlen(&plen, NULL, NULL, &inf, &cst,
				&p, inlen, tag, aclass, opt, ctx);
	if (!ret)
		{
		ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ERR_R_NESTED_ASN1_ERROR);
		return 0;
		}
	else if (ret == -1)
		return -1;
        ret = 0;
	/* SEQUENCE, SET and "OTHER" are left in encoded form */
	if ((utype == V_ASN1_SEQUENCE)
		|| (utype == V_ASN1_SET) || (utype == V_ASN1_OTHER))
		{
		/* Clear context cache for type OTHER because the auto clear
		 * when we have a exact match wont work
		 */
		if (utype == V_ASN1_OTHER)
			{
			asn1_tlc_clear(ctx);
			}
		/* SEQUENCE and SET must be constructed */
		else if (!cst)
			{
			ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
				ASN1_R_TYPE_NOT_CONSTRUCTED);
			return 0;
			}

		cont = *in;
		/* If indefinite length constructed find the real end */
		if (inf)
			{
			if (!asn1_find_end(&p, plen, inf))
				 goto err;
			len = p - cont;
			}
		else
			{
			len = p - cont + plen;
			p += plen;
			buf.data = NULL;
			}
		}
	else if (cst)
		{
		buf.length = 0;
		buf.max = 0;
		buf.data = NULL;
		/* Should really check the internal tags are correct but
		 * some things may get this wrong. The relevant specs
		 * say that constructed string types should be OCTET STRINGs
		 * internally irrespective of the type. So instead just check
		 * for UNIVERSAL class and ignore the tag.
		 */
		if (!asn1_collect(&buf, &p, plen, inf, -1, V_ASN1_UNIVERSAL))
			{