tasn_dec.c

openssl包含TLS

		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_EX_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_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_D2I, ERR_R_NESTED_ASN1_ERROR);
				goto err;
			}
			len -= p - q;
			if(!sk_push((STACK *)*val, (char *)skfield)) {
				ASN1err(ASN1_F_ASN1_TEMPLATE_D2I, ERR_R_MALLOC_FAILURE);
				goto err;
			}
		}
		if(sk_eoc) {
			ASN1err(ASN1_F_ASN1_TEMPLATE_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_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_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, 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;
	unsigned char *p;
	BUF_MEM buf;
	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;
	/* 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)) goto err;
		len = buf.length;
		/* Append a final null to string */
		if(!BUF_MEM_grow_clean(&buf, len + 1)) {
			ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ERR_R_MALLOC_FAILURE);
			return 0;
		}
		buf.data[len] = 0;
		cont = (unsigned char *)buf.data;
		free_cont = 1;
	} else {
		cont = p;
		len = plen;
		p += plen;
	}

	/* We now have content length and type: translate into a structure */
	if(!asn1_ex_c2i(pval, cont, len, utype, &free_cont, it)) goto err;

	*in = p;
	ret = 1;
	err:
	if(free_cont && buf.data) OPENSSL_free(buf.data);
	return ret;
}

/* Translate ASN1 content octets into a structure */

int asn1_ex_c2i(ASN1_VALUE **pval, unsigned char *cont, int len, int utype, char *free_cont, const ASN1_ITEM *it)
{
	ASN1_VALUE **opval = NULL;
	ASN1_STRING *stmp;
	ASN1_TYPE *typ = NULL;
	int ret = 0;
	const ASN1_PRIMITIVE_FUNCS *pf;
	ASN1_INTEGER **tint;
	pf = it->funcs;
	if(pf && pf->prim_c2i) return pf->prim_c2i(pval, cont, len, utype, free_cont, it);
	/* If ANY type clear type and set pointer to internal value */
	if(it->utype == V_ASN1_ANY) {
		if(!*pval) {
			typ = ASN1_TYPE_new();
			*pval = (ASN1_VALUE *)typ;
		} else typ = (ASN1_TYPE *)*pval;
		if(utype != typ->type) ASN1_TYPE_set(typ, utype, NULL);
		opval = pval;
		pval = (ASN1_VALUE **)&typ->value.ptr;
	}
	switch(utype) {
		case V_ASN1_OBJECT:
		if(!c2i_ASN1_OBJECT((ASN1_OBJECT **)pval, &cont, len)) goto err;
		break;

		case V_ASN1_NULL:
		if(len) {
			ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ASN1_R_NULL_IS_WRONG_LENGTH);
			goto err;
		}
		*pval = (ASN1_VALUE *)1;
		break;

		case V_ASN1_BOOLEAN:
		if(len != 1) {
			ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ASN1_R_BOOLEAN_IS_WRONG_LENGTH);
			goto err;
		} else {
			ASN1_BOOLEAN *tbool;
			tbool = (ASN1_BOOLEAN *)pval;
			*tbool = *cont;
		}
		break;

		case V_ASN1_BIT_STRING:
		if(!c2i_ASN1_BIT_STRING((ASN1_BIT_STRING **)pval, &cont, len)) goto err;
		break;

		case V_ASN1_INTEGER:
		case V_ASN1_NEG_INTEGER:
		case V_ASN1_ENUMERATED:
		case V_ASN1_NEG_ENUMERATED:
		tint = (ASN1_INTEGER **)pval;
		if(!c2i_ASN1_INTEGER(tint, &cont, len)) goto err;
		/* Fixup type to match the expected form */
		(*tint)->type = utype | ((*tint)->type & V_ASN1_NEG);
		break;

		case V_ASN1_OCTET_STRING:
		case V_ASN1_NUMERICSTRING:
		case V_ASN1_PRINTABLESTRING:
		case V_ASN1_T61STRING:
		case V_ASN1_VIDEOTEXSTRING:
		case V_ASN1_IA5STRING:
		case V_ASN1_UTCTIME:
		case V_ASN1_GENERALIZEDTIME:
		case V_ASN1_GRAPHICSTRING:
		case V_ASN1_VISIBLESTRING:
		case V_ASN1_GENERALSTRING:
		case V_ASN1_UNIVERSALSTRING:
		case V_ASN1_BMPSTRING:
		case V_ASN1_UTF8STRING:
		case V_ASN1_OTHER:
		case V_ASN1_SET:
		case V_ASN1_SEQUENCE:
		default:
		/* All based on ASN1_STRING and handled the same */
		if(!*pval) {
			stmp = ASN1_STRING_type_new(utype);
			if(!stmp) {
				ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ERR_R_MALLOC_FAILURE);
				goto err;
			}
			*pval = (ASN1_VALUE *)stmp;
		} else {
			stmp = (ASN1_STRING *)*pval;
			stmp->type = utype;
		}
		/* If we've already allocated a buffer use it */
		if(*free_cont) {
			if(stmp->data) OPENSSL_free(stmp->data);
			stmp->data = cont;
			stmp->length = len;
			*free_cont = 0;
		} else {
			if(!ASN1_STRING_set(stmp, cont, len)) {
				ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ERR_R_MALLOC_FAILURE);
				ASN1_STRING_free(stmp);	
				*pval = NULL;
				goto err;
			}
		}
		break;
	}
	/* If ASN1_ANY and NULL type fix up value */
	if(typ && utype==V_ASN1_NULL) typ->value.ptr = NULL;

	ret = 1;
	err:
	if(!ret)
		{
		ASN1_TYPE_free(typ);
		if (opval)
			*opval = NULL;
		}
	return ret;
}

/* This function finds the end of an ASN1 structure when passed its maximum
 * length, whether it is indefinite length and a pointer to the content.
 * This is more efficient than calling asn1_collect because it does not
 * recurse on each indefinite length header.
 */

static int asn1_find_end(unsigned char **in, long len, char inf)
	{
	int expected_eoc;
	long plen;
	unsigned char *p = *in, *q;
	/* If not indefinite length constructed just add length */
	if (inf == 0)
		{
		*in += len;
		return 1;
		}
	expected_eoc = 1;
	/* Indefinite length constructed form. Find the end when enough EOCs
	 * are found. If more indefinite length constructed headers
	 * are encountered increment the expected eoc count otherwise justi
	 * skip to the end of the data.
	 */
	while (len > 0)
		{
		if(asn1_check_eoc(&p, len))
			{
			expected_eoc--;
			if (expected_eoc == 0)
				break;
			len -= 2;
			continue;
			}
		q = p;
		/* Just read in a header: only care about the length */
		if(!asn1_check_tlen(&plen, NULL, NULL, &inf, NULL, &p, len,
				-1, 0, 0, NULL))
			{
			ASN1err(ASN1_F_ASN1_FIND_END, ERR_R_NESTED_ASN1_ERROR);
			return 0;
			}
		if (inf)
			expected_eoc++;
		else
			p += plen;
		len -= p - q;
		}
	if (expected_eoc)
		{
		ASN1err(ASN1_F_ASN1_FIND_END, ASN1_R_MISSING_EOC);
		return 0;
		}
	*in = p;
	return 1;
	}

/* This function collects the asn1 data from a constructred string
 * type into a buffer. The values of 'in' and 'len' should refer
 * to the contents of the constructed type and 'inf' should be set
 * if it is indefinite length.
 */

static int asn1_collect(BUF_MEM *buf, unsigned char **in, long len, char inf, int tag, int aclass)
{
	unsigned char *p, *q;
	long plen;
	char cst, ininf;
	p = *in;
	inf &= 1;
	while(len > 0) {
		q = p;
		/* Check for EOC */
		if(asn1_check_eoc(&p, len)) {
			/* EOC is illegal outside indefinite length constructed form */
			if(!inf) {
				ASN1err(ASN1_F_ASN1_COLLECT, ASN1_R_UNEXPECTED_EOC);
				return 0;
			}
			inf = 0;
			break;
		}
		if(!asn1_check_tlen(&plen, NULL, NULL, &ininf, &cst, &p, len, tag, aclass, 0, NULL)) {
			ASN1err(ASN1_F_ASN1_COLLECT, ERR_R_NESTED_ASN1_ERROR);
			return 0;
		}
		/* If indefinite length constructed update max length */
		if(cst) {
#ifdef OPENSSL_ALLOW_NESTED_ASN1_STRINGS
			if (!asn1_collect(buf, &p, plen, ininf, tag, aclass))
				return 0;
#else
			ASN1err(ASN1_F_ASN1_COLLECT, ASN1_R_NESTED_ASN1_STRING);
			return 0;
#endif
		} else {
			if(plen && !collect_data(buf, &p, plen)) return 0;
		}
		len -= p - q;
	}
	if(inf) {
		ASN1err(ASN1_F_ASN1_COLLECT, ASN1_R_MISSING_EOC);
		return 0;
	}
	*in = p;
	return 1;
}

static int collect_data(BUF_MEM *buf, unsigned char **p, long plen)
{
		int len;
		if(buf) {
			len = buf->length;
			if(!BUF_MEM_grow_clean(buf, len + plen)) {
				ASN1err(ASN1_F_COLLECT_DATA, ERR_R_MALLOC_FAILURE);
				return 0;
			}
			memcpy(buf->data + len, *p, plen);
		}
		*p += plen;
		return 1;
}

/* Check for ASN1 EOC and swallow it if found */

static int asn1_check_eoc(unsigned char **in, long len)
{
	unsigned char *p;
	if(len < 2) return 0;
	p = *in;
	if(!p[0] && !p[1]) {
		*in += 2;
		return 1;
	}
	return 0;
}

/* Check an ASN1 tag and length: a bit like ASN1_get_object
 * but it sets the length for indefinite length constructed
 * form, we don't know the exact length but we can set an
 * upper bound to the amount of data available minus the
 * header length just read.
 */

static int asn1_check_tlen(long *olen, int *otag, unsigned char *oclass, char *inf, char *cst,
		unsigned char **in, long len, int exptag, int expclass, char opt, ASN1_TLC *ctx)
{
	int i;
	int ptag, pclass;
	long plen;
	unsigned char *p, *q;
	p = *in;
	q = p;

	if(ctx && ctx->valid) {
		i = ctx->ret;
		plen = ctx->plen;
		pclass = ctx->pclass;
		ptag = ctx->ptag;
		p += ctx->hdrlen;
	} else {
		i = ASN1_get_object(&p, &plen, &ptag, &pclass, len);
		if(ctx) {
			ctx->ret = i;
			ctx->plen = plen;
			ctx->pclass = pclass;
			ctx->ptag = ptag;
			ctx->hdrlen = p - q;
			ctx->valid = 1;
			/* If definite length, and no error, length +
			 * header can't exceed total amount of data available. 
			 */
			if(!(i & 0x81) && ((plen + ctx->hdrlen) > len)) {
				ASN1err(ASN1_F_ASN1_CHECK_TLEN, ASN1_R_TOO_LONG);
				asn1_tlc_clear(ctx);
				return 0;
			}
		}
	}

	if(i & 0x80) {
		ASN1err(ASN1_F_ASN1_CHECK_TLEN, ASN1_R_BAD_OBJECT_HEADER);
		asn1_tlc_clear(ctx);
		return 0;
	}
	if(exptag >= 0) {
		if((exptag != ptag) || (expclass != pclass)) {
			/* If type is OPTIONAL, not an error, but indicate missing
			 * type.
			 */
			if(opt) return -1;
			asn1_tlc_clear(ctx);
			ASN1err(ASN1_F_ASN1_CHECK_TLEN, ASN1_R_WRONG_TAG);
			return 0;
		}
		/* We have a tag and class match, so assume we are going to do something with it */
		asn1_tlc_clear(ctx);
	}

	if(i & 1) plen = len - (p - q);

	if(inf) *inf = i & 1;

	if(cst) *cst = i & V_ASN1_CONSTRUCTED;

	if(olen) *olen = plen;
	if(oclass) *oclass = pclass;
	if(otag) *otag = ptag;

	*in = p;
	return 1;
}