-/* $OpenBSD: tasn_dec.c,v 1.56 2022/05/04 10:53:26 jsing Exp $ */
+/* $OpenBSD: tasn_dec.c,v 1.57 2022/05/04 10:57:48 jsing Exp $ */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
* project 2000.
*/
#define ASN1_MAX_CONSTRUCTED_NEST 30
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_check_eoc_cbs(CBS *cbs);
+static int asn1_find_end(CBS *cbs, size_t length, char indefinite);
-static int asn1_collect(CBB *cbb, const unsigned char **in, long len,
- char inf, int tag, int aclass, int depth);
+static int asn1_collect(CBB *cbb, CBS *cbs, char indefinite, int expected_tag,
+ int expected_class, int depth);
static int asn1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in,
long len, const ASN1_ITEM *it, int tag, int aclass, char opt, int depth);
}
content = *in;
- if (!asn1_find_end(&p, plen, inf))
+ if (plen < 0)
goto err;
+ CBS_init(&cbs, p, plen);
+ if (!asn1_find_end(&cbs, plen, inf))
+ goto err;
+ p = CBS_data(&cbs);
len = p - content;
} else if (cst) {
/*
*/
if (!CBB_init(&cbb, 0))
goto err;
- if (!asn1_collect(&cbb, &p, plen, inf, -1, V_ASN1_UNIVERSAL, 0))
+ if (plen < 0)
+ goto err;
+ CBS_init(&cbs, p, plen);
+ if (!asn1_collect(&cbb, &cbs, inf, -1, V_ASN1_UNIVERSAL, 0))
goto err;
+ p = CBS_data(&cbs);
if (!CBB_finish(&cbb, &data, &data_len))
goto err;
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.
- */
-
+/* Find the end of an ASN.1 object. */
static int
-asn1_find_end(const unsigned char **in, long len, char inf)
+asn1_find_end(CBS *cbs, size_t length, char indefinite)
{
- int expected_eoc;
- long plen;
- const unsigned char *p = *in, *q;
+ size_t eoc_count;
- /* If not indefinite length constructed just add length */
- if (inf == 0) {
- *in += len;
+ if (!indefinite) {
+ if (!CBS_skip(cbs, length)) {
+ ASN1error(ERR_R_NESTED_ASN1_ERROR);
+ return 0;
+ }
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 just
- * skip to the end of the data.
- */
- while (len > 0) {
- if (asn1_check_eoc(&p, len)) {
- expected_eoc--;
- if (expected_eoc == 0)
+
+ eoc_count = 1;
+
+ while (CBS_len(cbs) > 0) {
+ if (asn1_check_eoc_cbs(cbs)) {
+ if (--eoc_count == 0)
break;
- len -= 2;
continue;
}
- q = p;
- /* Just read in a header: only care about the length */
- if (!asn1_check_tag(&plen, NULL, NULL, &inf, NULL, &p, len,
- -1, 0, 0)) {
+ if (!asn1_check_tag_cbs(cbs, &length, NULL, NULL,
+ &indefinite, NULL, -1, 0, 0)) {
ASN1error(ERR_R_NESTED_ASN1_ERROR);
return 0;
}
- if (inf)
- expected_eoc++;
- else
- p += plen;
- len -= p - q;
+ if (indefinite) {
+ eoc_count++;
+ continue;
+ }
+ if (!CBS_skip(cbs, length))
+ return 0;
}
- if (expected_eoc) {
+
+ if (eoc_count > 0) {
ASN1error(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.
- */
#ifndef ASN1_MAX_STRING_NEST
/* This determines how many levels of recursion are permitted in ASN1
#define ASN1_MAX_STRING_NEST 5
#endif
+/* Collect the contents from a constructed ASN.1 object. */
static int
-asn1_collect(CBB *cbb, const unsigned char **in, long len, char inf,
- int tag, int aclass, int depth)
+asn1_collect(CBB *cbb, CBS *cbs, char indefinite, int expected_tag,
+ int expected_class, int depth)
{
- const unsigned char *p, *q;
- long plen;
- char cst, ininf;
+ char constructed;
+ size_t length;
+ CBS content;
+ int need_eoc;
if (depth > ASN1_MAX_STRING_NEST) {
ASN1error(ASN1_R_NESTED_ASN1_STRING);
return 0;
}
- p = *in;
- inf &= 1;
+ need_eoc = indefinite;
- while (len > 0) {
- q = p;
- /* Check for EOC */
- if (asn1_check_eoc(&p, len)) {
- /* EOC is illegal outside indefinite length
- * constructed form */
- if (!inf) {
+ while (CBS_len(cbs) > 0) {
+ if (asn1_check_eoc_cbs(cbs)) {
+ if (!need_eoc) {
ASN1error(ASN1_R_UNEXPECTED_EOC);
return 0;
}
- inf = 0;
- break;
+ return 1;
}
-
- if (!asn1_check_tag(&plen, NULL, NULL, &ininf, &cst, &p, len,
- tag, aclass, 0)) {
+ if (!asn1_check_tag_cbs(cbs, &length, NULL, NULL, &indefinite,
+ &constructed, expected_tag, expected_class, 0)) {
ASN1error(ERR_R_NESTED_ASN1_ERROR);
return 0;
}
- /* If indefinite length constructed update max length */
- if (cst) {
- if (!asn1_collect(cbb, &p, plen, ininf, tag, aclass,
- depth + 1))
- return 0;
- } else if (plen > 0) {
- if (!CBB_add_bytes(cbb, p, plen))
+ if (constructed) {
+ if (!asn1_collect(cbb, cbs, indefinite, expected_tag,
+ expected_class, depth + 1))
return 0;
- p += plen;
+ continue;
}
- len -= p - q;
+
+ if (!CBS_get_bytes(cbs, &content, length)) {
+ ASN1error(ERR_R_NESTED_ASN1_ERROR);
+ return 0;
+ }
+ if (!CBB_add_bytes(cbb, CBS_data(&content), CBS_len(&content)))
+ return 0;
}
- if (inf) {
+
+ if (need_eoc) {
ASN1error(ASN1_R_MISSING_EOC);
return 0;
}
- *in = p;
+
return 1;
}
-/* Check for ASN1 EOC and swallow it if found */
+static int
+asn1_check_eoc_cbs(CBS *cbs)
+{
+ uint16_t eoc;
+
+ if (!CBS_peek_u16(cbs, &eoc))
+ return 0;
+ if (eoc != 0)
+ return 0;
+
+ return CBS_skip(cbs, 2);
+}
static int
asn1_check_eoc(const unsigned char **in, long len)
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