--- /dev/null
+/* Copyright (c) 2014, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <openssl/bytestring.h>
+
+#include <assert.h>
+#include <string.h>
+
+#include "internal.h"
+#include "../internal.h"
+
+
+// kMaxDepth is a just a sanity limit. The code should be such that the length
+// of the input being processes always decreases. None the less, a very large
+// input could otherwise cause the stack to overflow.
+static const unsigned kMaxDepth = 2048;
+
+// is_string_type returns one if |tag| is a string type and zero otherwise. It
+// ignores the constructed bit.
+static int is_string_type(unsigned tag) {
+ switch (tag & ~CBS_ASN1_CONSTRUCTED) {
+ case CBS_ASN1_BITSTRING:
+ case CBS_ASN1_OCTETSTRING:
+ case CBS_ASN1_UTF8STRING:
+ case CBS_ASN1_NUMERICSTRING:
+ case CBS_ASN1_PRINTABLESTRING:
+ case CBS_ASN1_T61STRING:
+ case CBS_ASN1_VIDEOTEXSTRING:
+ case CBS_ASN1_IA5STRING:
+ case CBS_ASN1_GRAPHICSTRING:
+ case CBS_ASN1_VISIBLESTRING:
+ case CBS_ASN1_GENERALSTRING:
+ case CBS_ASN1_UNIVERSALSTRING:
+ case CBS_ASN1_BMPSTRING:
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+// cbs_find_ber walks an ASN.1 structure in |orig_in| and sets |*ber_found|
+// depending on whether an indefinite length element or constructed string was
+// found. The value of |orig_in| is not changed. It returns one on success (i.e.
+// |*ber_found| was set) and zero on error.
+static int cbs_find_ber(const CBS *orig_in, char *ber_found, unsigned depth) {
+ CBS in;
+
+ if (depth > kMaxDepth) {
+ return 0;
+ }
+
+ CBS_init(&in, CBS_data(orig_in), CBS_len(orig_in));
+ *ber_found = 0;
+
+ while (CBS_len(&in) > 0) {
+ CBS contents;
+ unsigned tag;
+ size_t header_len;
+
+ if (!CBS_get_any_ber_asn1_element(&in, &contents, &tag, &header_len)) {
+ return 0;
+ }
+ if (CBS_len(&contents) == header_len &&
+ header_len > 0 &&
+ CBS_data(&contents)[header_len-1] == 0x80) {
+ // Found an indefinite-length element.
+ *ber_found = 1;
+ return 1;
+ }
+ if (tag & CBS_ASN1_CONSTRUCTED) {
+ if (is_string_type(tag)) {
+ // Constructed strings are only legal in BER and require conversion.
+ *ber_found = 1;
+ return 1;
+ }
+ if (!CBS_skip(&contents, header_len) ||
+ !cbs_find_ber(&contents, ber_found, depth + 1)) {
+ return 0;
+ }
+ }
+ }
+
+ return 1;
+}
+
+// is_eoc returns true if |header_len| and |contents|, as returned by
+// |CBS_get_any_ber_asn1_element|, indicate an "end of contents" (EOC) value.
+static char is_eoc(size_t header_len, CBS *contents) {
+ return header_len == 2 && CBS_len(contents) == 2 &&
+ OPENSSL_memcmp(CBS_data(contents), "\x00\x00", 2) == 0;
+}
+
+// cbs_convert_ber reads BER data from |in| and writes DER data to |out|. If
+// |string_tag| is non-zero, then all elements must match |string_tag| up to the
+// constructed bit and primitive element bodies are written to |out| without
+// element headers. This is used when concatenating the fragments of a
+// constructed string. If |looking_for_eoc| is set then any EOC elements found
+// will cause the function to return after consuming it. It returns one on
+// success and zero on error.
+static int cbs_convert_ber(CBS *in, CBB *out, unsigned string_tag,
+ char looking_for_eoc, unsigned depth) {
+ assert(!(string_tag & CBS_ASN1_CONSTRUCTED));
+
+ if (depth > kMaxDepth) {
+ return 0;
+ }
+
+ while (CBS_len(in) > 0) {
+ CBS contents;
+ unsigned tag, child_string_tag = string_tag;
+ size_t header_len;
+ CBB *out_contents, out_contents_storage;
+
+ if (!CBS_get_any_ber_asn1_element(in, &contents, &tag, &header_len)) {
+ return 0;
+ }
+
+ if (is_eoc(header_len, &contents)) {
+ return looking_for_eoc;
+ }
+
+ if (string_tag != 0) {
+ // This is part of a constructed string. All elements must match
+ // |string_tag| up to the constructed bit and get appended to |out|
+ // without a child element.
+ if ((tag & ~CBS_ASN1_CONSTRUCTED) != string_tag) {
+ return 0;
+ }
+ out_contents = out;
+ } else {
+ unsigned out_tag = tag;
+ if ((tag & CBS_ASN1_CONSTRUCTED) && is_string_type(tag)) {
+ // If a constructed string, clear the constructed bit and inform
+ // children to concatenate bodies.
+ out_tag &= ~CBS_ASN1_CONSTRUCTED;
+ child_string_tag = out_tag;
+ }
+ if (!CBB_add_asn1(out, &out_contents_storage, out_tag)) {
+ return 0;
+ }
+ out_contents = &out_contents_storage;
+ }
+
+ if (CBS_len(&contents) == header_len && header_len > 0 &&
+ CBS_data(&contents)[header_len - 1] == 0x80) {
+ // This is an indefinite length element.
+ if (!cbs_convert_ber(in, out_contents, child_string_tag,
+ 1 /* looking for eoc */, depth + 1) ||
+ !CBB_flush(out)) {
+ return 0;
+ }
+ continue;
+ }
+
+ if (!CBS_skip(&contents, header_len)) {
+ return 0;
+ }
+
+ if (tag & CBS_ASN1_CONSTRUCTED) {
+ // Recurse into children.
+ if (!cbs_convert_ber(&contents, out_contents, child_string_tag,
+ 0 /* not looking for eoc */, depth + 1)) {
+ return 0;
+ }
+ } else {
+ // Copy primitive contents as-is.
+ if (!CBB_add_bytes(out_contents, CBS_data(&contents),
+ CBS_len(&contents))) {
+ return 0;
+ }
+ }
+
+ if (!CBB_flush(out)) {
+ return 0;
+ }
+ }
+
+ return looking_for_eoc == 0;
+}
+
+int CBS_asn1_ber_to_der(CBS *in, uint8_t **out, size_t *out_len) {
+ CBB cbb;
+
+ // First, do a quick walk to find any indefinite-length elements. Most of the
+ // time we hope that there aren't any and thus we can quickly return.
+ char conversion_needed;
+ if (!cbs_find_ber(in, &conversion_needed, 0)) {
+ return 0;
+ }
+
+ if (!conversion_needed) {
+ *out = NULL;
+ *out_len = 0;
+ return 1;
+ }
+
+ if (!CBB_init(&cbb, CBS_len(in)) ||
+ !cbs_convert_ber(in, &cbb, 0, 0, 0) ||
+ !CBB_finish(&cbb, out, out_len)) {
+ CBB_cleanup(&cbb);
+ return 0;
+ }
+
+ return 1;
+}
+
+int CBS_get_asn1_implicit_string(CBS *in, CBS *out, uint8_t **out_storage,
+ unsigned outer_tag, unsigned inner_tag) {
+ assert(!(outer_tag & CBS_ASN1_CONSTRUCTED));
+ assert(!(inner_tag & CBS_ASN1_CONSTRUCTED));
+ assert(is_string_type(inner_tag));
+
+ if (CBS_peek_asn1_tag(in, outer_tag)) {
+ // Normal implicitly-tagged string.
+ *out_storage = NULL;
+ return CBS_get_asn1(in, out, outer_tag);
+ }
+
+ // Otherwise, try to parse an implicitly-tagged constructed string.
+ // |CBS_asn1_ber_to_der| is assumed to have run, so only allow one level deep
+ // of nesting.
+ CBB result;
+ CBS child;
+ if (!CBB_init(&result, CBS_len(in)) ||
+ !CBS_get_asn1(in, &child, outer_tag | CBS_ASN1_CONSTRUCTED)) {
+ goto err;
+ }
+
+ while (CBS_len(&child) > 0) {
+ CBS chunk;
+ if (!CBS_get_asn1(&child, &chunk, inner_tag) ||
+ !CBB_add_bytes(&result, CBS_data(&chunk), CBS_len(&chunk))) {
+ goto err;
+ }
+ }
+
+ uint8_t *data;
+ size_t len;
+ if (!CBB_finish(&result, &data, &len)) {
+ goto err;
+ }
+
+ CBS_init(out, data, len);
+ *out_storage = data;
+ return 1;
+
+err:
+ CBB_cleanup(&result);
+ return 0;
+}
git://repos.xcallymotion.com / motion2.git / blobdiff