394 lines
8.4 KiB
C
394 lines
8.4 KiB
C
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/* Copyright (c) 2014, Google Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
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#include <openssl/bytestring.h>
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#include <assert.h>
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#include <string.h>
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#include <openssl/mem.h>
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void CBB_zero(CBB *cbb) {
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memset(cbb, 0, sizeof(CBB));
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}
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static int cbb_init(CBB *cbb, uint8_t *buf, size_t cap) {
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struct cbb_buffer_st *base;
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base = OPENSSL_malloc(sizeof(struct cbb_buffer_st));
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if (base == NULL) {
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return 0;
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}
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base->buf = buf;
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base->len = 0;
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base->cap = cap;
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base->can_resize = 1;
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memset(cbb, 0, sizeof(CBB));
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cbb->base = base;
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cbb->is_top_level = 1;
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return 1;
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}
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int CBB_init(CBB *cbb, size_t initial_capacity) {
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uint8_t *buf;
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buf = OPENSSL_malloc(initial_capacity);
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if (initial_capacity > 0 && buf == NULL) {
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return 0;
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}
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if (!cbb_init(cbb, buf, initial_capacity)) {
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OPENSSL_free(buf);
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return 0;
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}
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return 1;
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}
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int CBB_init_fixed(CBB *cbb, uint8_t *buf, size_t len) {
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if (!cbb_init(cbb, buf, len)) {
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return 0;
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}
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cbb->base->can_resize = 0;
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return 1;
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}
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void CBB_cleanup(CBB *cbb) {
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if (cbb->base) {
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if (cbb->base->can_resize) {
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OPENSSL_free(cbb->base->buf);
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}
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OPENSSL_free(cbb->base);
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}
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cbb->base = NULL;
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}
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static int cbb_buffer_add(struct cbb_buffer_st *base, uint8_t **out,
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size_t len) {
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size_t newlen;
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if (base == NULL) {
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return 0;
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}
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newlen = base->len + len;
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if (newlen < base->len) {
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/* Overflow */
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return 0;
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}
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if (newlen > base->cap) {
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size_t newcap = base->cap * 2;
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uint8_t *newbuf;
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if (!base->can_resize) {
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return 0;
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}
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if (newcap < base->cap || newcap < newlen) {
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newcap = newlen;
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}
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newbuf = OPENSSL_realloc(base->buf, newcap);
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if (newbuf == NULL) {
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return 0;
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}
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base->buf = newbuf;
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base->cap = newcap;
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}
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if (out) {
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*out = base->buf + base->len;
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}
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base->len = newlen;
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return 1;
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}
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static int cbb_buffer_add_u(struct cbb_buffer_st *base, uint32_t v,
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size_t len_len) {
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uint8_t *buf;
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size_t i;
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if (len_len == 0) {
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return 1;
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}
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if (!cbb_buffer_add(base, &buf, len_len)) {
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return 0;
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}
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for (i = len_len - 1; i < len_len; i--) {
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buf[i] = v;
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v >>= 8;
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}
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return 1;
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}
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int CBB_finish(CBB *cbb, uint8_t **out_data, size_t *out_len) {
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if (!cbb->is_top_level) {
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return 0;
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}
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if (!CBB_flush(cbb)) {
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return 0;
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}
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if (cbb->base->can_resize && (out_data == NULL || out_len == NULL)) {
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/* |out_data| and |out_len| can only be NULL if the CBB is fixed. */
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return 0;
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}
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if (out_data != NULL) {
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*out_data = cbb->base->buf;
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}
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if (out_len != NULL) {
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*out_len = cbb->base->len;
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}
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cbb->base->buf = NULL;
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CBB_cleanup(cbb);
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return 1;
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}
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/* CBB_flush recurses and then writes out any pending length prefix. The
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* current length of the underlying base is taken to be the length of the
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* length-prefixed data. */
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int CBB_flush(CBB *cbb) {
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size_t child_start, i, len;
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if (cbb->base == NULL) {
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return 0;
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}
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if (cbb->child == NULL || cbb->pending_len_len == 0) {
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return 1;
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}
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child_start = cbb->offset + cbb->pending_len_len;
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if (!CBB_flush(cbb->child) ||
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child_start < cbb->offset ||
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cbb->base->len < child_start) {
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return 0;
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}
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len = cbb->base->len - child_start;
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if (cbb->pending_is_asn1) {
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/* For ASN.1 we assume that we'll only need a single byte for the length.
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* If that turned out to be incorrect, we have to move the contents along
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* in order to make space. */
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size_t len_len;
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uint8_t initial_length_byte;
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assert (cbb->pending_len_len == 1);
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if (len > 0xfffffffe) {
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/* Too large. */
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return 0;
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} else if (len > 0xffffff) {
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len_len = 5;
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initial_length_byte = 0x80 | 4;
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} else if (len > 0xffff) {
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len_len = 4;
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initial_length_byte = 0x80 | 3;
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} else if (len > 0xff) {
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len_len = 3;
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initial_length_byte = 0x80 | 2;
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} else if (len > 0x7f) {
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len_len = 2;
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initial_length_byte = 0x80 | 1;
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} else {
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len_len = 1;
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initial_length_byte = len;
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len = 0;
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}
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if (len_len != 1) {
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/* We need to move the contents along in order to make space. */
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size_t extra_bytes = len_len - 1;
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if (!cbb_buffer_add(cbb->base, NULL, extra_bytes)) {
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return 0;
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}
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memmove(cbb->base->buf + child_start + extra_bytes,
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cbb->base->buf + child_start, len);
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}
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cbb->base->buf[cbb->offset++] = initial_length_byte;
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cbb->pending_len_len = len_len - 1;
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}
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for (i = cbb->pending_len_len - 1; i < cbb->pending_len_len; i--) {
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cbb->base->buf[cbb->offset + i] = len;
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len >>= 8;
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}
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if (len != 0) {
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return 0;
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}
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cbb->child->base = NULL;
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cbb->child = NULL;
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cbb->pending_len_len = 0;
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cbb->pending_is_asn1 = 0;
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cbb->offset = 0;
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return 1;
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}
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size_t CBB_len(const CBB *cbb) {
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assert(cbb->child == NULL);
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return cbb->base->len;
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}
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static int cbb_add_length_prefixed(CBB *cbb, CBB *out_contents,
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size_t len_len) {
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uint8_t *prefix_bytes;
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if (!CBB_flush(cbb)) {
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return 0;
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}
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cbb->offset = cbb->base->len;
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if (!cbb_buffer_add(cbb->base, &prefix_bytes, len_len)) {
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return 0;
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}
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memset(prefix_bytes, 0, len_len);
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memset(out_contents, 0, sizeof(CBB));
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out_contents->base = cbb->base;
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cbb->child = out_contents;
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cbb->pending_len_len = len_len;
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cbb->pending_is_asn1 = 0;
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return 1;
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}
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int CBB_add_u8_length_prefixed(CBB *cbb, CBB *out_contents) {
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return cbb_add_length_prefixed(cbb, out_contents, 1);
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}
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int CBB_add_u16_length_prefixed(CBB *cbb, CBB *out_contents) {
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return cbb_add_length_prefixed(cbb, out_contents, 2);
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}
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int CBB_add_u24_length_prefixed(CBB *cbb, CBB *out_contents) {
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return cbb_add_length_prefixed(cbb, out_contents, 3);
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}
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int CBB_add_asn1(CBB *cbb, CBB *out_contents, uint8_t tag) {
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if ((tag & 0x1f) == 0x1f) {
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/* Long form identifier octets are not supported. */
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return 0;
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}
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if (!CBB_flush(cbb) ||
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!CBB_add_u8(cbb, tag)) {
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return 0;
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}
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cbb->offset = cbb->base->len;
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if (!CBB_add_u8(cbb, 0)) {
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return 0;
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}
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memset(out_contents, 0, sizeof(CBB));
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out_contents->base = cbb->base;
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cbb->child = out_contents;
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cbb->pending_len_len = 1;
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cbb->pending_is_asn1 = 1;
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return 1;
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}
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int CBB_add_bytes(CBB *cbb, const uint8_t *data, size_t len) {
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uint8_t *dest;
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if (!CBB_flush(cbb) ||
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!cbb_buffer_add(cbb->base, &dest, len)) {
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return 0;
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}
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memcpy(dest, data, len);
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return 1;
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}
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int CBB_add_space(CBB *cbb, uint8_t **out_data, size_t len) {
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if (!CBB_flush(cbb) ||
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!cbb_buffer_add(cbb->base, out_data, len)) {
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return 0;
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}
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return 1;
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}
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int CBB_add_u8(CBB *cbb, uint8_t value) {
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if (!CBB_flush(cbb)) {
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return 0;
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}
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return cbb_buffer_add_u(cbb->base, value, 1);
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}
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int CBB_add_u16(CBB *cbb, uint16_t value) {
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if (!CBB_flush(cbb)) {
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return 0;
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}
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return cbb_buffer_add_u(cbb->base, value, 2);
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}
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int CBB_add_u24(CBB *cbb, uint32_t value) {
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if (!CBB_flush(cbb)) {
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return 0;
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}
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return cbb_buffer_add_u(cbb->base, value, 3);
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}
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int CBB_add_asn1_uint64(CBB *cbb, uint64_t value) {
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CBB child;
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size_t i;
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int started = 0;
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if (!CBB_add_asn1(cbb, &child, CBS_ASN1_INTEGER)) {
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return 0;
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}
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for (i = 0; i < 8; i++) {
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uint8_t byte = (value >> 8*(7-i)) & 0xff;
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if (!started) {
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if (byte == 0) {
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/* Don't encode leading zeros. */
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continue;
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}
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/* If the high bit is set, add a padding byte to make it
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* unsigned. */
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if ((byte & 0x80) && !CBB_add_u8(&child, 0)) {
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return 0;
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}
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started = 1;
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}
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if (!CBB_add_u8(&child, byte)) {
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return 0;
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}
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}
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/* 0 is encoded as a single 0, not the empty string. */
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if (!started && !CBB_add_u8(&child, 0)) {
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return 0;
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}
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return CBB_flush(cbb);
|
||
|
|
}
|