| /* 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 <openssl/mem.h> |
| |
| |
| void CBB_zero(CBB *cbb) { |
| memset(cbb, 0, sizeof(CBB)); |
| } |
| |
| static int cbb_init(CBB *cbb, uint8_t *buf, size_t cap) { |
| struct cbb_buffer_st *base; |
| |
| base = OPENSSL_malloc(sizeof(struct cbb_buffer_st)); |
| if (base == NULL) { |
| return 0; |
| } |
| |
| base->buf = buf; |
| base->len = 0; |
| base->cap = cap; |
| base->can_resize = 1; |
| |
| memset(cbb, 0, sizeof(CBB)); |
| cbb->base = base; |
| cbb->is_top_level = 1; |
| return 1; |
| } |
| |
| int CBB_init(CBB *cbb, size_t initial_capacity) { |
| uint8_t *buf; |
| |
| buf = OPENSSL_malloc(initial_capacity); |
| if (initial_capacity > 0 && buf == NULL) { |
| return 0; |
| } |
| |
| if (!cbb_init(cbb, buf, initial_capacity)) { |
| OPENSSL_free(buf); |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| int CBB_init_fixed(CBB *cbb, uint8_t *buf, size_t len) { |
| if (!cbb_init(cbb, buf, len)) { |
| return 0; |
| } |
| |
| cbb->base->can_resize = 0; |
| return 1; |
| } |
| |
| void CBB_cleanup(CBB *cbb) { |
| if (cbb->base) { |
| /* Only top-level |CBB|s are cleaned up. Child |CBB|s are non-owning. They |
| * are implicitly discarded when the parent is flushed or cleaned up. */ |
| assert(cbb->is_top_level); |
| |
| if (cbb->base->can_resize) { |
| OPENSSL_free(cbb->base->buf); |
| } |
| OPENSSL_free(cbb->base); |
| } |
| cbb->base = NULL; |
| } |
| |
| static int cbb_buffer_add(struct cbb_buffer_st *base, uint8_t **out, |
| size_t len) { |
| size_t newlen; |
| |
| if (base == NULL) { |
| return 0; |
| } |
| |
| newlen = base->len + len; |
| if (newlen < base->len) { |
| /* Overflow */ |
| return 0; |
| } |
| |
| if (newlen > base->cap) { |
| size_t newcap = base->cap * 2; |
| uint8_t *newbuf; |
| |
| if (!base->can_resize) { |
| return 0; |
| } |
| |
| if (newcap < base->cap || newcap < newlen) { |
| newcap = newlen; |
| } |
| newbuf = OPENSSL_realloc(base->buf, newcap); |
| if (newbuf == NULL) { |
| return 0; |
| } |
| |
| base->buf = newbuf; |
| base->cap = newcap; |
| } |
| |
| if (out) { |
| *out = base->buf + base->len; |
| } |
| base->len = newlen; |
| return 1; |
| } |
| |
| static int cbb_buffer_add_u(struct cbb_buffer_st *base, uint32_t v, |
| size_t len_len) { |
| uint8_t *buf; |
| size_t i; |
| |
| if (len_len == 0) { |
| return 1; |
| } |
| if (!cbb_buffer_add(base, &buf, len_len)) { |
| return 0; |
| } |
| |
| for (i = len_len - 1; i < len_len; i--) { |
| buf[i] = v; |
| v >>= 8; |
| } |
| return 1; |
| } |
| |
| int CBB_finish(CBB *cbb, uint8_t **out_data, size_t *out_len) { |
| if (!cbb->is_top_level) { |
| return 0; |
| } |
| |
| if (!CBB_flush(cbb)) { |
| return 0; |
| } |
| |
| if (cbb->base->can_resize && (out_data == NULL || out_len == NULL)) { |
| /* |out_data| and |out_len| can only be NULL if the CBB is fixed. */ |
| return 0; |
| } |
| |
| if (out_data != NULL) { |
| *out_data = cbb->base->buf; |
| } |
| if (out_len != NULL) { |
| *out_len = cbb->base->len; |
| } |
| cbb->base->buf = NULL; |
| CBB_cleanup(cbb); |
| return 1; |
| } |
| |
| /* CBB_flush recurses and then writes out any pending length prefix. The |
| * current length of the underlying base is taken to be the length of the |
| * length-prefixed data. */ |
| int CBB_flush(CBB *cbb) { |
| size_t child_start, i, len; |
| |
| if (cbb->base == NULL) { |
| return 0; |
| } |
| |
| if (cbb->child == NULL || cbb->pending_len_len == 0) { |
| return 1; |
| } |
| |
| child_start = cbb->offset + cbb->pending_len_len; |
| |
| if (!CBB_flush(cbb->child) || |
| child_start < cbb->offset || |
| cbb->base->len < child_start) { |
| return 0; |
| } |
| |
| len = cbb->base->len - child_start; |
| |
| if (cbb->pending_is_asn1) { |
| /* For ASN.1 we assume that we'll only need a single byte for the length. |
| * If that turned out to be incorrect, we have to move the contents along |
| * in order to make space. */ |
| size_t len_len; |
| uint8_t initial_length_byte; |
| |
| assert (cbb->pending_len_len == 1); |
| |
| if (len > 0xfffffffe) { |
| /* Too large. */ |
| return 0; |
| } else if (len > 0xffffff) { |
| len_len = 5; |
| initial_length_byte = 0x80 | 4; |
| } else if (len > 0xffff) { |
| len_len = 4; |
| initial_length_byte = 0x80 | 3; |
| } else if (len > 0xff) { |
| len_len = 3; |
| initial_length_byte = 0x80 | 2; |
| } else if (len > 0x7f) { |
| len_len = 2; |
| initial_length_byte = 0x80 | 1; |
| } else { |
| len_len = 1; |
| initial_length_byte = len; |
| len = 0; |
| } |
| |
| if (len_len != 1) { |
| /* We need to move the contents along in order to make space. */ |
| size_t extra_bytes = len_len - 1; |
| if (!cbb_buffer_add(cbb->base, NULL, extra_bytes)) { |
| return 0; |
| } |
| memmove(cbb->base->buf + child_start + extra_bytes, |
| cbb->base->buf + child_start, len); |
| } |
| cbb->base->buf[cbb->offset++] = initial_length_byte; |
| cbb->pending_len_len = len_len - 1; |
| } |
| |
| for (i = cbb->pending_len_len - 1; i < cbb->pending_len_len; i--) { |
| cbb->base->buf[cbb->offset + i] = len; |
| len >>= 8; |
| } |
| if (len != 0) { |
| return 0; |
| } |
| |
| cbb->child->base = NULL; |
| cbb->child = NULL; |
| cbb->pending_len_len = 0; |
| cbb->pending_is_asn1 = 0; |
| cbb->offset = 0; |
| |
| return 1; |
| } |
| |
| size_t CBB_len(const CBB *cbb) { |
| assert(cbb->child == NULL); |
| |
| return cbb->base->len; |
| } |
| |
| static int cbb_add_length_prefixed(CBB *cbb, CBB *out_contents, |
| size_t len_len) { |
| uint8_t *prefix_bytes; |
| |
| if (!CBB_flush(cbb)) { |
| return 0; |
| } |
| |
| cbb->offset = cbb->base->len; |
| if (!cbb_buffer_add(cbb->base, &prefix_bytes, len_len)) { |
| return 0; |
| } |
| |
| memset(prefix_bytes, 0, len_len); |
| memset(out_contents, 0, sizeof(CBB)); |
| out_contents->base = cbb->base; |
| cbb->child = out_contents; |
| cbb->pending_len_len = len_len; |
| cbb->pending_is_asn1 = 0; |
| |
| return 1; |
| } |
| |
| int CBB_add_u8_length_prefixed(CBB *cbb, CBB *out_contents) { |
| return cbb_add_length_prefixed(cbb, out_contents, 1); |
| } |
| |
| int CBB_add_u16_length_prefixed(CBB *cbb, CBB *out_contents) { |
| return cbb_add_length_prefixed(cbb, out_contents, 2); |
| } |
| |
| int CBB_add_u24_length_prefixed(CBB *cbb, CBB *out_contents) { |
| return cbb_add_length_prefixed(cbb, out_contents, 3); |
| } |
| |
| int CBB_add_asn1(CBB *cbb, CBB *out_contents, uint8_t tag) { |
| if ((tag & 0x1f) == 0x1f) { |
| /* Long form identifier octets are not supported. */ |
| return 0; |
| } |
| |
| if (!CBB_flush(cbb) || |
| !CBB_add_u8(cbb, tag)) { |
| return 0; |
| } |
| |
| cbb->offset = cbb->base->len; |
| if (!CBB_add_u8(cbb, 0)) { |
| return 0; |
| } |
| |
| memset(out_contents, 0, sizeof(CBB)); |
| out_contents->base = cbb->base; |
| cbb->child = out_contents; |
| cbb->pending_len_len = 1; |
| cbb->pending_is_asn1 = 1; |
| |
| return 1; |
| } |
| |
| int CBB_add_bytes(CBB *cbb, const uint8_t *data, size_t len) { |
| uint8_t *dest; |
| |
| if (!CBB_flush(cbb) || |
| !cbb_buffer_add(cbb->base, &dest, len)) { |
| return 0; |
| } |
| memcpy(dest, data, len); |
| return 1; |
| } |
| |
| int CBB_add_space(CBB *cbb, uint8_t **out_data, size_t len) { |
| if (!CBB_flush(cbb) || |
| !cbb_buffer_add(cbb->base, out_data, len)) { |
| return 0; |
| } |
| return 1; |
| } |
| |
| int CBB_add_u8(CBB *cbb, uint8_t value) { |
| if (!CBB_flush(cbb)) { |
| return 0; |
| } |
| |
| return cbb_buffer_add_u(cbb->base, value, 1); |
| } |
| |
| int CBB_add_u16(CBB *cbb, uint16_t value) { |
| if (!CBB_flush(cbb)) { |
| return 0; |
| } |
| |
| return cbb_buffer_add_u(cbb->base, value, 2); |
| } |
| |
| int CBB_add_u24(CBB *cbb, uint32_t value) { |
| if (!CBB_flush(cbb)) { |
| return 0; |
| } |
| |
| return cbb_buffer_add_u(cbb->base, value, 3); |
| } |
| |
| void CBB_discard_child(CBB *cbb) { |
| if (cbb->child == NULL) { |
| return; |
| } |
| |
| cbb->base->len = cbb->offset; |
| |
| cbb->child->base = NULL; |
| cbb->child = NULL; |
| cbb->pending_len_len = 0; |
| cbb->pending_is_asn1 = 0; |
| cbb->offset = 0; |
| } |
| |
| int CBB_add_asn1_uint64(CBB *cbb, uint64_t value) { |
| CBB child; |
| size_t i; |
| int started = 0; |
| |
| if (!CBB_add_asn1(cbb, &child, CBS_ASN1_INTEGER)) { |
| return 0; |
| } |
| |
| for (i = 0; i < 8; i++) { |
| uint8_t byte = (value >> 8*(7-i)) & 0xff; |
| if (!started) { |
| if (byte == 0) { |
| /* Don't encode leading zeros. */ |
| continue; |
| } |
| /* If the high bit is set, add a padding byte to make it |
| * unsigned. */ |
| if ((byte & 0x80) && !CBB_add_u8(&child, 0)) { |
| return 0; |
| } |
| started = 1; |
| } |
| if (!CBB_add_u8(&child, byte)) { |
| return 0; |
| } |
| } |
| |
| /* 0 is encoded as a single 0, not the empty string. */ |
| if (!started && !CBB_add_u8(&child, 0)) { |
| return 0; |
| } |
| |
| return CBB_flush(cbb); |
| } |