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/* Copyright (c) 2016, 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 <limits.h>
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#include <string.h>
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#include <openssl/mem.h>
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#include "internal.h"
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#include "../internal.h"
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int CBB_finish_i2d(CBB *cbb, uint8_t **outp) {
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Make CBB_init_fixed infallible and allocationless.
Today, every use of CBB, even CBB_init_fixed, requires a small, fallible
allocation to allocate the top-level CBB's cbb_buffer_st. We could embed
cbb_buffer_st directly in CBB, but then every child CBB wastes that
space, and needs an extra pointer to point back to the cbb_buffer_st.
But top-level and child CBBs have disjoint representations anyway. We
share a cbb_buffer_st pointer, but it's owning in one case and
borrowed in another. Child CBBs have length prefix information, but it's
never filed in for a top-level CBB.
Make this a sum type, with is_child as the discriminator and a union for
the two structures. (Elsewhere I've been trying to get rid of unions,
but this isn't using unions for type-punning, so it should valid even in
C++. We never access inactive arms.)
The implementation gains a few more branches, but now CBB_init_fixed is
infallible and allocation-less. I'm hoping this will let us more freely
convert functions like UTF8_putc into CBB because we don't need to worry
about cleanup or introducing allocations.
Change-Id: If0b28cd9e079418f35d5a614058c0aa73658822e
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/54645
Reviewed-by: Bob Beck <bbe@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
3 years ago
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assert(!cbb->is_child);
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assert(cbb->u.base.can_resize);
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uint8_t *der;
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size_t der_len;
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if (!CBB_finish(cbb, &der, &der_len)) {
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CBB_cleanup(cbb);
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return -1;
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}
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if (der_len > INT_MAX) {
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OPENSSL_free(der);
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return -1;
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}
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if (outp != NULL) {
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if (*outp == NULL) {
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*outp = der;
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der = NULL;
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} else {
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OPENSSL_memcpy(*outp, der, der_len);
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*outp += der_len;
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}
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}
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OPENSSL_free(der);
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return (int)der_len;
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}
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