boringssl/crypto/bytestring/asn1_compat.c
David Benjamin 17cf2cb1d2 Work around language and compiler bug in memcpy, etc.
Most C standard library functions are undefined if passed NULL, even
when the corresponding length is zero. This gives them (and, in turn,
all functions which call them) surprising behavior on empty arrays.
Some compilers will miscompile code due to this rule. See also
https://www.imperialviolet.org/2016/06/26/nonnull.html

Add OPENSSL_memcpy, etc., wrappers which avoid this problem.

BUG=23

Change-Id: I95f42b23e92945af0e681264fffaf578e7f8465e
Reviewed-on: https://boringssl-review.googlesource.com/12928
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
2016-12-21 20:34:47 +00:00

53 lines
1.4 KiB
C

/* Copyright (c) 2016, 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 <limits.h>
#include <string.h>
#include <openssl/mem.h>
#include "internal.h"
#include "../internal.h"
int CBB_finish_i2d(CBB *cbb, uint8_t **outp) {
assert(cbb->base->can_resize);
uint8_t *der;
size_t der_len;
if (!CBB_finish(cbb, &der, &der_len)) {
CBB_cleanup(cbb);
return -1;
}
if (der_len > INT_MAX) {
OPENSSL_free(der);
return -1;
}
if (outp != NULL) {
if (*outp == NULL) {
*outp = der;
der = NULL;
} else {
OPENSSL_memcpy(*outp, der, der_len);
*outp += der_len;
}
}
OPENSSL_free(der);
return (int)der_len;
}