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/** \file asn1_helpers.c
*
* \brief Helper functions for tests that manipulate ASN.1 data.
*/
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
*/
#include <test/helpers.h>
#include <test/macros.h>
#if defined(MBEDTLS_ASN1_PARSE_C)
#include <mbedtls/asn1.h>
int mbedtls_test_asn1_skip_integer(unsigned char **p, const unsigned char *end,
size_t min_bits, size_t max_bits,
int must_be_odd)
{
size_t len;
size_t actual_bits;
unsigned char msb;
TEST_EQUAL(mbedtls_asn1_get_tag(p, end, &len,
MBEDTLS_ASN1_INTEGER),
0);
/* Check if the retrieved length doesn't extend the actual buffer's size.
* It is assumed here, that end >= p, which validates casting to size_t. */
TEST_ASSERT(len <= (size_t) (end - *p));
/* Tolerate a slight departure from DER encoding:
* - 0 may be represented by an empty string or a 1-byte string.
* - The sign bit may be used as a value bit. */
if ((len == 1 && (*p)[0] == 0) ||
(len > 1 && (*p)[0] == 0 && ((*p)[1] & 0x80) != 0)) {
++(*p);
--len;
}
if (min_bits == 0 && len == 0) {
return 1;
}
msb = (*p)[0];
TEST_ASSERT(msb != 0);
actual_bits = 8 * (len - 1);
while (msb != 0) {
msb >>= 1;
++actual_bits;
}
TEST_ASSERT(actual_bits >= min_bits);
TEST_ASSERT(actual_bits <= max_bits);
if (must_be_odd) {
TEST_ASSERT(((*p)[len-1] & 1) != 0);
}
*p += len;
return 1;
exit:
return 0;
}
#endif /* MBEDTLS_ASN1_PARSE_C */
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