1 /**
2 * \file bignum_helpers.c
3 *
4 * \brief This file contains the prototypes of helper functions for
5 * bignum-related testing.
6 */
7
8 /*
9 * Copyright The Mbed TLS Contributors
10 * SPDX-License-Identifier: Apache-2.0
11 *
12 * Licensed under the Apache License, Version 2.0 (the "License"); you may
13 * not use this file except in compliance with the License.
14 * You may obtain a copy of the License at
15 *
16 * http://www.apache.org/licenses/LICENSE-2.0
17 *
18 * Unless required by applicable law or agreed to in writing, software
19 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
20 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
21 * See the License for the specific language governing permissions and
22 * limitations under the License.
23 */
24
25 #define MBEDTLS_ALLOW_PRIVATE_ACCESS
26 #include <test/bignum_helpers.h>
27
28 #if defined(MBEDTLS_BIGNUM_C)
29
30 #include <stdlib.h>
31 #include <string.h>
32
33 #include <mbedtls/bignum.h>
34 #include <bignum_core.h>
35 #include <bignum_mod.h>
36 #include <bignum_mod_raw.h>
37
38 #include <test/helpers.h>
39 #include <test/macros.h>
40
mbedtls_test_read_mpi_core(mbedtls_mpi_uint ** pX,size_t * plimbs,const char * input)41 int mbedtls_test_read_mpi_core(mbedtls_mpi_uint **pX, size_t *plimbs,
42 const char *input)
43 {
44 /* Sanity check */
45 if (*pX != NULL) {
46 return MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
47 }
48
49 size_t hex_len = strlen(input);
50 size_t byte_len = (hex_len + 1) / 2;
51 *plimbs = CHARS_TO_LIMBS(byte_len);
52
53 /* A core bignum is not allowed to be empty. Forbid it as test data,
54 * this way static analyzers have a chance of knowing we don't expect
55 * the bignum functions to support empty inputs. */
56 if (*plimbs == 0) {
57 return MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
58 }
59
60 *pX = mbedtls_calloc(*plimbs, sizeof(**pX));
61 if (*pX == NULL) {
62 return MBEDTLS_ERR_MPI_ALLOC_FAILED;
63 }
64
65 unsigned char *byte_start = (unsigned char *) *pX;
66 if (byte_len % sizeof(mbedtls_mpi_uint) != 0) {
67 byte_start += sizeof(mbedtls_mpi_uint) - byte_len % sizeof(mbedtls_mpi_uint);
68 }
69 if ((hex_len & 1) != 0) {
70 /* mbedtls_test_unhexify wants an even number of hex digits */
71 TEST_ASSERT(mbedtls_test_ascii2uc(*input, byte_start) == 0);
72 ++byte_start;
73 ++input;
74 --byte_len;
75 }
76 TEST_ASSERT(mbedtls_test_unhexify(byte_start,
77 byte_len,
78 input,
79 &byte_len) == 0);
80
81 mbedtls_mpi_core_bigendian_to_host(*pX, *plimbs);
82 return 0;
83
84 exit:
85 mbedtls_free(*pX);
86 return MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
87 }
88
mbedtls_test_read_mpi_modulus(mbedtls_mpi_mod_modulus * N,const char * s,mbedtls_mpi_mod_rep_selector int_rep)89 int mbedtls_test_read_mpi_modulus(mbedtls_mpi_mod_modulus *N,
90 const char *s,
91 mbedtls_mpi_mod_rep_selector int_rep)
92 {
93 mbedtls_mpi_uint *p = NULL;
94 size_t limbs = 0;
95 if (N->limbs != 0) {
96 return MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
97 }
98 int ret = mbedtls_test_read_mpi_core(&p, &limbs, s);
99 if (ret != 0) {
100 return ret;
101 }
102 ret = mbedtls_mpi_mod_modulus_setup(N, p, limbs, int_rep);
103 if (ret != 0) {
104 mbedtls_free(p);
105 }
106 return ret;
107 }
108
mbedtls_test_mpi_mod_modulus_free_with_limbs(mbedtls_mpi_mod_modulus * N)109 void mbedtls_test_mpi_mod_modulus_free_with_limbs(mbedtls_mpi_mod_modulus *N)
110 {
111 mbedtls_free((mbedtls_mpi_uint *) N->p);
112 mbedtls_mpi_mod_modulus_free(N);
113 }
114
mbedtls_test_read_mpi(mbedtls_mpi * X,const char * s)115 int mbedtls_test_read_mpi(mbedtls_mpi *X, const char *s)
116 {
117 int negative = 0;
118 /* Always set the sign bit to -1 if the input has a minus sign, even for 0.
119 * This creates an invalid representation, which mbedtls_mpi_read_string()
120 * avoids but we want to be able to create that in test data. */
121 if (s[0] == '-') {
122 ++s;
123 negative = 1;
124 }
125 /* mbedtls_mpi_read_string() currently retains leading zeros.
126 * It always allocates at least one limb for the value 0. */
127 if (s[0] == 0) {
128 mbedtls_mpi_free(X);
129 return 0;
130 }
131 int ret = mbedtls_mpi_read_string(X, 16, s);
132 if (ret != 0) {
133 return ret;
134 }
135 if (negative) {
136 if (mbedtls_mpi_cmp_int(X, 0) == 0) {
137 ++mbedtls_test_case_uses_negative_0;
138 }
139 X->s = -1;
140 }
141 return 0;
142 }
143
144 #endif /* MBEDTLS_BIGNUM_C */
145
