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1 | | /* |
2 | | * Copyright (C) 2011-2012 Free Software Foundation, Inc. |
3 | | * |
4 | | * Author: Nikos Mavrogiannopoulos |
5 | | * |
6 | | * This file is part of GnuTLS. |
7 | | * |
8 | | * The GnuTLS is free software; you can redistribute it and/or |
9 | | * modify it under the terms of the GNU Lesser General Public License |
10 | | * as published by the Free Software Foundation; either version 2.1 of |
11 | | * the License, or (at your option) any later version. |
12 | | * |
13 | | * This library is distributed in the hope that it will be useful, but |
14 | | * WITHOUT ANY WARRANTY; without even the implied warranty of |
15 | | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
16 | | * Lesser General Public License for more details. |
17 | | * |
18 | | * You should have received a copy of the GNU Lesser General Public License |
19 | | * along with this program. If not, see <https://www.gnu.org/licenses/> |
20 | | * |
21 | | */ |
22 | | |
23 | | /* Helper functions for ECC handling |
24 | | * based on public domain code by Tom St. Dennis. |
25 | | */ |
26 | | #include "gnutls_int.h" |
27 | | #include "mpi.h" |
28 | | #include "ecc.h" |
29 | | #include "algorithms.h" |
30 | | #include "errors.h" |
31 | | |
32 | | int _gnutls_ecc_ansi_x962_export(gnutls_ecc_curve_t curve, bigint_t x, |
33 | | bigint_t y, gnutls_datum_t *out) |
34 | 0 | { |
35 | 0 | int numlen = gnutls_ecc_curve_get_size(curve); |
36 | 0 | int byte_size, ret; |
37 | 0 | size_t size; |
38 | |
|
39 | 0 | if (numlen == 0) |
40 | 0 | return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST); |
41 | | |
42 | 0 | out->size = 1 + 2 * numlen; |
43 | |
|
44 | 0 | out->data = gnutls_malloc(out->size); |
45 | 0 | if (out->data == NULL) |
46 | 0 | return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR); |
47 | | |
48 | 0 | memset(out->data, 0, out->size); |
49 | | |
50 | | /* store byte 0x04 */ |
51 | 0 | out->data[0] = 0x04; |
52 | | |
53 | | /* pad and store x */ |
54 | 0 | byte_size = (_gnutls_mpi_get_nbits(x) + 7) / 8; |
55 | 0 | if (numlen < byte_size) { |
56 | 0 | ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST); |
57 | 0 | goto cleanup; |
58 | 0 | } |
59 | | |
60 | 0 | size = out->size - (1 + (numlen - byte_size)); |
61 | 0 | ret = _gnutls_mpi_print(x, &out->data[1 + (numlen - byte_size)], &size); |
62 | 0 | if (ret < 0) { |
63 | 0 | gnutls_assert(); |
64 | 0 | goto cleanup; |
65 | 0 | } |
66 | | |
67 | 0 | byte_size = (_gnutls_mpi_get_nbits(y) + 7) / 8; |
68 | 0 | if (numlen < byte_size) { |
69 | 0 | ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST); |
70 | 0 | goto cleanup; |
71 | 0 | } |
72 | | |
73 | 0 | size = out->size - (1 + (numlen + numlen - byte_size)); |
74 | 0 | ret = _gnutls_mpi_print(y, &out->data[1 + numlen + numlen - byte_size], |
75 | 0 | &size); |
76 | 0 | if (ret < 0) { |
77 | 0 | gnutls_assert(); |
78 | 0 | goto cleanup; |
79 | 0 | } |
80 | | |
81 | | /* pad and store y */ |
82 | 0 | return 0; |
83 | 0 | cleanup: |
84 | 0 | _gnutls_free_datum(out); |
85 | 0 | return ret; |
86 | 0 | } |
87 | | |
88 | | int _gnutls_ecc_ansi_x962_import(const uint8_t *in, unsigned long inlen, |
89 | | bigint_t *x, bigint_t *y) |
90 | 0 | { |
91 | 0 | int ret; |
92 | | |
93 | | /* must be odd */ |
94 | 0 | if ((inlen & 1) == 0) { |
95 | 0 | return GNUTLS_E_INVALID_REQUEST; |
96 | 0 | } |
97 | | |
98 | | /* check for 4 */ |
99 | 0 | if (in[0] != 4) { |
100 | 0 | return gnutls_assert_val(GNUTLS_E_PARSING_ERROR); |
101 | 0 | } |
102 | | |
103 | | /* read data */ |
104 | 0 | ret = _gnutls_mpi_init_scan(x, in + 1, (inlen - 1) >> 1); |
105 | 0 | if (ret < 0) |
106 | 0 | return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR); |
107 | | |
108 | 0 | ret = _gnutls_mpi_init_scan(y, in + 1 + ((inlen - 1) >> 1), |
109 | 0 | (inlen - 1) >> 1); |
110 | 0 | if (ret < 0) { |
111 | 0 | _gnutls_mpi_release(x); |
112 | 0 | return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR); |
113 | 0 | } |
114 | | |
115 | 0 | return 0; |
116 | 0 | } |