1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
|
// Copyright 2021 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
///////////////////////////////////////////////////////////////////////////////
#include "tink/internal/bn_util.h"
#include <stddef.h>
#include <memory>
#include <string>
#include <utility>
#include "absl/status/status.h"
#include "absl/strings/string_view.h"
#include "absl/types/span.h"
#include "openssl/bn.h"
#include "tink/internal/ssl_unique_ptr.h"
#include "tink/subtle/subtle_util.h"
#include "tink/util/secret_data.h"
#include "tink/util/status.h"
#include "tink/util/statusor.h"
namespace crypto {
namespace tink {
namespace internal {
util::Status BignumToBinaryPadded(absl::Span<char> buffer,
const BIGNUM *bignum) {
if (bignum == nullptr) {
return util::Status(absl::StatusCode::kInvalidArgument, "BIGNUM is NULL");
}
if (BN_is_negative(bignum)) {
return util::Status(absl::StatusCode::kInternal,
"Value must not be negative");
}
// BN_bn2binpad returns the length of the buffer on success and -1 on failure.
int len = BN_bn2binpad(
bignum, reinterpret_cast<unsigned char *>(buffer.data()), buffer.size());
if (len == -1) {
return util::Status(absl::StatusCode::kInternal,
"Value too large to fit into the given buffer");
}
return util::OkStatus();
}
util::StatusOr<std::string> BignumToString(const BIGNUM *bn, size_t len) {
if (bn == nullptr) {
return util::Status(absl::StatusCode::kInvalidArgument, "BIGNUM is NULL");
}
std::string buffer;
subtle::ResizeStringUninitialized(&buffer, len);
util::Status res = BignumToBinaryPadded(absl::MakeSpan(&buffer[0], len), bn);
if (!res.ok()) {
return res;
}
return buffer;
}
util::StatusOr<util::SecretData> BignumToSecretData(const BIGNUM *bn,
size_t len) {
if (bn == nullptr) {
return util::Status(absl::StatusCode::kInvalidArgument, "BIGNUM is NULL");
}
util::SecretData secret_data(len);
util::Status res = BignumToBinaryPadded(
absl::MakeSpan(reinterpret_cast<char *>(secret_data.data()),
secret_data.size()),
bn);
if (!res.ok()) {
return res;
}
return secret_data;
}
util::StatusOr<internal::SslUniquePtr<BIGNUM>> StringToBignum(
absl::string_view bigendian_bn_str) {
internal::SslUniquePtr<BIGNUM> bn(BN_bin2bn(
reinterpret_cast<const unsigned char *>(bigendian_bn_str.data()),
bigendian_bn_str.length(), /*ret=*/nullptr));
if (bn.get() == nullptr) {
return util::Status(absl::StatusCode::kInternal,
"BIGNUM allocation failed");
}
return std::move(bn);
}
int CompareBignumWithWord(const BIGNUM *bignum, BN_ULONG word) {
#ifdef OPENSSL_IS_BORINGSSL
return BN_cmp_word(bignum, word);
#else
internal::SslUniquePtr<BIGNUM> bn_word(BN_new());
BN_set_word(bn_word.get(), word);
return BN_cmp(bignum, bn_word.get());
#endif
}
} // namespace internal
} // namespace tink
} // namespace crypto
|
