1 /*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #define LOG_TAG "keystore"
18
19 #include "auth_token_table.h"
20
21 #include <assert.h>
22 #include <time.h>
23
24 #include <algorithm>
25
26 #include <log/log.h>
27
28 namespace keystore {
29
30 template <typename IntType, uint32_t byteOrder> struct choose_hton;
31
32 template <typename IntType> struct choose_hton<IntType, __ORDER_LITTLE_ENDIAN__> {
htonkeystore::choose_hton33 inline static IntType hton(const IntType& value) {
34 IntType result = 0;
35 const unsigned char* inbytes = reinterpret_cast<const unsigned char*>(&value);
36 unsigned char* outbytes = reinterpret_cast<unsigned char*>(&result);
37 for (int i = sizeof(IntType) - 1; i >= 0; --i) {
38 *(outbytes++) = inbytes[i];
39 }
40 return result;
41 }
42 };
43
44 template <typename IntType> struct choose_hton<IntType, __ORDER_BIG_ENDIAN__> {
htonkeystore::choose_hton45 inline static IntType hton(const IntType& value) { return value; }
46 };
47
hton(const IntType & value)48 template <typename IntType> inline IntType hton(const IntType& value) {
49 return choose_hton<IntType, __BYTE_ORDER__>::hton(value);
50 }
51
ntoh(const IntType & value)52 template <typename IntType> inline IntType ntoh(const IntType& value) {
53 // same operation and hton
54 return choose_hton<IntType, __BYTE_ORDER__>::hton(value);
55 }
56
57 //
58 // Some trivial template wrappers around std algorithms, so they take containers not ranges.
59 //
60 template <typename Container, typename Predicate>
find_if(Container & container,Predicate pred)61 typename Container::iterator find_if(Container& container, Predicate pred) {
62 return std::find_if(container.begin(), container.end(), pred);
63 }
64
65 template <typename Container, typename Predicate>
remove_if(Container & container,Predicate pred)66 typename Container::iterator remove_if(Container& container, Predicate pred) {
67 return std::remove_if(container.begin(), container.end(), pred);
68 }
69
min_element(Container & container)70 template <typename Container> typename Container::iterator min_element(Container& container) {
71 return std::min_element(container.begin(), container.end());
72 }
73
clock_gettime_raw()74 time_t clock_gettime_raw() {
75 struct timespec time;
76 clock_gettime(CLOCK_MONOTONIC_RAW, &time);
77 return time.tv_sec;
78 }
79
AddAuthenticationToken(HardwareAuthToken && auth_token)80 void AuthTokenTable::AddAuthenticationToken(HardwareAuthToken&& auth_token) {
81 Entry new_entry(std::move(auth_token), clock_function_());
82 // STOPSHIP: debug only, to be removed
83 ALOGD("AddAuthenticationToken: timestamp = %llu, time_received = %lld",
84 static_cast<unsigned long long>(new_entry.token().timestamp),
85 static_cast<long long>(new_entry.time_received()));
86
87 std::lock_guard<std::mutex> lock(entries_mutex_);
88 RemoveEntriesSupersededBy(new_entry);
89 if (entries_.size() >= max_entries_) {
90 ALOGW("Auth token table filled up; replacing oldest entry");
91 *min_element(entries_) = std::move(new_entry);
92 } else {
93 entries_.push_back(std::move(new_entry));
94 }
95 }
96
is_secret_key_operation(Algorithm algorithm,KeyPurpose purpose)97 inline bool is_secret_key_operation(Algorithm algorithm, KeyPurpose purpose) {
98 if ((algorithm != Algorithm::RSA && algorithm != Algorithm::EC)) return true;
99 if (purpose == KeyPurpose::SIGN || purpose == KeyPurpose::DECRYPT) return true;
100 return false;
101 }
102
KeyRequiresAuthentication(const AuthorizationSet & key_info,KeyPurpose purpose)103 inline bool KeyRequiresAuthentication(const AuthorizationSet& key_info, KeyPurpose purpose) {
104 auto algorithm = defaultOr(key_info.GetTagValue(TAG_ALGORITHM), Algorithm::AES);
105 return is_secret_key_operation(algorithm, purpose) &&
106 key_info.find(Tag::NO_AUTH_REQUIRED) == -1;
107 }
108
KeyRequiresAuthPerOperation(const AuthorizationSet & key_info,KeyPurpose purpose)109 inline bool KeyRequiresAuthPerOperation(const AuthorizationSet& key_info, KeyPurpose purpose) {
110 auto algorithm = defaultOr(key_info.GetTagValue(TAG_ALGORITHM), Algorithm::AES);
111 return is_secret_key_operation(algorithm, purpose) && key_info.find(Tag::AUTH_TIMEOUT) == -1;
112 }
113
114 std::tuple<AuthTokenTable::Error, HardwareAuthToken>
FindAuthorization(const AuthorizationSet & key_info,KeyPurpose purpose,uint64_t op_handle)115 AuthTokenTable::FindAuthorization(const AuthorizationSet& key_info, KeyPurpose purpose,
116 uint64_t op_handle) {
117
118 std::lock_guard<std::mutex> lock(entries_mutex_);
119
120 if (!KeyRequiresAuthentication(key_info, purpose)) return {AUTH_NOT_REQUIRED, {}};
121
122 auto auth_type =
123 defaultOr(key_info.GetTagValue(TAG_USER_AUTH_TYPE), HardwareAuthenticatorType::NONE);
124
125 std::vector<uint64_t> key_sids;
126 ExtractSids(key_info, &key_sids);
127
128 if (KeyRequiresAuthPerOperation(key_info, purpose))
129 return FindAuthPerOpAuthorization(key_sids, auth_type, op_handle);
130 else
131 return FindTimedAuthorization(key_sids, auth_type, key_info);
132 }
133
FindAuthPerOpAuthorization(const std::vector<uint64_t> & sids,HardwareAuthenticatorType auth_type,uint64_t op_handle)134 std::tuple<AuthTokenTable::Error, HardwareAuthToken> AuthTokenTable::FindAuthPerOpAuthorization(
135 const std::vector<uint64_t>& sids, HardwareAuthenticatorType auth_type, uint64_t op_handle) {
136 if (op_handle == 0) return {OP_HANDLE_REQUIRED, {}};
137
138 auto matching_op = find_if(
139 entries_, [&](Entry& e) { return e.token().challenge == op_handle && !e.completed(); });
140
141 if (matching_op == entries_.end()) return {AUTH_TOKEN_NOT_FOUND, {}};
142
143 if (!matching_op->SatisfiesAuth(sids, auth_type)) return {AUTH_TOKEN_WRONG_SID, {}};
144
145 return {OK, matching_op->token()};
146 }
147
148 std::tuple<AuthTokenTable::Error, HardwareAuthToken>
FindTimedAuthorization(const std::vector<uint64_t> & sids,HardwareAuthenticatorType auth_type,const AuthorizationSet & key_info)149 AuthTokenTable::FindTimedAuthorization(const std::vector<uint64_t>& sids,
150 HardwareAuthenticatorType auth_type,
151 const AuthorizationSet& key_info) {
152 Entry* newest_match = nullptr;
153 for (auto& entry : entries_)
154 if (entry.SatisfiesAuth(sids, auth_type) && entry.is_newer_than(newest_match))
155 newest_match = &entry;
156
157 if (!newest_match) return {AUTH_TOKEN_NOT_FOUND, {}};
158
159 auto timeout = defaultOr(key_info.GetTagValue(TAG_AUTH_TIMEOUT), 0);
160
161 time_t now = clock_function_();
162 if (static_cast<int64_t>(newest_match->time_received()) + timeout < static_cast<int64_t>(now))
163 return {AUTH_TOKEN_EXPIRED, {}};
164
165 if (key_info.GetTagValue(TAG_ALLOW_WHILE_ON_BODY).isOk()) {
166 if (static_cast<int64_t>(newest_match->time_received()) <
167 static_cast<int64_t>(last_off_body_)) {
168 return {AUTH_TOKEN_EXPIRED, {}};
169 }
170 }
171
172 newest_match->UpdateLastUse(now);
173 return {OK, newest_match->token()};
174 }
175
ExtractSids(const AuthorizationSet & key_info,std::vector<uint64_t> * sids)176 void AuthTokenTable::ExtractSids(const AuthorizationSet& key_info, std::vector<uint64_t>* sids) {
177 assert(sids);
178 for (auto& param : key_info)
179 if (param.tag == Tag::USER_SECURE_ID)
180 sids->push_back(authorizationValue(TAG_USER_SECURE_ID, param).value());
181 }
182
RemoveEntriesSupersededBy(const Entry & entry)183 void AuthTokenTable::RemoveEntriesSupersededBy(const Entry& entry) {
184 entries_.erase(remove_if(entries_, [&](Entry& e) { return entry.Supersedes(e); }),
185 entries_.end());
186 }
187
onDeviceOffBody()188 void AuthTokenTable::onDeviceOffBody() {
189 last_off_body_ = clock_function_();
190 }
191
Clear()192 void AuthTokenTable::Clear() {
193 std::lock_guard<std::mutex> lock(entries_mutex_);
194
195 entries_.clear();
196 }
197
size() const198 size_t AuthTokenTable::size() const {
199 std::lock_guard<std::mutex> lock(entries_mutex_);
200 return entries_.size();
201 }
202
IsSupersededBySomeEntry(const Entry & entry)203 bool AuthTokenTable::IsSupersededBySomeEntry(const Entry& entry) {
204 return std::any_of(entries_.begin(), entries_.end(),
205 [&](Entry& e) { return e.Supersedes(entry); });
206 }
207
MarkCompleted(const uint64_t op_handle)208 void AuthTokenTable::MarkCompleted(const uint64_t op_handle) {
209 std::lock_guard<std::mutex> lock(entries_mutex_);
210
211 auto found = find_if(entries_, [&](Entry& e) { return e.token().challenge == op_handle; });
212 if (found == entries_.end()) return;
213
214 assert(!IsSupersededBySomeEntry(*found));
215 found->mark_completed();
216
217 if (IsSupersededBySomeEntry(*found)) entries_.erase(found);
218 }
219
Entry(HardwareAuthToken && token,time_t current_time)220 AuthTokenTable::Entry::Entry(HardwareAuthToken&& token, time_t current_time)
221 : token_(std::move(token)), time_received_(current_time), last_use_(current_time),
222 operation_completed_(token_.challenge == 0) {}
223
SatisfiesAuth(const std::vector<uint64_t> & sids,HardwareAuthenticatorType auth_type)224 bool AuthTokenTable::Entry::SatisfiesAuth(const std::vector<uint64_t>& sids,
225 HardwareAuthenticatorType auth_type) {
226 for (auto sid : sids) {
227 if (SatisfiesAuth(sid, auth_type)) return true;
228 }
229 return false;
230 }
231
UpdateLastUse(time_t time)232 void AuthTokenTable::Entry::UpdateLastUse(time_t time) {
233 this->last_use_ = time;
234 }
235
Supersedes(const Entry & entry) const236 bool AuthTokenTable::Entry::Supersedes(const Entry& entry) const {
237 if (!entry.completed()) return false;
238
239 return (token_.userId == entry.token_.userId &&
240 token_.authenticatorType == entry.token_.authenticatorType &&
241 token_.authenticatorId == entry.token_.authenticatorId && is_newer_than(&entry));
242 }
243
244 } // namespace keystore
245