1 /*
2 * Copyright (C) 2016 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 "keystore_utils.h"
20
21 #include <errno.h>
22 #include <string.h>
23 #include <unistd.h>
24
25 #include <log/log.h>
26 #include <private/android_filesystem_config.h>
27 #include <private/android_logger.h>
28
29 #include <log/log_event_list.h>
30
31 #include <keystore/keymaster_types.h>
32 #include <keystore/keystore_client.h>
33
34 #include <android-base/logging.h>
35 #include <android-base/unique_fd.h>
36
37 #include "blob.h"
38
readFully(int fd,uint8_t * data,size_t size)39 size_t readFully(int fd, uint8_t* data, size_t size) {
40 size_t remaining = size;
41 while (remaining > 0) {
42 ssize_t n = TEMP_FAILURE_RETRY(read(fd, data, remaining));
43 if (n <= 0) {
44 return size - remaining;
45 }
46 data += n;
47 remaining -= n;
48 }
49 return size;
50 }
51
writeFully(int fd,uint8_t * data,size_t size)52 size_t writeFully(int fd, uint8_t* data, size_t size) {
53 size_t remaining = size;
54 while (remaining > 0) {
55 ssize_t n = TEMP_FAILURE_RETRY(write(fd, data, remaining));
56 if (n < 0) {
57 ALOGW("write failed: %s", strerror(errno));
58 return size - remaining;
59 }
60 data += n;
61 remaining -= n;
62 }
63 if (TEMP_FAILURE_RETRY(fsync(fd)) == -1) {
64 ALOGW("fsync failed: %s", strerror(errno));
65 return -1;
66 }
67 return size;
68 }
69
getContainingDirectory(const std::string & filename)70 std::string getContainingDirectory(const std::string& filename) {
71 std::string containing_dir;
72 size_t last_pos;
73 size_t pos = std::string::npos;
74
75 __builtin_add_overflow(filename.size(), -1, &last_pos);
76
77 // strip all trailing '/'
78 while ((pos = filename.find_last_of('/', last_pos)) == last_pos && pos != 0) {
79 --last_pos;
80 }
81
82 if (pos == 0) {
83 containing_dir = "/";
84 } else if (pos == std::string::npos) {
85 containing_dir = ".";
86 } else {
87 containing_dir = filename.substr(0, pos);
88 }
89
90 return containing_dir;
91 }
92
fsyncDirectory(const std::string & path)93 void fsyncDirectory(const std::string& path) {
94 android::base::unique_fd dir_fd(TEMP_FAILURE_RETRY(open(path.c_str(), O_DIRECTORY | O_RDONLY)));
95
96 if (dir_fd < 0) {
97 LOG(WARNING) << "Could not open dir: " << path << " error: " << strerror(errno);
98 return;
99 }
100
101 if (TEMP_FAILURE_RETRY(fsync(dir_fd)) == -1) {
102 LOG(WARNING) << "Failed to fsync the directory " << path << " error: " << strerror(errno);
103 }
104
105 return;
106 }
107
add_legacy_key_authorizations(int keyType,keystore::AuthorizationSet * params)108 void add_legacy_key_authorizations(int keyType, keystore::AuthorizationSet* params) {
109 using namespace keystore;
110 params->push_back(TAG_PURPOSE, KeyPurpose::SIGN);
111 params->push_back(TAG_PURPOSE, KeyPurpose::VERIFY);
112 params->push_back(TAG_PURPOSE, KeyPurpose::ENCRYPT);
113 params->push_back(TAG_PURPOSE, KeyPurpose::DECRYPT);
114 params->push_back(TAG_PADDING, PaddingMode::NONE);
115 if (keyType == EVP_PKEY_RSA) {
116 params->push_back(TAG_PADDING, PaddingMode::RSA_PKCS1_1_5_SIGN);
117 params->push_back(TAG_PADDING, PaddingMode::RSA_PKCS1_1_5_ENCRYPT);
118 params->push_back(TAG_PADDING, PaddingMode::RSA_PSS);
119 params->push_back(TAG_PADDING, PaddingMode::RSA_OAEP);
120 }
121 params->push_back(TAG_DIGEST, Digest::NONE);
122 params->push_back(TAG_DIGEST, Digest::MD5);
123 params->push_back(TAG_DIGEST, Digest::SHA1);
124 params->push_back(TAG_DIGEST, Digest::SHA_2_224);
125 params->push_back(TAG_DIGEST, Digest::SHA_2_256);
126 params->push_back(TAG_DIGEST, Digest::SHA_2_384);
127 params->push_back(TAG_DIGEST, Digest::SHA_2_512);
128 params->push_back(TAG_NO_AUTH_REQUIRED);
129 params->push_back(TAG_ORIGINATION_EXPIRE_DATETIME, LLONG_MAX);
130 params->push_back(TAG_USAGE_EXPIRE_DATETIME, LLONG_MAX);
131 params->push_back(TAG_ACTIVE_DATETIME, 0);
132 }
133
get_app_id(uid_t uid)134 uid_t get_app_id(uid_t uid) {
135 return uid % AID_USER;
136 }
137
get_user_id(uid_t uid)138 uid_t get_user_id(uid_t uid) {
139 return uid / AID_USER;
140 }
141
log_key_integrity_violation(const char * name,uid_t uid)142 void log_key_integrity_violation(const char* name, uid_t uid) {
143 if (!__android_log_security()) return;
144 android_log_event_list(SEC_TAG_KEY_INTEGRITY_VIOLATION)
145 << name << int32_t(uid) << LOG_ID_SECURITY;
146 }
147
148 namespace keystore {
149
blob2hidlVec(const Blob & blob)150 hidl_vec<uint8_t> blob2hidlVec(const Blob& blob) {
151 hidl_vec<uint8_t> result(blob.getValue(), blob.getValue() + blob.getLength());
152 return result;
153 }
154
flagsToSecurityLevel(int32_t flags)155 SecurityLevel flagsToSecurityLevel(int32_t flags) {
156 switch (flags & (KEYSTORE_FLAG_FALLBACK | KEYSTORE_FLAG_STRONGBOX)) {
157 case KEYSTORE_FLAG_FALLBACK:
158 // treating Strongbox flag as "don't care" if Fallback is set
159 case (KEYSTORE_FLAG_FALLBACK | KEYSTORE_FLAG_STRONGBOX):
160 return SecurityLevel::SOFTWARE;
161 case KEYSTORE_FLAG_STRONGBOX:
162 return SecurityLevel::STRONGBOX;
163 default:
164 return SecurityLevel::TRUSTED_ENVIRONMENT;
165 }
166 }
167
securityLevelToFlags(SecurityLevel secLevel)168 uint32_t securityLevelToFlags(SecurityLevel secLevel) {
169 switch (secLevel) {
170 case SecurityLevel::SOFTWARE:
171 return KEYSTORE_FLAG_FALLBACK;
172 case SecurityLevel::STRONGBOX:
173 return KEYSTORE_FLAG_STRONGBOX;
174 default:
175 return 0;
176 }
177 }
178
179 } // namespace keystore
180