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 #include <keymaster/keymaster_configuration.h>
18
19 #include <regex>
20 #include <string>
21
22 #include <regex.h>
23
24 #define LOG_TAG "keymaster"
25 #include <cutils/log.h>
26
27 #ifndef KEYMASTER_UNIT_TEST_BUILD
28 #include <cutils/properties.h>
29 #else
30 #define PROPERTY_VALUE_MAX 80 /* Value doesn't matter */
property_get(const char *,char *,const char *)31 void property_get(const char* /* prop_name */, char* /* prop */, const char* /* default */) {}
32 #endif
33
34 #include <keymaster/authorization_set.h>
35
36 namespace keymaster {
37
38 namespace {
39
40 constexpr char kPlatformVersionProp[] = "ro.build.version.release";
41 constexpr char kPlatformVersionRegex[] = "^([0-9]{1,2})(\\.([0-9]{1,2}))?(\\.([0-9]{1,2}))?";
42 constexpr size_t kMajorVersionMatch = 1;
43 constexpr size_t kMinorVersionMatch = 3;
44 constexpr size_t kSubminorVersionMatch = 5;
45 constexpr size_t kPlatformVersionMatchCount = kSubminorVersionMatch + 1;
46
47 constexpr char kPlatformPatchlevelProp[] = "ro.build.version.security_patch";
48 constexpr char kPlatformPatchlevelRegex[] = "^([0-9]{4})-([0-9]{2})-[0-9]{2}$";
49 constexpr size_t kYearMatch = 1;
50 constexpr size_t kMonthMatch = 2;
51 constexpr size_t kPlatformPatchlevelMatchCount = kMonthMatch + 1;
52
match_to_uint32(const char * expression,const regmatch_t & match)53 uint32_t match_to_uint32(const char* expression, const regmatch_t& match) {
54 if (match.rm_so == -1)
55 return 0;
56
57 size_t len = match.rm_eo - match.rm_so;
58 std::string s(expression + match.rm_so, len);
59 return std::stoul(s);
60 }
61
62 } // anonymous namespace
63
ConfigureDevice(keymaster2_device_t * dev,uint32_t os_version,uint32_t os_patchlevel)64 keymaster_error_t ConfigureDevice(keymaster2_device_t* dev, uint32_t os_version,
65 uint32_t os_patchlevel) {
66 AuthorizationSet config_params(AuthorizationSetBuilder()
67 .Authorization(keymaster::TAG_OS_VERSION, os_version)
68 .Authorization(keymaster::TAG_OS_PATCHLEVEL, os_patchlevel));
69 return dev->configure(dev, &config_params);
70 }
71
ConfigureDevice(keymaster2_device_t * dev)72 keymaster_error_t ConfigureDevice(keymaster2_device_t* dev) {
73 char version_str[PROPERTY_VALUE_MAX];
74 property_get(kPlatformVersionProp, version_str, "" /* default */);
75 uint32_t version = GetOsVersion(version_str);
76
77 char patchlevel_str[PROPERTY_VALUE_MAX];
78 property_get(kPlatformPatchlevelProp, patchlevel_str, "" /* default */);
79 uint32_t patchlevel = GetOsPatchlevel(patchlevel_str);
80
81 return ConfigureDevice(dev, version, patchlevel);
82 }
83
GetOsVersion(const char * version_str)84 uint32_t GetOsVersion(const char* version_str) {
85 regex_t regex;
86 if (regcomp(®ex, kPlatformVersionRegex, REG_EXTENDED)) {
87 ALOGE("Failed to compile version regex! (%s)", kPlatformVersionRegex);
88 return 0;
89 }
90
91 regmatch_t matches[kPlatformVersionMatchCount];
92 if (regexec(®ex, version_str, kPlatformVersionMatchCount, matches, 0 /* flags */)) {
93 ALOGI("Platform version string does not match expected format. Using version 0.");
94 return 0;
95 }
96
97 uint32_t major = match_to_uint32(version_str, matches[kMajorVersionMatch]);
98 uint32_t minor = match_to_uint32(version_str, matches[kMinorVersionMatch]);
99 uint32_t subminor = match_to_uint32(version_str, matches[kSubminorVersionMatch]);
100
101 return (major * 100 + minor) * 100 + subminor;
102 }
103
GetOsPatchlevel(const char * patchlevel_str)104 uint32_t GetOsPatchlevel(const char* patchlevel_str) {
105 regex_t regex;
106 if (regcomp(®ex, kPlatformPatchlevelRegex, REG_EXTENDED) != 0) {
107 ALOGE("Failed to compile platform patchlevel regex! (%s)", kPlatformPatchlevelRegex);
108 return 0;
109 }
110
111 regmatch_t matches[kPlatformPatchlevelMatchCount];
112 if (regexec(®ex, patchlevel_str, kPlatformPatchlevelMatchCount, matches, 0 /* flags */)) {
113 ALOGI("Platform patchlevel string does not match expected format. Using patchlevel 0");
114 return 0;
115 }
116
117 uint32_t year = match_to_uint32(patchlevel_str, matches[kYearMatch]);
118 uint32_t month = match_to_uint32(patchlevel_str, matches[kMonthMatch]);
119
120 if (month < 1 || month > 12) {
121 ALOGE("Invalid patch month %d", month);
122 return 0;
123 }
124 return year * 100 + month;
125 }
126
127 } // namespace keymaster
128