android13/system/keymaster/android_keymaster/keymaster_configuration.cpp

267 lines
8.5 KiB
C++

/*
* Copyright (C) 2016 The Android Open Source Project
*
* 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 <keymaster/keymaster_configuration.h>
#include <regex>
#include <string>
#include <regex.h>
#define LOG_TAG "keymaster"
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <log/log.h>
#include <keymaster/authorization_set.h>
namespace keymaster {
namespace {
constexpr char kPlatformVersionProp[] = "ro.build.version.release";
constexpr char kPlatformVersionRegex[] = "^([0-9]{1,2})(\\.([0-9]{1,2}))?(\\.([0-9]{1,2}))?";
constexpr size_t kMajorVersionMatch = 1;
constexpr size_t kMinorVersionMatch = 3;
constexpr size_t kSubminorVersionMatch = 5;
constexpr size_t kPlatformVersionMatchCount = kSubminorVersionMatch + 1;
constexpr char kPlatformPatchlevelProp[] = "ro.build.version.security_patch";
constexpr char kVendorPatchlevelProp[] = "ro.vendor.build.security_patch";
constexpr char kPatchlevelRegex[] = "^([0-9]{4})-([0-9]{2})-([0-9]{2})$";
constexpr char kVerifiedBootStateProp[] = "ro.boot.verifiedbootstate";
constexpr char kVbmetaDeviceStateProp[] = "ro.boot.vbmeta.device_state";
constexpr char kVbmetaDigestProp[] = "ro.boot.vbmeta.digest";
constexpr size_t kYearMatch = 1;
constexpr size_t kMonthMatch = 2;
constexpr size_t kDayMatch = 3;
constexpr size_t kPatchlevelMatchCount = kDayMatch + 1;
uint32_t match_to_uint32(const char* expression, const regmatch_t& match) {
if (match.rm_so == -1) return 0;
size_t len = match.rm_eo - match.rm_so;
std::string s(expression + match.rm_so, len);
return std::stoul(s);
}
std::string wait_and_get_property(const char* prop) {
std::string prop_value;
#ifndef KEYMASTER_UNIT_TEST_BUILD
while (!android::base::WaitForPropertyCreation(prop)) {
SLOGE("waited 15s for %s, still waiting...", prop);
}
prop_value = android::base::GetProperty(prop, "" /* default */);
#endif
return prop_value;
}
enum class PatchlevelOutput { kYearMonthDay, kYearMonth };
uint32_t GetPatchlevel(const char* patchlevel_str, PatchlevelOutput detail) {
regex_t regex;
if (regcomp(&regex, kPatchlevelRegex, REG_EXTENDED) != 0) {
ALOGE("Failed to compile platform patchlevel regex! (%s)", kPatchlevelRegex);
return 0;
}
regmatch_t matches[kPatchlevelMatchCount];
int not_match = regexec(&regex, patchlevel_str, kPatchlevelMatchCount, matches, 0 /* flags */);
regfree(&regex);
if (not_match) {
ALOGI(" patchlevel string does not match expected format. Using patchlevel 0");
return 0;
}
uint32_t year = match_to_uint32(patchlevel_str, matches[kYearMatch]);
uint32_t month = match_to_uint32(patchlevel_str, matches[kMonthMatch]);
if (month < 1 || month > 12) {
ALOGE("Invalid patch month %d", month);
return 0;
}
switch (detail) {
case PatchlevelOutput::kYearMonthDay: {
uint32_t day = match_to_uint32(patchlevel_str, matches[kDayMatch]);
if (day < 1 || day > 31) {
ALOGE("Invalid patch day %d", day);
return 0;
}
return year * 10000 + month * 100 + day;
}
case PatchlevelOutput::kYearMonth:
return year * 100 + month;
}
return 0;
}
} // anonymous namespace
keymaster_error_t ConfigureDevice(keymaster2_device_t* dev, uint32_t os_version,
uint32_t os_patchlevel) {
AuthorizationSet config_params(AuthorizationSetBuilder()
.Authorization(keymaster::TAG_OS_VERSION, os_version)
.Authorization(keymaster::TAG_OS_PATCHLEVEL, os_patchlevel));
return dev->configure(dev, &config_params);
}
keymaster_error_t ConfigureDevice(keymaster2_device_t* dev) {
return ConfigureDevice(dev, GetOsVersion(), GetOsPatchlevel());
}
uint32_t GetOsVersion(const char* version_str) {
regex_t regex;
if (regcomp(&regex, kPlatformVersionRegex, REG_EXTENDED)) {
ALOGE("Failed to compile version regex! (%s)", kPlatformVersionRegex);
return 0;
}
regmatch_t matches[kPlatformVersionMatchCount];
int not_match =
regexec(&regex, version_str, kPlatformVersionMatchCount, matches, 0 /* flags */);
regfree(&regex);
if (not_match) {
ALOGI("Platform version string \"%s\" does not match expected format. Using version 0.",
version_str);
return 0;
}
uint32_t major = match_to_uint32(version_str, matches[kMajorVersionMatch]);
uint32_t minor = match_to_uint32(version_str, matches[kMinorVersionMatch]);
uint32_t subminor = match_to_uint32(version_str, matches[kSubminorVersionMatch]);
return (major * 100 + minor) * 100 + subminor;
}
uint32_t GetOsVersion() {
std::string version = wait_and_get_property(kPlatformVersionProp);
return GetOsVersion(version.c_str());
}
uint32_t GetOsPatchlevel(const char* patchlevel_str) {
return GetPatchlevel(patchlevel_str, PatchlevelOutput::kYearMonth);
}
uint32_t GetOsPatchlevel() {
std::string patchlevel = wait_and_get_property(kPlatformPatchlevelProp);
return GetOsPatchlevel(patchlevel.c_str());
}
uint32_t GetVendorPatchlevel() {
std::string patchlevel = wait_and_get_property(kVendorPatchlevelProp);
return GetPatchlevel(patchlevel.c_str(), PatchlevelOutput::kYearMonthDay);
}
std::string GetVerifiedBootState() {
// Do not wait for bootloader-set properties. They are passed to the kernel
// on the command line, and should always be available. If not available at
// this point, it will never be available.
return android::base::GetProperty(kVerifiedBootStateProp, /*default_value=*/"red");
}
std::string GetBootloaderState() {
// Do not wait for bootloader-set properties. They are passed to the kernel
// on the command line, and should always be available. If not available at
// this point, it will never be available.
return android::base::GetProperty(kVbmetaDeviceStateProp, /*default_value=*/"unlocked");
}
std::optional<uint8_t> HexCharToInt(char c) {
switch (c) {
case '0':
return 0x0;
case '1':
return 0x1;
case '2':
return 0x2;
case '3':
return 0x3;
case '4':
return 0x4;
case '5':
return 0x5;
case '6':
return 0x6;
case '7':
return 0x7;
case '8':
return 0x8;
case '9':
return 0x9;
case 'a':
return 0xa;
case 'A':
return 0xa;
case 'b':
return 0xb;
case 'B':
return 0xb;
case 'c':
return 0xc;
case 'C':
return 0xc;
case 'd':
return 0xd;
case 'D':
return 0xd;
case 'e':
return 0xe;
case 'E':
return 0xe;
case 'f':
return 0xf;
case 'F':
return 0xf;
default:
return std::nullopt;
}
}
std::optional<std::vector<uint8_t>> GetVbmetaDigest(std::string_view vbmeta_string) {
if (vbmeta_string.size() % 2 == 1) {
LOG(ERROR) << "hex string has an odd length (" << vbmeta_string.size() << ")";
return std::nullopt;
}
std::vector<uint8_t> out;
out.reserve(vbmeta_string.size() / 2);
for (auto next = vbmeta_string.begin(); next != vbmeta_string.end(); next += 2) {
auto high_nibble = HexCharToInt(*next);
auto low_nibble = HexCharToInt(*(next + 1));
if (!high_nibble || !low_nibble) {
LOG(ERROR) << "invalid input: '" << *next << "' or '" << *(next + 1) << "'";
return std::nullopt;
}
out.push_back((*high_nibble << 4) | *low_nibble);
}
return out;
}
std::optional<std::vector<uint8_t>> GetVbmetaDigest() {
// Do not wait for bootloader-set properties. They are passed to the kernel
// on the command line, and should always be available. If not available at
// this point, it will never be available.
auto vbmeta_string = android::base::GetProperty(
kVbmetaDigestProp,
/*default_value=*/"0000000000000000000000000000000000000000000000000000000000000000");
return GetVbmetaDigest(vbmeta_string);
}
} // namespace keymaster