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Compare the fingerprint before reading the partition

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The update_verifier now compares the fingerprint of a partition before
performing the blocks read. If the fingerprint of the current system property
mismatches the one embedded in the care_map, verification of this partition
will be skipped. This is useful for the possible system only updates in the
future.

Bug: 114778109
Test: unit tests pass
Change-Id: Iea309148a05109b5810dfb533d94260d77ab8540
This commit is contained in:
Tianjie Xu
2018-09-14 12:52:02 -07:00
parent f89067ab97
commit 9eed65e1db
3 changed files with 140 additions and 29 deletions
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update_verifier/update_verifier.cpp
+36 -11
View File
@@ -65,6 +65,8 @@ using android::hardware::boot::V1_0::IBootControl;
using android::hardware::boot::V1_0::BoolResult;
using android::hardware::boot::V1_0::CommandResult;
constexpr const char* kDefaultCareMapPrefix = "/data/ota_package/care_map";
// Find directories in format of "/sys/block/dm-X".
static int dm_name_filter(const dirent* de) {
if (android::base::StartsWith(de->d_name, "dm-")) {
@@ -73,6 +75,10 @@ static int dm_name_filter(const dirent* de) {
return 0;
}
UpdateVerifier::UpdateVerifier()
: care_map_prefix_(kDefaultCareMapPrefix),
property_reader_([](const std::string& id) { return android::base::GetProperty(id, ""); }) {}
// Iterate the content of "/sys/block/dm-X/dm/name" and find all the dm-wrapped block devices.
// We will later read all the ("cared") blocks from "/dev/block/dm-X" to ensure the target
// partition's integrity.
@@ -224,18 +230,14 @@ bool UpdateVerifier::ParseCareMapPlainText(const std::string& content) {
return true;
}
bool UpdateVerifier::ParseCareMap(const std::string& file_name) {
bool UpdateVerifier::ParseCareMap() {
partition_map_.clear();
std::string care_map_name = file_name;
if (care_map_name.empty()) {
std::string care_map_prefix = "/data/ota_package/care_map";
care_map_name = care_map_prefix + ".pb";
if (access(care_map_name.c_str(), R_OK) == -1) {
LOG(WARNING) << care_map_name
<< " doesn't exist, falling back to read the care_map in plain text format.";
care_map_name = care_map_prefix + ".txt";
}
std::string care_map_name = care_map_prefix_ + ".pb";
if (access(care_map_name.c_str(), R_OK) == -1) {
LOG(WARNING) << care_map_name
<< " doesn't exist, falling back to read the care_map in plain text format.";
care_map_name = care_map_prefix_ + ".txt";
}
android::base::unique_fd care_map_fd(TEMP_FAILURE_RETRY(open(care_map_name.c_str(), O_RDONLY)));
@@ -283,7 +285,21 @@ bool UpdateVerifier::ParseCareMap(const std::string& file_name) {
return false;
}
// TODO(xunchang) compare the fingerprint of the partition.
// Continues to check other partitions if there is a fingerprint mismatch.
if (partition.id().empty() || partition.id() == "unknown") {
LOG(WARNING) << "Skip reading partition " << partition.name()
<< ": property_id is not provided to get fingerprint.";
continue;
}
std::string fingerprint = property_reader_(partition.id());
if (fingerprint != partition.fingerprint()) {
LOG(WARNING) << "Skip reading partition " << partition.name() << ": fingerprint "
<< fingerprint << " doesn't match the expected value "
<< partition.fingerprint();
continue;
}
partition_map_.emplace(partition.name(), ranges);
}
@@ -295,6 +311,15 @@ bool UpdateVerifier::ParseCareMap(const std::string& file_name) {
return true;
}
void UpdateVerifier::set_care_map_prefix(const std::string& prefix) {
care_map_prefix_ = prefix;
}
void UpdateVerifier::set_property_reader(
const std::function<std::string(const std::string&)>& property_reader) {
property_reader_ = property_reader;
}
static int reboot_device() {
if (android_reboot(ANDROID_RB_RESTART2, 0, nullptr) == -1) {
LOG(ERROR) << "Failed to reboot.";