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// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/extensions/omaha_attributes_handler.h"
#include <optional>
#include "base/metrics/histogram_functions.h"
#include "base/values.h"
#include "content/public/browser/browser_thread.h"
#include "extensions/browser/blocklist_extension_prefs.h"
#include "extensions/browser/blocklist_state.h"
#include "extensions/browser/extension_registrar.h"
#include "extensions/browser/extension_registry.h"
namespace extensions {
namespace {
// Logs UMA metrics when an extension is disabled remotely.
void ReportExtensionDisabledRemotely(bool should_be_remotely_disabled,
ExtensionUpdateCheckDataKey reason) {
// Report that the extension is newly disabled due to Omaha attributes.
if (should_be_remotely_disabled) {
base::UmaHistogramEnumeration("Extensions.ExtensionDisabledRemotely2",
reason);
}
// Report that the extension has added a new disable reason.
base::UmaHistogramEnumeration(
"Extensions.ExtensionAddDisabledRemotelyReason2", reason);
}
// Logs UMA metrics when the key is not found in Omaha attributes.
void ReportNoUpdateCheckKeys() {
base::UmaHistogramEnumeration("Extensions.ExtensionDisabledRemotely2",
ExtensionUpdateCheckDataKey::kNoKey);
}
// Logs UMA metrics when a remotely disabled extension is re-enabled.
void ReportReenableExtension(ExtensionUpdateCheckDataKey reason) {
const char* histogram = nullptr;
switch (reason) {
case ExtensionUpdateCheckDataKey::kMalware:
histogram = "Extensions.ExtensionReenabledRemotely";
break;
case ExtensionUpdateCheckDataKey::kPotentiallyUWS:
histogram = "Extensions.ExtensionReenabledRemotelyForPotentiallyUWS";
break;
case ExtensionUpdateCheckDataKey::kPolicyViolation:
histogram = "Extensions.ExtensionReenabledRemotelyForPolicyViolation";
break;
case ExtensionUpdateCheckDataKey::kNoKey:
NOTREACHED();
}
base::UmaHistogramCounts100(histogram, 1);
}
// Checks whether the `state` is in the `attributes`.
bool HasOmahaBlocklistStateInAttributes(const base::Value::Dict& attributes,
BitMapBlocklistState state) {
std::optional<bool> state_value;
switch (state) {
case BitMapBlocklistState::BLOCKLISTED_MALWARE:
state_value = attributes.FindBool("_malware");
break;
case BitMapBlocklistState::BLOCKLISTED_CWS_POLICY_VIOLATION:
state_value = attributes.FindBool("_policy_violation");
break;
case BitMapBlocklistState::BLOCKLISTED_POTENTIALLY_UNWANTED:
state_value = attributes.FindBool("_potentially_uws");
break;
case BitMapBlocklistState::NOT_BLOCKLISTED:
case BitMapBlocklistState::BLOCKLISTED_SECURITY_VULNERABILITY:
NOTREACHED()
<< "The other states are not applicable in Omaha attributes.";
}
return state_value.value_or(false);
}
} // namespace
OmahaAttributesHandler::OmahaAttributesHandler(
ExtensionPrefs* extension_prefs,
ExtensionRegistry* registry,
ExtensionRegistrar* registrar)
: extension_prefs_(extension_prefs),
registry_(registry),
registrar_(registrar) {}
void OmahaAttributesHandler::PerformActionBasedOnOmahaAttributes(
const ExtensionId& extension_id,
const base::Value::Dict& attributes) {
DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
// It is possible that an extension is uninstalled when the omaha attributes
// are notified by the update client asynchronously. In this case, we should
// ignore this extension.
if (!registry_->GetInstalledExtension(extension_id)) {
return;
}
HandleMalwareOmahaAttribute(extension_id, attributes);
HandleGreylistOmahaAttribute(
extension_id, attributes,
BitMapBlocklistState::BLOCKLISTED_CWS_POLICY_VIOLATION,
ExtensionUpdateCheckDataKey::kPolicyViolation);
HandleGreylistOmahaAttribute(
extension_id, attributes,
BitMapBlocklistState::BLOCKLISTED_POTENTIALLY_UNWANTED,
ExtensionUpdateCheckDataKey::kPotentiallyUWS);
}
void OmahaAttributesHandler::HandleMalwareOmahaAttribute(
const ExtensionId& extension_id,
const base::Value::Dict& attributes) {
bool has_malware_value = HasOmahaBlocklistStateInAttributes(
attributes, BitMapBlocklistState::BLOCKLISTED_MALWARE);
if (!has_malware_value) {
ReportNoUpdateCheckKeys();
if (!blocklist_prefs::HasOmahaBlocklistState(
extension_id, BitMapBlocklistState::BLOCKLISTED_MALWARE,
extension_prefs_)) {
return;
}
// The extension was previously blocklisted by Omaha, but is no longer.
// Clear the old omaha state.
ReportReenableExtension(ExtensionUpdateCheckDataKey::kMalware);
blocklist_prefs::RemoveOmahaBlocklistState(
extension_id, BitMapBlocklistState::BLOCKLISTED_MALWARE,
extension_prefs_);
registrar_->OnBlocklistStateRemoved(extension_id);
return;
}
if (blocklist_prefs::HasOmahaBlocklistState(
extension_id, BitMapBlocklistState::BLOCKLISTED_MALWARE,
extension_prefs_)) {
// The extension is already disabled. No work needs to be done.
return;
}
ReportExtensionDisabledRemotely(registrar_->IsExtensionEnabled(extension_id),
ExtensionUpdateCheckDataKey::kMalware);
blocklist_prefs::AddOmahaBlocklistState(
extension_id, BitMapBlocklistState::BLOCKLISTED_MALWARE,
extension_prefs_);
registrar_->OnBlocklistStateAdded(extension_id);
}
void OmahaAttributesHandler::HandleGreylistOmahaAttribute(
const ExtensionId& extension_id,
const base::Value::Dict& attributes,
BitMapBlocklistState greylist_state,
ExtensionUpdateCheckDataKey reason) {
bool has_attribute_value =
HasOmahaBlocklistStateInAttributes(attributes, greylist_state);
bool has_omaha_blocklist_state = blocklist_prefs::HasOmahaBlocklistState(
extension_id, greylist_state, extension_prefs_);
if (!has_attribute_value) {
if (has_omaha_blocklist_state) {
blocklist_prefs::RemoveOmahaBlocklistState(extension_id, greylist_state,
extension_prefs_);
ReportReenableExtension(reason);
}
registrar_->OnGreylistStateRemoved(extension_id);
return;
}
ReportExtensionDisabledRemotely(
/*should_be_remotely_disabled=*/!has_omaha_blocklist_state, reason);
blocklist_prefs::AddOmahaBlocklistState(extension_id, greylist_state,
extension_prefs_);
registrar_->OnGreylistStateAdded(extension_id, greylist_state);
}
} // namespace extensions
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