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/*
* Copyright (C) 2018 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.
*/
#ifndef ART_RUNTIME_HIDDEN_API_H_
#define ART_RUNTIME_HIDDEN_API_H_
#include "art_field-inl.h"
#include "art_method-inl.h"
#include "base/mutex.h"
#include "dex/hidden_api_access_flags.h"
#include "mirror/class-inl.h"
#include "reflection.h"
#include "runtime.h"
namespace art {
namespace hiddenapi {
// Hidden API enforcement policy
// This must be kept in sync with ApplicationInfo.ApiEnforcementPolicy in
// frameworks/base/core/java/android/content/pm/ApplicationInfo.java
enum class EnforcementPolicy {
kNoChecks = 0,
kAllLists = 1, // ban anything but whitelist
kDarkGreyAndBlackList = 2, // ban dark grey & blacklist
kBlacklistOnly = 3, // ban blacklist violations only
kMax = kBlacklistOnly,
};
inline EnforcementPolicy EnforcementPolicyFromInt(int api_policy_int) {
DCHECK_GE(api_policy_int, 0);
DCHECK_LE(api_policy_int, static_cast<int>(EnforcementPolicy::kMax));
return static_cast<EnforcementPolicy>(api_policy_int);
}
enum Action {
kAllow,
kAllowButWarn,
kAllowButWarnAndToast,
kDeny
};
enum AccessMethod {
kReflection,
kJNI,
kLinking,
};
inline Action GetMemberAction(uint32_t access_flags) {
EnforcementPolicy policy = Runtime::Current()->GetHiddenApiEnforcementPolicy();
if (policy == EnforcementPolicy::kNoChecks) {
// Exit early. Nothing to enforce.
return kAllow;
}
HiddenApiAccessFlags::ApiList api_list = HiddenApiAccessFlags::DecodeFromRuntime(access_flags);
if (api_list == HiddenApiAccessFlags::kWhitelist) {
return kAllow;
}
// The logic below relies on equality of values in the enums EnforcementPolicy and
// HiddenApiAccessFlags::ApiList, and their ordering. Assertions are in hidden_api.cc.
if (static_cast<int>(policy) > static_cast<int>(api_list)) {
return api_list == HiddenApiAccessFlags::kDarkGreylist
? kAllowButWarnAndToast
: kAllowButWarn;
} else {
return kDeny;
}
}
// Implementation details. DO NOT ACCESS DIRECTLY.
namespace detail {
// Class to encapsulate the signature of a member (ArtField or ArtMethod). This
// is used as a helper when matching prefixes, and when logging the signature.
class MemberSignature {
private:
std::string member_type_;
std::vector<std::string> signature_parts_;
std::string tmp_;
public:
explicit MemberSignature(ArtField* field) REQUIRES_SHARED(Locks::mutator_lock_);
explicit MemberSignature(ArtMethod* method) REQUIRES_SHARED(Locks::mutator_lock_);
void Dump(std::ostream& os) const;
// Performs prefix match on this member. Since the full member signature is
// composed of several parts, we match each part in turn (rather than
// building the entire thing in memory and performing a simple prefix match)
bool DoesPrefixMatch(const std::string& prefix) const;
bool IsExempted(const std::vector<std::string>& exemptions);
void WarnAboutAccess(AccessMethod access_method, HiddenApiAccessFlags::ApiList list);
};
template<typename T>
bool ShouldBlockAccessToMemberImpl(T* member,
Action action,
AccessMethod access_method)
REQUIRES_SHARED(Locks::mutator_lock_);
// Returns true if the caller is either loaded by the boot strap class loader or comes from
// a dex file located in ${ANDROID_ROOT}/framework/.
ALWAYS_INLINE
inline bool IsCallerInPlatformDex(ObjPtr<mirror::ClassLoader> caller_class_loader,
ObjPtr<mirror::DexCache> caller_dex_cache)
REQUIRES_SHARED(Locks::mutator_lock_) {
if (caller_class_loader.IsNull()) {
return true;
} else if (caller_dex_cache.IsNull()) {
return false;
} else {
const DexFile* caller_dex_file = caller_dex_cache->GetDexFile();
return caller_dex_file != nullptr && caller_dex_file->IsPlatformDexFile();
}
}
} // namespace detail
// Returns true if access to `member` should be denied to the caller of the
// reflective query. The decision is based on whether the caller is in the
// platform or not. Because different users of this function determine this
// in a different way, `fn_caller_in_platform(self)` is called and should
// return true if the caller is located in the platform.
// This function might print warnings into the log if the member is hidden.
template<typename T>
inline bool ShouldBlockAccessToMember(T* member,
Thread* self,
std::function<bool(Thread*)> fn_caller_in_platform,
AccessMethod access_method)
REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(member != nullptr);
Action action = GetMemberAction(member->GetAccessFlags());
if (action == kAllow) {
// Nothing to do.
return false;
}
// Member is hidden. Invoke `fn_caller_in_platform` and find the origin of the access.
// This can be *very* expensive. Save it for last.
if (fn_caller_in_platform(self)) {
// Caller in the platform. Exit.
return false;
}
// Member is hidden and caller is not in the platform.
return detail::ShouldBlockAccessToMemberImpl(member, action, access_method);
}
inline bool IsCallerInPlatformDex(ObjPtr<mirror::Class> caller)
REQUIRES_SHARED(Locks::mutator_lock_) {
return !caller.IsNull() &&
detail::IsCallerInPlatformDex(caller->GetClassLoader(), caller->GetDexCache());
}
// Returns true if access to `member` should be denied to a caller loaded with
// `caller_class_loader`.
// This function might print warnings into the log if the member is hidden.
template<typename T>
inline bool ShouldBlockAccessToMember(T* member,
ObjPtr<mirror::ClassLoader> caller_class_loader,
ObjPtr<mirror::DexCache> caller_dex_cache,
AccessMethod access_method)
REQUIRES_SHARED(Locks::mutator_lock_) {
bool caller_in_platform = detail::IsCallerInPlatformDex(caller_class_loader, caller_dex_cache);
return ShouldBlockAccessToMember(member,
/* thread */ nullptr,
[caller_in_platform] (Thread*) { return caller_in_platform; },
access_method);
}
} // namespace hiddenapi
} // namespace art
#endif // ART_RUNTIME_HIDDEN_API_H_
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