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Don't propagate StrictMode over one-way Binder calls. 

This was causing stack stitching problems where a one-way call with
violations followed by a two-way call without violations was getting
the previous one-way call's violation stack stitched on to the second
caller's stack.

The solution is a little more indirect than I would've liked
(preserving the binder's onTransact flags until enforceInterface) but
was seemingly necessary to work without changing the AIDL compiler.
It should also be sufficiently cheap, since no new calls to
thread-local IPCThreadState lookups were required.  The additional
work is just same-thread getter/setters on the existing
IPCThreadState.

Change-Id: I4b6db1d445c56e868e6d0d7be3ba6849f4ef23ae
This commit is contained in:
Brad Fitzpatrick 2010-08-30 16:01:16 -07:00
parent 00807f5ab9
commit 5273603e98
3 changed files with 32 additions and 7 deletions
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6
include/binder/IPCThreadState.h
View File

@ -43,7 +43,10 @@ public:
void setStrictModePolicy(int32_t policy);
int32_t getStrictModePolicy() const;
void setLastTransactionBinderFlags(int32_t flags);
int32_t getLastTransactionBinderFlags() const;
int64_t clearCallingIdentity();
void restoreCallingIdentity(int64_t token);
@ -113,6 +116,7 @@ private:
pid_t mCallingPid;
uid_t mCallingUid;
int32_t mStrictModePolicy;
int32_t mLastTransactionBinderFlags;
};
}; // namespace android

22
libs/binder/IPCThreadState.cpp
View File

@ -377,6 +377,16 @@ int32_t IPCThreadState::getStrictModePolicy() const
return mStrictModePolicy;
}
void IPCThreadState::setLastTransactionBinderFlags(int32_t flags)
{
mLastTransactionBinderFlags = flags;
}
int32_t IPCThreadState::getLastTransactionBinderFlags() const
{
return mLastTransactionBinderFlags;
}
void IPCThreadState::restoreCallingIdentity(int64_t token)
{
mCallingUid = (int)(token>>32);
@ -598,8 +608,10 @@ status_t IPCThreadState::clearDeathNotification(int32_t handle, BpBinder* proxy)
}
IPCThreadState::IPCThreadState()
: mProcess(ProcessState::self()), mMyThreadId(androidGetTid()),
mStrictModePolicy(0)
: mProcess(ProcessState::self()),
mMyThreadId(androidGetTid()),
mStrictModePolicy(0),
mLastTransactionBinderFlags(0)
{
pthread_setspecific(gTLS, this);
clearCaller();
@ -983,11 +995,11 @@ status_t IPCThreadState::executeCommand(int32_t cmd)
}
if (tr.target.ptr) {
sp<BBinder> b((BBinder*)tr.cookie);
const status_t error = b->transact(tr.code, buffer, &reply, 0);
const status_t error = b->transact(tr.code, buffer, &reply, tr.flags);
if (error < NO_ERROR) reply.setError(error);
} else {
const status_t error = the_context_object->transact(tr.code, buffer, &reply, 0);
const status_t error = the_context_object->transact(tr.code, buffer, &reply, tr.flags);
if (error < NO_ERROR) reply.setError(error);
}

11
libs/binder/Parcel.cpp
View File

@ -464,7 +464,16 @@ bool Parcel::enforceInterface(const String16& interface,
if (threadState == NULL) {
threadState = IPCThreadState::self();
}
threadState->setStrictModePolicy(strictPolicy);
if ((threadState->getLastTransactionBinderFlags() &
IBinder::FLAG_ONEWAY) != 0) {
// For one-way calls, the callee is running entirely
// disconnected from the caller, so disable StrictMode entirely.
// Not only does disk/network usage not impact the caller, but
// there's no way to commuicate back any violations anyway.
threadState->setStrictModePolicy(0);
} else {
threadState->setStrictModePolicy(strictPolicy);
}
const String16 str(readString16());
if (str == interface) {
return true;