Fix an event injection bug when the policy is bypassed.

Added the concept of a "trusted" event to distinguish between events from
attached input devices or trusted injectors vs. other applications.
This change enables us to move certain policy decisions out of the
dispatcher and into the policy itself where they can be handled more
systematically.

Change-Id: I4d56fdcdd31aaa675d452088af39a70c4e039970

3 files changed, 36 insertions, 36 deletions

diff --git a/include/ui/Input.h b/include/ui/Input.h
index 66061fd719..8c6018bfee 100644
--- a/include/ui/Input.h
+++ b/include/ui/Input.h
@@ -95,6 +95,10 @@ enum {
     // Indicates that the input event was injected.
     POLICY_FLAG_INJECTED = 0x01000000,
 
+    // Indicates that the input event is from a trusted source such as a directly attached
+    // input device or an application with system-wide event injection permission.
+    POLICY_FLAG_TRUSTED = 0x02000000,
+
     /* These flags are set by the input reader policy as it intercepts each event. */
 
     // Indicates that the screen was off when the event was received and the event
diff --git a/include/ui/InputDispatcher.h b/include/ui/InputDispatcher.h
index 0834e86505..3599163d1b 100644
--- a/include/ui/InputDispatcher.h
+++ b/include/ui/InputDispatcher.h
@@ -913,7 +913,6 @@ private:
     void drainInboundQueueLocked();
     void releasePendingEventLocked();
     void releaseInboundEventLocked(EventEntry* entry);
-    bool isEventFromTrustedSourceLocked(EventEntry* entry);
 
     // Dispatch state.
     bool mDispatchEnabled;
@@ -960,10 +959,10 @@ private:
             nsecs_t currentTime, ConfigurationChangedEntry* entry);
     bool dispatchKeyLocked(
             nsecs_t currentTime, KeyEntry* entry, nsecs_t keyRepeatTimeout,
-            bool dropEvent, nsecs_t* nextWakeupTime);
+            DropReason* dropReason, nsecs_t* nextWakeupTime);
     bool dispatchMotionLocked(
             nsecs_t currentTime, MotionEntry* entry,
-            bool dropEvent, nsecs_t* nextWakeupTime);
+            DropReason* dropReason, nsecs_t* nextWakeupTime);
     void dispatchEventToCurrentInputTargetsLocked(
             nsecs_t currentTime, EventEntry* entry, bool resumeWithAppendedMotionSample);
 
diff --git a/libs/ui/InputDispatcher.cpp b/libs/ui/InputDispatcher.cpp
index 58c2cdfda8..41b6ff318d 100644
--- a/libs/ui/InputDispatcher.cpp
+++ b/libs/ui/InputDispatcher.cpp
@@ -370,7 +370,7 @@ void InputDispatcher::dispatchOnceInnerLocked(nsecs_t keyRepeatTimeout,
             }
         }
         done = dispatchKeyLocked(currentTime, typedEntry, keyRepeatTimeout,
-                dropReason != DROP_REASON_NOT_DROPPED, nextWakeupTime);
+                &dropReason, nextWakeupTime);
         break;
     }
 
@@ -380,7 +380,7 @@ void InputDispatcher::dispatchOnceInnerLocked(nsecs_t keyRepeatTimeout,
             dropReason = DROP_REASON_APP_SWITCH;
         }
         done = dispatchMotionLocked(currentTime, typedEntry,
-                dropReason != DROP_REASON_NOT_DROPPED, nextWakeupTime);
+                &dropReason, nextWakeupTime);
         break;
     }
 
@@ -431,6 +431,9 @@ void InputDispatcher::dropInboundEventLocked(EventEntry* entry, DropReason dropR
     const char* reason;
     switch (dropReason) {
     case DROP_REASON_POLICY:
+#if DEBUG_INBOUND_EVENT_DETAILS
+        LOGD("Dropped event because policy requested that it not be delivered to the application.");
+#endif
         reason = "inbound event was dropped because the policy requested that it not be "
                 "delivered to the application";
         break;
@@ -473,7 +476,7 @@ bool InputDispatcher::isAppSwitchKeyCode(int32_t keyCode) {
 bool InputDispatcher::isAppSwitchKeyEventLocked(KeyEntry* keyEntry) {
     return ! (keyEntry->flags & AKEY_EVENT_FLAG_CANCELED)
             && isAppSwitchKeyCode(keyEntry->keyCode)
-            && isEventFromTrustedSourceLocked(keyEntry)
+            && (keyEntry->policyFlags & POLICY_FLAG_TRUSTED)
             && (keyEntry->policyFlags & POLICY_FLAG_PASS_TO_USER);
 }
 
@@ -541,12 +544,6 @@ void InputDispatcher::releaseInboundEventLocked(EventEntry* entry) {
     mAllocator.releaseEventEntry(entry);
 }
 
-bool InputDispatcher::isEventFromTrustedSourceLocked(EventEntry* entry) {
-    InjectionState* injectionState = entry->injectionState;
-    return ! injectionState
-            || hasInjectionPermission(injectionState->injectorPid, injectionState->injectorUid);
-}
-
 void InputDispatcher::resetKeyRepeatLocked() {
     if (mKeyRepeatState.lastKeyEntry) {
         mAllocator.releaseKeyEntry(mKeyRepeatState.lastKeyEntry);
@@ -559,7 +556,8 @@ InputDispatcher::KeyEntry* InputDispatcher::synthesizeKeyRepeatLocked(
     KeyEntry* entry = mKeyRepeatState.lastKeyEntry;
 
     // Reuse the repeated key entry if it is otherwise unreferenced.
-    uint32_t policyFlags = entry->policyFlags & (POLICY_FLAG_RAW_MASK | POLICY_FLAG_PASS_TO_USER);
+    uint32_t policyFlags = (entry->policyFlags & POLICY_FLAG_RAW_MASK)
+            | POLICY_FLAG_PASS_TO_USER | POLICY_FLAG_TRUSTED;
     if (entry->refCount == 1) {
         mAllocator.recycleKeyEntry(entry);
         entry->eventTime = currentTime;
@@ -608,19 +606,13 @@ bool InputDispatcher::dispatchConfigurationChangedLocked(
 
 bool InputDispatcher::dispatchKeyLocked(
         nsecs_t currentTime, KeyEntry* entry, nsecs_t keyRepeatTimeout,
-        bool dropEvent, nsecs_t* nextWakeupTime) {
+        DropReason* dropReason, nsecs_t* nextWakeupTime) {
     // Give the policy a chance to intercept the key.
     if (entry->interceptKeyResult == KeyEntry::INTERCEPT_KEY_RESULT_UNKNOWN) {
-        bool trusted;
-        if (! dropEvent && mFocusedWindow) {
-            trusted = checkInjectionPermission(mFocusedWindow, entry->injectionState);
-        } else {
-            trusted = isEventFromTrustedSourceLocked(entry);
-        }
-        if (trusted) {
+        if (entry->policyFlags & POLICY_FLAG_PASS_TO_USER) {
             CommandEntry* commandEntry = postCommandLocked(
                     & InputDispatcher::doInterceptKeyBeforeDispatchingLockedInterruptible);
-            if (! dropEvent && mFocusedWindow) {
+            if (mFocusedWindow) {
                 commandEntry->inputChannel = mFocusedWindow->inputChannel;
             }
             commandEntry->keyEntry = entry;
@@ -630,13 +622,16 @@ bool InputDispatcher::dispatchKeyLocked(
             entry->interceptKeyResult = KeyEntry::INTERCEPT_KEY_RESULT_CONTINUE;
         }
     } else if (entry->interceptKeyResult == KeyEntry::INTERCEPT_KEY_RESULT_SKIP) {
+        if (*dropReason == DROP_REASON_NOT_DROPPED) {
+            *dropReason = DROP_REASON_POLICY;
+        }
         resetTargetsLocked();
         setInjectionResultLocked(entry, INPUT_EVENT_INJECTION_SUCCEEDED);
         return true;
     }
 
     // Clean up if dropping the event.
-    if (dropEvent) {
+    if (*dropReason != DROP_REASON_NOT_DROPPED) {
         resetTargetsLocked();
         setInjectionResultLocked(entry, INPUT_EVENT_INJECTION_FAILED);
         return true;
@@ -648,7 +643,8 @@ bool InputDispatcher::dispatchKeyLocked(
 
         if (entry->repeatCount == 0
                 && entry->action == AKEY_EVENT_ACTION_DOWN
-                && ! entry->isInjected()) {
+                && (entry->policyFlags & POLICY_FLAG_TRUSTED)
+                && !entry->isInjected()) {
             if (mKeyRepeatState.lastKeyEntry
                     && mKeyRepeatState.lastKeyEntry->keyCode == entry->keyCode) {
                 // We have seen two identical key downs in a row which indicates that the device
@@ -713,9 +709,9 @@ void InputDispatcher::logOutboundKeyDetailsLocked(const char* prefix, const KeyE
 }
 
 bool InputDispatcher::dispatchMotionLocked(
-        nsecs_t currentTime, MotionEntry* entry, bool dropEvent, nsecs_t* nextWakeupTime) {
+        nsecs_t currentTime, MotionEntry* entry, DropReason* dropReason, nsecs_t* nextWakeupTime) {
     // Clean up if dropping the event.
-    if (dropEvent) {
+    if (*dropReason != DROP_REASON_NOT_DROPPED) {
         resetTargetsLocked();
         setInjectionResultLocked(entry, INPUT_EVENT_INJECTION_FAILED);
         return true;
@@ -2085,6 +2081,7 @@ void InputDispatcher::notifyKey(nsecs_t eventTime, int32_t deviceId, int32_t sou
         return;
     }
 
+    policyFlags |= POLICY_FLAG_TRUSTED;
     mPolicy->interceptKeyBeforeQueueing(eventTime, deviceId, action, /*byref*/ flags,
             keyCode, scanCode, /*byref*/ policyFlags);
 
@@ -2130,6 +2127,7 @@ void InputDispatcher::notifyMotion(nsecs_t eventTime, int32_t deviceId, int32_t
         return;
     }
 
+    policyFlags |= POLICY_FLAG_TRUSTED;
     mPolicy->interceptGenericBeforeQueueing(eventTime, /*byref*/ policyFlags);
 
     bool needWake;
@@ -2263,6 +2261,7 @@ void InputDispatcher::notifySwitch(nsecs_t when, int32_t switchCode, int32_t swi
             switchCode, switchValue, policyFlags);
 #endif
 
+    policyFlags |= POLICY_FLAG_TRUSTED;
     mPolicy->notifySwitch(when, switchCode, switchValue, policyFlags);
 }
 
@@ -2275,7 +2274,11 @@ int32_t InputDispatcher::injectInputEvent(const InputEvent* event,
 #endif
 
     nsecs_t endTime = now() + milliseconds_to_nanoseconds(timeoutMillis);
-    bool trusted = hasInjectionPermission(injectorPid, injectorUid);
+
+    uint32_t policyFlags = POLICY_FLAG_INJECTED;
+    if (hasInjectionPermission(injectorPid, injectorUid)) {
+        policyFlags |= POLICY_FLAG_TRUSTED;
+    }
 
     EventEntry* injectedEntry;
     switch (event->getType()) {
@@ -2291,11 +2294,8 @@ int32_t InputDispatcher::injectInputEvent(const InputEvent* event,
         int32_t flags = keyEvent->getFlags();
         int32_t keyCode = keyEvent->getKeyCode();
         int32_t scanCode = keyEvent->getScanCode();
-        uint32_t policyFlags = POLICY_FLAG_INJECTED;
-        if (trusted) {
-            mPolicy->interceptKeyBeforeQueueing(eventTime, deviceId, action, /*byref*/ flags,
-                    keyCode, scanCode, /*byref*/ policyFlags);
-        }
+        mPolicy->interceptKeyBeforeQueueing(eventTime, deviceId, action, /*byref*/ flags,
+                keyCode, scanCode, /*byref*/ policyFlags);
 
         mLock.lock();
         injectedEntry = mAllocator.obtainKeyEntry(eventTime, deviceId, keyEvent->getSource(),
@@ -2314,10 +2314,7 @@ int32_t InputDispatcher::injectInputEvent(const InputEvent* event,
         }
 
         nsecs_t eventTime = motionEvent->getEventTime();
-        uint32_t policyFlags = POLICY_FLAG_INJECTED;
-        if (trusted) {
-            mPolicy->interceptGenericBeforeQueueing(eventTime, /*byref*/ policyFlags);
-        }
+        mPolicy->interceptGenericBeforeQueueing(eventTime, /*byref*/ policyFlags);
 
         mLock.lock();
         const nsecs_t* sampleEventTimes = motionEvent->getSampleEventTimes();