Disallow reading object data from Parcels with non-object reads am: c517681c66

am: e69532fd03

Change-Id: If46b533d0d34ef21f979c50049f3dd8a4339fd67

1 files changed, 73 insertions, 0 deletions

diff --git a/libs/binder/Parcel.cpp b/libs/binder/Parcel.cpp
index e22179b15d..44357c3653 100644
--- a/libs/binder/Parcel.cpp
+++ b/libs/binder/Parcel.cpp
@@ -433,6 +433,7 @@ void Parcel::setDataPosition(size_t pos) const
 
     mDataPos = pos;
     mNextObjectHint = 0;
+    mObjectsSorted = false;
 }
 
 status_t Parcel::setDataCapacity(size_t size)
@@ -1469,6 +1470,59 @@ void Parcel::remove(size_t /*start*/, size_t /*amt*/)
     LOG_ALWAYS_FATAL("Parcel::remove() not yet implemented!");
 }
 
+status_t Parcel::validateReadData(size_t upperBound) const
+{
+    // Don't allow non-object reads on object data
+    if (mObjectsSorted || mObjectsSize <= 1) {
+data_sorted:
+        // Expect to check only against the next object
+        if (mNextObjectHint < mObjectsSize && upperBound > mObjects[mNextObjectHint]) {
+            // For some reason the current read position is greater than the next object
+            // hint. Iterate until we find the right object
+            size_t nextObject = mNextObjectHint;
+            do {
+                if (mDataPos < mObjects[nextObject] + sizeof(flat_binder_object)) {
+                    // Requested info overlaps with an object
+                    ALOGE("Attempt to read from protected data in Parcel %p", this);
+                    return PERMISSION_DENIED;
+                }
+                nextObject++;
+            } while (nextObject < mObjectsSize && upperBound > mObjects[nextObject]);
+            mNextObjectHint = nextObject;
+        }
+        return NO_ERROR;
+    }
+    // Quickly determine if mObjects is sorted.
+    binder_size_t* currObj = mObjects + mObjectsSize - 1;
+    binder_size_t* prevObj = currObj;
+    while (currObj > mObjects) {
+        prevObj--;
+        if(*prevObj > *currObj) {
+            goto data_unsorted;
+        }
+        currObj--;
+    }
+    mObjectsSorted = true;
+    goto data_sorted;
+
+data_unsorted:
+    // Insertion Sort mObjects
+    // Great for mostly sorted lists. If randomly sorted or reverse ordered mObjects become common,
+    // switch to std::sort(mObjects, mObjects + mObjectsSize);
+    for (binder_size_t* iter0 = mObjects + 1; iter0 < mObjects + mObjectsSize; iter0++) {
+        binder_size_t temp = *iter0;
+        binder_size_t* iter1 = iter0 - 1;
+        while (iter1 >= mObjects && *iter1 > temp) {
+            *(iter1 + 1) = *iter1;
+            iter1--;
+        }
+        *(iter1 + 1) = temp;
+    }
+    mNextObjectHint = 0;
+    mObjectsSorted = true;
+    goto data_sorted;
+}
+
 status_t Parcel::read(void* outData, size_t len) const
 {
     if (len > INT32_MAX) {
@@ -1479,6 +1533,10 @@ status_t Parcel::read(void* outData, size_t len) const
 
     if ((mDataPos+pad_size(len)) >= mDataPos && (mDataPos+pad_size(len)) <= mDataSize
             && len <= pad_size(len)) {
+        if (mObjectsSize > 0) {
+            status_t err = validateReadData(mDataPos + pad_size(len));
+            if(err != NO_ERROR) return err;
+        }
         memcpy(outData, mData+mDataPos, len);
         mDataPos += pad_size(len);
         ALOGV("read Setting data pos of %p to %zu", this, mDataPos);
@@ -1497,6 +1555,11 @@ const void* Parcel::readInplace(size_t len) const
 
     if ((mDataPos+pad_size(len)) >= mDataPos && (mDataPos+pad_size(len)) <= mDataSize
             && len <= pad_size(len)) {
+        if (mObjectsSize > 0) {
+            status_t err = validateReadData(mDataPos + pad_size(len));
+            if(err != NO_ERROR) return NULL;
+        }
+
         const void* data = mData+mDataPos;
         mDataPos += pad_size(len);
         ALOGV("readInplace Setting data pos of %p to %zu", this, mDataPos);
@@ -1510,6 +1573,11 @@ status_t Parcel::readAligned(T *pArg) const {
     COMPILE_TIME_ASSERT_FUNCTION_SCOPE(PAD_SIZE_UNSAFE(sizeof(T)) == sizeof(T));
 
     if ((mDataPos+sizeof(T)) <= mDataSize) {
+        if (mObjectsSize > 0) {
+            status_t err = validateReadData(mDataPos + sizeof(T));
+            if(err != NO_ERROR) return err;
+        }
+
         const void* data = mData+mDataPos;
         mDataPos += sizeof(T);
         *pArg =  *reinterpret_cast<const T*>(data);
@@ -2366,6 +2434,7 @@ void Parcel::ipcSetDataReference(const uint8_t* data, size_t dataSize,
     mObjects = const_cast<binder_size_t*>(objects);
     mObjectsSize = mObjectsCapacity = objectsCount;
     mNextObjectHint = 0;
+    mObjectsSorted = false;
     mOwner = relFunc;
     mOwnerCookie = relCookie;
     for (size_t i = 0; i < mObjectsSize; i++) {
@@ -2524,6 +2593,7 @@ status_t Parcel::restartWrite(size_t desired)
     mObjects = NULL;
     mObjectsSize = mObjectsCapacity = 0;
     mNextObjectHint = 0;
+    mObjectsSorted = false;
     mHasFds = false;
     mFdsKnown = true;
     mAllowFds = true;
@@ -2610,6 +2680,7 @@ status_t Parcel::continueWrite(size_t desired)
         mDataCapacity = desired;
         mObjectsSize = mObjectsCapacity = objectsSize;
         mNextObjectHint = 0;
+        mObjectsSorted = false;
 
     } else if (mData) {
         if (objectsSize < mObjectsSize) {
@@ -2631,6 +2702,7 @@ status_t Parcel::continueWrite(size_t desired)
             }
             mObjectsSize = objectsSize;
             mNextObjectHint = 0;
+            mObjectsSorted = false;
         }
 
         // We own the data, so we can just do a realloc().
@@ -2703,6 +2775,7 @@ void Parcel::initState()
     mObjectsSize = 0;
     mObjectsCapacity = 0;
     mNextObjectHint = 0;
+    mObjectsSorted = false;
     mHasFds = false;
     mFdsKnown = true;
     mAllowFds = true;