MTP: add strict bounds checking for all incoming packets

Previously we did not sanity check incoming MTP packets,
which could result in crashes due to reading off the edge of a packet.
Now all MTP packet getter functions return a boolean result
(true for OK, false for reading off the edge of the packet)
and we now return errors for malformed packets.

Bug: 18113092
Change-Id: Ic7623ee96f00652bdfb4f66acb16a93db5a1c105

1 files changed, 21 insertions, 11 deletions

diff --git a/media/mtp/MtpDevice.cpp b/media/mtp/MtpDevice.cpp
index d6d5dd5..e0d679d 100644
--- a/media/mtp/MtpDevice.cpp
+++ b/media/mtp/MtpDevice.cpp
@@ -313,8 +313,10 @@ MtpDeviceInfo* MtpDevice::getDeviceInfo() {
     MtpResponseCode ret = readResponse();
     if (ret == MTP_RESPONSE_OK) {
         MtpDeviceInfo* info = new MtpDeviceInfo;
-        info->read(mData);
-        return info;
+        if (info->read(mData))
+            return info;
+        else
+            delete info;
     }
     return NULL;
 }
@@ -346,8 +348,10 @@ MtpStorageInfo* MtpDevice::getStorageInfo(MtpStorageID storageID) {
     MtpResponseCode ret = readResponse();
     if (ret == MTP_RESPONSE_OK) {
         MtpStorageInfo* info = new MtpStorageInfo(storageID);
-        info->read(mData);
-        return info;
+        if (info->read(mData))
+            return info;
+        else
+            delete info;
     }
     return NULL;
 }
@@ -385,8 +389,10 @@ MtpObjectInfo* MtpDevice::getObjectInfo(MtpObjectHandle handle) {
     MtpResponseCode ret = readResponse();
     if (ret == MTP_RESPONSE_OK) {
         MtpObjectInfo* info = new MtpObjectInfo(handle);
-        info->read(mData);
-        return info;
+        if (info->read(mData))
+            return info;
+        else
+            delete info;
     }
     return NULL;
 }
@@ -547,8 +553,10 @@ MtpProperty* MtpDevice::getDevicePropDesc(MtpDeviceProperty code) {
     MtpResponseCode ret = readResponse();
     if (ret == MTP_RESPONSE_OK) {
         MtpProperty* property = new MtpProperty;
-        property->read(mData);
-        return property;
+        if (property->read(mData))
+            return property;
+        else
+            delete property;
     }
     return NULL;
 }
@@ -566,15 +574,17 @@ MtpProperty* MtpDevice::getObjectPropDesc(MtpObjectProperty code, MtpObjectForma
     MtpResponseCode ret = readResponse();
     if (ret == MTP_RESPONSE_OK) {
         MtpProperty* property = new MtpProperty;
-        property->read(mData);
-        return property;
+        if (property->read(mData))
+            return property;
+        else
+            delete property;
     }
     return NULL;
 }
 
 bool MtpDevice::readObject(MtpObjectHandle handle,
         bool (* callback)(void* data, int offset, int length, void* clientData),
-        int objectSize, void* clientData) {
+        size_t objectSize, void* clientData) {
     Mutex::Autolock autoLock(mMutex);
     bool result = false;