mm-video-v4l2: venc: Avoid processing ETBs/FTBs in invalid states

(per the spec) ETB/FTB should not be handled in states other than
Executing, Paused and Idle. This avoids accessing invalid buffers.
Also add a lock to protect the private-buffers from being deleted
while accessing from another thread.

Bug: 27903498
Security Vulnerability - Heap Use-After-Free and Possible LPE in
MediaServer (libOmxVenc problem #3)

CRs-Fixed: 1010088
CYNGNOS-3020

Change-Id: I898b42034c0add621d4f9d8e02ca0ed4403d4fd3
(cherry picked from commit f0fb3c97d56fa32bb5bf09b65d8a38a0efb19a1a)
(cherry picked from commit 52898b3ce13d92220173d59c6daa919fb2b31bf3)
(cherry picked from commit 6c6500c985c8dfa5c9cecdb052af4e66eb318815)

1 files changed, 17 insertions, 5 deletions

diff --git a/mm-video-v4l2/vidc/venc/src/omx_video_base.cpp b/mm-video-v4l2/vidc/venc/src/omx_video_base.cpp
index 7b5afeb1..5a084a82 100644
--- a/mm-video-v4l2/vidc/venc/src/omx_video_base.cpp
+++ b/mm-video-v4l2/vidc/venc/src/omx_video_base.cpp
@@ -2554,6 +2554,8 @@ OMX_ERRORTYPE omx_video::free_input_buffer(OMX_BUFFERHEADERTYPE *bufferHdr)
     }
 
     if (index < m_sInPortDef.nBufferCountActual && m_pInput_pmem) {
+        auto_lock l(m_lock);
+
         if (m_pInput_pmem[index].fd > 0 && input_use_buffer == false) {
             DEBUG_PRINT_LOW("FreeBuffer:: i/p AllocateBuffer case");
             if(!secure_session) {
@@ -2561,6 +2563,7 @@ OMX_ERRORTYPE omx_video::free_input_buffer(OMX_BUFFERHEADERTYPE *bufferHdr)
             } else {
                 free(m_pInput_pmem[index].buffer);
             }
+            m_pInput_pmem[index].buffer = NULL;
             close (m_pInput_pmem[index].fd);
 #ifdef USE_ION
             free_ion_memory(&m_pInput_ion[index]);
@@ -2573,7 +2576,8 @@ OMX_ERRORTYPE omx_video::free_input_buffer(OMX_BUFFERHEADERTYPE *bufferHdr)
                 DEBUG_PRINT_ERROR("ERROR: dev_free_buf() Failed for i/p buf");
             }
             if(!secure_session) {
-            munmap (m_pInput_pmem[index].buffer,m_pInput_pmem[index].size);
+                munmap (m_pInput_pmem[index].buffer,m_pInput_pmem[index].size);
+                m_pInput_pmem[index].buffer = NULL;
             }
             close (m_pInput_pmem[index].fd);
 #ifdef USE_ION
@@ -3281,7 +3285,9 @@ OMX_ERRORTYPE  omx_video::empty_this_buffer(OMX_IN OMX_HANDLETYPE         hComp,
     unsigned int nBufferIndex ;
 
     DEBUG_PRINT_LOW("ETB: buffer = %p, buffer->pBuffer[%p]", buffer, buffer->pBuffer);
-    if (m_state == OMX_StateInvalid) {
+    if (m_state != OMX_StateExecuting &&
+            m_state != OMX_StatePause &&
+            m_state != OMX_StateIdle) {
         DEBUG_PRINT_ERROR("ERROR: Empty this buffer in Invalid State");
         return OMX_ErrorInvalidState;
     }
@@ -3453,9 +3459,13 @@ OMX_ERRORTYPE  omx_video::empty_this_buffer_proxy(OMX_IN OMX_HANDLETYPE  hComp,
 #endif
     {
         DEBUG_PRINT_LOW("Heap UseBuffer case, so memcpy the data");
+
+        auto_lock l(m_lock);
         pmem_data_buf = (OMX_U8 *)m_pInput_pmem[nBufIndex].buffer;
-        memcpy (pmem_data_buf, (buffer->pBuffer + buffer->nOffset),
-                buffer->nFilledLen);
+        if (pmem_data_buf) {
+            memcpy (pmem_data_buf, (buffer->pBuffer + buffer->nOffset),
+                    buffer->nFilledLen);
+        }
         DEBUG_PRINT_LOW("memcpy() done in ETBProxy for i/p Heap UseBuf");
     } else if (mUseProxyColorFormat) {
         // Gralloc-source buffers with color-conversion
@@ -3511,7 +3521,9 @@ OMX_ERRORTYPE  omx_video::fill_this_buffer(OMX_IN OMX_HANDLETYPE  hComp,
         OMX_IN OMX_BUFFERHEADERTYPE* buffer)
 {
     DEBUG_PRINT_LOW("FTB: buffer->pBuffer[%p]", buffer->pBuffer);
-    if (m_state == OMX_StateInvalid) {
+    if (m_state != OMX_StateExecuting &&
+            m_state != OMX_StatePause &&
+            m_state != OMX_StateIdle) {
         DEBUG_PRINT_ERROR("ERROR: FTB in Invalid State");
         return OMX_ErrorInvalidState;
     }