mm-video-v4l2: vdec: add safety checks for freeing buffers

Allow only up to 64 buffers on input/output port (since the
allocation bitmap is only 64-wide).

Do not allow changing theactual buffer count while still
holding allocation (Client can technically negotiate
buffer count on a free/disabled port)
Add safety checks to free only as many buffers were allocated.

Fixes: Security Vulnerability - Heap Overflow and Possible Local
Privilege Escalation in MediaServer (libOmxVdec problem #3)
Ticket: CYNGNOS-2707
Bug: 27532282 27661749

Change-Id: I06dd680d43feaef3efdc87311e8a6703e234b523
(cherry picked from commit 6313abe468c2f6da4dfad72dd8914c4a8c8902fb)

2 files changed, 45 insertions, 11 deletions

diff --git a/mm-video-v4l2/vidc/vdec/inc/omx_vdec.h b/mm-video-v4l2/vidc/vdec/inc/omx_vdec.h
index 59fd8367..ef10e748 100755..100644
--- a/mm-video-v4l2/vidc/vdec/inc/omx_vdec.h
+++ b/mm-video-v4l2/vidc/vdec/inc/omx_vdec.h
@@ -181,7 +181,7 @@ class VideoHeap : public MemoryHeapBase
 #define DESC_BUFFER_SIZE (8192 * 16)
 
 #ifdef _ANDROID_
-#define MAX_NUM_INPUT_OUTPUT_BUFFERS 32
+#define MAX_NUM_INPUT_OUTPUT_BUFFERS 64
 #endif
 
 #ifdef _ION_HEAP_MASK_COMPATIBILITY_WA
diff --git a/mm-video-v4l2/vidc/vdec/src/omx_vdec_msm8974.cpp b/mm-video-v4l2/vidc/vdec/src/omx_vdec_msm8974.cpp
index 7665f478..3a6e72dd 100644
--- a/mm-video-v4l2/vidc/vdec/src/omx_vdec_msm8974.cpp
+++ b/mm-video-v4l2/vidc/vdec/src/omx_vdec_msm8974.cpp
@@ -3109,7 +3109,11 @@ OMX_ERRORTYPE  omx_vdec::set_parameter(OMX_IN OMX_HANDLETYPE     hComp,
                                                eRet = get_buffer_req(&drv_ctx.op_buf);
                                        }
                                    }
-                                   if (!client_buffers.get_buffer_req(buffer_size)) {
+                                   if (portDefn->nBufferCountActual > MAX_NUM_INPUT_OUTPUT_BUFFERS) {
+                                       DEBUG_PRINT_ERROR("Requested o/p buf count (%u) exceeds limit (%u)",
+                                               portDefn->nBufferCountActual, MAX_NUM_INPUT_OUTPUT_BUFFERS);
+                                       eRet = OMX_ErrorBadParameter;
+                                   } else if (!client_buffers.get_buffer_req(buffer_size)) {
                                        DEBUG_PRINT_ERROR("Error in getting buffer requirements");
                                        eRet = OMX_ErrorBadParameter;
                                    } else {
@@ -3211,6 +3215,19 @@ OMX_ERRORTYPE  omx_vdec::set_parameter(OMX_IN OMX_HANDLETYPE     hComp,
                                                eRet = get_buffer_req(&drv_ctx.op_buf);
                                        }
                                    }
+                                   if (portDefn->nBufferCountActual > MAX_NUM_INPUT_OUTPUT_BUFFERS) {
+                                       DEBUG_PRINT_ERROR("Requested i/p buf count (%u) exceeds limit (%u)",
+                                               portDefn->nBufferCountActual, MAX_NUM_INPUT_OUTPUT_BUFFERS);
+                                       eRet = OMX_ErrorBadParameter;
+                                       break;
+                                   }
+                                   // Buffer count can change only when port is disabled
+                                   if (!release_input_done()) {
+                                       DEBUG_PRINT_ERROR("Cannot change i/p buffer count since all buffers are not freed yet !");
+                                       eRet = OMX_ErrorInvalidState;
+                                       break;
+                                   }
+
                                    if (portDefn->nBufferCountActual >= drv_ctx.ip_buf.mincount
                                            || portDefn->nBufferSize != drv_ctx.ip_buf.buffer_size) {
                                        port_format_changed = true;
@@ -5397,7 +5414,8 @@ OMX_ERRORTYPE  omx_vdec::free_buffer(OMX_IN OMX_HANDLETYPE         hComp,
             nPortIndex = buffer - m_inp_heap_ptr;
 
         DEBUG_PRINT_LOW("free_buffer on i/p port - Port idx %d", nPortIndex);
-        if (nPortIndex < drv_ctx.ip_buf.actualcount) {
+        if (nPortIndex < drv_ctx.ip_buf.actualcount &&
+                BITMASK_PRESENT(&m_inp_bm_count, nPortIndex)) {
             // Clear the bit associated with it.
             BITMASK_CLEAR(&m_inp_bm_count,nPortIndex);
             BITMASK_CLEAR(&m_heap_inp_bm_count,nPortIndex);
@@ -5439,7 +5457,8 @@ OMX_ERRORTYPE  omx_vdec::free_buffer(OMX_IN OMX_HANDLETYPE         hComp,
     } else if (port == OMX_CORE_OUTPUT_PORT_INDEX) {
         // check if the buffer is valid
         nPortIndex = buffer - client_buffers.get_il_buf_hdr();
-        if (nPortIndex < drv_ctx.op_buf.actualcount) {
+        if (nPortIndex < drv_ctx.op_buf.actualcount &&
+                BITMASK_PRESENT(&m_out_bm_count, nPortIndex)) {
             DEBUG_PRINT_LOW("free_buffer on o/p port - Port idx %d", nPortIndex);
             // Clear the bit associated with it.
             BITMASK_CLEAR(&m_out_bm_count,nPortIndex);
@@ -6091,7 +6110,14 @@ OMX_ERRORTYPE  omx_vdec::component_deinit(OMX_IN OMX_HANDLETYPE hComp)
     if (m_out_mem_ptr) {
         DEBUG_PRINT_LOW("Freeing the Output Memory");
         for (i = 0; i < drv_ctx.op_buf.actualcount; i++ ) {
-            free_output_buffer (&m_out_mem_ptr[i]);
+            if (BITMASK_PRESENT(&m_out_bm_count, i)) {
+                BITMASK_CLEAR(&m_out_bm_count, i);
+                client_buffers.free_output_buffer (&m_out_mem_ptr[i]);
+            }
+
+            if (release_output_done()) {
+                break;
+            }
         }
 #ifdef _ANDROID_ICS_
         memset(&native_buffer, 0, (sizeof(nativebuffer) * MAX_NUM_INPUT_OUTPUT_BUFFERS));
@@ -6102,11 +6128,19 @@ OMX_ERRORTYPE  omx_vdec::component_deinit(OMX_IN OMX_HANDLETYPE hComp)
     if (m_inp_mem_ptr || m_inp_heap_ptr) {
         DEBUG_PRINT_LOW("Freeing the Input Memory");
         for (i = 0; i<drv_ctx.ip_buf.actualcount; i++ ) {
-            if (m_inp_mem_ptr)
-                free_input_buffer (i,&m_inp_mem_ptr[i]);
-            else
-                free_input_buffer (i,NULL);
-        }
+
+            if (BITMASK_PRESENT(&m_inp_bm_count, i)) {
+                BITMASK_CLEAR(&m_inp_bm_count, i);
+                if (m_inp_mem_ptr)
+                    free_input_buffer (i,&m_inp_mem_ptr[i]);
+                else
+                    free_input_buffer (i,NULL);
+            }
+
+            if (release_input_done()) {
+                break;
+            }
+       }
     }
     free_input_buffer_header();
     free_output_buffer_header();
@@ -6508,7 +6542,7 @@ bool omx_vdec::release_output_done(void)
     bool bRet = false;
     unsigned i=0,j=0;
 
-    DEBUG_PRINT_LOW("Value of m_out_mem_ptr %p",m_inp_mem_ptr);
+    DEBUG_PRINT_LOW("Value of m_out_mem_ptr %p",m_out_mem_ptr);
     if (m_out_mem_ptr) {
         for (; j < drv_ctx.op_buf.actualcount ; j++) {
             if (BITMASK_PRESENT(&m_out_bm_count,j)) {