Fix overflow check and check read result

Bug: 33861560
Test: build
AOSP-Change-Id: Ia85519766e19a6e37237166f309750b3e8323c4e

CVE-2017-0547

(cherry picked from commit 9667e3eff2d34c3797c3b529370de47b2c1f1bf6)

Change-Id: I171aa1c7c4a4a5095ac7041371db14e3a4f3676a

1 files changed, 10 insertions, 8 deletions

diff --git a/media/libmedia/IHDCP.cpp b/media/libmedia/IHDCP.cpp
index f3a8902..e8c8a3d 100644
--- a/media/libmedia/IHDCP.cpp
+++ b/media/libmedia/IHDCP.cpp
@@ -241,14 +241,11 @@ status_t BnHDCP::onTransact(
         case HDCP_ENCRYPT:
         {
             size_t size = data.readInt32();
-            size_t bufSize = 2 * size;
-
-            // watch out for overflow
             void *inData = NULL;
-            if (bufSize > size) {
-                inData = malloc(bufSize);
+            // watch out for overflow
+            if (size <= SIZE_MAX / 2) {
+                inData = malloc(2 * size);
             }
-
             if (inData == NULL) {
                 reply->writeInt32(ERROR_OUT_OF_RANGE);
                 return OK;
@@ -256,11 +253,16 @@ status_t BnHDCP::onTransact(
 
             void *outData = (uint8_t *)inData + size;
 
-            data.read(inData, size);
+            status_t err = data.read(inData, size);
+            if (err != OK) {
+                free(inData);
+                reply->writeInt32(err);
+                return OK;
+            }
 
             uint32_t streamCTR = data.readInt32();
             uint64_t inputCTR;
-            status_t err = encrypt(inData, size, streamCTR, &inputCTR, outData);
+            err = encrypt(inData, size, streamCTR, &inputCTR, outData);
 
             reply->writeInt32(err);