audio effects: filter reserved effect commands

Block effect commands reserved for framework use when
received on server side IAudioEffect. Applications have no reason
to use these commands and they present a unnecessary attack surface.

Bug: 62019992
Test: run CTS tests for audio effects
Change-Id: Ie680d5d5650f99dbabf93891703e1cde2c2e852d
(cherry picked from commit c7ab309ecbb289cd1296430f724166a26bd45afe)
CVE-2017-0768

1 files changed, 18 insertions, 0 deletions

diff --git a/services/audioflinger/Effects.cpp b/services/audioflinger/Effects.cpp
index 8a8b05b3b1..58df3bd385 100644
--- a/services/audioflinger/Effects.cpp
+++ b/services/audioflinger/Effects.cpp
@@ -1284,6 +1284,24 @@ status_t AudioFlinger::EffectHandle::command(uint32_t cmdCode,
     ALOGVV("command(), cmdCode: %d, mHasControl: %d, mEffect: %p",
             cmdCode, mHasControl, mEffect.unsafe_get());
 
+    // reject commands reserved for internal use by audio framework if coming from outside
+    // of audioserver
+    switch(cmdCode) {
+        case EFFECT_CMD_ENABLE:
+        case EFFECT_CMD_DISABLE:
+        case EFFECT_CMD_SET_PARAM:
+        case EFFECT_CMD_SET_PARAM_DEFERRED:
+        case EFFECT_CMD_SET_PARAM_COMMIT:
+        case EFFECT_CMD_GET_PARAM:
+            break;
+        default:
+            if (cmdCode >= EFFECT_CMD_FIRST_PROPRIETARY) {
+                break;
+            }
+            android_errorWriteLog(0x534e4554, "62019992");
+            return BAD_VALUE;
+    }
+
     if (cmdCode == EFFECT_CMD_ENABLE) {
         if (*replySize < sizeof(int)) {
             android_errorWriteLog(0x534e4554, "32095713");