From 1b41d44972c2c4bdce23c2400c3d7b7604387c65 Mon Sep 17 00:00:00 2001
From: Marco Nelissen <marcone@google.com>
Date: Thu, 6 Feb 2020 09:10:40 -0800
Subject: [PATCH] Avoid reading at negative offsets

PlayerServiceFileSource had the same logic as FileSource that could
cause reading at negative data source offsets, so fix that too.

Test: build
Bug: 141242340
Change-Id: I60226d85ece83339444d9ec1c0a741271e33e127
---
 .../datasource/PlayerServiceFileSource.cpp                     | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/media/libmediaplayerservice/datasource/PlayerServiceFileSource.cpp b/media/libmediaplayerservice/datasource/PlayerServiceFileSource.cpp
index bb4ba75a46..4d95de5262 100644
--- a/media/libmediaplayerservice/datasource/PlayerServiceFileSource.cpp
+++ b/media/libmediaplayerservice/datasource/PlayerServiceFileSource.cpp
@@ -71,6 +71,9 @@ ssize_t PlayerServiceFileSource::readAt(off64_t offset, void *data, size_t size)
     Mutex::Autolock autoLock(mLock);
 
     if (mLength >= 0) {
+        if (offset < 0) {
+            return UNKNOWN_ERROR;
+        }
         if (offset >= mLength) {
             return 0;  // read beyond EOF.
         }