commit a4429639e05db9921d3ef80d718e6c1d1b5b72b9
author Dhananjay Kumar <dhakumar@codeaurora.org> Sat Jul 11 02:53:37 2020 +0530
committer Dhananjay Kumar <dhakumar@codeaurora.org> Sat Jul 11 05:44:06 2020 +0530
tree 09d1b4f5f1f5aa1446b5e056268b4ed4eb152187
parent 290d89abc38a6cd17f8c8de923e6901ba84cadc1

hal: fix ubsan overflow error during call screen and WFD concurrency

Underrun calculation in out_write can hit overflow errors, add input
validation to avoid these possible overflows.

Change-Id: I6dba27b7f209815abdb3121ca5096d2ee09eaf42

hal/audio_hw.c

diff --git a/hal/audio_hw.c b/hal/audio_hw.c
index 5f53431..8aaab92 100644
--- a/hal/audio_hw.c
+++ b/hal/audio_hw.c
@@ -6026,8 +6026,10 @@
             if (out->last_fifo_valid) {
                 // compute drain to see if there is an underrun.
                 const int64_t current_ns = systemTime(SYSTEM_TIME_MONOTONIC); // sys call
-                const int64_t frames_by_time =
-                        (current_ns - out->last_fifo_time_ns) * out->config.rate / NANOS_PER_SECOND;
+                int64_t time_diff_ns = current_ns - out->last_fifo_time_ns;
+                int64_t frames_by_time =
+                        ((time_diff_ns > 0) && (time_diff_ns < (INT64_MAX / out->config.rate))) ?
+                                         (time_diff_ns * out->config.rate / NANOS_PER_SECOND) : 0;
                 const int64_t underrun = frames_by_time - out->last_fifo_frames_remaining;
 
                 if (underrun > 0) {