File 0127-es1370-check-total-frame-count-agai.patch of Package qemu.20428

From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Fri, 15 May 2020 01:36:08 +0530
Subject: es1370: check total frame count against current frame

Git-commit: 369ff955a8497988d079c4e3fa1e93c2570c1c69
References: bsc#1172384, CVE-2020-13361

A guest user may set channel frame count via es1370_write()
such that, in es1370_transfer_audio(), total frame count
'size' is lesser than the number of frames that are processed
'cnt'.

    int cnt = d->frame_cnt >> 16;
    int size = d->frame_cnt & 0xffff;

if (size < cnt), it results in incorrect calculations leading
to OOB access issue(s). Add check to avoid it.

Reported-by: Ren Ding <rding@gatech.edu>
Reported-by: Hanqing Zhao <hanqing@gatech.edu>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Message-id: 20200514200608.1744203-1-ppandit@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 hw/audio/es1370.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/hw/audio/es1370.c b/hw/audio/es1370.c
index 97789a07719626b5e8c001ef7d41..45baa66dba8cb5eacdc9cf8f712c 100644
--- a/hw/audio/es1370.c
+++ b/hw/audio/es1370.c
@@ -642,6 +642,9 @@ static void es1370_transfer_audio (ES1370State *s, struct chan *d, int loop_sel,
     int csc_bytes = (csc + 1) << d->shift;
     int cnt = d->frame_cnt >> 16;
     int size = d->frame_cnt & 0xffff;
+    if (size < cnt) {
+        return;
+    }
     int left = ((size - cnt + 1) << 2) + d->leftover;
     int transferred = 0;
     int temp = audio_MIN (max, audio_MIN (left, csc_bytes));
@@ -650,7 +653,7 @@ static void es1370_transfer_audio (ES1370State *s, struct chan *d, int loop_sel,
     addr += (cnt << 2) + d->leftover;
 
     if (index == ADC_CHANNEL) {
-        while (temp) {
+        while (temp > 0) {
             int acquired, to_copy;
 
             to_copy = audio_MIN ((size_t) temp, sizeof (tmpbuf));
@@ -668,7 +671,7 @@ static void es1370_transfer_audio (ES1370State *s, struct chan *d, int loop_sel,
     else {
         SWVoiceOut *voice = s->dac_voice[index];
 
-        while (temp) {
+        while (temp > 0) {
             int copied, to_copy;
 
             to_copy = audio_MIN ((size_t) temp, sizeof (tmpbuf));