[qemu-xen staging-4.14] es1370: check total frame count against current frame

[patchbot@xxxxxxx]

commit dd506af071328eae57995eacc4aa4128c5f6d8c8
Author:     Prasad J Pandit <pjp@xxxxxxxxxxxxxxxxx>
AuthorDate: Fri May 15 01:36:08 2020 +0530
Commit:     Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
CommitDate: Mon Aug 24 19:11:59 2020 -0500

    es1370: check total frame count against current frame
    
    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@xxxxxxxxxx>
    Reported-by: Hanqing Zhao <hanqing@xxxxxxxxxx>
    Signed-off-by: Prasad J Pandit <pjp@xxxxxxxxxxxxxxxxx>
    Message-id: 20200514200608.1744203-1-ppandit@xxxxxxxxxx
    Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
    (cherry picked from commit 369ff955a8497988d079c4e3fa1e93c2570c1c69)
    Signed-off-by: Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
---
 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 89c4dabcd4..5f8a83ff56 100644
--- a/hw/audio/es1370.c
+++ b/hw/audio/es1370.c
@@ -643,6 +643,9 @@ 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 = MIN (max, MIN (left, csc_bytes));
@@ -651,7 +654,7 @@ 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 = MIN ((size_t) temp, sizeof (tmpbuf));
@@ -669,7 +672,7 @@ 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 = MIN ((size_t) temp, sizeof (tmpbuf));
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#staging-4.14