File es1370-check-total-frame-count-against-c.patch of Package qemu

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File es1370-check-total-frame-count-against-c.patch of Package qemu (Revision 4283eb093dfb993e1be03be761699162)

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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 89c4dabcd44fb2d7782e3cabc51d..5f8a83ff56241d94347c1e51419e 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));

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File es1370-check-total-frame-count-against-c.patch of Package qemu (Revision 4283eb093dfb993e1be03be761699162)

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