From: Volker Rümelin <vr_qemu@t-online.de>
Date: Tue, 7 Jul 2020 18:08:36 +0000 (+0200)
Subject: ossaudio: fix out of bounds write
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=4f50d4a48e0caa1aad591f3ca437502e33b8699d;p=qemu.git

ossaudio: fix out of bounds write

In function oss_read() a read error currently does not exit the
read loop. With no data to read the variable pos will quickly
underflow and a subsequent successful read overwrites memory
outside the buffer. This patch adds the missing break statement
to the error path of the function.

To reproduce start qemu with -audiodev oss,id=audio0 and in the
guest start audio recording. After some time this will trigger
an exception.

Fixes: 3ba4066d08 "ossaudio: port to the new audio backend api"

Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
Message-id: 20200707180836.5435-1-vr_qemu@t-online.de
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---

diff --git a/audio/ossaudio.c b/audio/ossaudio.c
index f88d076ec2..a7dcaa31ad 100644
--- a/audio/ossaudio.c
+++ b/audio/ossaudio.c
@@ -691,6 +691,7 @@ static size_t oss_read(HWVoiceIn *hw, void *buf, size_t len)
                            len, dst);
                 break;
             }
+            break;
         }
 
         pos += nread;