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[Qemu-devel] [PULL 2/2] virtio-balloon: fix integer overflow in BALLOON_
From: |
Luiz Capitulino |
Subject: |
[Qemu-devel] [PULL 2/2] virtio-balloon: fix integer overflow in BALLOON_CHANGE QMP event |
Date: |
Fri, 19 Apr 2013 08:50:33 -0400 |
Because dev->actual is uint32_t, the expression 'dev->actual <<
VIRTIO_BALLOON_PFN_SHIFT' is truncated to 32 bits. This overflows when
dev->actual >= 1048576.
To reproduce:
1. Start a VM with a QMP socket and 5G of RAM
2. Connect to the QMP socket, negotiate capabilities and issue:
{ "execute":"balloon", "arguments": { "value": 1073741824 } }
3. Watch for BALLOON_CHANGE QMP events, the last one will incorretly be:
{ "timestamp": { "seconds": 1366228965, "microseconds": 245466 },
"event": "BALLOON_CHANGE", "data": { "actual": 5368709120 } }
To fix it this commit casts it to ram_addr_t, which is ram_size's type.
Signed-off-by: Luiz Capitulino <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
---
hw/virtio/virtio-balloon.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index c2c446e..76e32ce 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -275,7 +275,7 @@ static void virtio_balloon_set_config(VirtIODevice *vdev,
dev->actual = le32_to_cpu(config.actual);
if (dev->actual != oldactual) {
qemu_balloon_changed(ram_size -
- (dev->actual << VIRTIO_BALLOON_PFN_SHIFT));
+ ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT));
}
}
--
1.8.1.4