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[PULL 1/1] hw/vfio/pci: fix double free in vfio_msi_disable
From: |
Alex Williamson |
Subject: |
[PULL 1/1] hw/vfio/pci: fix double free in vfio_msi_disable |
Date: |
Thu, 10 Oct 2019 13:15:04 -0600 |
User-agent: |
StGit/0.19-dirty |
From: Evgeny Yakovlev <address@hidden>
The following guest behaviour patter leads to double free in VFIO PCI:
1. Guest enables MSI interrupts
vfio_msi_enable is called, but fails in vfio_enable_vectors.
In our case this was because VFIO GPU device was in D3 state.
Unhappy path in vfio_msi_enable will g_free(vdev->msi_vectors) but not
set this pointer to NULL
2. Guest still sees MSI an enabled after that because emulated config
write is done in vfio_pci_write_config unconditionally before calling
vfio_msi_enable
3. Guest disables MSI interrupts
vfio_msi_disable is called and tries to g_free(vdev->msi_vectors)
in vfio_msi_disable_common => double free
Signed-off-by: Evgeny Yakovlev <address@hidden>
Signed-off-by: Alex Williamson <address@hidden>
---
hw/vfio/pci.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index c5e6fe61cb3e..12fac3980465 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -651,6 +651,7 @@ retry:
}
g_free(vdev->msi_vectors);
+ vdev->msi_vectors = NULL;
if (ret > 0 && ret != vdev->nr_vectors) {
vdev->nr_vectors = ret;