vfio/pci: Reject invalid MSI-X Table and PBA BIR values
The 3-bit MSI-X BIR fields permit values 0-7, but VFIOPCIDevice::bars[] only contains BAR0-BAR5 (6 entries). An invalid BIR value of 6 or 7 can cause an out-of-bounds array access (CWE-129) in vfio_msix_early_setup(). Add range checks immediately after extracting the BIR values. Reported-by: Feifan Qian <bea1e@proton.me> Fixes: 65501a745dba ("vfio: vfio-pci device assignment driver") Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3878 Reviewed-by: Alex Williamson <alex@shazbot.org> Link: https://lore.kernel.org/qemu-devel/20260706161334.2165482-1-clg@redhat.com Signed-off-by: Cédric Le Goater <clg@redhat.com>
Cédric Le Goater committed
Jul 6, 2026 at 18:13 UTC
9daa7347ff2551038e0de055d309b420324b5a25
1 file changed
+8
hw/vfio/pci.c
+8
@@ -1791,6 +1791,14 @@ static bool vfio_msix_early_setup(VFIOPCIDevice *vdev, Error **errp)
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msix->pba_offset = pba & ~PCI_MSIX_FLAGS_BIRMASK;
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msix->entries = (ctrl & PCI_MSIX_FLAGS_QSIZE) + 1;
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+ if (msix->table_bar >= ARRAY_SIZE(vdev->bars) ||
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+ msix->pba_bar >= ARRAY_SIZE(vdev->bars)) {
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+ error_setg(errp, "invalid MSI-X BIR, table_bar=%d pba_bar=%d",
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+ msix->table_bar, msix->pba_bar);
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+ g_free(msix);
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+ return false;
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+ }
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+
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ret = vfio_device_get_irq_info(&vdev->vbasedev, VFIO_PCI_MSIX_IRQ_INDEX,
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&irq_info);
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if (ret < 0) {