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MSI-X: avoid array overrun upon MSI-X table writes
pt_msix_init() allocates msix->msix_entry[] to just cover
msix->total_entries entries. While pci_msix_readl() resorts to reading
physical memory for out of bounds reads, pci_msix_writel() so far
simply accessed/corrupted unrelated memory.
pt_iomem_map()'s call to cpu_register_physical_memory() registers a
page granular region, which is necessary as the Pending Bit Array may
share space with the MSI-X table (but nothing else is allowed to). This
also explains why pci_msix_readl() actually honors out of bounds reads,
but pci_msi_writel() doesn't need to.
This is XSA-164.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
--- a/hw/pt-msi.c
+++ b/hw/pt-msi.c
@@ -440,6 +440,13 @@ static void pci_msix_writel(void *opaque
return;
}
+ if ( addr - msix->mmio_base_addr >= msix->total_entries * 16 )
+ {
+ PT_LOG("Error: Out of bounds write to MSI-X table,"
+ " addr %016"PRIx64"\n", addr);
+ return;
+ }
+
entry_nr = (addr - msix->mmio_base_addr) / 16;
entry = &msix->msix_entry[entry_nr];
offset = ((addr - msix->mmio_base_addr) % 16) / 4;
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