[Qemu-devel] [PATCH V2 1/4] vmxnet3: validate interrupt indices coming from guest

[Dmitry Fleytman <dmitry@daynix.com>]

CVE-2013-4544

Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
Reported-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/net/vmxnet3.c | 36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
index 5be807c..0b317f8 100644
--- a/hw/net/vmxnet3.c
+++ b/hw/net/vmxnet3.c
@@ -52,6 +52,9 @@
 #define VMXNET3_DEVICE_VERSION    0x1
 #define VMXNET3_DEVICE_REVISION   0x1
 
+/* Number of interrupt vectors for non-MSIx modes */
+#define VMXNET3_MAX_NMSIX_INTRS   (1)
+
 /* Macros for rings descriptors access */
 #define VMXNET3_READ_TX_QUEUE_DESCR8(dpa, field) \
     (vmw_shmem_ld8(dpa + offsetof(struct Vmxnet3_TxQueueDesc, field)))
@@ -1305,6 +1308,34 @@ static bool vmxnet3_verify_intx(VMXNET3State *s, int intx)
            (pci_get_byte(s->parent_obj.config + PCI_INTERRUPT_PIN) - 1));
 }
 
+static void vmxnet3_validate_interrupt_idx(bool is_msix, int idx)
+{
+    int max_ints = is_msix ? VMXNET3_MAX_INTRS : VMXNET3_MAX_NMSIX_INTRS;
+    if (idx >= max_ints) {
+        hw_error("Bad interrupt index: %d\n", idx);
+    }
+}
+
+static void vmxnet3_validate_interrupts(VMXNET3State *s)
+{
+    int i;
+
+    VMW_CFPRN("Verifying event interrupt index (%d)", s->event_int_idx);
+    vmxnet3_validate_interrupt_idx(s->msix_used, s->event_int_idx);
+
+    for (i = 0; i < s->txq_num; i++) {
+        int idx = s->txq_descr[i].intr_idx;
+        VMW_CFPRN("Verifying TX queue %d interrupt index (%d)", i, idx);
+        vmxnet3_validate_interrupt_idx(s->msix_used, idx);
+    }
+
+    for (i = 0; i < s->rxq_num; i++) {
+        int idx = s->rxq_descr[i].intr_idx;
+        VMW_CFPRN("Verifying RX queue %d interrupt index (%d)", i, idx);
+        vmxnet3_validate_interrupt_idx(s->msix_used, idx);
+    }
+}
+
 static void vmxnet3_activate_device(VMXNET3State *s)
 {
     int i;
@@ -1447,6 +1478,8 @@ static void vmxnet3_activate_device(VMXNET3State *s)
                sizeof(s->rxq_descr[i].rxq_stats));
     }
 
+    vmxnet3_validate_interrupts(s);
+
     /* Make sure everything is in place before device activation */
     smp_wmb();
 
@@ -2005,7 +2038,6 @@ vmxnet3_cleanup_msix(VMXNET3State *s)
     }
 }
 
-#define VMXNET3_MSI_NUM_VECTORS   (1)
 #define VMXNET3_MSI_OFFSET        (0x50)
 #define VMXNET3_USE_64BIT         (true)
 #define VMXNET3_PER_VECTOR_MASK   (false)
@@ -2016,7 +2048,7 @@ vmxnet3_init_msi(VMXNET3State *s)
     PCIDevice *d = PCI_DEVICE(s);
     int res;
 
-    res = msi_init(d, VMXNET3_MSI_OFFSET, VMXNET3_MSI_NUM_VECTORS,
+    res = msi_init(d, VMXNET3_MSI_OFFSET, VMXNET3_MAX_NMSIX_INTRS,
                    VMXNET3_USE_64BIT, VMXNET3_PER_VECTOR_MASK);
     if (0 > res) {
         VMW_WRPRN("Failed to initialize MSI, error %d", res);
-- 
1.8.5.3