s390x/pci: add length checking for pci sclp handlers

The configure/deconfigure sclp commands need a SCCB with a length of
at least 16. Indicate in the response code if this is not fulfilled.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

hw/s390x/s390-pci-bus.c

@@ -113,6 +113,11 @@ void s390_pci_sclp_configure(SCCB *sccb)
     S390PCIBusDevice *pbdev = s390_pci_find_dev_by_fid(be32_to_cpu(psccb->aid));
     uint16_t rc;
 
+    if (be16_to_cpu(sccb->h.length) < 16) {
+        rc = SCLP_RC_INSUFFICIENT_SCCB_LENGTH;
+        goto out;
+    }
+
     if (pbdev) {
         if (pbdev->configured) {
             rc = SCLP_RC_NO_ACTION_REQUIRED;
@@ -124,7 +129,7 @@ void s390_pci_sclp_configure(SCCB *sccb)
         DPRINTF("sclp config no dev found\n");
         rc = SCLP_RC_ADAPTER_ID_NOT_RECOGNIZED;
     }
-
+out:
     psccb->header.response_code = cpu_to_be16(rc);
 }
 
@@ -134,6 +139,11 @@ void s390_pci_sclp_deconfigure(SCCB *sccb)
     S390PCIBusDevice *pbdev = s390_pci_find_dev_by_fid(be32_to_cpu(psccb->aid));
     uint16_t rc;
 
+    if (be16_to_cpu(sccb->h.length) < 16) {
+        rc = SCLP_RC_INSUFFICIENT_SCCB_LENGTH;
+        goto out;
+    }
+
     if (pbdev) {
         if (!pbdev->configured) {
             rc = SCLP_RC_NO_ACTION_REQUIRED;
@@ -151,7 +161,7 @@ void s390_pci_sclp_deconfigure(SCCB *sccb)
         DPRINTF("sclp deconfig no dev found\n");
         rc = SCLP_RC_ADAPTER_ID_NOT_RECOGNIZED;
     }
-
+out:
     psccb->header.response_code = cpu_to_be16(rc);
 }