[PATCH v1 1/2] s390x: Add sclp boundary check and fix error priority

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

From: Janosch Frank <frankja@linux.ibm.com>

* All sclp codes need to be checked for page boundary violations.
* Requests over 4k are not a spec exception.
* Invalid command checking has to be done before the boundary check.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>
---
 hw/s390x/event-facility.c |  3 ---
 hw/s390x/sclp.c           | 25 ++++++++++++++++++++++---
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/hw/s390x/event-facility.c b/hw/s390x/event-facility.c
index 797ecbb..6620569 100644
--- a/hw/s390x/event-facility.c
+++ b/hw/s390x/event-facility.c
@@ -377,9 +377,6 @@ static void command_handler(SCLPEventFacility *ef, SCCB *sccb, uint64_t code)
     case SCLP_CMD_WRITE_EVENT_MASK:
         write_event_mask(ef, sccb);
         break;
-    default:
-        sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND);
-        break;
     }
 }
 
diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
index fac7c3b..76feac8 100644
--- a/hw/s390x/sclp.c
+++ b/hw/s390x/sclp.c
@@ -213,14 +213,33 @@ int sclp_service_call(CPUS390XState *env, uint64_t sccb, uint32_t code)
     cpu_physical_memory_read(sccb, &work_sccb, sccb_len);
 
     /* Valid sccb sizes */
-    if (be16_to_cpu(work_sccb.h.length) < sizeof(SCCBHeader) ||
-        be16_to_cpu(work_sccb.h.length) > SCCB_SIZE) {
+    if (be16_to_cpu(work_sccb.h.length) < sizeof(SCCBHeader)) {
         r = -PGM_SPECIFICATION;
         goto out;
     }
 
-    sclp_c->execute(sclp, &work_sccb, code);
+    switch (code & SCLP_CMD_CODE_MASK) {
+    case SCLP_CMDW_READ_SCP_INFO:
+    case SCLP_CMDW_READ_SCP_INFO_FORCED:
+    case SCLP_CMDW_READ_CPU_INFO:
+    case SCLP_CMDW_CONFIGURE_IOA:
+    case SCLP_CMDW_DECONFIGURE_IOA:
+    case SCLP_CMD_READ_EVENT_DATA:
+    case SCLP_CMD_WRITE_EVENT_DATA:
+    case SCLP_CMD_WRITE_EVENT_MASK:
+        break;
+    default:
+        work_sccb.h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND);
+        goto out_write;
+    }
 
+    if ((sccb + work_sccb.h.length) > ((sccb & PAGE_MASK) + PAGE_SIZE)) {
+        work_sccb.h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION);
+        goto out_write;
+    }
+
+    sclp_c->execute(sclp, &work_sccb, code);
+out_write:
     cpu_physical_memory_write(sccb, &work_sccb,
                               be16_to_cpu(work_sccb.h.length));
 
-- 
2.7.4