[PULL 06/12] s390x: sclp: Report insufficient SCCB length

[Christian Borntraeger <borntraeger@de.ibm.com>]

From: Claudio Imbrenda <imbrenda@linux.ibm.com>

Return the correct error code when the SCCB buffer is too small to
contain all of the output, for the Read SCP Information and
Read CPU Information commands.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>
Message-Id: <1569591203-15258-5-git-send-email-imbrenda@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 hw/s390x/sclp.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
index abb6e5011f9c..f57ce7b73943 100644
--- a/hw/s390x/sclp.c
+++ b/hw/s390x/sclp.c
@@ -68,6 +68,12 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb)
 
     read_info->ibc_val = cpu_to_be32(s390_get_ibc_val());
 
+    if (be16_to_cpu(sccb->h.length) <
+            (sizeof(ReadInfo) + cpu_count * sizeof(CPUEntry))) {
+        sccb->h.response_code = cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH);
+        return;
+    }
+
     /* Configuration Characteristic (Extension) */
     s390_get_feat_block(S390_FEAT_TYPE_SCLP_CONF_CHAR,
                          read_info->conf_char);
@@ -118,6 +124,12 @@ static void sclp_read_cpu_info(SCLPDevice *sclp, SCCB *sccb)
     cpu_info->offset_configured = cpu_to_be16(offsetof(ReadCpuInfo, entries));
     cpu_info->nr_standby = cpu_to_be16(0);
 
+    if (be16_to_cpu(sccb->h.length) <
+            (sizeof(ReadCpuInfo) + cpu_count * sizeof(CPUEntry))) {
+        sccb->h.response_code = cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH);
+        return;
+    }
+
     /* The standby offset is 16-byte for each CPU */
     cpu_info->offset_standby = cpu_to_be16(cpu_info->offset_configured
         + cpu_info->nr_configured*sizeof(CPUEntry));
-- 
2.21.0