s390x: css: report errors from ccw_dstream_read/write

ccw_dstream_read/write functions returned values are sometime
not taking into account and reported back to the upper level
of interpretation of CCW instructions.

It follows that accessing an invalid address does not trigger
a subchannel status program check to the guest as it should.

Let's test the return values of ccw_dstream_write[_buf] and
ccw_dstream_read[_buf] and report it to the caller.

Cc: qemu-stable@nongnu.org
Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Message-Id: <1617899529-9329-2-git-send-email-pmorel@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

1 files changed, 48 insertions, 18 deletions

diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 314ed7b245..8195f3546e 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -288,14 +288,20 @@ static int virtio_ccw_handle_set_vq(SubchDev *sch, CCW1 ccw, bool check_len,
         return -EFAULT;
     }
     if (is_legacy) {
-        ccw_dstream_read(&sch->cds, linfo);
+        ret = ccw_dstream_read(&sch->cds, linfo);
+        if (ret) {
+            return ret;
+        }
         linfo.queue = be64_to_cpu(linfo.queue);
         linfo.align = be32_to_cpu(linfo.align);
         linfo.index = be16_to_cpu(linfo.index);
         linfo.num = be16_to_cpu(linfo.num);
         ret = virtio_ccw_set_vqs(sch, NULL, &linfo);
     } else {
-        ccw_dstream_read(&sch->cds, info);
+        ret = ccw_dstream_read(&sch->cds, info);
+        if (ret) {
+            return ret;
+        }
         info.desc = be64_to_cpu(info.desc);
         info.index = be16_to_cpu(info.index);
         info.num = be16_to_cpu(info.num);
@@ -371,7 +377,10 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
             VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
 
             ccw_dstream_advance(&sch->cds, sizeof(features.features));
-            ccw_dstream_read(&sch->cds, features.index);
+            ret = ccw_dstream_read(&sch->cds, features.index);
+            if (ret) {
+                break;
+            }
             if (features.index == 0) {
                 if (dev->revision >= 1) {
                     /* Don't offer legacy features for modern devices. */
@@ -392,9 +401,10 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
             }
             ccw_dstream_rewind(&sch->cds);
             features.features = cpu_to_le32(features.features);
-            ccw_dstream_write(&sch->cds, features.features);
-            sch->curr_status.scsw.count = ccw.count - sizeof(features);
-            ret = 0;
+            ret = ccw_dstream_write(&sch->cds, features.features);
+            if (!ret) {
+                sch->curr_status.scsw.count = ccw.count - sizeof(features);
+            }
         }
         break;
     case CCW_CMD_WRITE_FEAT:
@@ -411,7 +421,10 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
         if (!ccw.cda) {
             ret = -EFAULT;
         } else {
-            ccw_dstream_read(&sch->cds, features);
+            ret = ccw_dstream_read(&sch->cds, features);
+            if (ret) {
+                break;
+            }
             features.features = le32_to_cpu(features.features);
             if (features.index == 0) {
                 virtio_set_features(vdev,
@@ -454,9 +467,10 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
             ret = -EFAULT;
         } else {
             virtio_bus_get_vdev_config(&dev->bus, vdev->config);
-            ccw_dstream_write_buf(&sch->cds, vdev->config, len);
-            sch->curr_status.scsw.count = ccw.count - len;
-            ret = 0;
+            ret = ccw_dstream_write_buf(&sch->cds, vdev->config, len);
+            if (ret) {
+                sch->curr_status.scsw.count = ccw.count - len;
+            }
         }
         break;
     case CCW_CMD_WRITE_CONF:
@@ -511,7 +525,10 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
         if (!ccw.cda) {
             ret = -EFAULT;
         } else {
-            ccw_dstream_read(&sch->cds, status);
+            ret = ccw_dstream_read(&sch->cds, status);
+            if (ret) {
+                break;
+            }
             if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
                 virtio_ccw_stop_ioeventfd(dev);
             }
@@ -554,7 +571,10 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
         if (!ccw.cda) {
             ret = -EFAULT;
         } else {
-            ccw_dstream_read(&sch->cds, indicators);
+            ret = ccw_dstream_read(&sch->cds, indicators);
+            if (ret) {
+                break;
+            }
             indicators = be64_to_cpu(indicators);
             dev->indicators = get_indicator(indicators, sizeof(uint64_t));
             sch->curr_status.scsw.count = ccw.count - sizeof(indicators);
@@ -575,7 +595,10 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
         if (!ccw.cda) {
             ret = -EFAULT;
         } else {
-            ccw_dstream_read(&sch->cds, indicators);
+            ret = ccw_dstream_read(&sch->cds, indicators);
+            if (ret) {
+                break;
+            }
             indicators = be64_to_cpu(indicators);
             dev->indicators2 = get_indicator(indicators, sizeof(uint64_t));
             sch->curr_status.scsw.count = ccw.count - sizeof(indicators);
@@ -596,7 +619,10 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
         if (!ccw.cda) {
             ret = -EFAULT;
         } else {
-            ccw_dstream_read(&sch->cds, vq_config.index);
+            ret = ccw_dstream_read(&sch->cds, vq_config.index);
+            if (ret) {
+                break;
+            }
             vq_config.index = be16_to_cpu(vq_config.index);
             if (vq_config.index >= VIRTIO_QUEUE_MAX) {
                 ret = -EINVAL;
@@ -605,9 +631,10 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
             vq_config.num_max = virtio_queue_get_num(vdev,
                                                      vq_config.index);
             vq_config.num_max = cpu_to_be16(vq_config.num_max);
-            ccw_dstream_write(&sch->cds, vq_config.num_max);
-            sch->curr_status.scsw.count = ccw.count - sizeof(vq_config);
-            ret = 0;
+            ret = ccw_dstream_write(&sch->cds, vq_config.num_max);
+            if (!ret) {
+                sch->curr_status.scsw.count = ccw.count - sizeof(vq_config);
+            }
         }
         break;
     case CCW_CMD_SET_IND_ADAPTER:
@@ -664,7 +691,10 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
             ret = -EFAULT;
             break;
         }
-        ccw_dstream_read_buf(&sch->cds, &revinfo, 4);
+        ret = ccw_dstream_read_buf(&sch->cds, &revinfo, 4);
+        if (ret < 0) {
+            break;
+        }
         revinfo.revision = be16_to_cpu(revinfo.revision);
         revinfo.length = be16_to_cpu(revinfo.length);
         if (ccw.count < len + revinfo.length ||