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Allow mismatched virtio config-len 

Commit 'virtio: validate config_len on load' restricted config_len
loaded from the wire to match the config_len that the device had.

Unfortunately, there are cases where this isn't true, the one
we found it on was the wce addition in virtio-blk.

Allow mismatched config-lengths:
   *) If the version on the wire is shorter then fine
   *) If the version on the wire is longer, load what we have space
      for and skip the rest.

(This is mst@redhat.com's rework of what I originally posted)

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 2f5732e964)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
This commit is contained in:
Dr. David Alan Gilbert 2014-06-27 20:02:48 +01:00 committed by Michael Roth
parent 14d9fb02c2
commit 8fde73e138
1 changed files with 11 additions and 5 deletions
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16
hw/virtio/virtio.c
View File

@ -923,12 +923,18 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f)
return -1;
}
config_len = qemu_get_be32(f);
if (config_len != vdev->config_len) {
error_report("Unexpected config length 0x%x. Expected 0x%zx",
config_len, vdev->config_len);
return -1;
/*
* There are cases where the incoming config can be bigger or smaller
* than what we have; so load what we have space for, and skip
* any excess that's in the stream.
*/
qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len));
while (config_len > vdev->config_len) {
qemu_get_byte(f);
config_len--;
}
qemu_get_buffer(f, vdev->config, vdev->config_len);
num = qemu_get_be32(f);