[PATCH v2 3/3] hw/usb/dev-uas: Report command additional adb length as unsupported

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

We are not ready to handle additional CDB data.

If a guest sends a packet with such additional data,
report the command parameter as not supported.

Specify a size (of 1 byte) for the add_cdb member we
are not using, to fix the following warning:

  usb/dev-uas.c:157:31: error: field 'status' with variable sized type 'uas_iu' not at the end of a struct or class is a GNU extension [-Werror,-Wgnu-variable-sized-type-not-at-end]
      uas_iu                    status;
                                ^

Reported-by: Ed Maste <emaste@FreeBSD.org>
Reported-by: Daniele Buono <dbuono@linux.vnet.ibm.com>
Reported-by: Han Han <hhan@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gustavo A. R. Silva <gustavo@embeddedor.com>

v2: include Eric feedbacks
---
 hw/usb/dev-uas.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/hw/usb/dev-uas.c b/hw/usb/dev-uas.c
index cec071d96c4..a51402bc0bf 100644
--- a/hw/usb/dev-uas.c
+++ b/hw/usb/dev-uas.c
@@ -16,6 +16,7 @@
 #include "qemu/error-report.h"
 #include "qemu/main-loop.h"
 #include "qemu/module.h"
+#include "qemu/log.h"
 
 #include "hw/usb.h"
 #include "migration/vmstate.h"
@@ -70,7 +71,7 @@ typedef struct {
     uint8_t    reserved_2;
     uint64_t   lun;
     uint8_t    cdb[16];
-    uint8_t    add_cdb[];
+    uint8_t    add_cdb[1];      /* not supported by QEMU */
 } QEMU_PACKED  uas_iu_command;
 
 typedef struct {
@@ -700,6 +701,11 @@ static void usb_uas_command(UASDevice *uas, uas_iu *iu)
     uint32_t len;
     uint16_t tag = be16_to_cpu(iu->hdr.tag);
 
+    if (iu->command.add_cdb_length > 0) {
+        qemu_log_mask(LOG_UNIMP, "additional adb length not yet supported\n");
+        goto unsupported_len;
+    }
+
     if (uas_using_streams(uas) && tag > UAS_MAX_STREAMS) {
         goto invalid_tag;
     }
@@ -735,6 +741,10 @@ static void usb_uas_command(UASDevice *uas, uas_iu *iu)
     }
     return;
 
+unsupported_len:
+    usb_uas_queue_fake_sense(uas, tag, sense_code_INVALID_PARAM_VALUE);
+    return;
+
 invalid_tag:
     usb_uas_queue_fake_sense(uas, tag, sense_code_INVALID_TAG);
     return;
-- 
2.26.2