[Qemu-trivial] [PATCH RESEND 1/3] usb-ccid: make ccid_write_data_block() cope with null buffers

[Philippe Mathieu-Daudé]

static code analyzer complain:

hw/usb/dev-smartcard-reader.c:816:5: warning: Null pointer passed as an 
argument to a 'nonnull' parameter
    memcpy(p->abData, data, len);
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Reported-by: Clang Static Analyzer
Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
Reviewed-by: Marc-André Lureau <address@hidden>
---
 hw/usb/dev-smartcard-reader.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/hw/usb/dev-smartcard-reader.c b/hw/usb/dev-smartcard-reader.c
index 757b8b3f5a..c38a4e5886 100644
--- a/hw/usb/dev-smartcard-reader.c
+++ b/hw/usb/dev-smartcard-reader.c
@@ -799,8 +799,14 @@ static void ccid_write_parameters(USBCCIDState *s, 
CCID_Header *recv)
 static void ccid_write_data_block(USBCCIDState *s, uint8_t slot, uint8_t seq,
                                   const uint8_t *data, uint32_t len)
 {
-    CCID_DataBlock *p = ccid_reserve_recv_buf(s, sizeof(*p) + len);
+    CCID_DataBlock *p;
 
+    if (len == 0) {
+        return;
+    }
+    g_assert(data != NULL);
+
+    p = ccid_reserve_recv_buf(s, sizeof(*p) + len);
     if (p == NULL) {
         return;
     }
-- 
2.11.0