common/cnxk: fix possible out-of-bounds access

[ upstream commit 9a92937cf0c836b7f2b5e303523279ddf9473a35 ]

The subtraction expression in mbox_memcpy() can wrap around
causing an out-of-bounds access. Added a check on 'size' to
fix this.

Coverity issue: 384431, 384439
Fixes: 585bb3e ("common/cnxk: add VF support to base device class")

Signed-off-by: Satheesh Paul <psatheesh@marvell.com>
Reviewed-by: Harman Kalra <hkalra@marvell.com>

drivers/common/cnxk/roc_dev.c

@@ -466,6 +466,8 @@ pf_vf_mbox_send_up_msg(struct dev *dev, void *rec_msg)
 	size_t size;
 
 	size = PLT_ALIGN(mbox_id2size(msg->hdr.id), MBOX_MSG_ALIGN);
+	if (size < sizeof(struct mbox_msghdr))
+		return;
 	/* Send UP message to all VF's */
 	for (vf = 0; vf < vf_mbox->ndevs; vf++) {
 		/* VF active */