if_urndis: Organize buffer layouts more naturally

- Group the request header and I/O buffer in one structure, rather than
  assuming that both request structures have the same size.
- Pass a pointer to the whole structure to urndis_ctrl_query() and
  urndis_ctrl_set() rather than just the header.  Otherwise, on CHERI
  platforms, these functions violate subobject bounds since they modify
  the buffer following the header.

While here, there is no apparent reason for the request structure used
in urndis_attach() to be allocated statically.  Change it so that it's
allocated on the stack.

No functional change intended.

Reviewed by:	jhb
MFC after:	2 weeks
Sponsored by:	Innovate UK
Differential Revision:	https://reviews.freebsd.org/D45866

1 files changed, 11 insertions, 11 deletions

diff --git a/sys/dev/usb/net/if_urndis.c b/sys/dev/usb/net/if_urndis.c
index 824609aa869f..0a7cb3fed953 100644
--- a/sys/dev/usb/net/if_urndis.c
+++ b/sys/dev/usb/net/if_urndis.c
@@ -214,15 +214,15 @@ urndis_attach_post(struct usb_ether *ue)
 static int
 urndis_attach(device_t dev)
 {
-	static struct {
-		union {
+	union {
+		struct {
 			struct rndis_query_req query;
+			uint8_t addr[ETHER_ADDR_LEN];
+		} eaddr;
+		struct {
 			struct rndis_set_req set;
-		} hdr;
-		union {
-			uint8_t eaddr[ETHER_ADDR_LEN];
 			uint32_t filter;
-		} ibuf;
+		} filter;
 	} msg;
 	struct urndis_softc *sc = device_get_softc(dev);
 	struct usb_ether *ue = &sc->sc_ue;
@@ -278,10 +278,10 @@ urndis_attach(device_t dev)
 	}
 
 	/* Determine MAC address */
-	memset(msg.ibuf.eaddr, 0, sizeof(msg.ibuf.eaddr));
+	memset(msg.eaddr.addr, 0, sizeof(msg.eaddr.addr));
 	URNDIS_LOCK(sc);
 	error = urndis_ctrl_query(sc, OID_802_3_PERMANENT_ADDRESS,
-	    &msg.hdr.query, sizeof(msg.hdr.query) + sizeof(msg.ibuf.eaddr),
+	    (struct rndis_query_req *)&msg.eaddr, sizeof(msg.eaddr),
 	    &buf, &bufsz);
 	URNDIS_UNLOCK(sc);
 	if (error != (int)RNDIS_STATUS_SUCCESS) {
@@ -297,10 +297,10 @@ urndis_attach(device_t dev)
 	/* Initialize packet filter */
 	sc->sc_filter = NDIS_PACKET_TYPE_BROADCAST |
 	    NDIS_PACKET_TYPE_ALL_MULTICAST;
-	msg.ibuf.filter = htole32(sc->sc_filter);
+	msg.filter.filter = htole32(sc->sc_filter);
 	URNDIS_LOCK(sc);
 	error = urndis_ctrl_set(sc, OID_GEN_CURRENT_PACKET_FILTER,
-	    &msg.hdr.set, sizeof(msg.hdr.set) + sizeof(msg.ibuf.filter));
+	    (struct rndis_set_req *)&msg.filter, sizeof(msg.filter));
 	URNDIS_UNLOCK(sc);
 	if (error != (int)RNDIS_STATUS_SUCCESS) {
 		device_printf(dev, "Unable to set data filters\n");
@@ -641,7 +641,7 @@ urndis_ctrl_handle_reset(struct urndis_softc *sc,
 		msg_filter.filter = htole32(sc->sc_filter);
 
 		rval = urndis_ctrl_set(sc, OID_GEN_CURRENT_PACKET_FILTER,
-		    &msg_filter.hdr, sizeof(msg_filter));
+		    (struct rndis_set_req *)&msg_filter, sizeof(msg_filter));
 
 		if (rval != RNDIS_STATUS_SUCCESS) {
 			DPRINTF("unable to reset data filters\n");