enic: Avoid false positive under FORTIFY_SOURCE

FORTIFY_SOURCE has been ignoring 0-sized destinations while the kernel code base has been converted to flexible arrays. In order to enforce the 0-sized destinations (e.g. with __counted_by), the remaining 0-sized destinations need to be handled. Unfortunately, struct vic_provinfo resists full conversion, as it contains a flexible array of flexible arrays, which is only possible with the 0-sized fake flexible array.

Use unsafe_memcpy() to avoid future false positives under CONFIG_FORTIFY_SOURCE.

---
Cc: Christian Benvenuti <[email protected]>
Cc: Satish Kharat <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: Gustavo A. R. Silva <[email protected]>
Cc: [email protected]

---
 drivers/net/ethernet/cisco/enic/vnic_vic.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

index 20fcb20b42ed..66b577835338 100644
@@ -49,7 +49,8 @@ int vic_provinfo_add_tlv(struct vic_provinfo *vp, u16 type, u16 length,
 
 	tlv->type = htons(type);
 	tlv->length = htons(length);
-	memcpy(tlv->value, value, length);
+	unsafe_memcpy(tlv->value, value, length,
+		      /* Flexible array of flexible arrays */);
 
 	vp->num_tlvs = htonl(ntohl(vp->num_tlvs) + 1);
 	vp->length = htonl(ntohl(vp->length) +

2.34.1