staging: wfx: Use flex_array_size() helper in memcpy()

Make use of the flex_array_size() helper to calculate the size of a
flexible array member within an enclosing structure.

This helper offers defense-in-depth against potential integer
overflows, while at the same time makes it explicitly clear that
we are dealing with a flexible array member.

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200729233557.GA17693@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/wfx/hif_tx_mib.c b/drivers/staging/wfx/hif_tx_mib.c
index 1689cb42acc0d2b614fd63544533105471b89089..05f1e1e98af9e0598d818242310d3509d90964e1 100644 (file)
--- a/drivers/staging/wfx/hif_tx_mib.c
+++ b/drivers/staging/wfx/hif_tx_mib.c
@@ -113,7 +113,7 @@ int hif_set_beacon_filter_table(struct wfx_vif *wvif, int tbl_len,
        if (!val)
                return -ENOMEM;
        val->num_of_info_elmts = cpu_to_le32(tbl_len);
-       memcpy(val->ie_table, tbl, tbl_len * sizeof(*tbl));
+       memcpy(val->ie_table, tbl, flex_array_size(val, ie_table, tbl_len));
        ret = hif_write_mib(wvif->wdev, wvif->id,
                            HIF_MIB_ID_BEACON_FILTER_TABLE, val, buf_len);
        kfree(val);