net: mana: Use struct_size() in kzalloc()

Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows
that, in the worst scenario, could lead to heap overflows.

This code was detected with the help of Coccinelle and, audited and
fixed manually.

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index 04d067243457bdf7af487dcbbf325592d9859f05..46aee2c49f1b1b98d5f2da52cebba03c7580994f 100644 (file)
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -1387,8 +1387,7 @@ static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc,
 
        gc = gd->gdma_context;
 
-       rxq = kzalloc(sizeof(*rxq) +
-                     RX_BUFFERS_PER_QUEUE * sizeof(struct mana_recv_buf_oob),
+       rxq = kzalloc(struct_size(rxq, rx_oobs, RX_BUFFERS_PER_QUEUE),
                      GFP_KERNEL);
        if (!rxq)
                return NULL;