net: mana: Use struct_size() helper in mana_gd_create_dma_region()

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.

Also, address the following sparse warnings:
drivers/net/ethernet/microsoft/mana/gdma_main.c:677:24: warning: using sizeof on a flexible structure

Link: https://github.com/KSPP/linux/issues/174
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
index 636dfef..49b85ca 100644 (file)
--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
@@ -663,7 +663,7 @@ static int mana_gd_create_dma_region(struct gdma_dev *gd,
        struct gdma_context *gc = gd->gdma_context;
        struct hw_channel_context *hwc;
        u32 length = gmi->length;
-       u32 req_msg_size;
+       size_t req_msg_size;
        int err;
        int i;
 
@@ -674,7 +674,7 @@ static int mana_gd_create_dma_region(struct gdma_dev *gd,
                return -EINVAL;
 
        hwc = gc->hwc.driver_data;
-       req_msg_size = sizeof(*req) + num_page * sizeof(u64);
+       req_msg_size = struct_size(req, page_addr_list, num_page);
        if (req_msg_size > hwc->max_req_msg_size)
                return -EINVAL;