[PATCH v2 58/63] ethtool: stats: Use struct_group() to clear all stats at once

Kees Cook
2021-08-18T06:24:36Z

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memset(), avoid intentionally writing across
neighboring fields.

Add struct_group() to mark region of struct stats_reply_data that should
be initialized, which can now be done in a single memset() call.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Ido Schimmel <idosch@nvidia.com>
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
net/ethtool/stats.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/net/ethtool/stats.c b/net/ethtool/stats.c
index ec07f5765e03..a20e0a24ff61 100644
--- a/net/ethtool/stats.c
+++ b/net/ethtool/stats.c
@@ -14,10 +14,12 @@ struct stats_req_info {

struct stats_reply_data {
struct ethnl_reply_data base;
- struct ethtool_eth_phy_stats phy_stats;
- struct ethtool_eth_mac_stats mac_stats;
- struct ethtool_eth_ctrl_stats ctrl_stats;
- struct ethtool_rmon_stats rmon_stats;
+ struct_group(stats,
+ struct ethtool_eth_phy_stats phy_stats;
+ struct ethtool_eth_mac_stats mac_stats;
+ struct ethtool_eth_ctrl_stats ctrl_stats;
+ struct ethtool_rmon_stats rmon_stats;
+ );
const struct ethtool_rmon_hist_range *rmon_ranges;
};

@@ -117,10 +119,7 @@ static int stats_prepare_data(const struct ethnl_req_info *req_base,
/* Mark all stats as unset (see ETHTOOL_STAT_NOT_SET) to prevent them
* from being reported to user space in case driver did not set them.
*/
- memset(&data->phy_stats, 0xff, sizeof(data->phy_stats));
- memset(&data->mac_stats, 0xff, sizeof(data->mac_stats));
- memset(&data->ctrl_stats, 0xff, sizeof(data->ctrl_stats));
- memset(&data->rmon_stats, 0xff, sizeof(data->rmon_stats));
+ memset(&data->stats, 0xff, sizeof(data->stats));

if (test_bit(ETHTOOL_STATS_ETH_PHY, req_info->stat_mask) &&
dev->ethtool_ops->get_eth_phy_stats)
--
2.30.2