1 files changed, 36 insertions, 10 deletions

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 615812ff8974..0732710a4836 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -1290,6 +1290,40 @@ out:
 	return ret;
 }
 
+static struct ethtool_rxfh_context *
+ethtool_rxfh_ctx_alloc(const struct ethtool_ops *ops,
+		       u32 indir_size, u32 key_size)
+{
+	size_t indir_bytes, flex_len, key_off, size;
+	struct ethtool_rxfh_context *ctx;
+	u32 priv_bytes, indir_max;
+	u16 key_max;
+
+	key_max = max(key_size, ops->rxfh_key_space);
+	indir_max = max(indir_size, ops->rxfh_indir_space);
+
+	priv_bytes = ALIGN(ops->rxfh_priv_size, sizeof(u32));
+	indir_bytes = array_size(indir_max, sizeof(u32));
+
+	key_off = size_add(priv_bytes, indir_bytes);
+	flex_len = size_add(key_off, key_max);
+	size = struct_size_t(struct ethtool_rxfh_context, data, flex_len);
+
+	ctx = kzalloc(size, GFP_KERNEL_ACCOUNT);
+	if (!ctx)
+		return NULL;
+
+	ctx->indir_size = indir_size;
+	ctx->key_size = key_size;
+	ctx->key_off = key_off;
+	ctx->priv_size = ops->rxfh_priv_size;
+
+	ctx->hfunc = ETH_RSS_HASH_NO_CHANGE;
+	ctx->input_xfrm = RXH_XFRM_NO_CHANGE;
+
+	return ctx;
+}
+
 static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
 					       void __user *useraddr)
 {
@@ -1406,20 +1440,12 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
 			ret = -EINVAL;
 			goto out;
 		}
-		ctx = kzalloc(ethtool_rxfh_context_size(dev_indir_size,
-							dev_key_size,
-							ops->rxfh_priv_size),
-			      GFP_KERNEL_ACCOUNT);
+		ctx = ethtool_rxfh_ctx_alloc(ops, dev_indir_size, dev_key_size);
 		if (!ctx) {
 			ret = -ENOMEM;
 			goto out;
 		}
-		ctx->indir_size = dev_indir_size;
-		ctx->key_size = dev_key_size;
-		ctx->priv_size = ops->rxfh_priv_size;
-		/* Initialise to an empty context */
-		ctx->hfunc = ETH_RSS_HASH_NO_CHANGE;
-		ctx->input_xfrm = RXH_XFRM_NO_CHANGE;
+
 		if (ops->create_rxfh_context) {
 			u32 limit = ops->rxfh_max_context_id ?: U32_MAX;
 			u32 ctx_id;