Commit 3d883026 authored by Li RongQing's avatar Li RongQing Committed by David S. Miller
Browse files

net: ethtool: not call vzalloc for zero sized memory request 



NULL or ZERO_SIZE_PTR will be returned for zero sized memory
request, and derefencing them will lead to a segfault

so it is unnecessory to call vzalloc for zero sized memory
request and not call functions which maybe derefence the
NULL allocated memory

this also fixes a possible memory leak if phy_ethtool_get_stats
returns error, memory should be freed before exit

Signed-off-by: default avatarLi RongQing <lirongqing@baidu.com>
Reviewed-by: default avatarWang Li <wangli39@baidu.com>
Reviewed-by: default avatarMichal Kubecek <mkubecek@suse.cz>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c43ac97b

net/core/ethtool.c

+30 −16
Original line number Diff line number Diff line
@@ -1797,11 +1797,16 @@ static int ethtool_get_strings(struct net_device *dev, void __user *useraddr) 
	WARN_ON_ONCE(!ret);



	gstrings.len = ret;



	if (gstrings.len) {

		data = vzalloc(array_size(gstrings.len, ETH_GSTRING_LEN));

	if (gstrings.len && !data)

		if (!data)

			return -ENOMEM;



		__ethtool_get_strings(dev, gstrings.string_set, data);

	} else {

		data = NULL;

	}



	ret = -EFAULT;

	if (copy_to_user(useraddr, &gstrings, sizeof(gstrings)))
@@ -1897,11 +1902,15 @@ static int ethtool_get_stats(struct net_device *dev, void __user *useraddr) 
		return -EFAULT;



	stats.n_stats = n_stats;



	if (n_stats) {

		data = vzalloc(array_size(n_stats, sizeof(u64)));

	if (n_stats && !data)

		if (!data)

			return -ENOMEM;



		ops->get_ethtool_stats(dev, &stats, data);

	} else {

		data = NULL;

	}



	ret = -EFAULT;

	if (copy_to_user(useraddr, &stats, sizeof(stats)))
@@ -1941,17 +1950,22 @@ static int ethtool_get_phy_stats(struct net_device *dev, void __user *useraddr) 
		return -EFAULT;



	stats.n_stats = n_stats;



	if (n_stats) {

		data = vzalloc(array_size(n_stats, sizeof(u64)));

	if (n_stats && !data)

		if (!data)

			return -ENOMEM;



		if (dev->phydev && !ops->get_ethtool_phy_stats) {

			ret = phy_ethtool_get_stats(dev->phydev, &stats, data);

			if (ret < 0)

			return ret;

				goto out;

		} else {

			ops->get_ethtool_phy_stats(dev, &stats, data);

		}

	} else {

		data = NULL;

	}



	ret = -EFAULT;

	if (copy_to_user(useraddr, &stats, sizeof(stats)))

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