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Commit 77b924d9 authored by Li RongQing's avatar Li RongQing Committed by Greg Kroah-Hartman
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net: ethtool: not call vzalloc for zero sized memory request 



[ Upstream commit 3d8830266ffc28c16032b859e38a0252e014b631 ]

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>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 69967638

net/core/ethtool.c

+30 −17
Original line number Diff line number Diff line
@@ -1801,17 +1801,22 @@ static int ethtool_get_strings(struct net_device *dev, void __user *useraddr) 


	gstrings.len = ret;



	if (gstrings.len) {

		data = kcalloc(gstrings.len, ETH_GSTRING_LEN, GFP_USER);

		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)))

		goto out;

	useraddr += sizeof(gstrings);

	if (copy_to_user(useraddr, data, gstrings.len * ETH_GSTRING_LEN))

	if (gstrings.len &&

	    copy_to_user(useraddr, data, gstrings.len * ETH_GSTRING_LEN))

		goto out;

	ret = 0;
@@ -1899,17 +1904,21 @@ static int ethtool_get_stats(struct net_device *dev, void __user *useraddr) 
		return -EFAULT;



	stats.n_stats = n_stats;

	if (n_stats) {

		data = kmalloc(n_stats * sizeof(u64), GFP_USER);

		if (!data)

			return -ENOMEM;



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

	} else {

		data = NULL;

	}



	ret = -EFAULT;

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

		goto out;

	useraddr += sizeof(stats);

	if (copy_to_user(useraddr, data, stats.n_stats * sizeof(u64)))

	if (n_stats && copy_to_user(useraddr, data, n_stats * sizeof(u64)))

		goto out;

	ret = 0;
@@ -1938,6 +1947,7 @@ static int ethtool_get_phy_stats(struct net_device *dev, void __user *useraddr) 
		return -EFAULT;



	stats.n_stats = n_stats;

	if (n_stats) {

		data = kmalloc_array(n_stats, sizeof(u64), GFP_USER);

		if (!data)

			return -ENOMEM;
@@ -1945,12 +1955,15 @@ static int ethtool_get_phy_stats(struct net_device *dev, void __user *useraddr) 
		mutex_lock(&phydev->lock);

		phydev->drv->get_stats(phydev, &stats, data);

		mutex_unlock(&phydev->lock);

	} else {

		data = NULL;

	}



	ret = -EFAULT;

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

		goto out;

	useraddr += sizeof(stats);

	if (copy_to_user(useraddr, data, stats.n_stats * sizeof(u64)))

	if (n_stats && copy_to_user(useraddr, data, n_stats * sizeof(u64)))

		goto out;

	ret = 0;