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

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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: Li RongQing <lirongqing@baidu.com>
Reviewed-by: Wang Li <wangli39@baidu.com>
Reviewed-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Li RongQing 2019-03-29 09:18:02 +08:00 committed by David S. Miller
parent c43ac97bac
commit 3d8830266f
1 changed files with 30 additions and 16 deletions
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46
net/core/ethtool.c
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@ -1797,11 +1797,16 @@ static int ethtool_get_strings(struct net_device *dev, void __user *useraddr)
WARN_ON_ONCE(!ret);
gstrings.len = ret;
data = vzalloc(array_size(gstrings.len, ETH_GSTRING_LEN));
if (gstrings.len && !data)
return -ENOMEM;
__ethtool_get_strings(dev, gstrings.string_set, data);
if (gstrings.len) {
data = vzalloc(array_size(gstrings.len, ETH_GSTRING_LEN));
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;
data = vzalloc(array_size(n_stats, sizeof(u64)));
if (n_stats && !data)
return -ENOMEM;
ops->get_ethtool_stats(dev, &stats, data);
if (n_stats) {
data = vzalloc(array_size(n_stats, sizeof(u64)));
if (!data)
return -ENOMEM;
ops->get_ethtool_stats(dev, &stats, data);
} else {
data = NULL;
}
ret = -EFAULT;
if (copy_to_user(useraddr, &stats, sizeof(stats)))
@ -1941,16 +1950,21 @@ static int ethtool_get_phy_stats(struct net_device *dev, void __user *useraddr)
return -EFAULT;
stats.n_stats = n_stats;
data = vzalloc(array_size(n_stats, sizeof(u64)));
if (n_stats && !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;
if (n_stats) {
data = vzalloc(array_size(n_stats, sizeof(u64)));
if (!data)
return -ENOMEM;
if (dev->phydev && !ops->get_ethtool_phy_stats) {
ret = phy_ethtool_get_stats(dev->phydev, &stats, data);
if (ret < 0)
goto out;
} else {
ops->get_ethtool_phy_stats(dev, &stats, data);
}
} else {
ops->get_ethtool_phy_stats(dev, &stats, data);
data = NULL;
}
ret = -EFAULT;