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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: 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Li RongQing 2019-03-29 09:18:02 +08:00 committed by syphyr
parent b01a8531d0
commit 98015fa8e8
1 changed files with 19 additions and 10 deletions
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29
net/core/ethtool.c
View File

@ -1070,17 +1070,22 @@ static int ethtool_get_strings(struct net_device *dev, void __user *useraddr)
gstrings.len = ret;
data = kcalloc(gstrings.len, ETH_GSTRING_LEN, GFP_USER);
if (!data)
return -ENOMEM;
if (gstrings.len) {
data = kcalloc(gstrings.len, ETH_GSTRING_LEN, GFP_USER);
if (!data)
return -ENOMEM;
__ethtool_get_strings(dev, gstrings.string_set, data);
__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;
@ -1168,17 +1173,21 @@ static int ethtool_get_stats(struct net_device *dev, void __user *useraddr)
return -EFAULT;
stats.n_stats = n_stats;
data = kmalloc(n_stats * sizeof(u64), GFP_USER);
if (!data)
return -ENOMEM;
if (n_stats) {
data = kmalloc(n_stats * sizeof(u64), GFP_USER);
if (!data)
return -ENOMEM;
ops->get_ethtool_stats(dev, &stats, data);
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;