[ 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: Sasha Levin sashal@kernel.org --- net/core/ethtool.c | 46 ++++++++++++++++++++++++++++++---------------- 1 file changed, 30 insertions(+), 16 deletions(-)
diff --git a/net/core/ethtool.c b/net/core/ethtool.c index aeabc4831fca..7cc97f43f138 100644 --- a/net/core/ethtool.c +++ b/net/core/ethtool.c @@ -1863,11 +1863,16 @@ 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))) @@ -1963,11 +1968,15 @@ 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))) @@ -2007,16 +2016,21 @@ 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;