From eea06f38eb464ab6ebdc04ca5980120dd24ee48d Mon Sep 17 00:00:00 2001 From: Li RongQing Date: Fri, 29 Mar 2019 09:18:02 +0800 Subject: 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 Reviewed-by: Wang Li Reviewed-by: Michal Kubecek Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/ethtool.c | 41 ++++++++++++++++++++++++++--------------- 1 file changed, 26 insertions(+), 15 deletions(-) (limited to 'net/core') diff --git a/net/core/ethtool.c b/net/core/ethtool.c index 3469f5053c79..145cb343c1b0 100644 --- a/net/core/ethtool.c +++ b/net/core/ethtool.c @@ -1815,11 +1815,15 @@ static int ethtool_get_strings(struct net_device *dev, void __user *useraddr) WARN_ON_ONCE(!ret); gstrings.len = ret; - data = vzalloc(gstrings.len * ETH_GSTRING_LEN); - if (gstrings.len && !data) - return -ENOMEM; + if (gstrings.len) { + data = vzalloc(gstrings.len * ETH_GSTRING_LEN); + 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))) @@ -1915,11 +1919,14 @@ static int ethtool_get_stats(struct net_device *dev, void __user *useraddr) return -EFAULT; stats.n_stats = n_stats; - data = vzalloc(n_stats * sizeof(u64)); - if (n_stats && !data) - return -ENOMEM; - - ops->get_ethtool_stats(dev, &stats, data); + if (n_stats) { + data = vzalloc(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))) @@ -1955,13 +1962,17 @@ static int ethtool_get_phy_stats(struct net_device *dev, void __user *useraddr) return -EFAULT; stats.n_stats = n_stats; - data = vzalloc(n_stats * sizeof(u64)); - if (n_stats && !data) - return -ENOMEM; + if (n_stats) { + data = vzalloc(n_stats * sizeof(u64)); + if (!data) + return -ENOMEM; - mutex_lock(&phydev->lock); - phydev->drv->get_stats(phydev, &stats, data); - mutex_unlock(&phydev->lock); + 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))) -- cgit v1.2.3