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authorLi RongQing <lirongqing@baidu.com>2019-03-29 09:18:02 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-04-17 08:36:46 +0200
commit77b924d94dd7a7719933ba9d97a7ba4d19d09d00 (patch)
tree0ff3e75ea71fc49be102398996f2da872f89eca1
parent6996763856e1fb27ccae260e41fd73a3fff56678 (diff)
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>
-rw-r--r--net/core/ethtool.c47
1 files changed, 30 insertions, 17 deletions
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index a8a9938aeceb..20ae57fbe009 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -1801,17 +1801,22 @@ 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;
@@ -1899,17 +1904,21 @@ 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;
@@ -1938,19 +1947,23 @@ static int ethtool_get_phy_stats(struct net_device *dev, void __user *useraddr)
return -EFAULT;
stats.n_stats = n_stats;
- data = kmalloc_array(n_stats, sizeof(u64), GFP_USER);
- if (!data)
- return -ENOMEM;
+ if (n_stats) {
+ data = kmalloc_array(n_stats, sizeof(u64), GFP_USER);
+ 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)))
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;