CVE-2013-2634: Resource Management Errors (CWE-399)
value: net/dcb/dcbnl.c in the Linux kernel before 3.8.4 does not initialize certain structures, which allows local users to obtain sensitive information from kernel stack memory via a crafted application.
CWE description: Weaknesses in this category are related to improper management of system resources.
Published: 2013-03-22T11:59Z
Repository: https://github.com/torvalds/linux
Language: C
Files changed: net/dcb/dcbnl.c
Commit date: 2013-03-10 05:19:26 -0400
Commit message: dcbnl: fix various netlink info leaks

The dcb netlink interface leaks stack memory in various places:
* perm_addr[] buffer is only filled at max with 12 of the 32 bytes but
  copied completely,
* no in-kernel driver fills all fields of an IEEE 802.1Qaz subcommand,
  so we're leaking up to 58 bytes for ieee_ets structs, up to 136 bytes
  for ieee_pfc structs, etc.,
* the same is true for CEE -- no in-kernel driver fills the whole
  struct,

Prevent all of the above stack info leaks by properly initializing the
buffers/structures involved.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Diff: diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c
index 1b588e23cf80b5..21291f1abcd6d0 100644
--- a/net/dcb/dcbnl.c
+++ b/net/dcb/dcbnl.c
@@ -282,10 +282,11 @@ static int dcbnl_getperm_hwaddr(struct net_device *netdev, struct nlmsghdr *nlh,
 	u8 perm_addr[MAX_ADDR_LEN];
 
 	if (!netdev->dcbnl_ops->getpermhwaddr)
 		return -EOPNOTSUPP;
 
+	memset(perm_addr, 0, sizeof(perm_addr));
 	netdev->dcbnl_ops->getpermhwaddr(netdev, perm_addr);
 
 	return nla_put(skb, DCB_ATTR_PERM_HWADDR, sizeof(perm_addr), perm_addr);
 }
 
@@ -1040,18 +1041,20 @@ static int dcbnl_ieee_fill(struct sk_buff *skb, struct net_device *netdev)
 	if (!ieee)
 		return -EMSGSIZE;
 
 	if (ops->ieee_getets) {
 		struct ieee_ets ets;
+		memset(&ets, 0, sizeof(ets));
 		err = ops->ieee_getets(netdev, &ets);
 		if (!err &&
 		    nla_put(skb, DCB_ATTR_IEEE_ETS, sizeof(ets), &ets))
 			return -EMSGSIZE;
 	}
 
 	if (ops->ieee_getmaxrate) {
 		struct ieee_maxrate maxrate;
+		memset(&maxrate, 0, sizeof(maxrate));
 		err = ops->ieee_getmaxrate(netdev, &maxrate);
 		if (!err) {
 			err = nla_put(skb, DCB_ATTR_IEEE_MAXRATE,
 				      sizeof(maxrate), &maxrate);
 			if (err)
@@ -1059,10 +1062,11 @@ static int dcbnl_ieee_fill(struct sk_buff *skb, struct net_device *netdev)
 		}
 	}
 
 	if (ops->ieee_getpfc) {
 		struct ieee_pfc pfc;
+		memset(&pfc, 0, sizeof(pfc));
 		err = ops->ieee_getpfc(netdev, &pfc);
 		if (!err &&
 		    nla_put(skb, DCB_ATTR_IEEE_PFC, sizeof(pfc), &pfc))
 			return -EMSGSIZE;
 	}
@@ -1092,18 +1096,20 @@ static int dcbnl_ieee_fill(struct sk_buff *skb, struct net_device *netdev)
 	nla_nest_end(skb, app);
 
 	/* get peer info if available */
 	if (ops->ieee_peer_getets) {
 		struct ieee_ets ets;
+		memset(&ets, 0, sizeof(ets));
 		err = ops->ieee_peer_getets(netdev, &ets);
 		if (!err &&
 		    nla_put(skb, DCB_ATTR_IEEE_PEER_ETS, sizeof(ets), &ets))
 			return -EMSGSIZE;
 	}
 
 	if (ops->ieee_peer_getpfc) {
 		struct ieee_pfc pfc;
+		memset(&pfc, 0, sizeof(pfc));
 		err = ops->ieee_peer_getpfc(netdev, &pfc);
 		if (!err &&
 		    nla_put(skb, DCB_ATTR_IEEE_PEER_PFC, sizeof(pfc), &pfc))
 			return -EMSGSIZE;
 	}
@@ -1278,18 +1284,20 @@ static int dcbnl_cee_fill(struct sk_buff *skb, struct net_device *netdev)
 	}
 
 	/* peer info if available */
 	if (ops->cee_peer_getpg) {
 		struct cee_pg pg;
+		memset(&pg, 0, sizeof(pg));
 		err = ops->cee_peer_getpg(netdev, &pg);
 		if (!err &&
 		    nla_put(skb, DCB_ATTR_CEE_PEER_PG, sizeof(pg), &pg))
 			goto nla_put_failure;
 	}
 
 	if (ops->cee_peer_getpfc) {
 		struct cee_pfc pfc;
+		memset(&pfc, 0, sizeof(pfc));
 		err = ops->cee_peer_getpfc(netdev, &pfc);
 		if (!err &&
 		    nla_put(skb, DCB_ATTR_CEE_PEER_PFC, sizeof(pfc), &pfc))
 			goto nla_put_failure;
 	}

Fixed code: 	memset(perm_addr, 0, sizeof(perm_addr));
		memset(&ets, 0, sizeof(ets));
		memset(&maxrate, 0, sizeof(maxrate));
		memset(&pfc, 0, sizeof(pfc));
		memset(&ets, 0, sizeof(ets));
		memset(&pfc, 0, sizeof(pfc));
		memset(&pg, 0, sizeof(pg));
		memset(&pfc, 0, sizeof(pfc));