[078/152] net: packet: fix information leak to userland

Greg KH
2011-01-06T00:30:17Z

From: Vasiliy Kulikov <segooon@gmail.com>

[ Upstream commit 67286640f638f5ad41a946b9a3dc75327950248f ]

packet_getname_spkt() doesn't initialize all members of sa_data field of
sockaddr struct if strlen(dev->name) < 13. This structure is then copied
to userland. It leads to leaking of contents of kernel stack memory.
We have to fully fill sa_data with strncpy() instead of strlcpy().

The same with packet_getname(): it doesn't initialize sll_pkttype field of
sockaddr_ll. Set it to zero.

Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
net/packet/af_packet.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1721,7 +1721,7 @@ static int packet_getname_spkt(struct so
rcu_read_lock();
dev = dev_get_by_index_rcu(sock_net(sk), pkt_sk(sk)->ifindex);
if (dev)
- strlcpy(uaddr->sa_data, dev->name, 15);
+ strncpy(uaddr->sa_data, dev->name, 14);
else
memset(uaddr->sa_data, 0, 14);
rcu_read_unlock();
@@ -1744,6 +1744,7 @@ static int packet_getname(struct socket
sll->sll_family = AF_PACKET;
sll->sll_ifindex = po->ifindex;
sll->sll_protocol = po->num;
+ sll->sll_pkttype = 0;
rcu_read_lock();
dev = dev_get_by_index_rcu(sock_net(sk), po->ifindex);
if (dev) {