net: packet: fix information leak to userland

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>
This commit is contained in:
Vasiliy Kulikov 2010-11-10 12:09:10 -08:00 committed by David S. Miller
parent 57fe93b374
commit 67286640f6

View File

@ -1719,7 +1719,7 @@ static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr,
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();
@ -1742,6 +1742,7 @@ static int packet_getname(struct socket *sock, struct sockaddr *uaddr,
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) {