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Commit 67286640 authored by Vasiliy Kulikov's avatar Vasiliy Kulikov Committed by David S. Miller
Browse files

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: default avatarVasiliy Kulikov <segooon@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 57fe93b3

net/packet/af_packet.c

+2 −1
Original line number Diff line number Diff line
@@ -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) {