Vasiliy Kulikov schrieb:
> 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@xxxxxxxxx>
> ---
> net/packet/af_packet.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> index 3616f27..0856a13 100644
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -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);
if i understand the code correcly the max size for dev->name is IFNAMSIZ.
You can simply that part:
memset(uaddr->sa_data, 0, IFNAMSIZ);
dev = dev_get_by_index_rcu(sock_net(sk), pkt_sk(sk)->ifindex);
if (dev)
strlcpy(uaddr->sa_data, dev->name, IFNAMSIZ);
you should send that as separate patch.
re,
wh
> 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) {
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