From mboxrd@z Thu Jan 1 00:00:00 1970 From: walter harms Date: Mon, 01 Nov 2010 09:14:10 +0000 Subject: Re: [PATCH 2/3] net: packet: fix information leak to userland Message-Id: <4CCE84E2.9050801@bfs.de> List-Id: References: <1288545028-16436-1-git-send-email-segooon@gmail.com> In-Reply-To: <1288545028-16436-1-git-send-email-segooon@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Vasiliy Kulikov Cc: kernel-janitors@vger.kernel.org, "David S. Miller" , Jiri Pirko , Eric Dumazet , netdev@vger.kernel.org, linux-kernel@vger.kernel.org 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 > --- > 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) {