| Message ID | 20200904183331.369621-1-marcelo.cerri@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | [bionic:linux,bionic:linux-hwe-5.0] UBUNTU: SAUCE: net/packet: fix overflow in tpacket_rcv | expand |
On Fri, Sep 04, 2020 at 03:33:31PM -0300, Marcelo Henrique Cerri wrote: > From: Or Cohen <orcohen@paloaltonetworks.com> > > CVE-2020-14386 > > Using tp_reserve to calculate netoff can overflow as > tp_reserve is unsigned int and netoff is unsigned short. > > This may lead to macoff receving a smaller value then > sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr > is set, an out-of-bounds write will occur when > calling virtio_net_hdr_from_skb. > > The bug is fixed by converting netoff to unsigned int > and checking if it exceeds USHRT_MAX. > > This addresses CVE-2020-14386 > > Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt") > Signed-off-by: Or Cohen <orcohen@paloaltonetworks.com> > Signed-off-by: Eric Dumazet <edumazet@google.com> > > [ snu: backported to 4.9, changed tp_drops counting/locking ] > > Signed-off-by: Stefan Nuernberger <snu@amazon.com> > CC: David Woodhouse <dwmw@amazon.co.uk> > CC: Amit Shah <aams@amazon.com> > CC: stable@vger.kernel.org > > [ mhcerri: from the netdev mailing list: > https://lore.kernel.org/netdev/CAM6JnLf_8nwzq+UGO+amXpeApCDarJjwzOEHQd5qBhU7YKm3DQ@mail.gmail.com/ > This is the fixed proposed on the mailing list for 4.9, this fix > should be intended to any kernel that doesn't have commit id 8e8e2951e309 > ("net/packet: make tp_drops atomic"). For us, that means any kernel > before 5.3. > Tested with the reproducer proposed by the author.] > Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com> Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> > --- > net/packet/af_packet.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c > index 89d6b0957d07..cd5fbec69de8 100644 > --- a/net/packet/af_packet.c > +++ b/net/packet/af_packet.c > @@ -2160,7 +2160,8 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, > int skb_len = skb->len; > unsigned int snaplen, res; > unsigned long status = TP_STATUS_USER; > - unsigned short macoff, netoff, hdrlen; > + unsigned short macoff, hdrlen; > + unsigned int netoff; > struct sk_buff *copy_skb = NULL; > struct timespec ts; > __u32 ts_status; > @@ -2223,6 +2224,12 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, > } > macoff = netoff - maclen; > } > + if (netoff > USHRT_MAX) { > + spin_lock(&sk->sk_receive_queue.lock); > + po->stats.stats1.tp_drops++; > + spin_unlock(&sk->sk_receive_queue.lock); > + goto drop_n_restore; > + } > if (po->tp_version <= TPACKET_V2) { > if (macoff + snaplen > po->rx_ring.frame_size) { > if (po->copy_thresh && > -- > 2.25.1 > > > -- > kernel-team mailing list > kernel-team@lists.ubuntu.com > https://lists.ubuntu.com/mailman/listinfo/kernel-team
Acked-by: Khalid Elmously <khalid.elmously@canonical.com> On 2020-09-04 15:33:31 , Marcelo Henrique Cerri wrote: > From: Or Cohen <orcohen@paloaltonetworks.com> > > CVE-2020-14386 > > Using tp_reserve to calculate netoff can overflow as > tp_reserve is unsigned int and netoff is unsigned short. > > This may lead to macoff receving a smaller value then > sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr > is set, an out-of-bounds write will occur when > calling virtio_net_hdr_from_skb. > > The bug is fixed by converting netoff to unsigned int > and checking if it exceeds USHRT_MAX. > > This addresses CVE-2020-14386 > > Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt") > Signed-off-by: Or Cohen <orcohen@paloaltonetworks.com> > Signed-off-by: Eric Dumazet <edumazet@google.com> > > [ snu: backported to 4.9, changed tp_drops counting/locking ] > > Signed-off-by: Stefan Nuernberger <snu@amazon.com> > CC: David Woodhouse <dwmw@amazon.co.uk> > CC: Amit Shah <aams@amazon.com> > CC: stable@vger.kernel.org > > [ mhcerri: from the netdev mailing list: > https://lore.kernel.org/netdev/CAM6JnLf_8nwzq+UGO+amXpeApCDarJjwzOEHQd5qBhU7YKm3DQ@mail.gmail.com/ > This is the fixed proposed on the mailing list for 4.9, this fix > should be intended to any kernel that doesn't have commit id 8e8e2951e309 > ("net/packet: make tp_drops atomic"). For us, that means any kernel > before 5.3. > Tested with the reproducer proposed by the author.] > Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com> > --- > net/packet/af_packet.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c > index 89d6b0957d07..cd5fbec69de8 100644 > --- a/net/packet/af_packet.c > +++ b/net/packet/af_packet.c > @@ -2160,7 +2160,8 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, > int skb_len = skb->len; > unsigned int snaplen, res; > unsigned long status = TP_STATUS_USER; > - unsigned short macoff, netoff, hdrlen; > + unsigned short macoff, hdrlen; > + unsigned int netoff; > struct sk_buff *copy_skb = NULL; > struct timespec ts; > __u32 ts_status; > @@ -2223,6 +2224,12 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, > } > macoff = netoff - maclen; > } > + if (netoff > USHRT_MAX) { > + spin_lock(&sk->sk_receive_queue.lock); > + po->stats.stats1.tp_drops++; > + spin_unlock(&sk->sk_receive_queue.lock); > + goto drop_n_restore; > + } > if (po->tp_version <= TPACKET_V2) { > if (macoff + snaplen > po->rx_ring.frame_size) { > if (po->copy_thresh && > -- > 2.25.1 > > > -- > kernel-team mailing list > kernel-team@lists.ubuntu.com > https://lists.ubuntu.com/mailman/listinfo/kernel-team
Applied. Thanks! On Fri, Sep 04, 2020 at 03:33:31PM -0300, Marcelo Henrique Cerri wrote: > From: Or Cohen <orcohen@paloaltonetworks.com> > > CVE-2020-14386 > > Using tp_reserve to calculate netoff can overflow as > tp_reserve is unsigned int and netoff is unsigned short. > > This may lead to macoff receving a smaller value then > sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr > is set, an out-of-bounds write will occur when > calling virtio_net_hdr_from_skb. > > The bug is fixed by converting netoff to unsigned int > and checking if it exceeds USHRT_MAX. > > This addresses CVE-2020-14386 > > Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt") > Signed-off-by: Or Cohen <orcohen@paloaltonetworks.com> > Signed-off-by: Eric Dumazet <edumazet@google.com> > > [ snu: backported to 4.9, changed tp_drops counting/locking ] > > Signed-off-by: Stefan Nuernberger <snu@amazon.com> > CC: David Woodhouse <dwmw@amazon.co.uk> > CC: Amit Shah <aams@amazon.com> > CC: stable@vger.kernel.org > > [ mhcerri: from the netdev mailing list: > https://lore.kernel.org/netdev/CAM6JnLf_8nwzq+UGO+amXpeApCDarJjwzOEHQd5qBhU7YKm3DQ@mail.gmail.com/ > This is the fixed proposed on the mailing list for 4.9, this fix > should be intended to any kernel that doesn't have commit id 8e8e2951e309 > ("net/packet: make tp_drops atomic"). For us, that means any kernel > before 5.3. > Tested with the reproducer proposed by the author.] > Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com> > --- > net/packet/af_packet.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c > index 89d6b0957d07..cd5fbec69de8 100644 > --- a/net/packet/af_packet.c > +++ b/net/packet/af_packet.c > @@ -2160,7 +2160,8 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, > int skb_len = skb->len; > unsigned int snaplen, res; > unsigned long status = TP_STATUS_USER; > - unsigned short macoff, netoff, hdrlen; > + unsigned short macoff, hdrlen; > + unsigned int netoff; > struct sk_buff *copy_skb = NULL; > struct timespec ts; > __u32 ts_status; > @@ -2223,6 +2224,12 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, > } > macoff = netoff - maclen; > } > + if (netoff > USHRT_MAX) { > + spin_lock(&sk->sk_receive_queue.lock); > + po->stats.stats1.tp_drops++; > + spin_unlock(&sk->sk_receive_queue.lock); > + goto drop_n_restore; > + } > if (po->tp_version <= TPACKET_V2) { > if (macoff + snaplen > po->rx_ring.frame_size) { > if (po->copy_thresh && > -- > 2.25.1 >
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 89d6b0957d07..cd5fbec69de8 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2160,7 +2160,8 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, int skb_len = skb->len; unsigned int snaplen, res; unsigned long status = TP_STATUS_USER; - unsigned short macoff, netoff, hdrlen; + unsigned short macoff, hdrlen; + unsigned int netoff; struct sk_buff *copy_skb = NULL; struct timespec ts; __u32 ts_status; @@ -2223,6 +2224,12 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, } macoff = netoff - maclen; } + if (netoff > USHRT_MAX) { + spin_lock(&sk->sk_receive_queue.lock); + po->stats.stats1.tp_drops++; + spin_unlock(&sk->sk_receive_queue.lock); + goto drop_n_restore; + } if (po->tp_version <= TPACKET_V2) { if (macoff + snaplen > po->rx_ring.frame_size) { if (po->copy_thresh &&