diff options
| author | Or Cohen <orcohen@paloaltonetworks.com> | 2020-09-03 21:05:28 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-10-07 08:00:08 +0200 |
| commit | 1c3886dc302329f199cc04f8a56ba44d17a0df16 (patch) | |
| tree | d579ffe3c892f45e9c6ea6d6afe07259c0fe546d | |
| parent | b6f69f72c15d7f973f5709c5351f378f235b3654 (diff) | |
net/packet: fix overflow in tpacket_rcv
commit acf69c946233259ab4d64f8869d4037a198c7f06 upstream.
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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ snu: backported to pre-5.3, 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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/packet/af_packet.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index b3caf1eac6af..16b745d254fe 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2162,7 +2162,8 @@ 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; @@ -2225,6 +2226,12 @@ 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 && |