diff options
| author | Or Cohen <orcohen@paloaltonetworks.com> | 2020-09-03 21:05:28 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-09-09 19:12:29 +0200 |
| commit | bc846b58fe5cecaa2632d566355e607954779d45 (patch) | |
| tree | cb4d0bf5dbeaafb0ff5e99ef002628e47b39bcca /net/packet | |
| parent | e3d109c3484e2efe5de60df3935b6a2246391cd9 (diff) | |
net/packet: fix overflow in tpacket_rcv
[ Upstream commit acf69c946233259ab4d64f8869d4037a198c7f06 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net/packet')
| -rw-r--r-- | net/packet/af_packet.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 7735340c892e..fbc2d4dfddf0 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2169,7 +2169,8 @@ 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; @@ -2238,6 +2239,10 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, } macoff = netoff - maclen; } + if (netoff > USHRT_MAX) { + atomic_inc(&po->tp_drops); + goto drop_n_restore; + } if (po->tp_version <= TPACKET_V2) { if (macoff + snaplen > po->rx_ring.frame_size) { if (po->copy_thresh && |