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| author | Or Cohen <orcohen@paloaltonetworks.com> | 2020-09-03 21:05:28 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-09-04 11:56:02 -0700 |
| commit | acf69c946233259ab4d64f8869d4037a198c7f06 (patch) | |
| tree | 45b5adb90a74f16effbdeb788c763e87c47bb84b /net/packet | |
| parent | b25d1dc9474e1f0cefca994885e82beea271acfe (diff) | |
| download | linux-acf69c946233259ab4d64f8869d4037a198c7f06.tar.gz linux-acf69c946233259ab4d64f8869d4037a198c7f06.tar.bz2 linux-acf69c946233259ab4d64f8869d4037a198c7f06.zip | |
net/packet: fix overflow in tpacket_rcv
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>
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 da8254e680f9..2b33e977a905 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2170,7 +2170,8 @@ 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 timespec64 ts; __u32 ts_status; @@ -2239,6 +2240,10 @@ 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 && |