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| author | Maxim Mikityanskiy <maximmi@mellanox.com> | 2019-02-21 12:39:57 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-02-22 12:55:31 -0800 |
| commit | d2aa125d629080c4f3e31f23b7f612ef6b8492ac (patch) | |
| tree | 85cd897e246a879c33393582949935cb26ad1784 /drivers/net/tap.c | |
| parent | 5328b633c9b3c3af38bec8cb70120658c0866e0a (diff) | |
| download | lwn-d2aa125d629080c4f3e31f23b7f612ef6b8492ac.tar.gz lwn-d2aa125d629080c4f3e31f23b7f612ef6b8492ac.zip | |
net: Don't set transport offset to invalid value
If the socket was created with socket(AF_PACKET, SOCK_RAW, 0),
skb->protocol will be unset, __skb_flow_dissect() will fail, and
skb_probe_transport_header() will fall back to the offset_hint, making
the resulting skb_transport_offset incorrect.
If, however, there is no transport header in the packet,
transport_header shouldn't be set to an arbitrary value.
Fix it by leaving the transport offset unset if it couldn't be found, to
be explicit rather than to fill it with some wrong value. It changes the
behavior, but if some code relied on the old behavior, it would be
broken anyway, as the old one is incorrect.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/tap.c')
| -rw-r--r-- | drivers/net/tap.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/tap.c b/drivers/net/tap.c index c0b52e48f0e6..2ea9b4976f4a 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -712,7 +712,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, goto err_kfree; } - skb_probe_transport_header(skb, ETH_HLEN); + skb_probe_transport_header(skb); /* Move network header to the right position for VLAN tagged packets */ if ((skb->protocol == htons(ETH_P_8021Q) || @@ -1187,7 +1187,7 @@ static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp) tap = rcu_dereference(q->tap); if (tap) { skb->dev = tap->dev; - skb_probe_transport_header(skb, ETH_HLEN); + skb_probe_transport_header(skb); dev_queue_xmit(skb); } else { kfree_skb(skb); |