From: Xin Long lucien.xin@gmail.com
[ Upstream commit ba56d8ce38c8252fff5b745db3899cf092578ede ]
Fei Liu reported a crash when doing netperf on a topo of macsec dev over veth:
[ 448.919128] refcount_t: underflow; use-after-free. [ 449.090460] Call trace: [ 449.092895] refcount_sub_and_test+0xb4/0xc0 [ 449.097155] tcp_wfree+0x2c/0x150 [ 449.100460] ip_rcv+0x1d4/0x3a8 [ 449.103591] __netif_receive_skb_core+0x554/0xae0 [ 449.108282] __netif_receive_skb+0x28/0x78 [ 449.112366] netif_receive_skb_internal+0x54/0x100 [ 449.117144] napi_gro_complete+0x70/0xc0 [ 449.121054] napi_gro_flush+0x6c/0x90 [ 449.124703] napi_complete_done+0x50/0x130 [ 449.128788] gro_cell_poll+0x8c/0xa8 [ 449.132351] net_rx_action+0x16c/0x3f8 [ 449.136088] __do_softirq+0x128/0x320
The issue was caused by skb's true_size changed without its sk's sk_wmem_alloc increased in tcp/skb_gro_receive(). Later when the skb is being freed and the skb's truesize is subtracted from its sk's sk_wmem_alloc in tcp_wfree(), underflow occurs.
macsec is calling gro_cells_receive() to receive a packet, which actually requires skb->sk to be NULL. However when macsec dev is over veth, it's possible the skb->sk is still set if the skb was not unshared or expanded from the peer veth.
ip_rcv() is calling skb_orphan() to drop the skb's sk for tproxy, but it is too late for macsec's calling gro_cells_receive(). So fix it by dropping the skb's sk earlier on rx path of macsec.
Fixes: 5491e7c6b1a9 ("macsec: enable GRO and RPS on macsec devices") Reported-by: Xiumei Mu xmu@redhat.com Reported-by: Fei Liu feliu@redhat.com Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/macsec.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/net/macsec.c +++ b/drivers/net/macsec.c @@ -1234,6 +1234,7 @@ deliver: macsec_rxsa_put(rx_sa); macsec_rxsc_put(rx_sc);
+ skb_orphan(skb); ret = gro_cells_receive(&macsec->gro_cells, skb); if (ret == NET_RX_SUCCESS) count_rx(dev, skb->len);