lwn.git/net/packet, branch docs-5.2a

net/packet: Remove redundant skb->protocol set

2019-02-22T20:55:31+00:00

c72219b75f introduced tpacket_set_protocol that parses the Ethernet L2 header and sets skb->protocol if it's unset. It is no longer needed since the introduction of packet_parse_headers. In case of SOCK_RAW and unset skb->protocol, packet_parse_headers asks the driver to tell the protocol number, and it's implemented for all Ethernet devices. As the old function supported only Ethernet, no functionality is lost. Signed-off-by: Maxim Mikityanskiy Signed-off-by: David S. Miller

net/packet: Ask driver for protocol if not provided by user

2019-02-22T20:55:31+00:00

If a socket was created with socket(AF_PACKET, SOCK_RAW, 0), the protocol number is unavailable. Try to ask the driver to extract it from the L2 header in order for skb_try_probe_transport_header to succeed. Signed-off-by: Maxim Mikityanskiy Signed-off-by: David S. Miller

net: Don't set transport offset to invalid value

2019-02-22T20:55:31+00:00

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 Signed-off-by: David S. Miller

net/packet: fix 4gb buffer limit due to overflow check

2019-02-12T18:37:23+00:00

When calculating rb->frames_per_block * req->tp_block_nr the result can overflow. Check it for overflow without limiting the total buffer size to UINT_MAX. This change fixes support for packet ring buffers >= UINT_MAX. Fixes: 8f8d28e4d6d8 ("net/packet: fix overflow in check for tp_frame_nr") Signed-off-by: Kal Conley Signed-off-by: David S. Miller

af_packet: fix raw sockets over 6in4 tunnel

2019-01-17T23:54:45+00:00

Since commit cb9f1b783850, scapy (which uses an AF_PACKET socket in SOCK_RAW mode) is unable to send a basic icmp packet over a sit tunnel: Here is a example of the setup: $ ip link set ntfp2 up $ ip addr add 10.125.0.1/24 dev ntfp2 $ ip tunnel add tun1 mode sit ttl 64 local 10.125.0.1 remote 10.125.0.2 dev ntfp2 $ ip addr add fd00:cafe:cafe::1/128 dev tun1 $ ip link set dev tun1 up $ ip route add fd00:200::/64 dev tun1 $ scapy >>> p = [] >>> p += IPv6(src='fd00:100::1', dst='fd00:200::1')/ICMPv6EchoRequest() >>> send(p, count=1, inter=0.1) >>> quit() $ ip -s link ls dev tun1 | grep -A1 "TX.*errors" TX: bytes packets errors dropped carrier collsns 0 0 1 0 0 0 The problem is that the network offset is set to the hard_header_len of the output device (tun1, ie 14 + 20) and in our case, because the packet is small (48 bytes) the pskb_inet_may_pull() fails (it tries to pull 40 bytes (ipv6 header) starting from the network offset). This problem is more generally related to device with variable hard header length. To avoid a too intrusive patch in the current release, a (ugly) workaround is proposed in this patch. It has to be cleaned up in net-next. Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=993675a3100b1 Link: http://patchwork.ozlabs.org/patch/1024489/ Fixes: cb9f1b783850 ("ip: validate header length on virtual device xmit") CC: Willem de Bruijn CC: Maxim Mikityanskiy Signed-off-by: Nicolas Dichtel Acked-by: Willem de Bruijn Signed-off-by: David S. Miller

packet: Do not leak dev refcounts on error exit

2019-01-09T02:41:40+00:00

'dev' is non NULL when the addr_len check triggers so it must goto a label that does the dev_put otherwise dev will have a leaked refcount. This bug causes the ib_ipoib module to become unloadable when using systemd-network as it triggers this check on InfiniBand links. Fixes: 99137b7888f4 ("packet: validate address length") Reported-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe Acked-by: Willem de Bruijn Signed-off-by: David S. Miller

packet: validate address length if non-zero

2018-12-22T23:12:04+00:00

Validate packet socket address length if a length is given. Zero length is equivalent to not setting an address. Fixes: 99137b7888f4 ("packet: validate address length") Reported-by: Ido Schimmel Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller

packet: validate address length

2018-12-21T17:11:25+00:00

Packet sockets with SOCK_DGRAM may pass an address for use in dev_hard_header. Ensure that it is of sufficient length. Reported-by: syzbot Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller

net: add missing SOF_TIMESTAMPING_OPT_ID support

2018-12-18T07:27:00+00:00

SOF_TIMESTAMPING_OPT_ID is supported on TCP, UDP and RAW sockets. But it was missing on RAW with IPPROTO_IP, PF_PACKET and CAN. Add skb_setup_tx_timestamp that configures both tx_flags and tskey for these paths that do not need corking or use bytestream keys. Fixes: 09c2d251b707 ("net-timestamp: add key to disambiguate concurrent datagrams") Signed-off-by: Willem de Bruijn Acked-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller

packet: copy user buffers before orphan or clone

2018-11-23T19:08:03+00:00

tpacket_snd sends packets with user pages linked into skb frags. It notifies that pages can be reused when the skb is released by setting skb->destructor to tpacket_destruct_skb. This can cause data corruption if the skb is orphaned (e.g., on transmit through veth) or cloned (e.g., on mirror to another psock). Create a kernel-private copy of data in these cases, same as tun/tap zerocopy transmission. Reuse that infrastructure: mark the skb as SKBTX_ZEROCOPY_FRAG, which will trigger copy in skb_orphan_frags(_rx). Unlike other zerocopy packets, do not set shinfo destructor_arg to struct ubuf_info. tpacket_destruct_skb already uses that ptr to notify when the original skb is released and a timestamp is recorded. Do not change this timestamp behavior. The ubuf_info->callback is not needed anyway, as no zerocopy notification is expected. Mark destructor_arg as not-a-uarg by setting the lower bit to 1. The resulting value is not a valid ubuf_info pointer, nor a valid tpacket_snd frame address. Add skb_zcopy_.._nouarg helpers for this. The fix relies on features introduced in commit 52267790ef52 ("sock: add MSG_ZEROCOPY"), so can be backported as is only to 4.14. Tested with from `./in_netns.sh ./txring_overwrite` from http://github.com/wdebruij/kerneltools/tests Fixes: 69e3c75f4d54 ("net: TX_RING and packet mmap") Reported-by: Anand H. Krishnan Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller