linux-toradex.git/drivers/net/tun.c, branch v5.9-rc5

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2020-08-04T01:27:40+00:00

Daniel Borkmann says:

====================
pull-request: bpf-next 2020-08-04

The following pull-request contains BPF updates for your *net-next* tree.

We've added 73 non-merge commits during the last 9 day(s) which contain
a total of 135 files changed, 4603 insertions(+), 1013 deletions(-).

The main changes are:

1) Implement bpf_link support for XDP. Also add LINK_DETACH operation for the BPF
   syscall allowing processes with BPF link FD to force-detach, from Andrii Nakryiko.

2) Add BPF iterator for map elements and to iterate all BPF programs for efficient
   in-kernel inspection, from Yonghong Song and Alexei Starovoitov.

3) Separate bpf_get_{stack,stackid}() helpers for perf events in BPF to avoid
   unwinder errors, from Song Liu.

4) Allow cgroup local storage map to be shared between programs on the same
   cgroup. Also extend BPF selftests with coverage, from YiFei Zhu.

5) Add BPF exception tables to ARM64 JIT in order to be able to JIT BPF_PROBE_MEM
   load instructions, from Jean-Philippe Brucker.

6) Follow-up fixes on BPF socket lookup in combination with reuseport group
   handling. Also add related BPF selftests, from Jakub Sitnicki.

7) Allow to use socket storage in BPF_PROG_TYPE_CGROUP_SOCK-typed programs for
   socket create/release as well as bind functions, from Stanislav Fomichev.

8) Fix an info leak in xsk_getsockopt() when retrieving XDP stats via old struct
   xdp_statistics, from Peilin Ye.

9) Fix PT_REGS_RC{,_CORE}() macros in libbpf for MIPS arch, from Jerry Crunchtime.

10) Extend BPF kernel test infra with skb->family and skb->{local,remote}_ip{4,6}
    fields and allow user space to specify skb->dev via ifindex, from Dmitry Yakunin.

11) Fix a bpftool segfault due to missing program type name and make it more robust
    to prevent them in future gaps, from Quentin Monnet.

12) Consolidate cgroup helper functions across selftests and fix a v6 localhost
    resolver issue, from John Fastabend.
====================

Signed-off-by: David S. Miller

tun: add missing rcu annotation in tun_set_ebpf()

2020-08-01T00:17:53+00:00

We expecte prog_p to be protected by rcu, so adding the rcu annotation
to fix the following sparse warning:

drivers/net/tun.c:3003:36: warning: incorrect type in argument 2 (different address spaces)
drivers/net/tun.c:3003:36:    expected struct tun_prog [noderef] __rcu **prog_p
drivers/net/tun.c:3003:36:    got struct tun_prog **prog_p
drivers/net/tun.c:3292:42: warning: incorrect type in argument 2 (different address spaces)
drivers/net/tun.c:3292:42:    expected struct tun_prog **prog_p
drivers/net/tun.c:3292:42:    got struct tun_prog [noderef] __rcu **
drivers/net/tun.c:3296:42: warning: incorrect type in argument 2 (different address spaces)
drivers/net/tun.c:3296:42:    expected struct tun_prog **prog_p
drivers/net/tun.c:3296:42:    got struct tun_prog [noderef] __rcu **

Reported-by: Michael S. Tsirkin 
Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller

bpf, xdp: Remove XDP_QUERY_PROG and XDP_QUERY_PROG_HW XDP commands

2020-07-26T03:37:02+00:00

Now that BPF program/link management is centralized in generic net_device
code, kernel code never queries program id from drivers, so
XDP_QUERY_PROG/XDP_QUERY_PROG_HW commands are unnecessary.

This patch removes all the implementations of those commands in kernel, along
the xdp_attachment_query().

This patch was compile-tested on allyesconfig.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20200722064603.3350758-10-andriin@fb.com

tun: implement header_ops->parse_protocol for AF_PACKET

2020-06-30T19:29:39+00:00

The tun driver passes up skb->protocol to userspace in the form of PI headers.
For AF_PACKET injection, we need to support its call chain of:

    packet_sendmsg -> packet_snd -> packet_parse_headers ->
      dev_parse_header_protocol -> parse_protocol

Without a valid parse_protocol, this returns zero, and the tun driver
then gives userspace bogus values that it can't deal with.

Note that this isn't the case with tap, because tap already benefits
from the shared infrastructure for ethernet headers. But with tun,
there's nothing.

Signed-off-by: Jason A. Donenfeld 
Signed-off-by: David S. Miller

xdp: Rename convert_to_xdp_frame in xdp_convert_buff_to_frame

2020-06-01T22:02:53+00:00

In order to use standard 'xdp' prefix, rename convert_to_xdp_frame
utility routine in xdp_convert_buff_to_frame and replace all the
occurrences

Signed-off-by: Lorenzo Bianconi 
Signed-off-by: Alexei Starovoitov 
Acked-by: Jesper Dangaard Brouer 
Link: https://lore.kernel.org/bpf/6344f739be0d1a08ab2b9607584c4d5478c8c083.1590698295.git.lorenzo@kernel.org

tun: correct header offsets in napi frags mode

2020-06-01T19:01:46+00:00

Tun in IFF_NAPI_FRAGS mode calls napi_gro_frags. Unlike netif_rx and
netif_gro_receive, this expects skb->data to point to the mac layer.

But skb_probe_transport_header, __skb_get_hash_symmetric, and
xdp_do_generic in tun_get_user need skb->data to point to the network
header. Flow dissection also needs skb->protocol set, so
eth_type_trans has to be called.

Ensure the link layer header lies in linear as eth_type_trans pulls
ETH_HLEN. Then take the same code paths for frags as for not frags.
Push the link layer header back just before calling napi_gro_frags.

By pulling up to ETH_HLEN from frag0 into linear, this disables the
frag0 optimization in the special case when IFF_NAPI_FRAGS is used
with zero length iov[0] (and thus empty skb->linear).

Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver")
Signed-off-by: Willem de Bruijn 
Acked-by: Petar Penkov 
Signed-off-by: David S. Miller

tun: Add XDP frame size

2020-05-15T04:21:55+00:00

The tun driver have two code paths for running XDP (bpf_prog_run_xdp).
In both cases 'buflen' contains enough tailroom for skb_shared_info.

Signed-off-by: Jesper Dangaard Brouer 
Signed-off-by: Alexei Starovoitov 
Acked-by: Michael S. Tsirkin 
Acked-by: Jason Wang 
Link: https://lore.kernel.org/bpf/158945343419.97035.9594485183958037621.stgit@firesoul

net: tun: record RX queue in skb before do_xdp_generic()

2020-04-13T03:58:24+00:00

This allows netif_receive_generic_xdp() to correctly determine the RX
queue from which the skb is coming, so that the context passed to the
XDP program will contain the correct RX queue index.

Signed-off-by: Gilberto Bertin 
Signed-off-by: David S. Miller

tun: Don't put_page() for all negative return values from XDP program

2020-04-06T17:00:43+00:00

When an XDP program is installed, tun_build_skb() grabs a reference to
the current page fragment page if the program returns XDP_REDIRECT or
XDP_TX. However, since tun_xdp_act() passes through negative return
values from the XDP program, it is possible to trigger the error path by
mistake and accidentally drop a reference to the fragments page without
taking one, leading to a spurious free. This is believed to be the cause
of some KASAN use-after-free reports from syzbot [1], although without a
reproducer it is not possible to confirm whether this patch fixes the
problem.

Ensure that we only drop a reference to the fragments page if the XDP
transmit or redirect operations actually fail.

[1] https://syzkaller.appspot.com/bug?id=e76a6af1be4acd727ff6bbca669833f98cbf5d95

Cc: "David S. Miller" 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
CC: Eric Dumazet 
Acked-by: Jason Wang 
Fixes: 8ae1aff0b331 ("tuntap: split out XDP logic")
Signed-off-by: Will Deacon 
Signed-off-by: David S. Miller