Petar Penkov says:

====================
This patch series hardens the RX stack by allowing flow dissection in BPF,
as previously discussed [1]. Because of the rigorous checks of the BPF
verifier, this provides significant security guarantees. In particular, the
BPF flow dissector cannot get inside of an infinite loop, as with
CVE-2013-4348, because BPF programs are guaranteed to terminate. It cannot
read outside of packet bounds, because all memory accesses are checked.
Also, with BPF the administrator can decide which protocols to support,
reducing potential attack surface. Rarely encountered protocols can be
excluded from dissection and the program can be updated without kernel
recompile or reboot if a bug is discovered.

Patch 1 adds infrastructure to execute a BPF program in __skb_flow_dissect.
This includes a new BPF program and attach type.

Patch 2 adds the new BPF flow dissector definitions to tools/uapi.

Patch 3 adds support for the new BPF program type to libbpf and bpftool.

Patch 4 adds a flow dissector program in BPF. This parses most protocols in
__skb_flow_dissect in BPF for a subset of flow keys (basic, control, ports,
and address types).

Patch 5 adds a selftest that attaches the BPF program to the flow dissector
and sends traffic with different levels of encapsulation.

Performance Evaluation:
The in-kernel implementation was compared against the demo program from
patch 4 using the test in patch 5 with IPv4/UDP traffic over 10 seconds.
	$perf record -a -C 4 taskset -c 4 ./test_flow_dissector -i 4 -f 8 \
		-t 10

In-kernel Dissector:
	__skb_flow_dissect overhead: 2.12%
	Total Packets: 3,272,597 (from output of ./test_flow_dissector)

BPF Dissector:
	__skb_flow_dissect overhead: 1.63%
	Total Packets: 3,232,356 (from output of ./test_flow_dissector)

No-op BPF Dissector:
	__skb_flow_dissect overhead: 1.52%
	Total Packets: 3,330,635 (from output of ./test_flow_dissector)

Changes since v3:
1/ struct bpf_flow_keys reorganized to remove holes in patch 1 and patch 2.

Changes since v2:
1/ Changes to tools/include/uapi pulled into a separate patch 2
2/ Changes to tools/lib and tools/bpftool pulled into a separate patch 3
3/ Changed flow_keys in __sk_buff from __u32 to struct bpf_flow_keys *
4/ Added nhoff field in struct bpf_flow_keys to pass initial offset
5/ Saving all of the modified control block, rather than just the qdisc
6/ Sample BPF program in patch 4 modified to use the changes above

Changes since v1:
1/ LD_ABS instructions now disallowed for the new BPF prog type
2/ now checks if skb is NULL in __skb_flow_dissect()
3/ fixed incorrect accesses in flow_dissector_is_valid_access()
	- writes to the flow_keys field now disallowed
	- reads/writes to tc_classid and data_meta now disallowed
4/ headers pulled with bpf_skb_load_data if direct access fails

Changes since RFC:
1/ Flow dissector hook changed from global to per-netns
2/ Defined struct bpf_flow_keys to be used in BPF flow dissector
programs instead of exposing the internal flow keys layout. Added a
function to translate from bpf_flow_keys to the internal layout after BPF
dissection is complete. The pointer to this struct is stored in
qdisc_skb_cb rather than inside of the 20 byte control block which
simplifies verification and allows access to all 20 bytes of the cb.
3/ Removed GUE parsing as it relied on a hardcoded port
4/ MPLS parsing now stops at the first label which is consistent
with the in-kernel flow dissector
5/ Refactored to use direct packet access and to write out to
struct bpf_flow_keys

[1] http://vger.kernel.org/netconf2017_files/rx_hardening_and_udp_gso.pdf
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Adds a test that sends different types of packets over multiple
tunnels and verifies that valid packets are dissected correctly.  To do
so, a tc-flower rule is added to drop packets on UDP src port 9, and
packets are sent from ports 8, 9, and 10. Only the packets on port 9
should be dropped. Because tc-flower relies on the flow dissector to
match flows, correct classification demonstrates correct dissection.

Also add support logic to load the BPF program and to inject the test
packets.
Signed-off-by: Petar Penkov <ppenkov@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This eBPF program extracts basic/control/ip address/ports keys from
incoming packets. It supports recursive parsing for IP encapsulation,
and VLAN, along with IPv4/IPv6 and extension headers.  This program is
meant to show how flow dissection and key extraction can be done in
eBPF.

Link: http://vger.kernel.org/netconf2017_files/rx_hardening_and_udp_gso.pdfSigned-off-by: Petar Penkov <ppenkov@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This patch extends libbpf and bpftool to work with programs of type
BPF_PROG_TYPE_FLOW_DISSECTOR.
Signed-off-by: Petar Penkov <ppenkov@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This patch syncs tools/include/uapi/linux/bpf.h with the flow dissector
definitions from include/uapi/linux/bpf.h
Signed-off-by: Petar Penkov <ppenkov@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Adds a hook for programs of type BPF_PROG_TYPE_FLOW_DISSECTOR and
attach type BPF_FLOW_DISSECTOR that is executed in the flow dissector
path. The BPF program is per-network namespace.
Signed-off-by: Petar Penkov <ppenkov@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Building with CONFIG_INET=n will show the warning below:
net/core/filter.c: In function ‘____bpf_getsockopt’:
net/core/filter.c:4048:19: warning: unused variable ‘tp’ [-Wunused-variable]
  struct tcp_sock *tp;
                   ^~
net/core/filter.c:4046:31: warning: unused variable ‘icsk’ [-Wunused-variable]
  struct inet_connection_sock *icsk;
                               ^~~~
Move the variable declarations inside the {} block where they are used.

Fixes: 1e215300 ("bpf: add TCP_SAVE_SYN/TCP_SAVED_SYN options for bpf_(set|get)sockopt")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Commit f7010770 ("tools/bpf: move bpf/lib netlink related
functions into a new file") introduced a while loop for the
netlink recv path. This while loop is needed since the
buffer in recv syscall may not be enough to hold all the
information and in such cases multiple recv calls are needed.

There is a bug introduced by the above commit as
the while loop may block on recv syscall if there is no
more messages are expected. The netlink message header
flag NLM_F_MULTI is used to indicate that more messages
are expected and this patch fixed the bug by doing
further recv syscall only if multipart message is expected.

The patch added another fix regarding to message length of 0.
When netlink recv returns message length of 0, there will be
no more messages for returning data so the while loop
can end.

Fixes: f7010770 ("tools/bpf: move bpf/lib netlink related functions into a new file")
Reported-by: Björn Töpel <bjorn.topel@intel.com>
Tested-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Yonghong Song says:

====================
The support to dump program array and map_in_map maps
for bpffs and bpftool is added. Patch #1 added bpffs support
and Patch #2 added bpftool support. Please see
individual patches for example output.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Currently, prog array map and map of maps are not supported
in bpftool. This patch added the support.
Different from other map types, for prog array map and
map of maps, the key returned bpf_get_next_key() may not
point to a valid value. So for these two map types,
no error will be printed out when such a scenario happens.

The following is the plain and json dump if btf is not available:
  $ ./bpftool map dump id 10
    key: 08 00 00 00  value: 5c 01 00 00
    Found 1 element
  $ ./bpftool -jp map dump id 10
    [{
        "key": ["0x08","0x00","0x00","0x00"
        ],
        "value": ["0x5c","0x01","0x00","0x00"
        ]
    }]

If the BTF is available, the dump looks below:
  $ ./bpftool map dump id 2
    [{
            "key": 0,
            "value": 7
        }
    ]
  $ ./bpftool -jp map dump id 2
    [{
        "key": ["0x00","0x00","0x00","0x00"
        ],
        "value": ["0x07","0x00","0x00","0x00"
        ],
        "formatted": {
            "key": 0,
            "value": 7
        }
    }]
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Added bpffs pretty print for program array map. For a particular
array index, if the program array points to a valid program,
the "<index>: <prog_id>" will be printed out like
   0: 6
which means bpf program with id "6" is installed at index "0".
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Add "bpftool net" support. Networking devices are enumerated
to dump device index/name associated with xdp progs.

For each networking device, tc classes and qdiscs are enumerated
in order to check their bpf filters.
In addition, root handle and clsact ingress/egress are also checked for
bpf filters.  Not all filter information is printed out. Only ifindex,
kind, filter name, prog_id and tag are printed out, which are good
enough to show attachment information. If the filter action
is a bpf action, its bpf program id, bpf name and tag will be
printed out as well.

For example,
  $ ./bpftool net
  xdp [
  ifindex 2 devname eth0 prog_id 198
  ]
  tc_filters [
  ifindex 2 kind qdisc_htb name prefix_matcher.o:[cls_prefix_matcher_htb]
            prog_id 111727 tag d08fe3b4319bc2fd act []
  ifindex 2 kind qdisc_clsact_ingress name fbflow_icmp
            prog_id 130246 tag 3f265c7f26db62c9 act []
  ifindex 2 kind qdisc_clsact_egress name prefix_matcher.o:[cls_prefix_matcher_clsact]
            prog_id 111726 tag 99a197826974c876
  ifindex 2 kind qdisc_clsact_egress name cls_fg_dscp
            prog_id 108619 tag dc4630674fd72dcc act []
  ifindex 2 kind qdisc_clsact_egress name fbflow_egress
            prog_id 130245 tag 72d2d830d6888d2c
  ]
  $ ./bpftool -jp net
  [{
        "xdp": [{
                "ifindex": 2,
                "devname": "eth0",
                "prog_id": 198
            }
        ],
        "tc_filters": [{
                "ifindex": 2,
                "kind": "qdisc_htb",
                "name": "prefix_matcher.o:[cls_prefix_matcher_htb]",
                "prog_id": 111727,
                "tag": "d08fe3b4319bc2fd",
                "act": []
            },{
                "ifindex": 2,
                "kind": "qdisc_clsact_ingress",
                "name": "fbflow_icmp",
                "prog_id": 130246,
                "tag": "3f265c7f26db62c9",
                "act": []
            },{
                "ifindex": 2,
                "kind": "qdisc_clsact_egress",
                "name": "prefix_matcher.o:[cls_prefix_matcher_clsact]",
                "prog_id": 111726,
                "tag": "99a197826974c876"
            },{
                "ifindex": 2,
                "kind": "qdisc_clsact_egress",
                "name": "cls_fg_dscp",
                "prog_id": 108619,
                "tag": "dc4630674fd72dcc",
                "act": []
            },{
                "ifindex": 2,
                "kind": "qdisc_clsact_egress",
                "name": "fbflow_egress",
                "prog_id": 130245,
                "tag": "72d2d830d6888d2c"
            }
        ]
    }
  ]
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This patch added a few netlink attribute parsing functions
and the netlink API functions to query networking links, tc classes,
tc qdiscs and tc filters. For example, the following API is
to get networking links:
  int nl_get_link(int sock, unsigned int nl_pid,
                  dump_nlmsg_t dump_link_nlmsg,
                  void *cookie);

Note that when the API is called, the user also provided a
callback function with the following signature:
  int (*dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);

The "cookie" is the parameter the user passed to the API and will
be available for the callback function.
The "msg" is the information about the result, e.g., ifinfomsg or
tcmsg. The "tb" is the parsed netlink attributes.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

There are no functionality change for this patch.

In the subsequent patches, more netlink related library functions
will be added and a separate file is better than cluttering bpf.c.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Among others, this header will be used later for
bpftool net support.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

The errno man page states: "The value in errno is significant only when
the return value of the call indicated an error..." then it is not correct
to check it, it could be different than zero even if the function
succeeded.

It causes some false positives if errno is set by a previous function.
Signed-off-by: Mauricio Vasquez B <mauricio.vasquez@polito.it>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Signed-off-by: Mauricio Vasquez B <mauricio.vasquez@polito.it>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

The compiler does an efficient job of inlining static C functions.
Perf top clearly shows that almost everything gets inlined into the
function call xdp_do_redirect.

The function xdp_do_redirect end-up containing and interleaving the
map and non-map redirect code.  This is sub-optimal, as it would be
strange for an XDP program to use both types of redirect in the same
program. The two use-cases are separate, and interleaving the code
just cause more instruction-cache pressure.

I would like to stress (again) that the non-map variant bpf_redirect
is very slow compared to the bpf_redirect_map variant, approx half the
speed.  Measured with driver i40e the difference is:

- map     redirect: 13,250,350 pps
- non-map redirect:  7,491,425 pps

For this reason, the function name of the non-map variant of redirect
have been called xdp_do_redirect_slow.  This hopefully gives a hint
when using perf, that this is not the optimal XDP redirect operating mode.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

The compiler chooses to not-inline the function __xdp_map_lookup_elem,
because it can see that it is used by both Generic-XDP and native-XDP
do redirect calls (xdp_do_generic_redirect_map and xdp_do_redirect_map).

The compiler cannot know that this is a bad choice, as it cannot know
that a net device cannot run both XDP modes (Generic or Native) at the
same time.  Thus, mark this function inline, even-though we normally
leave this up-to the compiler.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Notice the compiler generated ASM code layout was suboptimal.  It
assumed map enqueue errors as the likely case, which is shouldn't.
It assumed that xdp_do_flush_map() was a likely case, due to maps
changing between packets, which should be very unlikely.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Edward Cree says:
In check_mem_access(), for the PTR_TO_CTX case, after check_ctx_access()
has supplied a reg_type, the other members of the register state are set
appropriately.  Previously reg.range was set to 0, but as it is in a
union with reg.map_ptr, which is larger, upper bytes of the latter were
left in place.  This then caused the memcmp() in regsafe() to fail,
preventing some branches from being pruned (and occasionally causing the
same program to take a varying number of processed insns on repeated
verifier runs).

Fix the instability by clearing bpf_reg_state in __mark_reg_[un]known()

Fixes: f1174f77 ("bpf/verifier: rework value tracking")
Debugged-by: Edward Cree <ecree@solarflare.com>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

After the commit eac7d845 ("tools: libbpf: don't return '.text'
as a program for multi-function programs"), bpf_program__next()
in bpf_object__for_each_program skips the function storage such as .text,
so eliminate the duplicate checking.

Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

As Linus noted, the test for 0 is needless, groups type can follow the
usual kernel style and 8*sizeof(unsigned long) is BITS_PER_LONG:

> The code [..] isn't technically incorrect...
> But it is stupid.
> Why stupid? Because the test for 0 is pointless.
>
> Just doing
>        if (nlk->ngroups < 8*sizeof(groups))
>                groups &= (1UL << nlk->ngroups) - 1;
>
> would have been fine and more understandable, since the "mask by shift
> count" already does the right thing for a ngroups value of 0. Now that
> test for zero makes me go "what's special about zero?". It turns out
> that the answer to that is "nothing".
[..]
> The type of "groups" is kind of silly too.
>
> Yeah, "long unsigned int" isn't _technically_ wrong. But we normally
> call that type "unsigned long".

Cleanup my piece of pointlessness.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: netdev@vger.kernel.org
Fairly-blamed-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently, the only way to ignore outgoing packets on a packet socket is
via the BPF filter.  With MSG_ZEROCOPY, packets that are looped into
AF_PACKET are copied in dev_queue_xmit_nit(), and this copy happens even
if the filter run from packet_rcv() would reject them.  So the presence
of a packet socket on the interface takes away the benefits of
MSG_ZEROCOPY, even if the packet socket is not interested in outgoing
packets.  (Even when MSG_ZEROCOPY is not used, the skb is unnecessarily
cloned, but the cost for that is much lower.)

Add a socket option to allow AF_PACKET sockets to ignore outgoing
packets to solve this.  Note that the *BSDs already have something
similar: BIOCSSEESENT/BIOCSDIRECTION and BIOCSDIRFILT.

The first intended user is lldpd.
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fixes the following sparse warning:

drivers/net/ethernet/microchip/lan743x_ptp.c:980:6: warning:
 symbol 'lan743x_ptp_set_sync_ts_insert' was not declared. Should it be static?
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fixes the following sparse warning:

drivers/net/ethernet/mellanox/mlx5/core/ipoib/ipoib.c:119:6: warning:
 symbol 'mlx5i_grp_sw_update_stats' was not declared. Should it be static?
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'mac80211-next-for-davem-2018-09-05' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next

Johannes Berg says:

====================
This time, we have some pretty impactful work. Among
the changes:
 * changes to make PTK rekeying work better, or actually
   better/safely if drivers get updated
 * VHT extended NSS support - some APs had capabilities
   that didn't fit into the VHT (11ac) spec, so the spec
   was updated and we follow that now
 * some TXQ and A-MSDU building work - will allow iwlwifi
   to use this soon
 * more HE work, including aligning to 802.11ax Draft 3.0
 * L-SIG and 0-length-PSDU support in radiotap
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Add validation check for wmm rule when copy rules from fwdb and print
error when rule is invalid.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Both old and new cannot be NULL at the same time, hence checking
new when old is not NULL is unnecessary.

Also, notice that new is being dereferenced before it is checked:

	idx = new->conf.keyidx;

The above triggers a static code analysis warning.

Address this by removing the NULL check on new and adding a code
comment based on the following piece of code:

387        /* caller must provide at least one old/new */
388        if (WARN_ON(!new && !old))
389                return 0;

Addresses-Coverity-ID: 1473176 ("Dereference before null check")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Some hardwares have limitations on the packets' type in AMSDU.
Add an optional driver callback to determine if two skbs can
be used in the same AMSDU or not.
Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Some drivers may have AMSDU size limitation per TID, due to
HW constrains. Add an option to set this limit.
Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

We have a TXQ abstraction for non-data packets that need
powersave buffering. Since the AP cannot sleep, in case
of station we can use this TXQ for all management frames,
regardless if they are bufferable. Add HW flag to allow
that.
Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Align to new 11ax draft D3.0.  Change/add new MAC and PHY capabilities
and update drivers' 11ax capabilities and mac80211's debugfs
accordingly.
Signed-off-by: Shaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

After masking the he_oper_params, to get the requested values as
integers one must rshift and not lshift.  Fix that by using the
le32_get_bits() macro.

Fixes: 41cbb0f5 ("mac80211: add support for HE")
Signed-off-by: Naftali Goldstein <naftali.goldstein@intel.com>
[converted to use le32_get_bits()]
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

For certain sounding frames, it may be useful to report them
to userspace even though they don't have a PSDU in order to
determine the PHY parameters (e.g. VHT rate/stream config.)
Add support for this to mac80211.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Shaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Rekeying PTK keys without "Extended Key ID for Individually Addressed
Frames" did use a procedure not suitable to replace in-use keys and
could caused the following issues:

 1) Freeze caused by incoming frames:
    If the local STA installed the key prior to the remote STA we still
    had the old key active in the hardware when mac80211 switched over
    to the new key.
    Therefore there was a window where the card could hand over frames
    decoded with the old key to mac80211 and bump the new PN (IV) value
    to an incorrect high number. When it happened the local replay
    detection silently started to drop all frames sent with the new key.

 2) Freeze caused by outgoing frames:
    If mac80211 was providing the PN (IV) and handed over a clear text
    frame for encryption to the hardware prior to a key change the
    driver/card could have processed the queued frame after switching
    to the new key. This bumped the PN value on the remote STA to an
    incorrect high number, tricking the remote STA to discard all frames
    we sent later.

 3) Freeze caused by RX aggregation reorder buffer:
    An aggregation session started with the old key and ending after the
    switch to the new key also bumped the PN to an incorrect high number,
    freezing the connection quite similar to 1).

 4) Freeze caused by repeating lost frames in an aggregation session:
    A driver could repeat a lost frame and encrypt it with the new key
    while in a TX aggregation session without updating the PN for the
    new key. This also could freeze connections similar to 2).

 5) Clear text leak:
    Removing encryption offload from the card cleared the encryption
    offload flag only after the card had deleted the key and we did not
    stop TX during the rekey. The driver/card could therefore get
    unencrypted frames from mac80211 while no longer be instructed to
    encrypt them.

To prevent those issues the key install logic has been changed:
 - Mac80211 divers known to be able to rekey PTK0 keys have to set
   @NL80211_EXT_FEATURE_CAN_REPLACE_PTK0,
 - mac80211 stops queuing frames depending on the key during the replace
 - the key is first replaced in the hardware and after that in mac80211
 - and mac80211 stops/blocks new aggregation sessions during the rekey.

For drivers not setting
@NL80211_EXT_FEATURE_CAN_REPLACE_PTK0 the user space must avoid PTK
rekeys if "Extended Key ID for Individually Addressed Frames" is not
being used. Rekeys for mac80211 drivers without this flag will generate a
warning and use an extra call to ieee80211_flush_queues() to both
highlight and try to prevent the issues with not updated drivers.

The core of the fix changes the key install procedure from:
 - atomic switch over to the new key in mac80211
 - remove the old key in the hardware (stops encryption offloading, fall
   back to software encryption with a potential clear text packet leak
   in between)
 - delete the inactive old key in mac80211
 - enable hardware encryption offloading for the new key
to:
 - if it's a PTK mark the old key as tainted to drop TX frames with the
   outgoing key
 - replace the key in hardware with the new one
 - atomic switch over to the new (not marked as tainted) key in
   mac80211 (which also resumes TX)
 - delete the inactive old key in mac80211

With the new sequence the hardware will be unable to decrypt frames
encrypted with the old key prior to switching to the new key in mac80211
and thus prevent PNs from packets decrypted with the old key to be
accounted against the new key.

For that to work the drivers have to provide a clear boundary.
Mac80211 drivers setting @NL80211_EXT_FEATURE_CAN_REPLACE_PTK0 confirm
to provide it and mac80211 will then be able to correctly rekey in-use
PTK keys with those drivers.

The mac80211 requirements for drivers to set the flag have been added to
the "Hardware crypto acceleration" documentation section. It drills down
to:
The drivers must not hand over frames decrypted with the old key to
mac80211 once the call to set_key() with %DISABLE_KEY has been
completed. It's allowed to either drop or continue to use the old key
for any outgoing frames which are already in the queues, but it must not
send out any of them unencrypted or encrypted with the new key.

Even with the new boundary in place aggregation sessions with the
reorder buffer are problematic:
RX aggregation session started prior and completed after the rekey could
still dump frames received with the old key at mac80211 after it
switched over to the new key. This is side stepped by stopping all (RX
and TX) aggregation sessions when replacing a PTK key and hardware key
offloading.
Stopping TX aggregation sessions avoids the need to get
the PNs (IVs) updated in frames prepared for the old key and
(re)transmitted after the switch to the new key. As a bonus it improves
the compatibility when the remote STA is not handling rekeys as it
should.

When using software crypto aggregation sessions are not stopped.
Mac80211 won't be able to decode the dangerous frames and discard them
without special handling.
Signed-off-by: Alexander Wetzel <alexander@wetzel-home.de>
[trim overly long rekey warning]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Drivers able to correctly replace a in-use key should set
@NL80211_EXT_FEATURE_CAN_REPLACE_PTK0 to allow the user space (e.g.
hostapd or wpa_supplicant) to rekey PTK keys.

The user space must detect a PTK rekey attempt and only go ahead with it
when the driver has set this flag. If the driver is not supporting the
feature the user space either must not replace the PTK key or perform a
full re-association instead.

Ignoring this flag and continuing to rekey the connection can still work
but has to be considered insecure and broken. Depending on the driver it
can leak clear text packets or freeze the connection and is only
supported to allow the user space to be updated.
Signed-off-by: Alexander Wetzel <alexander@wetzel-home.de>
Reviewed-by: Denis Kenzior <denkenz@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

As before with HE, the data needs to be provided by the
driver in the skb head, since there's not enough space
in the skb CB.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Shaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Make it possibly for drivers to adjust the default skb_pacing_shift
by storing it in the hardware struct.
Signed-off-by: Wen Gong <wgong@codeaurora.org>
[adjust commit log, move & adjust comment]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

When taking VHT capabilities for a station, copy the new
fields if we support them as a transmitter. Also adjust
the maximum bandwidth the station supports appropriately.

Also, since it was missing, copy tx_highest and rx_highest.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>