Граф коммитов

167 Коммитов

Автор SHA1 Сообщение Дата
Stanislav Fomichev 086f956821 bpf/flow_dissector: pass input flags to BPF flow dissector program
C flow dissector supports input flags that tell it to customize parsing
by either stopping early or trying to parse as deep as possible. Pass
those flags to the BPF flow dissector so it can make the same
decisions. In the next commits I'll add support for those flags to
our reference bpf_flow.c

v3:
* Export copy of flow dissector flags instead of moving (Alexei Starovoitov)

Acked-by: Petar Penkov <ppenkov@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Petar Penkov <ppenkov@google.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-07-25 18:00:41 -07:00
Paul Blakey 75a56758d6 net/flow_dissector: add connection tracking dissection
Retreives connection tracking zone, mark, label, and state from
a SKB.

Signed-off-by: Paul Blakey <paulb@mellanox.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-07-09 12:11:59 -07:00
Jiri Pirko 82828b88f0 flow_dissector: add support for ingress ifindex dissection
Add new key meta that contains ingress ifindex value and add a function
to dissect this from skb. The key and function is prepared to cover
other potential skb metadata values dissection.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-19 10:09:21 -04:00
Stanislav Fomichev 1cc26450a8 flow_dissector: remove unused FLOW_DISSECTOR_F_STOP_AT_L3 flag
This flag is not used by any caller, remove it.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-03 14:56:35 -07:00
Thomas Gleixner 457c899653 treewide: Add SPDX license identifier for missed files
Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have EXPORT_.*_SYMBOL_GPL inside which was used in the
   initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 10:50:45 +02:00
Eric Dumazet b1c17a9a35 flow_dissector: disable preemption around BPF calls
Various things in eBPF really require us to disable preemption
before running an eBPF program.

syzbot reported :

BUG: assuming atomic context at net/core/flow_dissector.c:737
in_atomic(): 0, irqs_disabled(): 0, pid: 24710, name: syz-executor.3
2 locks held by syz-executor.3/24710:
 #0: 00000000e81a4bf1 (&tfile->napi_mutex){+.+.}, at: tun_get_user+0x168e/0x3ff0 drivers/net/tun.c:1850
 #1: 00000000254afebd (rcu_read_lock){....}, at: __skb_flow_dissect+0x1e1/0x4bb0 net/core/flow_dissector.c:822
CPU: 1 PID: 24710 Comm: syz-executor.3 Not tainted 5.1.0+ #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 __cant_sleep kernel/sched/core.c:6165 [inline]
 __cant_sleep.cold+0xa3/0xbb kernel/sched/core.c:6142
 bpf_flow_dissect+0xfe/0x390 net/core/flow_dissector.c:737
 __skb_flow_dissect+0x362/0x4bb0 net/core/flow_dissector.c:853
 skb_flow_dissect_flow_keys_basic include/linux/skbuff.h:1322 [inline]
 skb_probe_transport_header include/linux/skbuff.h:2500 [inline]
 skb_probe_transport_header include/linux/skbuff.h:2493 [inline]
 tun_get_user+0x2cfe/0x3ff0 drivers/net/tun.c:1940
 tun_chr_write_iter+0xbd/0x156 drivers/net/tun.c:2037
 call_write_iter include/linux/fs.h:1872 [inline]
 do_iter_readv_writev+0x5fd/0x900 fs/read_write.c:693
 do_iter_write fs/read_write.c:970 [inline]
 do_iter_write+0x184/0x610 fs/read_write.c:951
 vfs_writev+0x1b3/0x2f0 fs/read_write.c:1015
 do_writev+0x15b/0x330 fs/read_write.c:1058
 __do_sys_writev fs/read_write.c:1131 [inline]
 __se_sys_writev fs/read_write.c:1128 [inline]
 __x64_sys_writev+0x75/0xb0 fs/read_write.c:1128
 do_syscall_64+0x103/0x670 arch/x86/entry/common.c:298
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fixes: d58e468b11 ("flow_dissector: implements flow dissector BPF hook")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Petar Penkov <ppenkov@google.com>
Cc: Stanislav Fomichev <sdf@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-13 09:53:42 -07:00
Stanislav Fomichev 118c8e9ae6 bpf: support BPF_PROG_QUERY for BPF_FLOW_DISSECTOR attach_type
target_fd is target namespace. If there is a flow dissector BPF program
attached to that namespace, its (single) id is returned.

v5:
* drop net ref right after rcu unlock (Daniel Borkmann)

v4:
* add missing put_net (Jann Horn)

v3:
* add missing inline to skb_flow_dissector_prog_query static def
  (kbuild test robot <lkp@intel.com>)

v2:
* don't sleep in rcu critical section (Jakub Kicinski)
* check input prog_cnt (exit early)

Cc: Jann Horn <jannh@google.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-04-25 23:49:06 +02:00
Stanislav Fomichev 9b52e3f267 flow_dissector: handle no-skb use case
When called without skb, gather all required data from the
__skb_flow_dissect's arguments and use recently introduces
no-skb mode of bpf flow dissector.

Note: WARN_ON_ONCE(!net) will now trigger for eth_get_headlen users.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-04-23 18:36:34 +02:00
Stanislav Fomichev 3cbf4ffba5 net: plumb network namespace into __skb_flow_dissect
This new argument will be used in the next patches for the
eth_get_headlen use case. eth_get_headlen calls flow dissector
with only data (without skb) so there is currently no way to
pull attached BPF flow dissector program. With this new argument,
we can amend the callers to explicitly pass network namespace
so we can use attached BPF program.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-04-23 18:36:34 +02:00
Stanislav Fomichev 089b19a920 flow_dissector: switch kernel context to struct bpf_flow_dissector
struct bpf_flow_dissector has a small subset of sk_buff fields that
flow dissector BPF program is allowed to access and an optional
pointer to real skb. Real skb is used only in bpf_skb_load_bytes
helper to read non-linear data.

The real motivation for this is to be able to call flow dissector
from eth_get_headlen context where we don't have an skb and need
to dissect raw bytes.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-04-23 18:36:33 +02:00
David S. Miller f83f715195 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Minor comment merge conflict in mlx5.

Staging driver has a fixup due to the skb->xmit_more changes
in 'net-next', but was removed in 'net'.

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-05 14:14:19 -07:00
Stanislav Fomichev b9e9c8599f flow_dissector: fix clamping of BPF flow_keys for non-zero nhoff
Don't allow BPF program to set flow_keys->nhoff to less than initial
value. We currently don't read the value afterwards in anything but
the tests, but it's still a good practice to return consistent
values to the test programs.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-04-03 16:49:48 +02:00
Stanislav Fomichev 822fe61795 net/flow_dissector: pass flow_keys->n_proto to BPF programs
This is a preparation for the next commit that would prohibit access to
the most fields of __sk_buff from the BPF programs.

Instead of requiring BPF flow dissector programs to look into skb,
pass all input data in the flow_keys.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-04-03 16:49:48 +02:00
Bart Van Assche d79b3bafab net/core: Document __skb_flow_dissect() flags argument
This patch avoids that the following warning is reported when building
with W=1:

warning: Function parameter or member 'flags' not described in '__skb_flow_dissect'

Cc: Tom Herbert <tom@herbertland.com>
Fixes: cd79a2382a ("flow_dissector: Add flags argument to skb_flow_dissector functions") # v4.3.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-27 13:49:43 -07:00
Stanislav Fomichev c8aa703822 net/flow_dissector: move bpf case into __skb_flow_bpf_dissect
This way, we can reuse it for flow dissector in BPF_PROG_TEST_RUN.

No functional changes.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-01-29 01:08:29 +01:00
David S. Miller 2be09de7d6 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Lots of conflicts, by happily all cases of overlapping
changes, parallel adds, things of that nature.

Thanks to Stephen Rothwell, Saeed Mahameed, and others
for their guidance in these resolutions.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-12-20 11:53:36 -08:00
Stanislav Fomichev ec3d837aac net/flow_dissector: correctly cap nhoff and thoff in case of BPF
We want to make sure that the following condition holds:
0 <= nhoff <= thoff <= skb->len

BPF program can set out-of-bounds nhoff and thoff, which is dangerous, see
recent commit d0c081b491 ("flow_dissector: properly cap thoff field")'.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-12-07 13:38:29 -08:00
Stanislav Fomichev 13e56ec2cc selftests/bpf: use thoff instead of nhoff in BPF flow dissector
We are returning thoff from the flow dissector, not the nhoff. Pass
thoff along with nhoff to the bpf program (initially thoff == nhoff)
and expect flow dissector amend/return thoff, not nhoff.

This avoids confusion, when by the time bpf flow dissector exits,
nhoff == thoff, which doesn't make much sense.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-12-07 13:38:12 -08:00
David S. Miller 2b9b7502df Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-11-11 17:57:54 -08:00
배석진 62230715fd flow_dissector: do not dissect l4 ports for fragments
Only first fragment has the sport/dport information,
not the following ones.

If we want consistent hash for all fragments, we need to
ignore ports even for first fragment.

This bug is visible for IPv6 traffic, if incoming fragments
do not have a flow label, since skb_get_hash() will give
different results for first fragment and following ones.

It is also visible if any routing rule wants dissection
and sport or dport.

See commit 5e5d6fed37 ("ipv6: route: dissect flow
in input path if fib rules need it") for details.

[edumazet] rewrote the changelog completely.

Fixes: 06635a35d1 ("flow_dissect: use programable dissector in skb_flow_dissect and friends")
Signed-off-by: 배석진 <soukjin.bae@samsung.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-09 20:01:21 -08:00
Michał Mirosław 9b319148cb net/vlan: include the shift in skb_vlan_tag_get_prio()
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-07 22:41:19 -08:00
David S. Miller 105bc1306e Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
pull-request: bpf-next 2018-09-25

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

The main changes are:

1) Allow for RX stack hardening by implementing the kernel's flow
   dissector in BPF. Idea was originally presented at netconf 2017 [0].
   Quote from merge commit:

     [...] 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. [...]

   Also, a sample flow dissector has been implemented in BPF as part
   of this work, from Petar and Willem.

   [0] http://vger.kernel.org/netconf2017_files/rx_hardening_and_udp_gso.pdf

2) Add support for bpftool to list currently active attachment
   points of BPF networking programs providing a quick overview
   similar to bpftool's perf subcommand, from Yonghong.

3) Fix a verifier pruning instability bug where a union member
   from the register state was not cleared properly leading to
   branches not being pruned despite them being valid candidates,
   from Alexei.

4) Various smaller fast-path optimizations in XDP's map redirect
   code, from Jesper.

5) Enable to recognize BPF_MAP_TYPE_REUSEPORT_SOCKARRAY maps
   in bpftool, from Roman.

6) Remove a duplicate check in libbpf that probes for function
   storage, from Taeung.

7) Fix an issue in test_progs by avoid checking for errno since
   on success its value should not be checked, from Mauricio.

8) Fix unused variable warning in bpf_getsockopt() helper when
   CONFIG_INET is not configured, from Anders.

9) Fix a compilation failure in the BPF sample code's use of
   bpf_flow_keys, from Prashant.

10) Minor cleanups in BPF code, from Yue and Zhong.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-25 20:29:38 -07:00
Willem de Bruijn d0e13a1488 flow_dissector: lookup netns by skb->sk if skb->dev is NULL
BPF flow dissectors are configured per network namespace.
__skb_flow_dissect looks up the netns through dev_net(skb->dev).

In some dissector paths skb->dev is NULL, such as for Unix sockets.
In these cases fall back to looking up the netns by socket.

Analyzing the codepaths leading to __skb_flow_dissect I did not find
a case where both skb->dev and skb->sk are NULL. Warn and fall back to
standard flow dissector if one is found.

Fixes: d58e468b11 ("flow_dissector: implements flow dissector BPF hook")
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-09-25 17:31:19 +02:00
zhong jiang f195efb47d net: core: Use FIELD_SIZEOF directly instead of reimplementing its function
FIELD_SIZEOF is defined as a macro to calculate the specified value. Therefore,
We prefer to use the macro rather than calculating its value.

Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-19 20:58:04 -07:00
Petar Penkov d58e468b11 flow_dissector: implements flow dissector BPF hook
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>
2018-09-14 12:04:33 -07:00
Simon Horman 92e2c40536 flow_dissector: allow dissection of tunnel options from metadata
Allow the existing 'dissection' of tunnel metadata to 'dissect'
options already present in tunnel metadata. This dissection is
controlled by a new dissector key, FLOW_DISSECTOR_KEY_ENC_OPTS.

This dissection only occurs when skb_flow_dissect_tunnel_info()
is called, currently only the Flower classifier makes that call.
So there should be no impact on other users of the flow dissector.

This is in preparation for allowing the flower classifier to
match on Geneve options.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Pieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-07 12:22:14 -07:00
Or Gerlitz 5544adb970 flow_dissector: Dissect tos and ttl from the tunnel info
Add dissection of the tos and ttl from the ip tunnel headers
fields in case a match is needed on them.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-19 23:26:01 -07:00
Jianbo Liu 24c590e3b0 net/flow_dissector: Add support for QinQ dissection
Dissect the QinQ packets to get both outer and inner vlan information,
then store to the extended flow keys.

Signed-off-by: Jianbo Liu <jianbol@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-07 20:51:53 +09:00
Jianbo Liu 2064c3d4c0 net/flow_dissector: Save vlan ethertype from headers
Change vlan dissector key to save vlan tpid to support both 802.1Q
and 802.1AD ethertype.

Signed-off-by: Jianbo Liu <jianbol@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-07 20:51:53 +09:00
Michal Kubecek fa1be7e01e ipv6: omit traffic class when calculating flow hash
Some of the code paths calculating flow hash for IPv6 use flowlabel member
of struct flowi6 which, despite its name, encodes both flow label and
traffic class. If traffic class changes within a TCP connection (as e.g.
ssh does), ECMP route can switch between path. It's also inconsistent with
other code paths where ip6_flowlabel() (returning only flow label) is used
to feed the key.

Use only flow label everywhere, including one place where hash key is set
using ip6_flowinfo().

Fixes: 51ebd31815 ("ipv6: add support of equal cost multipath (ECMP)")
Fixes: f70ea018da ("net: Add functions to get skb->hash based on flow structures")
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-04 13:21:18 -04:00
David S. Miller a925ab48da Revert "ipv6: omit traffic class when calculating flow hash"
This reverts commit 87ae68c8b4.

Applied the wrong version of this fix, correct version
coming up.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-04 13:20:38 -04:00
Michal Kubecek 87ae68c8b4 ipv6: omit traffic class when calculating flow hash
Some of the code paths calculating flow hash for IPv6 use flowlabel member
of struct flowi6 which, despite its name, encodes both flow label and
traffic class. If traffic class changes within a TCP connection (as e.g.
ssh does), ECMP route can switch between path. It's also incosistent with
other code paths where ip6_flowlabel() (returning only flow label) is used
to feed the key.

Use only flow label everywhere, including one place where hash key is set
using ip6_flowinfo().

Fixes: 51ebd31815 ("ipv6: add support of equal cost multipath (ECMP)")
Fixes: f70ea018da ("net: Add functions to get skb->hash based on flow structures")
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Tested-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-04 13:18:35 -04:00
Paolo Abeni d869dea664 flow_dissector: do not rely on implicit casts
This change fixes a couple of type mismatch reported by the sparse
tool, explicitly using the requested type for the offending arguments.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-08 00:02:41 -04:00
Paolo Abeni 72a338bcc6 net: core: rework basic flow dissection helper
When the core networking needs to detect the transport offset in a given
packet and parse it explicitly, a full-blown flow_keys struct is used for
storage.
This patch introduces a smaller keys store, rework the basic flow dissect
helper to use it, and apply this new helper where possible - namely in
skb_probe_transport_header(). The used flow dissector data structures
are renamed to match more closely the new role.

The above gives ~50% performance improvement in micro benchmarking around
skb_probe_transport_header() and ~30% around eth_get_headlen(), mostly due
to the smaller memset. Small, but measurable improvement is measured also
in macro benchmarking.

v1 -> v2: use the new helper in eth_get_headlen() and skb_get_poff(),
  as per DaveM suggestion

Suggested-by: David Miller <davem@davemloft.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-08 00:02:36 -04:00
David Ahern de7a0f871f net: Remove unused get_hash_from_flow functions
__get_hash_from_flowi6 is still used for flowlabels, but the IPv4
variant and the wrappers to both are not used. Remove them.

Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-03-04 13:04:23 -05:00
David S. Miller 8565d26bcb Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
The BPF verifier conflict was some minor contextual issue.

The TUN conflict was less trivial.  Cong Wang fixed a memory leak of
tfile->tx_array in 'net'.  This is an skb_array.  But meanwhile in
net-next tun changed tfile->tx_arry into tfile->tx_ring which is a
ptr_ring.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-19 22:59:33 -05:00
Eric Dumazet d0c081b491 flow_dissector: properly cap thoff field
syzbot reported yet another crash [1] that is caused by
insufficient validation of DODGY packets.

Two bugs are happening here to trigger the crash.

1) Flow dissection leaves with incorrect thoff field.

2) skb_probe_transport_header() sets transport header to this invalid
thoff, even if pointing after skb valid data.

3) qdisc_pkt_len_init() reads out-of-bound data because it
trusts tcp_hdrlen(skb)

Possible fixes :

- Full flow dissector validation before injecting bad DODGY packets in
the stack.
 This approach was attempted here : https://patchwork.ozlabs.org/patch/
861874/

- Have more robust functions in the core.
  This might be needed anyway for stable versions.

This patch fixes the flow dissection issue.

[1]
CPU: 1 PID: 3144 Comm: syzkaller271204 Not tainted 4.15.0-rc4-mm1+ #49
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:355 [inline]
 kasan_report+0x23b/0x360 mm/kasan/report.c:413
 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:432
 __tcp_hdrlen include/linux/tcp.h:35 [inline]
 tcp_hdrlen include/linux/tcp.h:40 [inline]
 qdisc_pkt_len_init net/core/dev.c:3160 [inline]
 __dev_queue_xmit+0x20d3/0x2200 net/core/dev.c:3465
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3554
 packet_snd net/packet/af_packet.c:2943 [inline]
 packet_sendmsg+0x3ad5/0x60a0 net/packet/af_packet.c:2968
 sock_sendmsg_nosec net/socket.c:628 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:638
 sock_write_iter+0x31a/0x5d0 net/socket.c:907
 call_write_iter include/linux/fs.h:1776 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x684/0x970 fs/read_write.c:482
 vfs_write+0x189/0x510 fs/read_write.c:544
 SYSC_write fs/read_write.c:589 [inline]
 SyS_write+0xef/0x220 fs/read_write.c:581
 entry_SYSCALL_64_fastpath+0x1f/0x96

Fixes: 34fad54c25 ("net: __skb_flow_dissect() must cap its return value")
Fixes: a6e544b0a8 ("flow_dissector: Jump to exit code in __skb_flow_dissect")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-18 16:25:49 -05:00
Sven Eckelmann 5b0890a972 flow_dissector: Parse batman-adv unicast headers
The batman-adv unicast packets contain a full layer 2 frame in encapsulated
form. The flow dissector must therefore be able to parse the batman-adv
unicast header to reach the layer 2+3 information.

  +--------------------+
  | ip(v6)hdr          |
  +--------------------+
  | inner ethhdr       |
  +--------------------+
  | batadv unicast hdr |
  +--------------------+
  | outer ethhdr       |
  +--------------------+

The obtained information from the upper layer can then be used by RPS to
schedule the processing on separate cores. This allows better distribution
of multiple flows from the same neighbor to different cores.

Signed-off-by: Sven Eckelmann <sven.eckelmann@openmesh.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-21 15:35:53 -05:00
Simon Horman 62b32379fd flow_dissector: dissect tunnel info outside __skb_flow_dissect()
Move dissection of tunnel info to outside of the main flow dissection
function, __skb_flow_dissect(). The sole user of this feature, the flower
classifier, is updated to call tunnel info dissection directly, using
skb_flow_dissect_tunnel_info().

This results in a slightly less complex implementation of
__skb_flow_dissect(), in particular removing logic from that call path
which is not used by the majority of users. The expense of this is borne by
the flower classifier which now has to make an extra call for tunnel info
dissection.

This patch should not result in any behavioural change.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-05 12:09:18 -05:00
Jon Maloy 8d6e79d3ce tipc: improve link resiliency when rps is activated
Currently, the TIPC RPS dissector is based only on the incoming packets'
source node address, hence steering all traffic from a node to the same
core. We have seen that this makes the links vulnerable to starvation
and unnecessary resets when we turn down the link tolerance to very low
values.

To reduce the risk of this happening, we exempt probe and probe replies
packets from the convergence to one core per source node. Instead, we do
the opposite, - we try to diverge those packets across as many cores as
possible, by randomizing the flow selector key.

To make such packets identifiable to the dissector, we add a new
'is_keepalive' bit to word 0 of the LINK_PROTOCOL header. This bit is
set both for PROBE and PROBE_REPLY messages, and only for those.

It should be noted that these packets are not part of any flow anyway,
and only constitute a minuscule fraction of all packets sent across a
link. Hence, there is no risk that this will affect overall performance.

Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-11 15:36:05 +09:00
Simon Horman a38402bc50 flow_dissector: dissect tunnel info
Move dissection of tunnel info from the flower classifier to the flow
dissector where all other dissection occurs.  This should not have any
behavioural affect on other users of the flow dissector.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-02 11:06:07 -07:00
Tom Herbert 1eed4dfb81 flow_dissector: Add limit for number of headers to dissect
In flow dissector there are no limits to the number of nested
encapsulations or headers that might be dissected which makes for a
nice DOS attack. This patch sets a limit of the number of headers
that flow dissector will parse.

Headers includes network layer headers, transport layer headers, shim
headers for encapsulation, IPv6 extension headers, etc. The limit for
maximum number of headers to parse has be set to fifteen to account for
a reasonable number of encapsulations, extension headers, VLAN,
in a packet. Note that this limit does not supercede the STOP_AT_*
flags which may stop processing before the headers limit is reached.

Reported-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-05 11:40:08 -07:00
Tom Herbert 3a1214e8b0 flow_dissector: Cleanup control flow
__skb_flow_dissect is riddled with gotos that make discerning the flow,
debugging, and extending the capability difficult. This patch
reorganizes things so that we only perform goto's after the two main
switch statements (no gotos within the cases now). It also eliminates
several goto labels so that there are only two labels that can be target
for goto.

Reported-by: Alexander Popov <alex.popov@linux.com>
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-05 11:40:08 -07:00
Craig Gallek 7324157b8a dsa: fix flow disector null pointer
A recent change to fix up DSA device behavior made the assumption that
all skbs passing through the flow disector will be associated with a
device. This does not appear to be a safe assumption.  Syzkaller found
the crash below by attaching a BPF socket filter that tries to find the
payload offset of a packet passing between two unix sockets.

kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 2940 Comm: syzkaller872007 Not tainted 4.13.0-rc4-next-20170811 #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d1b425c0 task.stack: ffff8801d0bc0000
RIP: 0010:__skb_flow_dissect+0xdcd/0x3ae0 net/core/flow_dissector.c:445
RSP: 0018:ffff8801d0bc7340 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000060 RSI: ffffffff856dc080 RDI: 0000000000000300
RBP: ffff8801d0bc7870 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000008 R11: ffffed003a178f1e R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff856dc080 R15: ffff8801ce223140
FS:  00000000016ed880(0000) GS:ffff8801dc000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020008000 CR3: 00000001ce22d000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 skb_flow_dissect_flow_keys include/linux/skbuff.h:1176 [inline]
 skb_get_poff+0x9a/0x1a0 net/core/flow_dissector.c:1079
 ______skb_get_pay_offset net/core/filter.c:114 [inline]
 __skb_get_pay_offset+0x15/0x20 net/core/filter.c:112
Code: 80 3c 02 00 44 89 6d 10 0f 85 44 2b 00 00 4d 8b 67 20 48 b8 00 00 00 00 00 fc ff df 49 8d bc 24 00 03 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 13 2b 00 00 4d 8b a4 24 00 03 00 00 4d 85 e4
RIP: __skb_flow_dissect+0xdcd/0x3ae0 net/core/flow_dissector.c:445 RSP: ffff8801d0bc7340

Fixes: 43e665287f ("net-next: dsa: fix flow dissection")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Craig Gallek <kraig@google.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-15 17:18:35 -07:00
John Crispin 2d57164564 net: core: fix compile error inside flow_dissector due to new dsa callback
The following error was introduced by
commit 43e665287f ("net-next: dsa: fix flow dissection")
due to a missing #if guard

net/core/flow_dissector.c: In function '__skb_flow_dissect':
net/core/flow_dissector.c:448:18: error: 'struct net_device' has no member named 'dsa_ptr'
ops = skb->dev->dsa_ptr->tag_ops;
                ^
make[3]: *** [net/core/flow_dissector.o] Error 1

Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-10 09:16:05 -07:00
John Crispin 43e665287f net-next: dsa: fix flow dissection
RPS and probably other kernel features are currently broken on some if not
all DSA devices. The root cause of this is that skb_hash will call the
flow_dissector. At this point the skb still contains the magic switch
header and the skb->protocol field is not set up to the correct 802.3
value yet. By the time the tag specific code is called, removing the header
and properly setting the protocol an invalid hash is already set. In the
case of the mt7530 this will result in all flows always having the same
hash.

Signed-off-by: Muciri Gatimu <muciri@openmesh.com>
Signed-off-by: Shashidhar Lakkavalli <shashidhar.lakkavalli@openmesh.com>
Signed-off-by: John Crispin <john@phrozen.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-09 22:51:47 -07:00
WANG Cong b2f9d432de flow_dissector: remove unused functions
They are introduced by commit f70ea018da
("net: Add functions to get skb->hash based on flow structures")
but never gets used in tree.

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-02 10:50:03 -07:00
Or Gerlitz 518d8a2e9b net/flow_dissector: add support for dissection of misc ip header fields
Add support for dissection of ip tos and ttl and ipv6 traffic-class
and hoplimit. Both are dissected into the same struct.

Uses similar call to ip dissection function as with tcp, arp and others.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-04 18:12:23 -04:00
Jiri Pirko ac4bb5de27 net: flow_dissector: add support for dissection of tcp flags
Add support for dissection of tcp flags. Uses similar function call to
tcp dissection function as arp, mpls and others.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 16:22:11 -04:00
Benjamin LaHaise 029c1ecbb2 flow_dissector: add mpls support (v2)
Add support for parsing MPLS flows to the flow dissector in preparation for
adding MPLS match support to cls_flower.

Signed-off-by: Benjamin LaHaise <benjamin.lahaise@netronome.com>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Simon Horman <simon.horman@netronome.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@mellanox.com>
Cc: Eric Dumazet <jhs@mojatatu.com>
Cc: Hadar Hen Zion <hadarh@mellanox.com>
Cc: Gao Feng <fgao@ikuai8.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-24 14:30:46 -04:00