linux-stable.git/include/linux/skbuff.h, branch v5.3.11

net/flow_dissector: switch to siphash

2019-11-10T10:34:55+00:00

commit 55667441c84fa5e0911a0aac44fb059c15ba6da2 upstream.

UDP IPv6 packets auto flowlabels are using a 32bit secret
(static u32 hashrnd in net/core/flow_dissector.c) and
apply jhash() over fields known by the receivers.

Attackers can easily infer the 32bit secret and use this information
to identify a device and/or user, since this 32bit secret is only
set at boot time.

Really, using jhash() to generate cookies sent on the wire
is a serious security concern.

Trying to change the rol32(hash, 16) in ip6_make_flowlabel() would be
a dead end. Trying to periodically change the secret (like in sch_sfq.c)
could change paths taken in the network for long lived flows.

Let's switch to siphash, as we did in commit df453700e8d8
("inet: switch IP ID generator to siphash")

Using a cryptographically strong pseudo random function will solve this
privacy issue and more generally remove other weak points in the stack.

Packet schedulers using skb_get_hash_perturb() benefit from this change.

Fixes: b56774163f99 ("ipv6: Enable auto flow labels by default")
Fixes: 42240901f7c4 ("ipv6: Implement different admin modes for automatic flow labels")
Fixes: 67800f9b1f4e ("ipv6: Call skb_get_hash_flowi6 to get skb->hash in ip6_make_flowlabel")
Fixes: cb1ce2ef387b ("ipv6: Implement automatic flow label generation on transmit")
Signed-off-by: Eric Dumazet 
Reported-by: Jonathan Berger 
Reported-by: Amit Klein 
Reported-by: Benny Pinkas 
Cc: Tom Herbert 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: add skb_queue_empty_lockless()

2019-11-10T10:34:43+00:00

[ Upstream commit d7d16a89350ab263484c0aa2b523dd3a234e4a80 ]

Some paths call skb_queue_empty() without holding
the queue lock. We must use a barrier in order
to not let the compiler do strange things, and avoid
KCSAN splats.

Adding a barrier in skb_queue_empty() might be overkill,
I prefer adding a new helper to clearly identify
points where the callers might be lockless. This might
help us finding real bugs.

The corresponding WRITE_ONCE() should add zero cost
for current compilers.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/sched: fix corrupted L2 header with MPLS 'push' and 'pop' actions

2019-10-29T08:22:00+00:00

[ Upstream commit fa4e0f8855fcba600e0be2575ee29c69166f74bd ]

the following script:

 # tc qdisc add dev eth0 clsact
 # tc filter add dev eth0 egress protocol ip matchall \
 > action mpls push protocol mpls_uc label 0x355aa bos 1

causes corruption of all IP packets transmitted by eth0. On TC egress, we
can't rely on the value of skb->mac_len, because it's 0 and a MPLS 'push'
operation will result in an overwrite of the first 4 octets in the packet
L2 header (e.g. the Destination Address if eth0 is an Ethernet); the same
error pattern is present also in the MPLS 'pop' operation. Fix this error
in act_mpls data plane, computing 'mac_len' as the difference between the
network header and the mac header (when not at TC ingress), and use it in
MPLS 'push'/'pop' core functions.

v2: unbreak 'make htmldocs' because of missing documentation of 'mac_len'
    in skb_mpls_pop(), reported by kbuild test robot

CC: Lorenzo Bianconi 
Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC")
Reviewed-by: Simon Horman 
Acked-by: John Hurley 
Signed-off-by: Davide Caratti 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/tls: prevent skb_orphan() from leaking TLS plain text with offload

2019-08-09T05:39:35+00:00

sk_validate_xmit_skb() and drivers depend on the sk member of
struct sk_buff to identify segments requiring encryption.
Any operation which removes or does not preserve the original TLS
socket such as skb_orphan() or skb_clone() will cause clear text
leaks.

Make the TCP socket underlying an offloaded TLS connection
mark all skbs as decrypted, if TLS TX is in offload mode.
Then in sk_validate_xmit_skb() catch skbs which have no socket
(or a socket with no validation) and decrypted flag set.

Note that CONFIG_SOCK_VALIDATE_XMIT, CONFIG_TLS_DEVICE and
sk->sk_validate_xmit_skb are slightly interchangeable right now,
they all imply TLS offload. The new checks are guarded by
CONFIG_TLS_DEVICE because that's the option guarding the
sk_buff->decrypted member.

Second, smaller issue with orphaning is that it breaks
the guarantee that packets will be delivered to device
queues in-order. All TLS offload drivers depend on that
scheduling property. This means skb_orphan_partial()'s
trick of preserving partial socket references will cause
issues in the drivers. We need a full orphan, and as a
result netem delay/throttling will cause all TLS offload
skbs to be dropped.

Reusing the sk_buff->decrypted flag also protects from
leaking clear text when incoming, decrypted skb is redirected
(e.g. by TC).

See commit 0608c69c9a80 ("bpf: sk_msg, sock{map|hash} redirect
through ULP") for justification why the internal flag is safe.
The only location which could leak the flag in is tcp_bpf_sendmsg(),
which is taken care of by clearing the previously unused bit.

v2:
 - remove superfluous decrypted mark copy (Willem);
 - remove the stale doc entry (Boris);
 - rely entirely on EOR marking to prevent coalescing (Boris);
 - use an internal sendpages flag instead of marking the socket
   (Boris).
v3 (Willem):
 - reorganize the can_skb_orphan_partial() condition;
 - fix the flag leak-in through tcp_bpf_sendmsg.

Signed-off-by: Jakub Kicinski 
Acked-by: Willem de Bruijn 
Reviewed-by: Boris Pismenny 
Signed-off-by: David S. Miller

net/flow_dissector: add connection tracking dissection

2019-07-09T19:11:59+00:00

Retreives connection tracking zone, mark, label, and state from
a SKB.

Signed-off-by: Paul Blakey 
Signed-off-by: Marcelo Ricardo Leitner 
Acked-by: Jiri Pirko 
Signed-off-by: David S. Miller

net: sched: add mpls manipulation actions to TC

2019-07-09T02:50:13+00:00

Currently, TC offers the ability to match on the MPLS fields of a packet
through the use of the flow_dissector_key_mpls struct. However, as yet, TC
actions do not allow the modification or manipulation of such fields.

Add a new module that registers TC action ops to allow manipulation of
MPLS. This includes the ability to push and pop headers as well as modify
the contents of new or existing headers. A further action to decrement the
TTL field of an MPLS header is also provided with a new helper added to
support this.

Examples of the usage of the new action with flower rules to push and pop
MPLS labels are:

tc filter add dev eth0 protocol ip parent ffff: flower \
    action mpls push protocol mpls_uc label 123  \
    action mirred egress redirect dev eth1

tc filter add dev eth0 protocol mpls_uc parent ffff: flower \
    action mpls pop protocol ipv4  \
    action mirred egress redirect dev eth1

Signed-off-by: John Hurley 
Reviewed-by: Jakub Kicinski 
Reviewed-by: Simon Horman 
Reviewed-by: Willem de Bruijn 
Acked-by: Cong Wang 
Signed-off-by: David S. Miller

net: core: add MPLS update core helper and use in OvS

2019-07-09T02:50:13+00:00

Open vSwitch allows the updating of an existing MPLS header on a packet.
In preparation for supporting similar functionality in TC, move this to a
common skb helper function.

Signed-off-by: John Hurley 
Reviewed-by: Jakub Kicinski 
Reviewed-by: Simon Horman 
Reviewed-by: Willem de Bruijn 
Acked-by: Cong Wang 
Signed-off-by: David S. Miller

net: core: move pop MPLS functionality from OvS to core helper

2019-07-09T02:50:13+00:00

Open vSwitch provides code to pop an MPLS header to a packet. In
preparation for supporting this in TC, move the pop code to an skb helper
that can be reused.

Remove the, now unused, update_ethertype static function from OvS.

Signed-off-by: John Hurley 
Reviewed-by: Jakub Kicinski 
Reviewed-by: Simon Horman 
Reviewed-by: Willem de Bruijn 
Acked-by: Cong Wang 
Signed-off-by: David S. Miller

net: core: move push MPLS functionality from OvS to core helper

2019-07-09T02:50:13+00:00

Open vSwitch provides code to push an MPLS header to a packet. In
preparation for supporting this in TC, move the push code to an skb helper
that can be reused.

Signed-off-by: John Hurley 
Reviewed-by: Jakub Kicinski 
Reviewed-by: Simon Horman 
Reviewed-by: Willem de Bruijn 
Acked-by: Cong Wang 
Signed-off-by: David S. Miller

skbuff: increase verbosity when dumping skb data

2019-07-09T02:38:46+00:00

skb_warn_bad_offload and netdev_rx_csum_fault trigger on hard to debug
issues. Dump more state and the header.

Optionally dump the entire packet and linear segment. This is required
to debug checksum bugs that may include bytes past skb_tail_pointer().

Both call sites call this function inside a net_ratelimit() block.
Limit full packet log further to a hard limit of can_dump_full (5).

Based on an earlier patch by Cong Wang, see link below.

Changes v1 -> v2
  - dump frag_list only on full_pkt

Link: https://patchwork.ozlabs.org/patch/1000841/
Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller