xfrm: replay: Fix ESN wrap around for GSO

When using GSO it can happen that the wrong seq_hi is used for the last
packets before the wrap around. This can lead to double usage of a
sequence number. To avoid this, we should serialize this last GSO
packet.

Fixes: d7dbefc45cf5 ("xfrm: Add xfrm_replay_overflow functions for offloading")
Co-developed-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Christian Langrock <christian.langrock@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: add extack support to xfrm_init_replay

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: replay: remove last replay indirection

This replaces the overflow indirection with the new xfrm_replay_overflow
helper. After this, the 'repl' pointer in xfrm_state is no longer
needed and can be removed as well.

xfrm_replay_overflow() is added in two incarnations, one is used
when the kernel is compiled with xfrm hardware offload support enabled,
the other when its disabled.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: replay: avoid replay indirection

Add and use xfrm_replay_check helper instead of indirection.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: replay: remove recheck indirection

Adds new xfrm_replay_recheck() helper and calls it from
xfrm input path instead of the indirection.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: replay: remove advance indirection

Similar to other patches: add a new helper to avoid
an indirection.

v2: fix 'net/xfrm/xfrm_replay.c:519:13: warning: 'seq' may be used
uninitialized in this function' warning.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: replay: avoid xfrm replay notify indirection

replay protection is implemented using a callback structure and then
called via

x->repl->notify(), x->repl->recheck(), and so on.

all the differect functions are always built-in, so this could be direct
calls instead.

This first patch prepares for removal of the x->repl structure.
Add an enum with the three available replay modes to the xfrm_state
structure and then replace all x->repl->notify() calls by the new
xfrm_replay_notify() helper.

The helper checks the enum internally to adapt behaviour as needed.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: introduce oseq-may-wrap flag

RFC 4303 in section 3.3.3 suggests to disable anti-replay for manually
distributed ICVs in which case the sender does not need to monitor or
reset the counter. However, the sender still increments the counter and
when it reaches the maximum value, the counter rolls over back to zero.

This patch introduces new extra_flag XFRM_SA_XFLAG_OSEQ_MAY_WRAP which
allows sequence number to cycle in outbound packets if set. This flag is
used only in legacy and bmp code, because esn should not be negotiated
if anti-replay is disabled (see note in 3.3.3 section).

Signed-off-by: Petr Vaněk <pv@excello.cz>
Acked-by: Christophe Gouault <christophe.gouault@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 335

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms and conditions of the gnu general public license
version 2 as published by the free software foundation this program
is distributed in the hope it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not write to the free
software foundation inc 51 franklin st fifth floor boston ma 02110
1301 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 111 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000436.567572064@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

xfrm: Fix ESN sequence number handling for IPsec GSO packets.

When IPsec offloading was introduced, we accidentally incremented
the sequence number counter on the xfrm_state by one packet
too much in the ESN case. This leads to a sequence number gap of
one packet after each GSO packet. Fix this by setting the sequence
number to the correct value.

Fixes: d7dbefc45cf5 ("xfrm: Add xfrm_replay_overflow functions for offloading")
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: Add ESN support for IPSec HW offload

This patch adds ESN support to IPsec device offload.
Adding new xfrm device operation to synchronize device ESN.

Signed-off-by: Yossef Efraim <yossefe@mellanox.com>
Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: Fix xfrm_replay_overflow_offload_esn

In case of wrap around, replay_esn->oseq_hi is not updated
before it is tested for it's actual value, leading function
to fail with overflow indication and packets being dropped.

This patch updates replay_esn->oseq_hi in the right place.

Fixes: d7dbefc45cf5 ("xfrm: Add xfrm_replay_overflow functions for offloading")
Signed-off-by: Yossef Efraim <yossefe@mellanox.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: Add xfrm_replay_overflow functions for offloading

This patch adds functions that handles IPsec sequence
numbers for GSO segments and TSO offloading. We need
to calculate and update the sequence numbers based
on the segments that GSO/TSO will generate. We need
this to keep software and hardware sequence number
counter in sync.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

esp: Add gso handlers for esp4 and esp6

This patch extends the xfrm_type by an encap function pointer
and implements esp4_gso_encap and esp6_gso_encap. These functions
doing the basic esp encapsulation for a GSO packet. In case the
GSO packet needs to be segmented in software, we add gso_segment
functions. This codepath is going to be used on esp hardware
offloads.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: constify xfrm_replay structures

The xfrm_replay structures are never modified, so declare them as const.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: Always zero high-order sequence number bits

As we're now always including the high bits of the sequence number
in the IV generation process we need to ensure that they don't
contain crap.

This patch ensures that the high sequence bits are always zeroed
so that we don't leak random data into the IV.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: Fix aevent generation for each received packet

If asynchronous events are enabled for a particular netlink socket,
the notify function is called by the advance function. The notify
function creates and dispatches a km_event if a replay timeout occurred,
or at least replay_maxdiff packets have been received since the last
asynchronous event has been sent. The function is supposed to return if
neither of the two events were detected for a state, or replay_maxdiff
is equal to zero.
Replay_maxdiff is initialized in xfrm_state_construct to the value of
the xfrm.sysctl_aevent_rseqth (2 by default), and updated if for a state
if the netlink attribute XFRMA_REPLAY_THRESH is set.
If, however, replay_maxdiff is set to zero, then all of the three notify
implementations perform a break from the switch statement instead of
checking whether a timeout occurred, and -- if not -- return. As a
result an asynchronous event is generated for every replay update of a
state that has a zero replay_maxdiff value.
This patch modifies the notify functions such that they immediately
return if replay_maxdiff has the value zero, unless a timeout occurred.

Signed-off-by: Thomas Egerer <thomas.egerer@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: Guard IPsec anti replay window against replay bitmap

For legacy IPsec anti replay mechanism:

bitmap in struct xfrm_replay_state could only provide a 32 bits
window size limit in current design, thus user level parameter
sadb_sa_replay should honor this limit, otherwise misleading
outputs("replay=244") by setkey -D will be:

192.168.25.2 192.168.22.2
esp mode=transport spi=147561170(0x08cb9ad2) reqid=0(0x00000000)
E: aes-cbc 9a8d7468 7655cf0b 719d27be b0ddaac2
A: hmac-sha1 2d2115c2 ebf7c126 1c54f186 3b139b58 264a7331
seq=0x00000000 replay=244 flags=0x00000000 state=mature
created: Sep 17 14:00:00 2013 current: Sep 17 14:00:22 2013
diff: 22(s) hard: 30(s) soft: 26(s)
last: Sep 17 14:00:00 2013 hard: 0(s) soft: 0(s)
current: 1408(bytes) hard: 0(bytes) soft: 0(bytes)
allocated: 22 hard: 0 soft: 0
sadb_seq=1 pid=4854 refcnt=0
192.168.22.2 192.168.25.2
esp mode=transport spi=255302123(0x0f3799eb) reqid=0(0x00000000)
E: aes-cbc 6485d990 f61a6bd5 e5660252 608ad282
A: hmac-sha1 0cca811a eb4fa893 c47ae56c 98f6e413 87379a88
seq=0x00000000 replay=244 flags=0x00000000 state=mature
created: Sep 17 14:00:00 2013 current: Sep 17 14:00:22 2013
diff: 22(s) hard: 30(s) soft: 26(s)
last: Sep 17 14:00:00 2013 hard: 0(s) soft: 0(s)
current: 1408(bytes) hard: 0(bytes) soft: 0(bytes)
allocated: 22 hard: 0 soft: 0
sadb_seq=0 pid=4854 refcnt=0

And also, optimizing xfrm_replay_check window checking by setting the
desirable x->props.replay_window with only doing the comparison once
for all when xfrm_state is first born.

Signed-off-by: Fan Du <fan.du@windriver.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: Fix esn sequence number diff calculation in xfrm_replay_notify_esn()

Commit 0017c0b "xfrm: Fix replay notification for esn." is off by one
for the sequence number wrapped case as UINT_MAX is 0xffffffff, not
0x100000000. ;)

Just calculate the diff like done everywhere else in the file.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: Fix replay notification for esn.

We may miscalculate the sequence number difference from the
last time we send a notification if a sequence number wrap
occured in the meantime. We fix this by adding a separate
replay notify function for esn. Here we take the high bits
of the sequence number into account to calculate the
difference.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/xfrm/xfrm_replay: avoid division by zero

All of the xfrm_replay->advance functions in xfrm_replay.c check if
x->replay_esn->replay_window is zero (and return if so). However,
one of them, xfrm_replay_advance_bmp(), divides by that value (in the
'%' operator) before doing the check, which can potentially trigger
a divide-by-zero exception. Some compilers will also assume that the
earlier division means the value cannot be zero later, and thus will
eliminate the subsequent zero check as dead code.

This patch moves the division to after the check.

Signed-off-by: Nickolai Zeldovich <nickolai@csail.mit.edu>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: remove redundant replay_esn check

x->replay_esn is already checked in if clause,
so remove check and ident properly

Signed-off-by: Ulrich Weber <ulrich.weber@sophos.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xfrm: Workaround incompatibility of ESN and async crypto

ESN for esp is defined in RFC 4303. This RFC assumes that the
sequence number counters are always up to date. However,
this is not true if an async crypto algorithm is employed.

If the sequence number counters are not up to date on sequence
number check, we may incorrectly update the upper 32 bit of
the sequence number. This leads to a DOS.

We workaround this by comparing the upper sequence number,
(used for authentication) with the upper sequence number
computed after the async processing. We drop the packet
if these numbers are different.

To do this, we introduce a recheck function that does this
check in the ESN case.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

xfrm: Access the replay notify functions via the registered callbacks

We call the wrong replay notify function when we use ESN replay
handling. This leads to the fact that we don't send notifications
if we use ESN. Fix this by calling the registered callbacks instead
of xfrm_replay_notify().

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules

These files are non modular, but need to export symbols using
the macros now living in export.h -- call out the include so
that things won't break when we remove the implicit presence
of module.h from everywhere.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

xfrm: Simplify the replay check and advance functions

The replay check and replay advance functions had some code
duplications. This patch removes the duplications.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

xfrm: Fix off by one in the replay advance functions

We may write 4 byte too much when we reinitialize the anti replay
window in the replay advance functions. This patch fixes this by
adjusting the last index of the initialization loop.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

xfrm: Don't allow esn with disabled anti replay detection

Unlike the standard case, disabled anti replay detection needs some
nontrivial extra treatment on ESN. RFC 4303 states:

Note: If a receiver chooses to not enable anti-replay for an SA, then
the receiver SHOULD NOT negotiate ESN in an SA management protocol.
Use of ESN creates a need for the receiver to manage the anti-replay
window (in order to determine the correct value for the high-order
bits of the ESN, which are employed in the ICV computation), which is
generally contrary to the notion of disabling anti-replay for an SA.

So return an error if an ESN state with disabled anti replay detection
is inserted for now and add the extra treatment later if we need it.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

xfrm: Fix replay window size calculation on initialization

On replay initialization, we compute the size of the replay
buffer to see if the replay window fits into the buffer.
This computation lacks a mutliplication by 8 because we need
the size in bit, not in byte. So we might return an error
even though the replay window would fit into the buffer.
This patch fixes this issue.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

xfrm: Move the test on replay window size into the replay check functions

As it is, the replay check is just performed if the replay window of the
legacy implementation is nonzero. So we move the test on a nonzero replay
window inside the replay check functions to be sure we are testing for the
right implementation.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

xfrm: Add support for IPsec extended sequence numbers

This patch adds support for IPsec extended sequence numbers (esn)
as defined in RFC 4303. The bits to manage the anti-replay window
are based on a patch from Alex Badea.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

xfrm: Support anti-replay window size bigger than 32 packets

As it is, the anti-replay bitmap in struct xfrm_replay_state can
only accomodate 32 packets. Even though it is possible to configure
anti-replay window sizes up to 255 packets from userspace. So we
reject any packet with a sequence number within the configured window
but outside the bitmap. With this patch, we represent the anti-replay
window as a bitmap of variable length that can be accessed via the
new struct xfrm_replay_state_esn. Thus, we have no limit on the
window size anymore. To use the new anti-replay window implementantion,
new userspace tools are required. We leave the old implementation
untouched to stay in sync with old userspace tools.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

xfrm: Move IPsec replay detection functions to a separate file

To support multiple versions of replay detection, we move the replay
detection functions to a separate file and make them accessible
via function pointers contained in the struct xfrm_replay.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>