when users replace cls_u32 filters with new ones having wrong parameters,
so that u32_change() fails to validate them, the kernel doesn't roll-back
correctly, and leaves semi-configured rules.

Fix this in u32_walk(), avoiding a call to the walker function on filters
that don't have a match rule connected. The side effect is, these "empty"
filters are not even dumped when present; but that shouldn't be a problem
as long as we are restoring the original behaviour, where semi-configured
filters were not even added in the error path of u32_change().

Fixes: 6676d5e4 ("net: sched: set dedicated tcf_walker flag when tp is empty")
Signed-off-by: NDavide Caratti <dcaratti@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Without rtnl lock protection filters can no longer safely manage block
offloads counter themselves. Refactor cls API to protect block offloadcnt
with tcf_block->cb_lock that is already used to protect driver callback
list and nooffloaddevcnt counter. The counter can be modified by concurrent
tasks by new functions that execute block callbacks (which is safe with
previous patch that changed its type to atomic_t), however, block
bind/unbind code that checks the counter value takes cb_lock in write mode
to exclude any concurrent modifications. This approach prevents race
conditions between bind/unbind and callback execution code but allows for
concurrency for tc rule update path.

Move block offload counter, filter in hardware counter and filter flags
management from classifiers into cls hardware offloads API. Make functions
tcf_block_offload_{inc|dec}() and tc_cls_offload_cnt_update() to be cls API
private. Implement following new cls API to be used instead:

  tc_setup_cb_add() - non-destructive filter add. If filter that wasn't
  already in hardware is successfully offloaded, increment block offloads
  counter, set filter in hardware counter and flag. On failure, previously
  offloaded filter is considered to be intact and offloads counter is not
  decremented.

  tc_setup_cb_replace() - destructive filter replace. Release existing
  filter block offload counter and reset its in hardware counter and flag.
  Set new filter in hardware counter and flag. On failure, previously
  offloaded filter is considered to be destroyed and offload counter is
  decremented.

  tc_setup_cb_destroy() - filter destroy. Unconditionally decrement block
  offloads counter.

  tc_setup_cb_reoffload() - reoffload filter to single cb. Execute cb() and
  call tc_cls_offload_cnt_update() if cb() didn't return an error.

Refactor all offload-capable classifiers to atomically offload filters to
hardware, change block offload counter, and set filter in hardware counter
and flag by means of the new cls API functions.
Signed-off-by: NVlad Buslov <vladbu@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Rename this type definition and adapt users.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This config option makes only couple of lines optional.
Two small helpers and an int in couple of cls structs.

Remove the config option and always compile this in.
This saves the user from unexpected surprises when he adds
a filter with ingress device match which is silently ignored
in case the config option is not set.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NAllison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Based on feedback from Jiri avoid carrying a pointer to the tcf_block
structure in the tc_cls_common_offload structure. Instead store
a flag in driver private data which indicates if offloads apply
to a shared block at block binding time.
Suggested-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NPieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com>
Reviewed-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some actions like the police action are stateful and could share state
between devices. This is incompatible with offloading to multiple devices
and drivers might want to test for shared blocks when offloading.
Store a pointer to the tcf_block structure in the tc_cls_common_offload
structure to allow drivers to determine when offloads apply to a shared
block.
Signed-off-by: NPieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com>
Reviewed-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes, in particular in the
context in which this code is being used.

So, replace code of the following form:

sizeof(*s) + s->nkeys*sizeof(struct tc_u32_key)

with:

struct_size(s, keys, s->nkeys)

This code was detected with the help of Coccinelle.
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We currently have two levels of strict validation:

 1) liberal (default)
     - undefined (type >= max) & NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted
     - garbage at end of message accepted
 2) strict (opt-in)
     - NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted

Split out parsing strictness into four different options:
 * TRAILING     - check that there's no trailing data after parsing
                  attributes (in message or nested)
 * MAXTYPE      - reject attrs > max known type
 * UNSPEC       - reject attributes with NLA_UNSPEC policy entries
 * STRICT_ATTRS - strictly validate attribute size

The default for future things should be *everything*.
The current *_strict() is a combination of TRAILING and MAXTYPE,
and is renamed to _deprecated_strict().
The current regular parsing has none of this, and is renamed to
*_parse_deprecated().

Additionally it allows us to selectively set one of the new flags
even on old policies. Notably, the UNSPEC flag could be useful in
this case, since it can be arranged (by filling in the policy) to
not be an incompatible userspace ABI change, but would then going
forward prevent forgetting attribute entries. Similar can apply
to the POLICY flag.

We end up with the following renames:
 * nla_parse           -> nla_parse_deprecated
 * nla_parse_strict    -> nla_parse_deprecated_strict
 * nlmsg_parse         -> nlmsg_parse_deprecated
 * nlmsg_parse_strict  -> nlmsg_parse_deprecated_strict
 * nla_parse_nested    -> nla_parse_nested_deprecated
 * nla_validate_nested -> nla_validate_nested_deprecated

Using spatch, of course:
    @@
    expression TB, MAX, HEAD, LEN, POL, EXT;
    @@
    -nla_parse(TB, MAX, HEAD, LEN, POL, EXT)
    +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression TB, MAX, NLA, POL, EXT;
    @@
    -nla_parse_nested(TB, MAX, NLA, POL, EXT)
    +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT)

    @@
    expression START, MAX, POL, EXT;
    @@
    -nla_validate_nested(START, MAX, POL, EXT)
    +nla_validate_nested_deprecated(START, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, MAX, POL, EXT;
    @@
    -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT)
    +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT)

For this patch, don't actually add the strict, non-renamed versions
yet so that it breaks compile if I get it wrong.

Also, while at it, make nla_validate and nla_parse go down to a
common __nla_validate_parse() function to avoid code duplication.

Ultimately, this allows us to have very strict validation for every
new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the
next patch, while existing things will continue to work as is.

In effect then, this adds fully strict validation for any new command.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most
netlink based interfaces (including recently added ones) are still not
setting it in kernel generated messages. Without the flag, message parsers
not aware of attribute semantics (e.g. wireshark dissector or libmnl's
mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display
the structure of their contents.

Unfortunately we cannot just add the flag everywhere as there may be
userspace applications which check nlattr::nla_type directly rather than
through a helper masking out the flags. Therefore the patch renames
nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start()
as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually
are rewritten to use nla_nest_start().

Except for changes in include/net/netlink.h, the patch was generated using
this semantic patch:

@@ expression E1, E2; @@
-nla_nest_start(E1, E2)
+nla_nest_start_noflag(E1, E2)

@@ expression E1, E2; @@
-nla_nest_start_noflag(E1, E2 | NLA_F_NESTED)
+nla_nest_start(E1, E2)
Signed-off-by: NMichal Kubecek <mkubecek@suse.cz>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For tcindex filter, it is too late to initialize the
net pointer in tcf_exts_validate(), as tcf_exts_get_net()
requires a non-NULL net pointer. We can just move its
initialization into tcf_exts_init(), which just requires
an additional parameter.

This makes the code in tcindex_alloc_perfect_hash()
prettier.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add 'rtnl_held' flag to tcf proto change, delete, destroy, dump, walk
functions to track rtnl lock status. Extend users of these function in cls
API to propagate rtnl lock status to them. This allows classifiers to
obtain rtnl lock when necessary and to pass rtnl lock status to extensions
and driver offload callbacks.

Add flags field to tcf proto ops. Add flag value to indicate that
classifier doesn't require rtnl lock.
Signed-off-by: NVlad Buslov <vladbu@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Actions API is already updated to not rely on rtnl lock for
synchronization. However, it need to be provided with rtnl status when
called from classifiers API in order to be able to correctly release the
lock when loading kernel module.

Extend extension validation function with 'rtnl_held' flag which is passed
to actions API. Add new 'rtnl_held' parameter to tcf_exts_validate() in cls
API. No classifier is currently updated to support unlocked execution, so
pass hardcoded 'true' flag parameter value.
Signed-off-by: NVlad Buslov <vladbu@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After commit 69bd4840 ("net/sched: Remove egdev mechanism"),
tc_setup_cb_call() is nearly identical to tcf_block_cb_call(),
so we can just fold tcf_block_cb_call() into tc_setup_cb_call()
and remove its unused parameter 'exts'.

Fixes: 69bd4840 ("net/sched: Remove egdev mechanism")
Cc: Oz Shlomo <ozsh@mellanox.com>
Cc: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Acked-by: NOz Shlomo <ozsh@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case of egress offloads the class/flowid assigned by the filter
may be very important for offloaded Qdisc selection.  Provide this
info to drivers.
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: NJohn Hurley <john.hurley@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that we have the knode count, we can instantly check if
any hnodes are non-empty.  And that kills the check for extra
references to root hnode - those could happen only if there was
a knode to carry such a link.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

allows to simplify u32_delete() considerably
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Both hnode ->tp_c and tp_c argument of u32_set_parms()
the latter is redundant, the former - never read...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It must be tc_u_common associated with that tp (i.e. tp->data).
Proof:
	* both ->ht_up and ->tp_c are assign-once
	* ->tp_c of anything inserted into tp_c->hlist is tp_c
	* hnodes never get reinserted into the lists or moved
between those, so anything found by u32_lookup_ht(tp->data, ...)
will have ->tp_c equal to tp->data.
	* tp->root->tp_c == tp->data.
	* ->ht_up of anything inserted into hnode->ht[...] is
equal to hnode.
	* knodes never get reinserted into hash chains or moved
between those, so anything returned by u32_lookup_key(ht, ...)
will have ->ht_up equal to ht.
	* any knode returned by u32_get(tp, ...) will have ->ht_up->tp_c
point to tp->data
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

the only thing we used ht for was ht->tp_c and callers can get that
without going through ->tp_c at all; start with lifting that into
the callers, next commits will massage those, eventually removing
->tp_c altogether.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

* calculate key *once*, not for each hash chain element
* let tc_u_hash() return the pointer to chain head rather than index -
callers are cleaner that way.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

unused
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

not used anymore
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Tested by modifying iproute2 to allow sending a divisor > 255
Tested-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Operation makes no sense.  Nothing will actually break if we do so
(depth limit in u32_classify() will prevent infinite loops), but
according to maintainers it's best prohibited outright.

NOTE: doing so guarantees that u32_destroy() will trigger the call
of u32_destroy_hnode(); we might want to make that unconditional.

Test:
tc qdisc add dev eth0 ingress
tc filter add dev eth0 parent ffff: protocol ip prio 100 u32 \
link 800: offset at 0 mask 0f00 shift 6 plus 0 eat match ip protocol 6 ff
should fail with
Error: cls_u32: Not linking to root node
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

... and produce consistent error on attempt to delete such.
Existing check in u32_delete() is inconsistent - after

tc qdisc add dev eth0 ingress
tc filter add dev eth0 parent ffff: protocol ip prio 100 handle 1: u32 \
divisor 1
tc filter add dev eth0 parent ffff: protocol ip prio 200 handle 2: u32 \
divisor 1

both

tc filter delete dev eth0 parent ffff: protocol ip prio 100 handle 801: u32

and

tc filter delete dev eth0 parent ffff: protocol ip prio 100 handle 800: u32

will fail (at least with refcounting fixes), but the former will complain
about an attempt to remove a busy table, while the latter will recognize
it as root and yield "Not allowed to delete root node" instead.

The problem with the existing check is that several tcf_proto instances
might share the same tp->data and handle-to-hnode lookup will be the same
for all of them. So comparing an hnode to be deleted with tp->root won't
catch the case when one tp is used to try deleting the root of another.
Solution is trivial - mark the root hnodes explicitly upon allocation and
check for that.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

cls_u32.c misuses refcounts for struct tc_u_hnode - it counts references
via ->hlist and via ->tp_root together.  u32_destroy() drops the former
and, in case when there had been links, leaves the sucker on the list.
As the result, there's nothing to protect it from getting freed once links
are dropped.
That also makes the "is it busy" check incapable of catching the root
hnode - it *is* busy (there's a reference from tp), but we don't see it as
something separate.  "Is it our root?" check partially covers that, but
the problem exists for others' roots as well.

AFAICS, the minimal fix preserving the existing behaviour (where it doesn't
include oopsen, that is) would be this:
        * count tp->root and tp_c->hlist as separate references.  I.e.
have u32_init() set refcount to 2, not 1.
	* in u32_destroy() we always drop the former;
in u32_destroy_hnode() - the latter.

	That way we have *all* references contributing to refcount.  List
removal happens in u32_destroy_hnode() (called only when ->refcnt is 1)
an in u32_destroy() in case of tc_u_common going away, along with
everything reachable from it.  IOW, that way we know that
u32_destroy_key() won't free something still on the list (or pointed to by
someone's ->root).

Reproducer:

tc qdisc add dev eth0 ingress
tc filter add dev eth0 parent ffff: protocol ip prio 100 handle 1: \
u32 divisor 1
tc filter add dev eth0 parent ffff: protocol ip prio 200 handle 2: \
u32 divisor 1
tc filter add dev eth0 parent ffff: protocol ip prio 100 \
handle 1:0:11 u32 ht 1: link 801: offset at 0 mask 0f00 shift 6 \
plus 0 eat match ip protocol 6 ff
tc filter delete dev eth0 parent ffff: protocol ip prio 200
tc filter change dev eth0 parent ffff: protocol ip prio 100 \
handle 1:0:11 u32 ht 1: link 0: offset at 0 mask 0f00 shift 6 plus 0 \
eat match ip protocol 6 ff
tc filter delete dev eth0 parent ffff: protocol ip prio 100
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Via u32_change(), TCA_U32_SEL has an unspecified type in the netlink
policy, so max length isn't enforced, only minimum. This means nkeys
(from userspace) was being trusted without checking the actual size of
nla_len(), which could lead to a memory over-read, and ultimately an
exposure via a call to u32_dump(). Reachability is CAP_NET_ADMIN within
a namespace.
Reported-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: NKees Cook <keescook@chromium.org>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add the offload tcf_proto_op in cls_u32 to generate an offload message for
each filter and the hashtable in the given tcf_proto. Call the specified
callback with this new offload message. The function only returns an error
if the callback rejects adding a 'hardware only' rule.

A filter contains a flag to indicate if it is in hardware or not. To
ensure the offload function properly maintains this flag, keep a reference
counter for the number of instances of the filter that are in hardware.
Only update the flag when this counter changes from or to 0.
Signed-off-by: NJohn Hurley <john.hurley@netronome.com>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 05f0fe6b ("RCU, workqueue: Implement rcu_work") introduces
new API's for dispatching work in a RCU callback. Now we can just
switch to the new API's for tc filters. This could get rid of a lot
of code.

Cc: Tejun Heo <tj@kernel.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When we delete a u32 key via u32_delete_key(), we forget to
call idr_remove() to remove its handle from IDR.

Fixes: e7614370 ("net_sched: use idr to allocate u32 filter handles")
Reported-by: NMarcin Kabiesz <admin@hostcenter.eu>
Tested-by: NMarcin Kabiesz <admin@hostcenter.eu>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The offending commit wrongly assumes 1:1 mapping between block and q.
However, there are multiple blocks for a single q for classful qdiscs.
Since the obscure tc_u_common sharing mechanism expects it to be shared
among a qdisc, fix it by storing q pointer in case the block is not
shared.
Reported-by: NPaweł Staszewski <pstaszewski@itcare.pl>
Reported-by: NCong Wang <xiyou.wangcong@gmail.com>
Fixes: 7fa9d974 ("net: sched: cls_u32: use block instead of q in tc_u_common")
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The following sequence is currently broken:

 # tc qdisc add dev foo ingress
 # tc filter replace dev foo protocol all ingress \
   u32 match u8 0 0 action mirred egress mirror dev bar1
 # tc filter replace dev foo protocol all ingress \
   handle 800::800 pref 49152 \
   u32 match u8 0 0 action mirred egress mirror dev bar2
 Error: cls_u32: Key node flags do not match passed flags.
 We have an error talking to the kernel, -1

The error comes from u32_change() when comparing new and
existing flags. The existing ones always contains one of
TCA_CLS_FLAGS_{,NOT}_IN_HW flag depending on offloading state.
These flags cannot be passed from userspace so the condition
(n->flags != flags) in u32_change() always fails.

Fix the condition so the flags TCA_CLS_FLAGS_NOT_IN_HW and
TCA_CLS_FLAGS_IN_HW are not taken into account.

Fixes: 24d3dc6d ("net/sched: cls_u32: Reflect HW offload status")
Signed-off-by: NIvan Vecera <ivecera@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

No real benefit to this classifier, but since we're allocating a u32
anyway, we should use this function.
Signed-off-by: NMatthew Wilcox <mawilcox@microsoft.com>

Commit e7614370 ("net_sched: use idr to allocate u32 filter handles)
converted htid allocation to use the IDR.  The ID allocated by this
scheme changes; it used to be cyclic, but now always allocates the
lowest available.  The IDR supports cyclic allocation, so just use
the right function.
Signed-off-by: NMatthew Wilcox <mawilcox@microsoft.com>

Changing idr_replace's 'id' argument to 'unsigned long' works for all
callers.  Callers which passed a negative ID now get -ENOENT instead of
-EINVAL.  No callers relied on this error value.
Signed-off-by: NMatthew Wilcox <mawilcox@microsoft.com>

Simply changing idr_remove's 'id' argument to 'unsigned long' suffices
for all callers.
Signed-off-by: NMatthew Wilcox <mawilcox@microsoft.com>

Li Shuang reported an Oops with cls_u32 due to an use-after-free
in u32_destroy_key(). The use-after-free can be triggered with:

dev=lo
tc qdisc add dev $dev root handle 1: htb default 10
tc filter add dev $dev parent 1: prio 5 handle 1: protocol ip u32 divisor 256
tc filter add dev $dev protocol ip parent 1: prio 5 u32 ht 800:: match ip dst\
 10.0.0.0/8 hashkey mask 0x0000ff00 at 16 link 1:
tc qdisc del dev $dev root

Which causes the following kasan splat:

 ==================================================================
 BUG: KASAN: use-after-free in u32_destroy_key.constprop.21+0x117/0x140 [cls_u32]
 Read of size 4 at addr ffff881b83dae618 by task kworker/u48:5/571

 CPU: 17 PID: 571 Comm: kworker/u48:5 Not tainted 4.15.0+ #87
 Hardware name: Dell Inc. PowerEdge R730/072T6D, BIOS 2.1.7 06/16/2016
 Workqueue: tc_filter_workqueue u32_delete_key_freepf_work [cls_u32]
 Call Trace:
  dump_stack+0xd6/0x182
  ? dma_virt_map_sg+0x22e/0x22e
  print_address_description+0x73/0x290
  kasan_report+0x277/0x360
  ? u32_destroy_key.constprop.21+0x117/0x140 [cls_u32]
  u32_destroy_key.constprop.21+0x117/0x140 [cls_u32]
  u32_delete_key_freepf_work+0x1c/0x30 [cls_u32]
  process_one_work+0xae0/0x1c80
  ? sched_clock+0x5/0x10
  ? pwq_dec_nr_in_flight+0x3c0/0x3c0
  ? _raw_spin_unlock_irq+0x29/0x40
  ? trace_hardirqs_on_caller+0x381/0x570
  ? _raw_spin_unlock_irq+0x29/0x40
  ? finish_task_switch+0x1e5/0x760
  ? finish_task_switch+0x208/0x760
  ? preempt_notifier_dec+0x20/0x20
  ? __schedule+0x839/0x1ee0
  ? check_noncircular+0x20/0x20
  ? firmware_map_remove+0x73/0x73
  ? find_held_lock+0x39/0x1c0
  ? worker_thread+0x434/0x1820
  ? lock_contended+0xee0/0xee0
  ? lock_release+0x1100/0x1100
  ? init_rescuer.part.16+0x150/0x150
  ? retint_kernel+0x10/0x10
  worker_thread+0x216/0x1820
  ? process_one_work+0x1c80/0x1c80
  ? lock_acquire+0x1a5/0x540
  ? lock_downgrade+0x6b0/0x6b0
  ? sched_clock+0x5/0x10
  ? lock_release+0x1100/0x1100
  ? compat_start_thread+0x80/0x80
  ? do_raw_spin_trylock+0x190/0x190
  ? _raw_spin_unlock_irq+0x29/0x40
  ? trace_hardirqs_on_caller+0x381/0x570
  ? _raw_spin_unlock_irq+0x29/0x40
  ? finish_task_switch+0x1e5/0x760
  ? finish_task_switch+0x208/0x760
  ? preempt_notifier_dec+0x20/0x20
  ? __schedule+0x839/0x1ee0
  ? kmem_cache_alloc_trace+0x143/0x320
  ? firmware_map_remove+0x73/0x73
  ? sched_clock+0x5/0x10
  ? sched_clock_cpu+0x18/0x170
  ? find_held_lock+0x39/0x1c0
  ? schedule+0xf3/0x3b0
  ? lock_downgrade+0x6b0/0x6b0
  ? __schedule+0x1ee0/0x1ee0
  ? do_wait_intr_irq+0x340/0x340
  ? do_raw_spin_trylock+0x190/0x190
  ? _raw_spin_unlock_irqrestore+0x32/0x60
  ? process_one_work+0x1c80/0x1c80
  ? process_one_work+0x1c80/0x1c80
  kthread+0x312/0x3d0
  ? kthread_create_worker_on_cpu+0xc0/0xc0
  ret_from_fork+0x3a/0x50

 Allocated by task 1688:
  kasan_kmalloc+0xa0/0xd0
  __kmalloc+0x162/0x380
  u32_change+0x1220/0x3c9e [cls_u32]
  tc_ctl_tfilter+0x1ba6/0x2f80
  rtnetlink_rcv_msg+0x4f0/0x9d0
  netlink_rcv_skb+0x124/0x320
  netlink_unicast+0x430/0x600
  netlink_sendmsg+0x8fa/0xd60
  sock_sendmsg+0xb1/0xe0
  ___sys_sendmsg+0x678/0x980
  __sys_sendmsg+0xc4/0x210
  do_syscall_64+0x232/0x7f0
  return_from_SYSCALL_64+0x0/0x75

 Freed by task 112:
  kasan_slab_free+0x71/0xc0
  kfree+0x114/0x320
  rcu_process_callbacks+0xc3f/0x1600
  __do_softirq+0x2bf/0xc06

 The buggy address belongs to the object at ffff881b83dae600
  which belongs to the cache kmalloc-4096 of size 4096
 The buggy address is located 24 bytes inside of
  4096-byte region [ffff881b83dae600, ffff881b83daf600)
 The buggy address belongs to the page:
 page:ffffea006e0f6a00 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
 flags: 0x17ffffc0008100(slab|head)
 raw: 0017ffffc0008100 0000000000000000 0000000000000000 0000000100070007
 raw: dead000000000100 dead000000000200 ffff880187c0e600 0000000000000000
 page dumped because: kasan: bad access detected

 Memory state around the buggy address:
  ffff881b83dae500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
  ffff881b83dae580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 >ffff881b83dae600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                             ^
  ffff881b83dae680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff881b83dae700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ==================================================================

The problem is that the htnode is freed before the linked knodes and the
latter will try to access the first at u32_destroy_key() time.
This change addresses the issue using the htnode refcnt to guarantee
the correct free order. While at it also add a RCU annotation,
to keep sparse happy.

v1 -> v2: use rtnl_derefence() instead of RCU read locks
v2 -> v3:
  - don't check refcnt in u32_destroy_hnode()
  - cleaned-up u32_destroy() implementation
  - cleaned-up code comment
v3 -> v4:
  - dropped unneeded comment
Reported-by: NLi Shuang <shuali@redhat.com>
Fixes: c0d378ef ("net_sched: use tcf_queue_work() in u32 filter")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In a couple of points of the control path, n->ht_down is currently
accessed without the required RCU annotation. The accesses are
safe, but sparse complaints. Since we already held the
rtnl lock, let use rtnl_dereference().

Fixes: a1b7c5fd ("net: sched: add cls_u32 offload hooks for netdevs")
Fixes: de5df632 ("net: sched: cls_u32 changes to knode must appear atomic to readers")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>