use RCU when accessing the action chain, to avoid use after free in the
traffic path when 'goto chain' is replaced on existing TC actions (see
script below). Since the control action is read in the traffic path
without holding the action spinlock, we need to explicitly ensure that
a->goto_chain is not NULL before dereferencing (i.e it's not sufficient
to rely on the value of TC_ACT_GOTO_CHAIN bits). Not doing so caused NULL
dereferences in tcf_action_goto_chain_exec() when the following script:
# tc chain add dev dd0 chain 42 ingress protocol ip flower \
> ip_proto udp action pass index 4
# tc filter add dev dd0 ingress protocol ip flower \
> ip_proto udp action csum udp goto chain 42 index 66
# tc chain del dev dd0 chain 42 ingress
(start UDP traffic towards dd0)
# tc action replace action csum udp pass index 66
was run repeatedly for several hours.
Suggested-by: Cong Wang <xiyou.wangcong@gmail.com>
Suggested-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
- pass a pointer to struct tcf_proto in each actions's init() handler,
to allow validating the control action, checking whether the chain
exists and (eventually) refcounting it.
- remove code that validates the control action after a successful call
to the action's init() handler, and replace it with a test that forbids
addition of actions having 'goto_chain' and NULL goto_chain pointer at
the same time.
- add tcf_action_check_ctrlact(), that will validate the control action
and eventually allocate the action 'goto_chain' within the init()
handler.
- add tcf_action_set_ctrlact(), that will assign the control action and
swap the current 'goto_chain' pointer with the new given one.
This disallows 'goto_chain' on actions that don't initialize it properly
in their init() handler, i.e. calling tcf_action_check_ctrlact() after
successful IDR reservation and then calling tcf_action_set_ctrlact()
to assign 'goto_chain' and 'tcf_action' consistently.
By doing this, the kernel does not leak anymore refcounts when a valid
'goto chain' handle is replaced in TC actions, causing kmemleak splats
like the following one:
# tc chain add dev dd0 chain 42 ingress protocol ip flower \
> ip_proto tcp action drop
# tc chain add dev dd0 chain 43 ingress protocol ip flower \
> ip_proto udp action drop
# tc filter add dev dd0 ingress matchall \
> action gact goto chain 42 index 66
# tc filter replace dev dd0 ingress matchall \
> action gact goto chain 43 index 66
# echo scan >/sys/kernel/debug/kmemleak
<...>
unreferenced object 0xffff93c0ee09f000 (size 1024):
comm "tc", pid 2565, jiffies 4295339808 (age 65.426s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 08 00 06 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<000000009b63f92d>] tc_ctl_chain+0x3d2/0x4c0
[<00000000683a8d72>] rtnetlink_rcv_msg+0x263/0x2d0
[<00000000ddd88f8e>] netlink_rcv_skb+0x4a/0x110
[<000000006126a348>] netlink_unicast+0x1a0/0x250
[<00000000b3340877>] netlink_sendmsg+0x2c1/0x3c0
[<00000000a25a2171>] sock_sendmsg+0x36/0x40
[<00000000f19ee1ec>] ___sys_sendmsg+0x280/0x2f0
[<00000000d0422042>] __sys_sendmsg+0x5e/0xa0
[<000000007a6c61f9>] do_syscall_64+0x5b/0x180
[<00000000ccd07542>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[<0000000013eaa334>] 0xffffffffffffffff
Fixes: db50514f9a ("net: sched: add termination action to allow goto chain")
Fixes: 97763dc0f4 ("net_sched: reject unknown tcfa_action values")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Modify the kernel users of the TCA_ACT_* macros to use TCA_ID_*. For
example, use TCA_ID_GACT instead of TCA_ACT_GACT. This will align with
TCA_ID_POLICE and also differentiates these identifier, used in struct
tc_action_ops type field, from other macros starting with TCA_ACT_.
To make things clearer, we name the enum defining the TCA_ID_*
identifiers and also change the "type" field of struct tc_action to
id.
Signed-off-by: Eli Cohen <eli@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In commit ec3ed293e7 ("net_sched: change tcf_del_walker() to take idrinfo->lock")
we move fl_hw_destroy_tmplt() to a workqueue to avoid blocking
with the spinlock held. Unfortunately, this causes a lot of
troubles here:
1. tcf_chain_destroy() could be called right after we queue the work
but before the work runs. This is a use-after-free.
2. The chain refcnt is already 0, we can't even just hold it again.
We can check refcnt==1 but it is ugly.
3. The chain with refcnt 0 is still visible in its block, which means
it could be still found and used!
4. The block has a refcnt too, we can't hold it without introducing a
proper API either.
We can make it working but the end result is ugly. Instead of wasting
time on reviewing it, let's just convert the troubling spinlock to
a mutex, which allows us to use non-atomic allocations too.
Fixes: ec3ed293e7 ("net_sched: change tcf_del_walker() to take idrinfo->lock")
Reported-by: Ido Schimmel <idosch@idosch.org>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Vlad Buslov <vladbu@mellanox.com>
Cc: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Tested-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add additional counters that will store the bytes/packets processed by
hardware. These will be exported through the netlink interface for
displaying by the iproute2 tc tool
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit 331a9295de ("net: sched: act: add extack for lookup callback").
This extack is never used after 6 months... In fact, it can be just
set in the caller, right after ->lookup().
Cc: Alexander Aring <aring@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After commit 90b73b77d0, list_head is no longer needed.
Now we just need to convert the list iteration to array
iteration for drivers.
Fixes: 90b73b77d0 ("net: sched: change action API to use array of pointers to actions")
Cc: Jiri Pirko <jiri@mellanox.com>
Cc: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tcf_idr_check() is replaced by tcf_idr_check_alloc(),
and __tcf_idr_check() now can be folded into tcf_idr_search().
Fixes: 0190c1d452 ("net: sched: atomically check-allocate action")
Cc: Jiri Pirko <jiri@mellanox.com>
Cc: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
All ops->delete() wants is getting the tn->idrinfo, but we already
have tc_action before calling ops->delete(), and tc_action has
a pointer ->idrinfo.
More importantly, each type of action does the same thing, that is,
just calling tcf_idr_delete_index().
So it can be just removed.
Fixes: b409074e66 ("net: sched: add 'delete' function to action ops")
Cc: Jiri Pirko <jiri@mellanox.com>
Cc: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As a preparation for removing dependency on rtnl lock from rules update
path, all users of shared objects must take reference while working with
them.
Extend action ops with put_dev() API to be used on net device returned by
get_dev().
Modify mirred action (only action that implements get_dev callback):
- Take reference to net device in get_dev.
- Implement put_dev API that releases reference to net device.
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Each lockless action currently does its own RCU locking in ->act().
This allows using plain RCU accessor, even if the context
is really RCU BH.
This change drops the per action RCU lock, replace the accessors
with the _bh variant, cleans up a bit the surrounding code and
documents the RCU status in the relevant header.
No functional nor performance change is intended.
The goal of this patch is clarifying that the RCU critical section
used by the tc actions extends up to the classifier's caller.
v1 -> v2:
- preserve rcu lock in act_bpf: it's needed by eBPF helpers,
as pointed out by Daniel
v3 -> v4:
- fixed some typos in the commit message (JiriP)
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Act API used linked list to pass set of actions to functions. It is
intrusive data structure that stores list nodes inside action structure
itself, which means it is not safe to modify such list concurrently.
However, action API doesn't use any linked list specific operations on this
set of actions, so it can be safely refactored into plain pointer array.
Refactor action API to use array of pointers to tc_actions instead of
linked list. Change argument 'actions' type of exported action init,
destroy and dump functions.
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Implement function that atomically checks if action exists and either takes
reference to it, or allocates idr slot for action index to prevent
concurrent allocations of actions with same index. Use EBUSY error pointer
to indicate that idr slot is reserved.
Implement cleanup helper function that removes temporary error pointer from
idr. (in case of error between idr allocation and insertion of newly
created action to specified index)
Refactor all action init functions to insert new action to idr using this
API.
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Extend action ops with 'delete' function. Each action type to implements
its own delete function that doesn't depend on rtnl lock.
Implement delete function that is required to delete actions without
holding rtnl lock. Use action API function that atomically deletes action
only if it is still in action idr. This implementation prevents concurrent
threads from deleting same action twice.
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Implement new action API function that atomically finds and deletes action
from idr by index. Intended to be used by lockless actions that do not rely
on rtnl lock.
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add additional 'rtnl_held' argument to act API init functions. It is
required to implement actions that need to release rtnl lock before loading
kernel module and reacquire if afterwards.
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Change type of action reference counter to refcount_t.
Change type of action bind counter to atomic_t.
This type is used to allow decrementing bind counter without testing
for 0 result.
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Create a new tcf_proto_op called 'reoffload' that generates a new offload
message for each node in a tcf_proto. Pointers to the tcf_proto and
whether the offload request is to add or delete the node are included.
Also included is a callback function to send the offload message to and
the option of priv data to go with the cb.
Signed-off-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a new callback in tc_action_ops, it will be needed by the tc actions
to compute its size when a ADD/DELETE notification message is constructed.
This routine has to take into account optional/variable size TLVs specific
per action.
Signed-off-by: Roman Mashak <mrv@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Introduce a new function argument to carry total attributes size for
correct allocation of skb in event messages.
Signed-off-by: Roman Mashak <mrv@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds extack handling for a common used TC act function
"tcf_generic_walker()" to add an extack message on failures.
The tcf_generic_walker() function can fail if get a invalid command
different than DEL and GET. The naming "action" here is wrong, the
correct naming would be command.
Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
