linux-stable.git/net/netfilter/nf_queue.c, branch v4.14.166

netfilter: nf_queue: enqueue skbs with NULL dst

2020-01-04T12:59:59+00:00

[ Upstream commit 0b9173f4688dfa7c5d723426be1d979c24ce3d51 ]

Bridge packets that are forwarded have skb->dst == NULL and get
dropped by the check introduced by
b60a77386b1d4868f72f6353d35dabe5fbe981f2 (net: make skb_dst_force
return true when dst is refcounted).

To fix this we check skb_dst() before skb_dst_force(), so we don't
drop skb packet with dst == NULL. This holds also for skb at the
PRE_ROUTING hook so we remove the second check.

Fixes: b60a77386b1d ("net: make skb_dst_force return true when dst is refcounted")
Signed-off-by: Marco Oliverio 
Signed-off-by: Rocco Folino 
Acked-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

net: make skb_dst_force return true when dst is refcounted

2019-07-31T05:28:46+00:00

[ Upstream commit b60a77386b1d4868f72f6353d35dabe5fbe981f2 ]

netfilter did not expect that skb_dst_force() can cause skb to lose its
dst entry.

I got a bug report with a skb->dst NULL dereference in netfilter
output path.  The backtrace contains nf_reinject(), so the dst might have
been cleared when skb got queued to userspace.

Other users were fixed via
if (skb_dst(skb)) {
	skb_dst_force(skb);
	if (!skb_dst(skb))
		goto handle_err;
}

But I think its preferable to make the 'dst might be cleared' part
of the function explicit.

In netfilter case, skb with a null dst is expected when queueing in
prerouting hook, so drop skb for the other hooks.

v2:
 v1 of this patch returned true in case skb had no dst entry.
 Eric said:
   Say if we have two skb_dst_force() calls for some reason
   on the same skb, only the first one will return false.

 This now returns false even when skb had no dst, as per Erics
 suggestion, so callers might need to check skb_dst() first before
 skb_dst_force().

Signed-off-by: Florian Westphal 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_queue: fix reinject verdict handling

2019-06-22T06:16:15+00:00

[ Upstream commit 946c0d8e6ed43dae6527e878d0077c1e11015db0 ]

This patch fixes netfilter hook traversal when there are more than 1 hooks
returning NF_QUEUE verdict. When the first queue reinjects the packet,
'nf_reinject' starts traversing hooks with a proper hook_index. However,
if it again receives a NF_QUEUE verdict (by some other netfilter hook), it
queues the packet with a wrong hook_index. So, when the second queue
reinjects the packet, it re-executes hooks in between.

Fixes: 960632ece694 ("netfilter: convert hook list to an array")
Signed-off-by: Jagdish Motwani 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: convert hook list to an array

2017-08-28T15:44:00+00:00

This converts the storage and layout of netfilter hook entries from a
linked list to an array.  After this commit, hook entries will be
stored adjacent in memory.  The next pointer is no longer required.

The ops pointers are stored at the end of the array as they are only
used in the register/unregister path and in the legacy br_netfilter code.

nf_unregister_net_hooks() is slower than needed as it just calls
nf_unregister_net_hook in a loop (i.e. at least n synchronize_net()
calls), this will be addressed in followup patch.

Test setup:
 - ixgbe 10gbit
 - netperf UDP_STREAM, 64 byte packets
 - 5 hooks: (raw + mangle prerouting, mangle+filter input, inet filter):
empty mangle and raw prerouting, mangle and filter input hooks:
353.9
this patch:
364.2

Signed-off-by: Aaron Conole 
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: conntrack: destroy functions need to free queued packets

2017-07-31T17:09:39+00:00

queued skbs might be using conntrack extensions that are being removed,
such as timeout.  This happens for skbs that have a skb->nfct in
unconfirmed state (i.e., not in hash table yet).

This is destructive, but there are only two use cases:
 - module removal (rare)
 - netns cleanup (most likely no conntracks exist, and if they do,
   they are removed anyway later on).

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: nf_queue: only call synchronize_net twice if nf_queue is active

2017-05-01T09:19:12+00:00

nf_unregister_net_hook(s) can avoid a second call to synchronize_net,
provided there is no nfqueue active in that net namespace (which is
the common case).

This also gets rid of the extra arg to nf_queue_nf_hook_drop(), normally
this gets called during netns cleanup so no packets should be queued.

For the rare case of base chain being unregistered or module removal
while nfqueue is in use the extra hiccup due to the packet drops isn't
a big deal.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: introduce accessor functions for hook entries

2016-12-06T20:42:15+00:00

This allows easier future refactoring.

Signed-off-by: Aaron Conole 
Signed-off-by: Pablo Neira Ayuso

netfilter: merge nf_iterate() into nf_hook_slow()

2016-11-03T10:52:59+00:00

nf_iterate() has become rather simple, we can integrate this code into
nf_hook_slow() to reduce the amount of LOC in the core path.

However, we still need nf_iterate() around for nf_queue packet handling,
so move this function there where we only need it. I think it should be
possible to refactor nf_queue code to get rid of it definitely, but
given this is slow path anyway, let's have a look this later.

Signed-off-by: Pablo Neira Ayuso

netfilter: remove hook_entries field from nf_hook_state

2016-11-03T10:52:58+00:00

This field is only useful for nf_queue, so store it in the
nf_queue_entry structure instead, away from the core path. Pass
hook_head to nf_hook_slow().

Since we always have a valid entry on the first iteration in
nf_iterate(), we can use 'do { ... } while (entry)' loop instead.

Signed-off-by: Pablo Neira Ayuso

netfilter: kill NF_HOOK_THRESH() and state->tresh

2016-11-03T09:56:12+00:00

Patch c5136b15ea36 ("netfilter: bridge: add and use br_nf_hook_thresh")
introduced br_nf_hook_thresh().

Replace NF_HOOK_THRESH() by br_nf_hook_thresh from
br_nf_forward_finish(), so we have no more callers for this macro.

As a result, state->thresh and explicit thresh parameter in the hook
state structure is not required anymore. And we can get rid of
skip-hook-under-thresh loop in nf_iterate() in the core path that is
only used by br_netfilter to search for the filter hook.

Suggested-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso