linux-stable.git/net/netfilter/nf_queue.c, branch v4.9.331

netfilter: nf_queue: fix possible use-after-free

2022-03-08T18:00:57+00:00

commit c3873070247d9e3c7a6b0cf9bf9b45e8018427b1 upstream.

Eric Dumazet says:
  The sock_hold() side seems suspect, because there is no guarantee
  that sk_refcnt is not already 0.

On failure, we cannot queue the packet and need to indicate an
error.  The packet will be dropped by the caller.

v2: split skb prefetch hunk into separate change

Fixes: 271b72c7fa82c ("udp: RCU handling for Unicast packets.")
Reported-by: Eric Dumazet 
Reviewed-by: Eric Dumazet 
Signed-off-by: Florian Westphal 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_queue: don't assume sk is full socket

2022-03-08T18:00:57+00:00

commit 747670fd9a2d1b7774030dba65ca022ba442ce71 upstream.

There is no guarantee that state->sk refers to a full socket.

If refcount transitions to 0, sock_put calls sk_free which then ends up
with garbage fields.

I'd like to thank Oleksandr Natalenko and Jiri Benc for considerable
debug work and pointing out state->sk oddities.

Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
Tested-by: Oleksandr Natalenko 
Signed-off-by: Florian Westphal 
Signed-off-by: Greg Kroah-Hartman

netfilter: fix nf_queue handling

2016-10-20T17:59:59+00:00

nf_queue handling is broken since e3b37f11e6e4 ("netfilter: replace
list_head with single linked list") for two reasons:

1) If the bypass flag is set on, there are no userspace listeners and
   we still have more hook entries to iterate over, then jump to the
   next hook. Otherwise accept the packet. On nf_reinject() path, the
   okfn() needs to be invoked.

2) We should not re-enter the same hook on packet reinjection. If the
   packet is accepted, we have to skip the current hook from where the
   packet was enqueued, otherwise the packets gets enqueued over and
   over again.

This restores the previous list_for_each_entry_continue() behaviour
happening from nf_iterate() that was dealing with these two cases.
This patch introduces a new nf_queue() wrapper function so this fix
becomes simpler.

Fixes: e3b37f11e6e4 ("netfilter: replace list_head with single linked list")
Signed-off-by: Pablo Neira Ayuso

netfilter: replace list_head with single linked list

2016-09-25T12:38:48+00:00

The netfilter hook list never uses the prev pointer, and so can be trimmed to
be a simple singly-linked list.

In addition to having a more light weight structure for hook traversal,
struct net becomes 5568 bytes (down from 6400) and struct net_device becomes
2176 bytes (down from 2240).

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

netfilter: nf_queue: Make the queue_handler pernet

2016-05-25T09:54:22+00:00

Florian Weber reported:
> Under full load (unshare() in loop -> OOM conditions) we can
> get kernel panic:
>
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
> IP: [] nfqnl_nf_hook_drop+0x35/0x70
> [..]
> task: ffff88012dfa3840 ti: ffff88012dffc000 task.ti: ffff88012dffc000
> RIP: 0010:[]  [] nfqnl_nf_hook_drop+0x35/0x70
> RSP: 0000:ffff88012dfffd80  EFLAGS: 00010206
> RAX: 0000000000000008 RBX: ffffffff81add0c0 RCX: ffff88013fd80000
> [..]
> Call Trace:
>  [] nf_queue_nf_hook_drop+0x18/0x20
>  [] nf_unregister_net_hook+0xdb/0x150
>  [] netfilter_net_exit+0x2f/0x60
>  [] ops_exit_list.isra.4+0x38/0x60
>  [] setup_net+0xc2/0x120
>  [] copy_net_ns+0x79/0x120
>  [] create_new_namespaces+0x11b/0x1e0
>  [] unshare_nsproxy_namespaces+0x57/0xa0
>  [] SyS_unshare+0x1b2/0x340
>  [] entry_SYSCALL_64_fastpath+0x1e/0xa8
> Code: 65 00 48 89 e5 41 56 41 55 41 54 53 83 e8 01 48 8b 97 70 12 00 00 48 98 49 89 f4 4c 8b 74 c2 18 4d 8d 6e 08 49 81 c6 88 00 00 00 <49> 8b 5d 00 48 85 db 74 1a 48 89 df 4c 89 e2 48 c7 c6 90 68 47
>

The simple fix for this requires a new pernet variable for struct
nf_queue that indicates when it is safe to use the dynamically
allocated nf_queue state.

As we need a variable anyway make nf_register_queue_handler and
nf_unregister_queue_handler pernet.  This allows the existing logic of
when it is safe to use the state from the nfnetlink_queue module to be
reused with no changes except for making it per net.

The syncrhonize_rcu from nf_unregister_queue_handler is moved to a new
function nfnl_queue_net_exit_batch so that the worst case of having a
syncrhonize_rcu in the pernet exit path is not experienced in batch
mode.

Reported-by: Florian Westphal 
Signed-off-by: "Eric W. Biederman" 
Acked-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: nf_queue: remove rcu_read_lock calls

2015-10-16T16:22:41+00:00

All verdict handlers make use of the nfnetlink .call_rcu callback
so rcu readlock is already held.

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

netfilter: make nf_queue_entry_get_refs return void

2015-10-16T16:22:23+00:00

We don't care if module is being unloaded anymore since hook unregister
handling will destroy queue entries using that hook.

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

netfilter: remove hook owner refcounting

2015-10-16T16:21:39+00:00

since commit 8405a8fff3f8 ("netfilter: nf_qeueue: Drop queue entries on
nf_unregister_hook") all pending queued entries are discarded.

So we can simply remove all of the owner handling -- when module is
removed it also needs to unregister all its hooks.

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

netfilter: nfqueue: don't use prev pointer

2015-10-13T10:03:24+00:00

Usage of -prev seems buggy.  While packet was out our hook cannot be
removed but we have no way to know if the previous one is still valid.

So better not use ->prev at all.  Since NF_REPEAT just asks to invoke
same hook function again, just do so, and continue with nf_interate
if we get an ACCEPT verdict.

A side effect of this change is that if nf_reinject(NF_REPEAT) causes
another REPEAT we will now drop the skb instead of a kernel loop.

However, NF_REPEAT loops would be a bug so this should not happen anyway.

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

netfilter: Push struct net down into nf_afinfo.reroute

2015-09-29T18:21:31+00:00

The network namespace is needed when routing a packet.
Stop making nf_afinfo.reroute guess which network namespace
is the proper namespace to route the packet in.

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Pablo Neira Ayuso