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Allows easier code-reuse in followup patches.
Reviewed-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Instead of freeing the entry from our list and then adding
it back again in the 'packet to closing connection' case just keep the
matching entry around. Also drop the found_ct != NULL test as
nf_ct_tuplehash_to_ctrack is just container_of().
Reviewed-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Simplifies followup patch that introduces separate locks for each of
the hash slots.
Reviewed-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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The family in the NAT expression is basically completely useless since
we have it available during runtime anyway. Nevertheless it is used to
decide the NAT family, so at least validate it properly. As we don't
support cross-family NAT, it needs to match the family of the table the
expression exists in.
Unfortunately we can't remove it completely since we need to dump it for
userspace (*sigh*), so at least reduce the memory waste.
Additionally clean up the module init function by removing useless
temporary variables.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Since we have the context available during destruction again, we can
remove the family from the private structure.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Since we have the context available again, we can restore notifications
for destruction of anonymous sets.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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In order to fix set destruction notifications and get rid of unnecessary
members in private data structures, pass the context to expressions'
destructor functions again.
In order to do so, replace various members in the nft_rule_trans structure
by the full context.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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The context argument logically comes first, and this is what every other
function dealing with contexts does.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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The hash set type is very broken and was never meant to be merged in this
state. Missing RCU synchronization on element removal, leaking chain
refcounts when used as a verdict map, races during lookups, a fixed table
size are probably just some of the problems. Luckily it is currently
never chosen by the kernel when the rbtree type is also available.
Rewrite it to be usable.
The new implementation supports automatic hash table resizing using RCU,
based on Paul McKenney's and Josh Triplett's algorithm "Optimized Resizing
For RCU-Protected Hash Tables" described in [1].
Resizing doesn't require a second list head in the elements, it works by
chosing a hash function that remaps elements to a predictable set of buckets,
only resizing by integral factors and
- during expansion: linking new buckets to the old bucket that contains
elements for any of the new buckets, thereby creating imprecise chains,
then incrementally seperating the elements until the new buckets only
contain elements that hash directly to them.
- during shrinking: linking the hash chains of all old buckets that hash
to the same new bucket to form a single chain.
Expansion requires at most the number of elements in the longest hash chain
grace periods, shrinking requires a single grace period.
Due to the requirement of having hash chains/elements linked to multiple
buckets during resizing, homemade single linked lists are used instead of
the existing list helpers, that don't support this in a clean fashion.
As a side effect, the amount of memory required per element is reduced by
one pointer.
Expansion is triggered when the load factors exceeds 75%, shrinking when
the load factor goes below 30%. Both operations are allowed to fail and
will be retried on the next insertion or removal if their respective
conditions still hold.
[1] http://dl.acm.org/citation.cfm?id=2002181.2002192
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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nf_conntrack_lock is a monolithic lock and suffers from huge contention
on current generation servers (8 or more core/threads).
Perf locking congestion is clear on base kernel:
- 72.56% ksoftirqd/6 [kernel.kallsyms] [k] _raw_spin_lock_bh
- _raw_spin_lock_bh
+ 25.33% init_conntrack
+ 24.86% nf_ct_delete_from_lists
+ 24.62% __nf_conntrack_confirm
+ 24.38% destroy_conntrack
+ 0.70% tcp_packet
+ 2.21% ksoftirqd/6 [kernel.kallsyms] [k] fib_table_lookup
+ 1.15% ksoftirqd/6 [kernel.kallsyms] [k] __slab_free
+ 0.77% ksoftirqd/6 [kernel.kallsyms] [k] inet_getpeer
+ 0.70% ksoftirqd/6 [nf_conntrack] [k] nf_ct_delete
+ 0.55% ksoftirqd/6 [ip_tables] [k] ipt_do_table
This patch change conntrack locking and provides a huge performance
improvement. SYN-flood attack tested on a 24-core E5-2695v2(ES) with
10Gbit/s ixgbe (with tool trafgen):
Base kernel: 810.405 new conntrack/sec
After patch: 2.233.876 new conntrack/sec
Notice other floods attack (SYN+ACK or ACK) can easily be deflected using:
# iptables -A INPUT -m state --state INVALID -j DROP
# sysctl -w net/netfilter/nf_conntrack_tcp_loose=0
Use an array of hashed spinlocks to protect insertions/deletions of
conntracks into the hash table. 1024 spinlocks seem to give good
results, at minimal cost (4KB memory). Due to lockdep max depth,
1024 becomes 8 if CONFIG_LOCKDEP=y
The hash resize is a bit tricky, because we need to take all locks in
the array. A seqcount_t is used to synchronize the hash table users
with the resizing process.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Netfilter expectations are protected with the same lock as conntrack
entries (nf_conntrack_lock). This patch split out expectations locking
to use it's own lock (nf_conntrack_expect_lock).
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Preparation for disconnecting the nf_conntrack_lock from the
expectations code. Once the nf_conntrack_lock is lifted, a race
condition is exposed.
The expectations master conntrack exp->master, can race with
delete operations, as the refcnt increment happens too late in
init_conntrack(). Race is against other CPUs invoking
->destroy() (destroy_conntrack()), or nf_ct_delete() (via timeout
or early_drop()).
Avoid this race in nf_ct_find_expectation() by using atomic_inc_not_zero(),
and checking if nf_ct_is_dying() (path via nf_ct_delete()).
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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One spinlock per cpu to protect dying/unconfirmed/template special lists.
(These lists are now per cpu, a bit like the untracked ct)
Add a @cpu field to nf_conn, to make sure we hold the appropriate
spinlock at removal time.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Changes while reading through the netfilter code.
Added hint about how conntrack nf_conn refcnt is accessed.
And renamed repl_hash to reply_hash for readability
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Via Simon Horman:
====================
* Whitespace cleanup spotted by checkpatch.pl from Tingwei Liu.
* Section conflict cleanup, basically removal of one wrong __read_mostly,
from Andi Kleen.
====================
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Add whitespace after operator and put open brace { on the previous line
Cc: Tingwei Liu <liutingwei@hisense.com>
Cc: lvs-devel@vger.kernel.org
Signed-off-by: Tingwei Liu <tingw.liu@gmail.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
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const __read_mostly does not make any sense, because const
data is already read-only. Remove the __read_mostly
for the ipvs genl_ops. This avoids a LTO
section conflict compile problem.
Cc: Wensong Zhang <wensong@linux-vs.org>
Cc: Simon Horman <horms@verge.net.au>
Cc: Patrick McHardy <kaber@trash.net>
Cc: lvs-devel@vger.kernel.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
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Adds a new property for hash set types, where if a set is created
with the 'forceadd' option and the set becomes full the next addition
to the set may succeed and evict a random entry from the set.
To keep overhead low eviction is done very simply. It checks to see
which bucket the new entry would be added. If the bucket's pos value
is non-zero (meaning there's at least one entry in the bucket) it
replaces the first entry in the bucket. If pos is zero, then it continues
down the normal add process.
This property is useful if you have a set for 'ban' lists where it may
not matter if you release some entries from the set early.
Signed-off-by: Josh Hunt <johunt@akamai.com>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
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Commit 1785e8f473 ("netfiler: ipset: Add net namespace for ipset") moved
the initialization print into net_init, which can get called a lot due
to namespaces. Move it back into init, reduce to pr_info.
Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
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Introduce packet mark mask for hash:ip,mark data type. This allows to
set mark bit filter for the ip set.
Change-Id: Id8dd9ca7e64477c4f7b022a1d9c1a5b187f1c96e
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
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Introduce packet mark support with new ip,mark hash set. This includes
userspace and kernelspace code, hash:ip,mark set tests and man page
updates.
The intended use of ip,mark set is similar to the ip:port type, but for
protocols which don't use a predictable port number. Instead of port
number it matches a firewall mark determined by a layer 7 filtering
program like opendpi.
As well as allowing or blocking traffic it will also be used for
accounting packets and bytes sent for each protocol.
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
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net/netfilter/ipset/ip_set_hash_netnet.c:115:8-9: WARNING: return of 0/1 in function 'hash_netnet4_data_list' with return type bool
/c/kernel-tests/src/cocci/net/netfilter/ipset/ip_set_hash_netnet.c:338:8-9: WARNING: return of 0/1 in function 'hash_netnet6_data_list' with return type bool
Return statements in functions returning bool should use
true/false instead of 1/0.
Generated by: coccinelle/misc/boolreturn.cocci
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
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ipset(8) for list:set says:
The match will try to find a matching entry in the sets and the
target will try to add an entry to the first set to which it can
be added.
However real behavior is bit differ from described. Consider example:
# ipset create test-1-v4 hash:ip family inet
# ipset create test-1-v6 hash:ip family inet6
# ipset create test-1 list:set
# ipset add test-1 test-1-v4
# ipset add test-1 test-1-v6
# iptables -A INPUT -p tcp --destination-port 25 -j SET --add-set test-1 src
# ip6tables -A INPUT -p tcp --destination-port 25 -j SET --add-set test-1 src
And then when iptables/ip6tables rule matches packet IPSET target
tries to add src from packet to the list:set test-1 where first
entry is test-1-v4 and the second one is test-1-v6.
For IPv4, as it first entry in test-1 src added to test-1-v4
correctly, but for IPv6 src not added!
Placing test-1-v6 to the first element of list:set makes behavior
correct for IPv6, but brokes for IPv4.
This is due to result, returned from ip_set_add() and ip_set_del() from
net/netfilter/ipset/ip_set_core.c when set in list:set equires more
parameters than given or address families do not match (which is this
case).
It seems wrong returning 0 from ip_set_add() and ip_set_del() in
this case, as 0 should be returned only when an element successfuly
added/deleted to/from the set, contrary to ip_set_test() which
returns 0 when no entry exists and >0 when entry found in set.
Signed-off-by: Sergey Popovich <popovich_sergei@mail.ru>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
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This allows us to store user comment strings, but it could be also
used to store any kind of information that the user application needs
to link to the rule.
Scratch 8 bits for the new ulen field that indicates the length the
user data area. 4 bits from the handle (so it's 42 bits long, according
to Patrick, it would last 139 years with 1000 new rules per second)
and 4 bits from dlen (so the expression data area is 4K, which seems
sufficient by now even considering the compatibility layer).
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Patrick McHardy <kaber@trash.net>
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Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Allow userspace to specify the queue number or the errno code for QUEUE
and DROP verdicts.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Add a lockdep_nfnl_is_held() function and a nfnl_dereference() macro for
RCU dereferences protected by a NFNL subsystem mutex.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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The next patch will introduce a nfnl_dereference() macro that actually
checks that the appropriate mutex is held and therefore needs a
subsystem argument.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This also adds NF_CT_LABELS_MAX_SIZE so it can be re-used
as BUILD_BUG_ON in nft_ct.
At this time, nft doesn't yet support writing to the label area;
when this changes the label->words handling needs to be moved
out of xt_connlabel.c into nf_conntrack_labels.c.
Also removes a useless run-time check: words cannot grow beyond
4 (32 bit) or 2 (64bit) since xt_connlabel enforces a maximum of
128 labels.
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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0-DAY kernel build testing backend reported:
sparse warnings: (new ones prefixed by >>)
>> >> net/netfilter/xt_ipcomp.c:63:26: sparse: restricted __be16 degrades to integer
>> >> net/netfilter/xt_ipcomp.c:63:26: sparse: cast to restricted __be32
Fix this by using ntohs without shifting.
Tested with: make C=1 CF=-D__CHECK_ENDIAN__
Signed-off-by: Fan Du <fan.du@windriver.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Quoting Andrey Vagin:
When a conntrack is created by kernel, it is initialized (sets
IPS_{DST,SRC}_NAT_DONE_BIT bits in nf_nat_setup_info) and only then it
is added in hashes (__nf_conntrack_hash_insert), so one conntract
can't be initialized from a few threads concurrently.
ctnetlink can add an uninitialized conntrack (w/o
IPS_{DST,SRC}_NAT_DONE_BIT) in hashes, then a few threads can look up
this conntrack and start initialize it concurrently. It's dangerous,
because BUG can be triggered from nf_nat_setup_info.
Fix this race by always setting up nat, even if no CTA_NAT_ attribute
was requested before inserting the ct into the hash table. In absence
of CTA_NAT_ attribute, a null binding is created.
This alters current behaviour: Before this patch, the first packet
matching the newly injected conntrack would be run through the nat
table since nf_nat_initialized() returns false. IOW, this forces
ctnetlink users to specify the desired nat transformation on ct
creation time.
Thanks for Florian Westphal, this patch is based on his original
patch to address this problem, including this patch description.
Reported-By: Andrey Vagin <avagin@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Florian Westphal <fw@strlen.de>
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Add a check if payload's length is a power of 2 when selecting ops.
The fast ops were meant for well aligned loads, also this fixes a
small bug when using a length of 3 with some offsets which causes
only 1 byte to be loaded because the fast ops are chosen.
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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There are two checks for CONFIG_NET_CLS_ROUTE, but the corresponding
Kconfig symbol was dropped in v2.6.39. Since the code guards access to
dst_entry.tclassid it seems CONFIG_IP_ROUTE_CLASSID should be used
instead.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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For IPv4 packets, we call both IPv4 and IPv6 reject.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Include appropriate header file net/netfilter/nf_tables_core.h in
net/netfilter/nft_lookup.c because it has prototype declaration of
functions defined in net/netfilter/nft_lookup.c.
This eliminates the following warning in net/netfilter/nft_lookup.c:
net/netfilter/nft_lookup.c:133:12: warning: no previous prototype for ‘nft_lookup_module_init’ [-Wmissing-prototypes]
net/netfilter/nft_lookup.c:138:6: warning: no previous prototype for ‘nft_lookup_module_exit’ [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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It makes no sense to inline a rarely used function meant for debugging
only that is called a total of five times in the main evaluation loop.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Fix access to uninitialized data for end interval elements. The
element data part is uninitialized in interval end elements.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch fixes several things which related to the handling of
end interval elements:
* Chain use underflow with intervals and map: If you add a rule
using intervals+map that introduces a loop, the error path of the
rbtree set decrements the chain refcount for each side of the
interval, leading to a chain use counter underflow.
* Don't copy the data part of the end interval element since, this
area is uninitialized and this confuses the loop detection code.
* Don't allocate room for the data part of end interval elements
since this is unused.
So, after this patch the idea is that end interval elements don't
have a data part.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Patrick McHardy <kaber@trash.net>
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This combination is not allowed since end interval elements cannot
contain data.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Patrick McHardy <kaber@trash.net>
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We may lost race if we flush the rule-set (which happens asynchronously
via call_rcu) and we try to remove the table (that userspace assumes
to be empty).
Fix this by recovering synchronous rule and chain deletion. This was
introduced time ago before we had no batch support, and synchronous
rule deletion performance was not good. Now that we have the batch
support, we can just postpone the purge of old rule in a second step
in the commit phase. All object deletions are synchronous after this
patch.
As a side effect, we save memory as we don't need rcu_head per rule
anymore.
Cc: Patrick McHardy <kaber@trash.net>
Reported-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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The log and queue expressions both store the family during ->init() and
use it to deliver packets. This is wrong when used in NFPROTO_INET since
they should both deliver to the actual AF of the packet, not the dummy
NFPROTO_INET.
Use the family from the hook ops to fix this.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Add a reject module for NFPROTO_INET. It does nothing but dispatch
to the AF-specific modules based on the hook family.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Currently the nft_reject module depends on symbols from ipv6. This is
wrong since no generic module should force IPv6 support to be loaded.
Split up the module into AF-specific and a generic part.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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For the reject module, we need to add AF-specific implementations to
get rid of incorrect module dependencies. Try to load an AF-specific
module first and fall back to generic modules.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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The key was missing in the list of valid keys, add it.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Commit c9c8e48597 (netfilter: nf_tables: dump sets in all existing families)
changed nft_ctx_init_from_setattr() to only look up the address family if it
is not NFPROTO_UNSPEC. However if it is NFPROTO_UNSPEC and a table attribute
is given, nftables_afinfo_lookup() will dereference the NULL afi pointer.
Fix by checking for non-NULL afi and also move a check added by that commit
to the proper position.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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The map that is used to allocate anonymous sets is indeed
BITS_PER_BYTE * PAGE_SIZE long.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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With this patch, the conntrack refcount is initially set to zero and
it is bumped once it is added to any of the list, so we fulfill
Eric's golden rule which is that all released objects always have a
refcount that equals zero.
Andrey Vagin reports that nf_conntrack_free can't be called for a
conntrack with non-zero ref-counter, because it can race with
nf_conntrack_find_get().
A conntrack slab is created with SLAB_DESTROY_BY_RCU. Non-zero
ref-counter says that this conntrack is used. So when we release
a conntrack with non-zero counter, we break this assumption.
CPU1 CPU2
____nf_conntrack_find()
nf_ct_put()
destroy_conntrack()
...
init_conntrack
__nf_conntrack_alloc (set use = 1)
atomic_inc_not_zero(&ct->use) (use = 2)
if (!l4proto->new(ct, skb, dataoff, timeouts))
nf_conntrack_free(ct); (use = 2 !!!)
...
__nf_conntrack_alloc (set use = 1)
if (!nf_ct_key_equal(h, tuple, zone))
nf_ct_put(ct); (use = 0)
destroy_conntrack()
/* continue to work with CT */
After applying the path "[PATCH] netfilter: nf_conntrack: fix RCU
race in nf_conntrack_find_get" another bug was triggered in
destroy_conntrack():
<4>[67096.759334] ------------[ cut here ]------------
<2>[67096.759353] kernel BUG at net/netfilter/nf_conntrack_core.c:211!
...
<4>[67096.759837] Pid: 498649, comm: atdd veid: 666 Tainted: G C --------------- 2.6.32-042stab084.18 #1 042stab084_18 /DQ45CB
<4>[67096.759932] RIP: 0010:[<ffffffffa03d99ac>] [<ffffffffa03d99ac>] destroy_conntrack+0x15c/0x190 [nf_conntrack]
<4>[67096.760255] Call Trace:
<4>[67096.760255] [<ffffffff814844a7>] nf_conntrack_destroy+0x17/0x30
<4>[67096.760255] [<ffffffffa03d9bb5>] nf_conntrack_find_get+0x85/0x130 [nf_conntrack]
<4>[67096.760255] [<ffffffffa03d9fb2>] nf_conntrack_in+0x352/0xb60 [nf_conntrack]
<4>[67096.760255] [<ffffffffa048c771>] ipv4_conntrack_local+0x51/0x60 [nf_conntrack_ipv4]
<4>[67096.760255] [<ffffffff81484419>] nf_iterate+0x69/0xb0
<4>[67096.760255] [<ffffffff814b5b00>] ? dst_output+0x0/0x20
<4>[67096.760255] [<ffffffff814845d4>] nf_hook_slow+0x74/0x110
<4>[67096.760255] [<ffffffff814b5b00>] ? dst_output+0x0/0x20
<4>[67096.760255] [<ffffffff814b66d5>] raw_sendmsg+0x775/0x910
<4>[67096.760255] [<ffffffff8104c5a8>] ? flush_tlb_others_ipi+0x128/0x130
<4>[67096.760255] [<ffffffff8100bc4e>] ? apic_timer_interrupt+0xe/0x20
<4>[67096.760255] [<ffffffff8100bc4e>] ? apic_timer_interrupt+0xe/0x20
<4>[67096.760255] [<ffffffff814c136a>] inet_sendmsg+0x4a/0xb0
<4>[67096.760255] [<ffffffff81444e93>] ? sock_sendmsg+0x13/0x140
<4>[67096.760255] [<ffffffff81444f97>] sock_sendmsg+0x117/0x140
<4>[67096.760255] [<ffffffff8102e299>] ? native_smp_send_reschedule+0x49/0x60
<4>[67096.760255] [<ffffffff81519beb>] ? _spin_unlock_bh+0x1b/0x20
<4>[67096.760255] [<ffffffff8109d930>] ? autoremove_wake_function+0x0/0x40
<4>[67096.760255] [<ffffffff814960f0>] ? do_ip_setsockopt+0x90/0xd80
<4>[67096.760255] [<ffffffff8100bc4e>] ? apic_timer_interrupt+0xe/0x20
<4>[67096.760255] [<ffffffff8100bc4e>] ? apic_timer_interrupt+0xe/0x20
<4>[67096.760255] [<ffffffff814457c9>] sys_sendto+0x139/0x190
<4>[67096.760255] [<ffffffff810efa77>] ? audit_syscall_entry+0x1d7/0x200
<4>[67096.760255] [<ffffffff810ef7c5>] ? __audit_syscall_exit+0x265/0x290
<4>[67096.760255] [<ffffffff81474daf>] compat_sys_socketcall+0x13f/0x210
<4>[67096.760255] [<ffffffff8104dea3>] ia32_sysret+0x0/0x5
I have reused the original title for the RFC patch that Andrey posted and
most of the original patch description.
Cc: Eric Dumazet <edumazet@google.com>
Cc: Andrew Vagin <avagin@parallels.com>
Cc: Florian Westphal <fw@strlen.de>
Reported-by: Andrew Vagin <avagin@parallels.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Andrew Vagin <avagin@parallels.com>
|
|
Lets look at destroy_conntrack:
hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
...
nf_conntrack_free(ct)
kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
net->ct.nf_conntrack_cachep is created with SLAB_DESTROY_BY_RCU.
The hash is protected by rcu, so readers look up conntracks without
locks.
A conntrack is removed from the hash, but in this moment a few readers
still can use the conntrack. Then this conntrack is released and another
thread creates conntrack with the same address and the equal tuple.
After this a reader starts to validate the conntrack:
* It's not dying, because a new conntrack was created
* nf_ct_tuple_equal() returns true.
But this conntrack is not initialized yet, so it can not be used by two
threads concurrently. In this case BUG_ON may be triggered from
nf_nat_setup_info().
Florian Westphal suggested to check the confirm bit too. I think it's
right.
task 1 task 2 task 3
nf_conntrack_find_get
____nf_conntrack_find
destroy_conntrack
hlist_nulls_del_rcu
nf_conntrack_free
kmem_cache_free
__nf_conntrack_alloc
kmem_cache_alloc
memset(&ct->tuplehash[IP_CT_DIR_MAX],
if (nf_ct_is_dying(ct))
if (!nf_ct_tuple_equal()
I'm not sure, that I have ever seen this race condition in a real life.
Currently we are investigating a bug, which is reproduced on a few nodes.
In our case one conntrack is initialized from a few tasks concurrently,
we don't have any other explanation for this.
<2>[46267.083061] kernel BUG at net/ipv4/netfilter/nf_nat_core.c:322!
...
<4>[46267.083951] RIP: 0010:[<ffffffffa01e00a4>] [<ffffffffa01e00a4>] nf_nat_setup_info+0x564/0x590 [nf_nat]
...
<4>[46267.085549] Call Trace:
<4>[46267.085622] [<ffffffffa023421b>] alloc_null_binding+0x5b/0xa0 [iptable_nat]
<4>[46267.085697] [<ffffffffa02342bc>] nf_nat_rule_find+0x5c/0x80 [iptable_nat]
<4>[46267.085770] [<ffffffffa0234521>] nf_nat_fn+0x111/0x260 [iptable_nat]
<4>[46267.085843] [<ffffffffa0234798>] nf_nat_out+0x48/0xd0 [iptable_nat]
<4>[46267.085919] [<ffffffff814841b9>] nf_iterate+0x69/0xb0
<4>[46267.085991] [<ffffffff81494e70>] ? ip_finish_output+0x0/0x2f0
<4>[46267.086063] [<ffffffff81484374>] nf_hook_slow+0x74/0x110
<4>[46267.086133] [<ffffffff81494e70>] ? ip_finish_output+0x0/0x2f0
<4>[46267.086207] [<ffffffff814b5890>] ? dst_output+0x0/0x20
<4>[46267.086277] [<ffffffff81495204>] ip_output+0xa4/0xc0
<4>[46267.086346] [<ffffffff814b65a4>] raw_sendmsg+0x8b4/0x910
<4>[46267.086419] [<ffffffff814c10fa>] inet_sendmsg+0x4a/0xb0
<4>[46267.086491] [<ffffffff814459aa>] ? sock_update_classid+0x3a/0x50
<4>[46267.086562] [<ffffffff81444d67>] sock_sendmsg+0x117/0x140
<4>[46267.086638] [<ffffffff8151997b>] ? _spin_unlock_bh+0x1b/0x20
<4>[46267.086712] [<ffffffff8109d370>] ? autoremove_wake_function+0x0/0x40
<4>[46267.086785] [<ffffffff81495e80>] ? do_ip_setsockopt+0x90/0xd80
<4>[46267.086858] [<ffffffff8100be0e>] ? call_function_interrupt+0xe/0x20
<4>[46267.086936] [<ffffffff8118cb10>] ? ub_slab_ptr+0x20/0x90
<4>[46267.087006] [<ffffffff8118cb10>] ? ub_slab_ptr+0x20/0x90
<4>[46267.087081] [<ffffffff8118f2e8>] ? kmem_cache_alloc+0xd8/0x1e0
<4>[46267.087151] [<ffffffff81445599>] sys_sendto+0x139/0x190
<4>[46267.087229] [<ffffffff81448c0d>] ? sock_setsockopt+0x16d/0x6f0
<4>[46267.087303] [<ffffffff810efa47>] ? audit_syscall_entry+0x1d7/0x200
<4>[46267.087378] [<ffffffff810ef795>] ? __audit_syscall_exit+0x265/0x290
<4>[46267.087454] [<ffffffff81474885>] ? compat_sys_setsockopt+0x75/0x210
<4>[46267.087531] [<ffffffff81474b5f>] compat_sys_socketcall+0x13f/0x210
<4>[46267.087607] [<ffffffff8104dea3>] ia32_sysret+0x0/0x5
<4>[46267.087676] Code: 91 20 e2 01 75 29 48 89 de 4c 89 f7 e8 56 fa ff ff 85 c0 0f 84 68 fc ff ff 0f b6 4d c6 41 8b 45 00 e9 4d fb ff ff e8 7c 19 e9 e0 <0f> 0b eb fe f6 05 17 91 20 e2 80 74 ce 80 3d 5f 2e 00 00 00 74
<1>[46267.088023] RIP [<ffffffffa01e00a4>] nf_nat_setup_info+0x564/0x590
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Florian Westphal <fw@strlen.de>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
