The code that hashes and unhashes connections from the connection table
is missing locking of the connection being modified, which opens up a
race condition and results in memory corruption when this race condition
is hit.
Here is what happens in pretty verbose form:
CPU 0 CPU 1
------------ ------------
An active connection is terminated and
we schedule ip_vs_conn_expire() on this
CPU to expire this connection.
IRQ assignment is changed to this CPU,
but the expire timer stays scheduled on
the other CPU.
New connection from same ip:port comes
in right before the timer expires, we
find the inactive connection in our
connection table and get a reference to
it. We proper lock the connection in
tcp_state_transition() and read the
connection flags in set_tcp_state().
ip_vs_conn_expire() gets called, we
unhash the connection from our
connection table and remove the hashed
flag in ip_vs_conn_unhash(), without
proper locking!
While still holding proper locks we
write the connection flags in
set_tcp_state() and this sets the hashed
flag again.
ip_vs_conn_expire() fails to expire the
connection, because the other CPU has
incremented the reference count. We try
to re-insert the connection into our
connection table, but this fails in
ip_vs_conn_hash(), because the hashed
flag has been set by the other CPU. We
re-schedule execution of
ip_vs_conn_expire(). Now this connection
has the hashed flag set, but isn't
actually hashed in our connection table
and has a dangling list_head.
We drop the reference we held on the
connection and schedule the expire timer
for timeouting the connection on this
CPU. Further packets won't be able to
find this connection in our connection
table.
ip_vs_conn_expire() gets called again,
we think it's already hashed, but the
list_head is dangling and while removing
the connection from our connection table
we write to the memory location where
this list_head points to.
The result will probably be a kernel oops at some other point in time.
This race condition is pretty subtle, but it can be triggered remotely.
It needs the IRQ assignment change or another circumstance where packets
coming from the same ip:port for the same service are being processed on
different CPUs. And it involves hitting the exact time at which
ip_vs_conn_expire() gets called. It can be avoided by making sure that
all packets from one connection are always processed on the same CPU and
can be made harder to exploit by changing the connection timeouts to
some custom values.
Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Cc: stable@kernel.org
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Patrick McHardy <kaber@trash.net>
commit f3c5c1bfd4 (netfilter: xtables: make ip_tables reentrant)
introduced a performance regression, because stackptr array is shared by
all cpus, adding cache line ping pongs. (16 cpus share a 64 bytes cache
line)
Fix this using alloc_percpu()
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-By: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
In xt_register_table, xt_jumpstack_alloc is called first, later
xt_replace_table is used. But in xt_replace_table, xt_jumpstack_alloc
will be used again. Then the memory allocated by previous xt_jumpstack_alloc
will be leaked. We can simply remove the previous xt_jumpstack_alloc because
there aren't any users of newinfo between xt_jumpstack_alloc and
xt_replace_table.
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jan Engelhardt <jengelh@medozas.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Acked-By: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
After commit 7fee226a (net: add a noref bit on skb dst), its wrong to
use : dst_release(skb_dst(skb)), since we could decrement a refcount
while skb dst was not refcounted.
We should use skb_dst_drop(skb) instead.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This race was triggered by a 'conntrack -F' command running in parallel
to the insertion of a hash for a new connection. Losing this race led to
a dead conntrack entry effectively blocking traffic for a particular
connection until timeout or flushing the conntrack hashes again.
Now the check for an already dying connection is done inside the lock.
Signed-off-by: Joerg Marx <joerg.marx@secunet.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Use low order bit of skb->_skb_dst to tell dst is not refcounted.
Change _skb_dst to _skb_refdst to make sure all uses are catched.
skb_dst() returns the dst, regardless of noref bit set or not, but
with a lockdep check to make sure a noref dst is not given if current
user is not rcu protected.
New skb_dst_set_noref() helper to set an notrefcounted dst on a skb.
(with lockdep check)
skb_dst_drop() drops a reference only if skb dst was refcounted.
skb_dst_force() helper is used to force a refcount on dst, when skb
is queued and not anymore RCU protected.
Use skb_dst_force() in __sk_add_backlog(), __dev_xmit_skb() if
!IFF_XMIT_DST_RELEASE or skb enqueued on qdisc queue, in
sock_queue_rcv_skb(), in __nf_queue().
Use skb_dst_force() in dev_requeue_skb().
Note: dst_use_noref() still dirties dst, we might transform it
later to do one dirtying per jiffies.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix xt_TEE build for the case of NF_CONNTRACK=m and
NETFILTER_XT_TARGET_TEE=y:
xt_TEE.c:(.text+0x6df5c): undefined reference to `nf_conntrack_untracked'
4x
Built with all 4 m/y combinations.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Handle non-linear skbs by linearizing them instead of silently failing.
Long term the helper should be fixed to either work with non-linear skbs
directly by using the string search API or work on a copy of the data.
Based on patch by Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This patch removes from net/ netfilter files
all the unnecessary return; statements that precede the
last closing brace of void functions.
It does not remove the returns that are immediately
preceded by a label as gcc doesn't like that.
Done via:
$ grep -rP --include=*.[ch] -l "return;\n}" net/ | \
xargs perl -i -e 'local $/ ; while (<>) { s/\n[ \t\n]+return;\n}/\n}/g; print; }'
Signed-off-by: Joe Perches <joe@perches.com>
[Patrick: changed to keep return statements in otherwise empty function bodies]
Signed-off-by: Patrick McHardy <kaber@trash.net>
Make sure all printk messages have a severity level.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Aviod these link-time errors when IPV6=m, XT_TEE=y:
net/built-in.o: In function `tee_tg_route6':
xt_TEE.c:(.text+0x45ca5): undefined reference to `ip6_route_output'
net/built-in.o: In function `tee_tg6':
xt_TEE.c:(.text+0x45d79): undefined reference to `ip6_local_out'
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since xt_action_param is writable, let's use it. The pointer to
'bool hotdrop' always worried (8 bytes (64-bit) to write 1 byte!).
Surprisingly results in a reduction in size:
text data bss filename
5457066 692730 357892 vmlinux.o-prev
5456554 692730 357892 vmlinux.o
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
In future, layer-3 matches will be an xt module of their own, and
need to set the fragoff and thoff fields. Adding more pointers would
needlessy increase memory requirements (esp. so for 64-bit, where
pointers are wider).
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Restore the rcu_dereference() calls in conntrack/expectation notifier
and logger registration/unregistration, but use the _protected variant,
which will be required by the upcoming __rcu annotations.
Based on patch by Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
I suspect an unfortunatly series of events occuring under a DDoS
attack, in function __nf_conntrack_find() nf_contrack_core.c.
Adding a stats counter to see if the search is restarted too often.
Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: Patrick McHardy <kaber@trash.net>
The jumpstack allocation needs to be moved out of the critical region.
Corrects this notice:
BUG: sleeping function called from invalid context at mm/slub.c:1705
[ 428.295762] in_atomic(): 1, irqs_disabled(): 0, pid: 9111, name: iptables
[ 428.295771] Pid: 9111, comm: iptables Not tainted 2.6.34-rc1 #2
[ 428.295776] Call Trace:
[ 428.295791] [<c012138e>] __might_sleep+0xe5/0xed
[ 428.295801] [<c019e8ca>] __kmalloc+0x92/0xfc
[ 428.295825] [<f865b3bb>] ? xt_jumpstack_alloc+0x36/0xff [x_tables]
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Define a new function to return the waitqueue of a "struct sock".
static inline wait_queue_head_t *sk_sleep(struct sock *sk)
{
return sk->sk_sleep;
}
Change all read occurrences of sk_sleep by a call to this function.
Needed for a future RCU conversion. sk_sleep wont be a field directly
available.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Replace the runtime oif name resolving by netdevice notifier based
resolving. When an oif is given, a netdevice notifier is registered
to resolve the name on NETDEV_REGISTER or NETDEV_CHANGE and unresolve
it again on NETDEV_UNREGISTER or NETDEV_CHANGE to a different name.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Since Xtables is now reentrant/nestable, the cloned packet can also go
through Xtables and be subject to rules itself.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Currently, the table traverser stores return addresses in the ruleset
itself (struct ip6t_entry->comefrom). This has a well-known drawback:
the jumpstack is overwritten on reentry, making it necessary for
targets to return absolute verdicts. Also, the ruleset (which might
be heavy memory-wise) needs to be replicated for each CPU that can
possibly invoke ip6t_do_table.
This patch decouples the jumpstack from struct ip6t_entry and instead
puts it into xt_table_info. Not being restricted by 'comefrom'
anymore, we can set up a stack as needed. By default, there is room
allocated for two entries into the traverser.
arp_tables is not touched though, because there is just one/two
modules and further patches seek to collapse the table traverser
anyhow.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
xt_TEE can be used to clone and reroute a packet. This can for
example be used to copy traffic at a router for logging purposes
to another dedicated machine.
References: http://www.gossamer-threads.com/lists/iptables/devel/68781
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Fix some coding styles and remove moduleparam.h
Signed-off-by: Zhitong Wang <zhitong.wangzt@alibaba-inc.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Add reference counting to the netfilter LED target, to fix errors when
multiple rules point to the same target ("LED trigger already exists").
Signed-off-by: Adam Nielsen <a.nielsen@shikadi.net>
Signed-off-by: Patrick McHardy <kaber@trash.net>
The CONFIG_PROVE_RCU option discovered a few invalid uses of
rcu_dereference() in netfilter. In all these cases, the code code
intends to check whether a pointer is already assigned when
performing registration or whether the assigned pointer matches
when performing unregistration. The entire registration/
unregistration is protected by a mutex, so we don't need the
rcu_dereference() calls.
Reported-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Tested-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
As we will set ip_summed to CHECKSUM_NONE when necessary in
nfqnl_mangle, there is no need to zap CHECKSUM_COMPLETE in
nfqnl_build_packet_message.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Patrick McHardy <kaber@trash.net>
When protocols use very long names, the sprintf calls might overflow
the on-stack buffer. No protocol in the kernel does this however.
Print the protocol name in the pr_debug statement directly to avoid
this.
Based on patch by Zhitong Wang <zhitong.wangzt@alibaba-inc.com>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Patrick McHardy <kaber@trash.net>
xt_hashlimit uses a central lock per hash table and suffers from
contention on some workloads. (Multiqueue NIC or if RPS is enabled)
After RCU conversion, central lock is only used when a writer wants to
add or delete an entry.
For 'readers', updating an existing entry, they use an individual lock
per entry.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Message size should be dependent on the presence of an accounting
extension, not on CONFIG_NF_CT_ACCT definition.
Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
A missing break statement in hashlimit_ipv6_mask(), and masks
between /64 and /95 are not working at all...
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
When extended status codes are available, such as ENOMEM on failed
allocations, or subsequent functions (e.g. nf_ct_get_l3proto), passing
them up to userspace seems like a good idea compared to just always
EINVAL.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Restore function signatures from bool to int so that we can report
memory allocation failures or similar using -ENOMEM rather than
always having to pass -EINVAL back.
// <smpl>
@@
type bool;
identifier check, par;
@@
-bool check
+int check
(struct xt_tgchk_param *par) { ... }
// </smpl>
Minus the change it does to xt_ct_find_proto.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Restore function signatures from bool to int so that we can report
memory allocation failures or similar using -ENOMEM rather than
always having to pass -EINVAL back.
This semantic patch may not be too precise (checking for functions
that use xt_mtchk_param rather than functions referenced by
xt_match.checkentry), but reviewed, it produced the intended result.
// <smpl>
@@
type bool;
identifier check, par;
@@
-bool check
+int check
(struct xt_mtchk_param *par) { ... }
// </smpl>
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
