commit 9d5c12a7c0 upstream.
This is a very conservative limit (134217728 rules), but good
enough to not trigger frequent oom from syzkaller.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7d7d7e0211 upstream.
no need to bother even trying to allocating huge compat offset arrays,
such ruleset is rejected later on anyway becaus we refuse to allocate
overly large rule blobs.
However, compat translation happens before blob allocation, so we should
add a check there too.
This is supposed to help with fuzzing by avoiding oom-killer.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9782a11efc upstream.
should have no impact, function still always returns 0.
This patch is only to ease review.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c84ca954ac upstream.
allows to have size checks in a single spot.
This is supposed to reduce oom situations when fuzz-testing xtables.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 19926968ea upstream.
Arbitrary limit, however, this still allows huge rulesets
(> 1 million rules). This helps with automated fuzzer as it prevents
oom-killer invocation.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b1d0a5d0cb upstream.
recent and hashlimit both create /proc files, but only check that
name is 0 terminated.
This can trigger WARN() from procfs when name is "" or "/".
Add helper for this and then use it for both.
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: <syzbot+0502b00edac2a0680b61@syzkaller.appspotmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 0537250fdc upstream.
syzbot has noticed that xt_alloc_table_info can allocate a lot of memory.
This is an admin only interface but an admin in a namespace is sufficient
as well. eacd86ca3b ("net/netfilter/x_tables.c: use kvmalloc() in
xt_alloc_table_info()") has changed the opencoded kmalloc->vmalloc
fallback into kvmalloc. It has dropped __GFP_NORETRY on the way because
vmalloc has simply never fully supported __GFP_NORETRY semantic. This is
still the case because e.g. page tables backing the vmalloc area are
hardcoded GFP_KERNEL.
Revert back to __GFP_NORETRY as a poors man defence against excessively
large allocation request here. We will not rule out the OOM killer
completely but __GFP_NORETRY should at least stop the large request in
most cases.
[akpm@linux-foundation.org: coding-style fixes]
Fixes: eacd86ca3b ("net/netfilter/x_tables.c: use kvmalloc() in xt_alloc_tableLink: http://lkml.kernel.org/r/20180130140104.GE21609@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit da17c73b6e upstream.
It looks like syzbot found its way into netfilter territory.
Issue here is that @name comes from user space and might
not be null terminated.
Out-of-bound reads happen, KASAN is not happy.
v2 added similar fix for xt_request_find_target(),
as Florian advised.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 889c604fd0 upstream.
syzkaller triggered OOM kills by passing ipt_replace.size = -1
to IPT_SO_SET_REPLACE. The root cause is that SMP_ALIGN() in
xt_alloc_table_info() causes int overflow and the size check passes
when it should not. SMP_ALIGN() is no longer needed leftover.
Remove SMP_ALIGN() call in xt_alloc_table_info().
Reported-by: syzbot+4396883fa8c4f64e0175@syzkaller.appspotmail.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
syzkaller reports an out of bound read in strlcpy(), triggered
by xt_copy_counters_from_user()
Fix this by using memcpy(), then forcing a zero byte at the last position
of the destination, as Florian did for the non COMPAT code.
Fixes: d7591f0c41 ("netfilter: x_tables: introduce and use xt_copy_counters_from_user")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The patch in the Fixes references COMPAT_XT_ALIGN in the definition
of XT_DATA_TO_USER, outside an #ifdef CONFIG_COMPAT block.
Split XT_DATA_TO_USER into separate compat and non compat variants and
define the first inside an CONFIG_COMPAT block.
This simplifies both variants by removing branches inside the macro.
Fixes: 324318f024 ("netfilter: xtables: zero padding in data_to_user")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
When looking up an iptables rule, the iptables binary compares the
aligned match and target data (XT_ALIGN). In some cases this can
exceed the actual data size to include padding bytes.
Before commit f77bc5b23f ("iptables: use match, target and data
copy_to_user helpers") the malloc()ed bytes were overwritten by the
kernel with kzalloced contents, zeroing the padding and making the
comparison succeed. After this patch, the kernel copies and clears
only data, leaving the padding bytes undefined.
Extend the clear operation from data size to aligned data size to
include the padding bytes, if any.
Padding bytes can be observed in both match and target, and the bug
triggered, by issuing a rule with match icmp and target ACCEPT:
iptables -t mangle -A INPUT -i lo -p icmp --icmp-type 1 -j ACCEPT
iptables -t mangle -D INPUT -i lo -p icmp --icmp-type 1 -j ACCEPT
Fixes: f77bc5b23f ("iptables: use match, target and data copy_to_user helpers")
Reported-by: Paul Moore <pmoore@redhat.com>
Reported-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
__vmalloc* allows users to provide gfp flags for the underlying
allocation. This API is quite popular
$ git grep "=[[:space:]]__vmalloc\|return[[:space:]]*__vmalloc" | wc -l
77
The only problem is that many people are not aware that they really want
to give __GFP_HIGHMEM along with other flags because there is really no
reason to consume precious lowmemory on CONFIG_HIGHMEM systems for pages
which are mapped to the kernel vmalloc space. About half of users don't
use this flag, though. This signals that we make the API unnecessarily
too complex.
This patch simply uses __GFP_HIGHMEM implicitly when allocating pages to
be mapped to the vmalloc space. Current users which add __GFP_HIGHMEM
are simplified and drop the flag.
Link: http://lkml.kernel.org/r/20170307141020.29107-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Cristopher Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are many code paths opencoding kvmalloc. Let's use the helper
instead. The main difference to kvmalloc is that those users are
usually not considering all the aspects of the memory allocator. E.g.
allocation requests <= 32kB (with 4kB pages) are basically never failing
and invoke OOM killer to satisfy the allocation. This sounds too
disruptive for something that has a reasonable fallback - the vmalloc.
On the other hand those requests might fallback to vmalloc even when the
memory allocator would succeed after several more reclaim/compaction
attempts previously. There is no guarantee something like that happens
though.
This patch converts many of those places to kv[mz]alloc* helpers because
they are more conservative.
Link: http://lkml.kernel.org/r/20170306103327.2766-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> # Xen bits
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Andreas Dilger <andreas.dilger@intel.com> # Lustre
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> # KVM/s390
Acked-by: Dan Williams <dan.j.williams@intel.com> # nvdim
Acked-by: David Sterba <dsterba@suse.com> # btrfs
Acked-by: Ilya Dryomov <idryomov@gmail.com> # Ceph
Acked-by: Tariq Toukan <tariqt@mellanox.com> # mlx4
Acked-by: Leon Romanovsky <leonro@mellanox.com> # mlx5
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Santosh Raspatur <santosh@chelsio.com>
Cc: Hariprasad S <hariprasad@chelsio.com>
Cc: Yishai Hadas <yishaih@mellanox.com>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Cc: "Yan, Zheng" <zyan@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
According to my static checker we should unlock here before the return.
That seems reasonable to me as well.
Fixes" b9e69e1273 ("netfilter: xtables: don't hook tables by default")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Fix typos and add the following to the scripts/spelling.txt:
aligment||alignment
I did not touch the "N_BYTE_ALIGMENT" macro in
drivers/net/wireless/realtek/rtlwifi/wifi.h to avoid unpredictable
impact.
I fixed "_aligment_handler" in arch/openrisc/kernel/entry.S because
it is surrounded by #if 0 ... #endif. It is surely safe and I
confirmed "_alignment_handler" is correct.
I also fixed the "controler" I found in the same hunk in
arch/openrisc/kernel/head.S.
Link: http://lkml.kernel.org/r/1481573103-11329-8-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert compat to copying entries, matches and targets one by one,
using the xt_match_to_user and xt_target_to_user helper functions.
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
xt_entry_target, xt_entry_match and their private data may contain
kernel data.
Introduce helper functions xt_match_to_user, xt_target_to_user and
xt_data_to_user that copy only the expected fields. These replace
existing logic that calls copy_to_user on entire structs, then
overwrites select fields.
Private data is defined in xt_match and xt_target. All matches and
targets that maintain kernel data store this at the tail of their
private structure. Extend xt_match and xt_target with .usersize to
limit how many bytes of data are copied. The remainder is cleared.
If compatsize is specified, usersize can only safely be used if all
fields up to usersize use platform-independent types. Otherwise, the
compat_to_user callback must be defined.
This patch does not yet enable the support logic.
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Andrey Konovalov reported that this vmalloc call is based on an
userspace request and that it's spewing traces, which may flood the logs
and cause DoS if abused.
Florian Westphal also mentioned that this call should not trigger OOM
killer.
This patch brings the vmalloc call in sync to kmalloc and disables the
warn trace on allocation failure and also disable OOM killer invocation.
Note, however, that under such stress situation, other places may
trigger OOM killer invocation.
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
instead of allocating each xt_counter individually, allocate 4k chunks
and then use these for counter allocation requests.
This should speed up rule evaluation by increasing data locality,
also speeds up ruleset loading because we reduce calls to the percpu
allocator.
As Eric points out we can't use PAGE_SIZE, page_allocator would fail on
arches with 64k page size.
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Keeps some noise away from a followup patch.
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
On SMP we overload the packet counter (unsigned long) to contain
percpu offset. Hide this from callers and pass xt_counters address
instead.
Preparation patch to allocate the percpu counters in page-sized batch
chunks.
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Since commit 7926dbfa4b ("netfilter: don't use
mutex_lock_interruptible()"), the function xt_find_table_lock can only
return NULL on an error. Simplify the call sites and update the
comment before the function.
The semantic patch that change the code is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
expression t,e;
@@
t = \(xt_find_table_lock(...)\|
try_then_request_module(xt_find_table_lock(...),...)\)
... when != t=e
- ! IS_ERR_OR_NULL(t)
+ t
@@
expression t,e;
@@
t = \(xt_find_table_lock(...)\|
try_then_request_module(xt_find_table_lock(...),...)\)
... when != t=e
- IS_ERR_OR_NULL(t)
+ !t
@@
expression t,e,e1;
@@
t = \(xt_find_table_lock(...)\|
try_then_request_module(xt_find_table_lock(...),...)\)
... when != t=e
?- t ? PTR_ERR(t) : e1
+ e1
... when any
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Markus Trippelsdorf reports:
WARNING: kmemcheck: Caught 64-bit read from uninitialized memory (ffff88001e605480)
4055601e0088ffff000000000000000090686d81ffffffff0000000000000000
u u u u u u u u u u u u u u u u i i i i i i i i u u u u u u u u
^
|RIP: 0010:[<ffffffff8166e561>] [<ffffffff8166e561>] nf_register_net_hook+0x51/0x160
[..]
[<ffffffff8166e561>] nf_register_net_hook+0x51/0x160
[<ffffffff8166eaaf>] nf_register_net_hooks+0x3f/0xa0
[<ffffffff816d6715>] ipt_register_table+0xe5/0x110
[..]
This warning is harmless; we copy 'uninitialized' data from the hook ops
but it will not be used.
Long term the structures keeping run-time data should be disentangled
from those only containing config-time data (such as where in the list
to insert a hook), but thats -next material.
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Aaron Conole <aconole@bytheb.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The dummy ruleset I used to test the original validation change was broken,
most rules were unreachable and were not tested by mark_source_chains().
In some cases rulesets that used to load in a few seconds now require
several minutes.
sample ruleset that shows the behaviour:
echo "*filter"
for i in $(seq 0 100000);do
printf ":chain_%06x - [0:0]\n" $i
done
for i in $(seq 0 100000);do
printf -- "-A INPUT -j chain_%06x\n" $i
printf -- "-A INPUT -j chain_%06x\n" $i
printf -- "-A INPUT -j chain_%06x\n" $i
done
echo COMMIT
[ pipe result into iptables-restore ]
This ruleset will be about 74mbyte in size, with ~500k searches
though all 500k[1] rule entries. iptables-restore will take forever
(gave up after 10 minutes)
Instead of always searching the entire blob for a match, fill an
array with the start offsets of every single ipt_entry struct,
then do a binary search to check if the jump target is present or not.
After this change ruleset restore times get again close to what one
gets when reverting 3647234101 (~3 seconds on my workstation).
[1] every user-defined rule gets an implicit RETURN, so we get
300k jumps + 100k userchains + 100k returns -> 500k rule entries
Fixes: 3647234101 ("netfilter: x_tables: validate targets of jumps")
Reported-by: Jeff Wu <wujiafu@gmail.com>
Tested-by: Jeff Wu <wujiafu@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
Netfilter updates for net-next
The following patchset contains Netfilter updates for net-next,
they are:
1) Don't use userspace datatypes in bridge netfilter code, from
Tobin Harding.
2) Iterate only once over the expectation table when removing the
helper module, instead of once per-netns, from Florian Westphal.
3) Extra sanitization in xt_hook_ops_alloc() to return error in case
we ever pass zero hooks, xt_hook_ops_alloc():
4) Handle NFPROTO_INET from the logging core infrastructure, from
Liping Zhang.
5) Autoload loggers when TRACE target is used from rules, this doesn't
change the behaviour in case the user already selected nfnetlink_log
as preferred way to print tracing logs, also from Liping Zhang.
6) Conntrack slabs with SLAB_HWCACHE_ALIGN to allow rearranging fields
by cache lines, increases the size of entries in 11% per entry.
From Florian Westphal.
7) Skip zone comparison if CONFIG_NF_CONNTRACK_ZONES=n, from Florian.
8) Remove useless defensive check in nf_logger_find_get() from Shivani
Bhardwaj.
9) Remove zone extension as place it in the conntrack object, this is
always include in the hashing and we expect more intensive use of
zones since containers are in place. Also from Florian Westphal.
10) Owner match now works from any namespace, from Eric Bierdeman.
11) Make sure we only reply with TCP reset to TCP traffic from
nf_reject_ipv4, patch from Liping Zhang.
12) Introduce --nflog-size to indicate amount of network packet bytes
that are copied to userspace via log message, from Vishwanath Pai.
This obsoletes --nflog-range that has never worked, it was designed
to achieve this but it has never worked.
13) Introduce generic macros for nf_tables object generation masks.
14) Use generation mask in table, chain and set objects in nf_tables.
This allows fixes interferences with ongoing preparation phase of
the commit protocol and object listings going on at the same time.
This update is introduced in three patches, one per object.
15) Check if the object is active in the next generation for element
deactivation in the rbtree implementation, given that deactivation
happens from the commit phase path we have to observe the future
status of the object.
16) Support for deletion of just added elements in the hash set type.
17) Allow to resize hashtable from /proc entry, not only from the
obscure /sys entry that maps to the module parameter, from Florian
Westphal.
18) Get rid of NFT_BASECHAIN_DISABLED, this code is not exercised
anymore since we tear down the ruleset whenever the netdevice
goes away.
19) Support for matching inverted set lookups, from Arturo Borrero.
20) Simplify the iptables_mangle_hook() by removing a superfluous
extra branch.
21) Introduce ether_addr_equal_masked() and use it from the netfilter
codebase, from Joe Perches.
22) Remove references to "Use netfilter MARK value as routing key"
from the Netfilter Kconfig description given that this toggle
doesn't exists already for 10 years, from Moritz Sichert.
23) Introduce generic NF_INVF() and use it from the xtables codebase,
from Joe Perches.
24) Setting logger to NONE via /proc was not working unless explicit
nul-termination was included in the string. This fixes seems to
leave the former behaviour there, so we don't break backward.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Since we cannot make sure that the 'hook_mask' will always be none
zero here. If it equals to zero, the num_hooks will be zero too,
and then kmalloc() will return ZERO_SIZE_PTR, which is (void *)16.
Then the following error check will fails:
ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL);
if (ops == NULL)
return ERR_PTR(-ENOMEM);
So this patch will fix this with just doing the zero check before
kmalloc() is called.
Maybe the case above will never happen here, but in theory.
Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Quoting John Stultz:
In updating a 32bit arm device from 4.6 to Linus' current HEAD, I
noticed I was having some trouble with networking, and realized that
/proc/net/ip_tables_names was suddenly empty.
Digging through the registration process, it seems we're catching on the:
if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0 &&
target_offset + sizeof(struct xt_standard_target) != next_offset)
return -EINVAL;
Where next_offset seems to be 4 bytes larger then the
offset + standard_target struct size.
next_offset needs to be aligned via XT_ALIGN (so we can access all members
of ip(6)t_entry struct).
This problem didn't show up on i686 as it only needs 4-byte alignment for
u64, but iptables userspace on other 32bit arches does insert extra padding.
Reported-by: John Stultz <john.stultz@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Fixes: 7ed2abddd2 ("netfilter: x_tables: check standard target size too")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The three variants use same copy&pasted code, condense this into a
helper and use that.
Make sure info.name is 0-terminated.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This looks like refactoring, but its also a bug fix.
Problem is that the compat path (32bit iptables, 64bit kernel) lacks a few
sanity tests that are done in the normal path.
For example, we do not check for underflows and the base chain policies.
While its possible to also add such checks to the compat path, its more
copy&pastry, for instance we cannot reuse check_underflow() helper as
e->target_offset differs in the compat case.
Other problem is that it makes auditing for validation errors harder; two
places need to be checked and kept in sync.
At a high level 32 bit compat works like this:
1- initial pass over blob:
validate match/entry offsets, bounds checking
lookup all matches and targets
do bookkeeping wrt. size delta of 32/64bit structures
assign match/target.u.kernel pointer (points at kernel
implementation, needed to access ->compatsize etc.)
2- allocate memory according to the total bookkeeping size to
contain the translated ruleset
3- second pass over original blob:
for each entry, copy the 32bit representation to the newly allocated
memory. This also does any special match translations (e.g.
adjust 32bit to 64bit longs, etc).
4- check if ruleset is free of loops (chase all jumps)
5-first pass over translated blob:
call the checkentry function of all matches and targets.
The alternative implemented by this patch is to drop steps 3&4 from the
compat process, the translation is changed into an intermediate step
rather than a full 1:1 translate_table replacement.
In the 2nd pass (step #3), change the 64bit ruleset back to a kernel
representation, i.e. put() the kernel pointer and restore ->u.user.name .
This gets us a 64bit ruleset that is in the format generated by a 64bit
iptables userspace -- we can then use translate_table() to get the
'native' sanity checks.
This has two drawbacks:
1. we re-validate all the match and target entry structure sizes even
though compat translation is supposed to never generate bogus offsets.
2. we put and then re-lookup each match and target.
THe upside is that we get all sanity tests and ruleset validations
provided by the normal path and can remove some duplicated compat code.
iptables-restore time of autogenerated ruleset with 300k chains of form
-A CHAIN0001 -m limit --limit 1/s -j CHAIN0002
-A CHAIN0002 -m limit --limit 1/s -j CHAIN0003
shows no noticeable differences in restore times:
old: 0m30.796s
new: 0m31.521s
64bit: 0m25.674s
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Validate that all matches (if any) add up to the beginning of
the target and that each match covers at least the base structure size.
The compat path should be able to safely re-use the function
as the structures only differ in alignment; added a
BUILD_BUG_ON just in case we have an arch that adds padding as well.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We're currently asserting that targetoff + targetsize <= nextoff.
Extend it to also check that targetoff is >= sizeof(xt_entry).
Since this is generic code, add an argument pointing to the start of the
match/target, we can then derive the base structure size from the delta.
We also need the e->elems pointer in a followup change to validate matches.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We have targets and standard targets -- the latter carries a verdict.
The ip/ip6tables validation functions will access t->verdict for the
standard targets to fetch the jump offset or verdict for chainloop
detection, but this happens before the targets get checked/validated.
Thus we also need to check for verdict presence here, else t->verdict
can point right after a blob.
Spotted with UBSAN while testing malformed blobs.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
32bit rulesets have different layout and alignment requirements, so once
more integrity checks get added to xt_check_entry_offsets it will reject
well-formed 32bit rulesets.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The target size includes the size of the xt_entry_target struct.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Currently arp/ip and ip6tables each implement a short helper to check that
the target offset is large enough to hold one xt_entry_target struct and
that t->u.target_size fits within the current rule.
Unfortunately these checks are not sufficient.
To avoid adding new tests to all of ip/ip6/arptables move the current
checks into a helper, then extend this helper in followup patches.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Ben Hawkes says:
integer overflow in xt_alloc_table_info, which on 32-bit systems can
lead to small structure allocation and a copy_from_user based heap
corruption.
Reported-by: Ben Hawkes <hawkes@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
delay hook registration until the table is being requested inside a
namespace.
Historically, a particular table (iptables mangle, ip6tables filter, etc)
was registered on module load.
When netns support was added to iptables only the ip/ip6tables ruleset was
made namespace aware, not the actual hook points.
This means f.e. that when ipt_filter table/module is loaded on a system,
then each namespace on that system has an (empty) iptables filter ruleset.
In other words, if a namespace sends a packet, such skb is 'caught' by
netfilter machinery and fed to hooking points for that table (i.e. INPUT,
FORWARD, etc).
Thanks to Eric Biederman, hooks are no longer global, but per namespace.
This means that we can avoid allocation of empty ruleset in a namespace and
defer hook registration until we need the functionality.
We register a tables hook entry points ONLY in the initial namespace.
When an iptables get/setockopt is issued inside a given namespace, we check
if the table is found in the per-namespace list.
If not, we attempt to find it in the initial namespace, and, if found,
create an empty default table in the requesting namespace and register the
needed hooks.
Hook points are destroyed only once namespace is deleted, there is no
'usage count' (it makes no sense since there is no 'remove table' operation
in xtables api).
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Various files are owned by root with 0440 permission. Reading them is
impossible in an unprivileged user namespace, interfering with firewall
tools. For instance, iptables-save relies on /proc/net/ip_tables_names
contents to dump only loaded tables.
This patch assigned ownership of the following files to root in the
current namespace:
- /proc/net/*_tables_names
- /proc/net/*_tables_matches
- /proc/net/*_tables_targets
- /proc/net/nf_conntrack
- /proc/net/nf_conntrack_expect
- /proc/net/netfilter/nfnetlink_log
A mapping for root must be available, so this order should be followed:
unshare(CLONE_NEWUSER);
/* Setup the mapping */
unshare(CLONE_NEWNET);
Signed-off-by: Philip Whineray <phil@firehol.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
since commit 8405a8fff3 ("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 <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Don't bother testing if we need to switch to alternate stack
unless TEE target is used.
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
In most cases there is no reentrancy into ip/ip6tables.
For skbs sent by REJECT or SYNPROXY targets, there is one level
of reentrancy, but its not relevant as those targets issue an absolute
verdict, i.e. the jumpstack can be clobbered since its not used
after the target issues absolute verdict (ACCEPT, DROP, STOLEN, etc).
So the only special case where it is relevant is the TEE target, which
returns XT_CONTINUE.
This patch changes ip(6)_do_table to always use the jump stack starting
from 0.
When we detect we're operating on an skb sent via TEE (percpu
nf_skb_duplicated is 1) we switch to an alternate stack to leave
the original one alone.
Since there is no TEE support for arptables, it doesn't need to
test if tee is active.
The jump stack overflow tests are no longer needed as well --
since ->stacksize is the largest call depth we cannot exceed it.
A much better alternative to the external jumpstack would be to just
declare a jumps[32] stack on the local stack frame, but that would mean
we'd have to reject iptables rulesets that used to work before.
Another alternative would be to start rejecting rulesets with a larger
call depth, e.g. 1000 -- in this case it would be feasible to allocate the
entire stack in the percpu area which would avoid one dereference.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The {arp,ip,ip6tables} jump stack is currently sized based
on the number of user chains.
However, its rather unlikely that every user defined chain jumps to the
next, so lets use the existing loop detection logic to also track the
chain depths.
The stacksize is then set to the largest chain depth seen.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
After Florian patches, there is no need for XT_TABLE_INFO_SZ anymore :
Only one copy of table is kept, instead of one copy per cpu.
We also can avoid a dereference if we put table data right after
xt_table_info. It reduces register pressure and helps compiler.
Then, we attempt a kmalloc() if total size is under order-3 allocation,
to reduce TLB pressure, as in many cases, rules fit in 32 KB.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We store the rule blob per (possible) cpu. Unfortunately this means we can
waste lot of memory on big smp machines. ipt_entry structure ('rule head')
is 112 byte, so e.g. with maxcpu=64 one single rule eats
close to 8k RAM.
Since previous patch made counters percpu it appears there is nothing
left in the rule blob that needs to be percpu.
On my test system (144 possible cpus, 400k dummy rules) this
change saves close to 9 Gigabyte of RAM.
Reported-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Using seq_has_overflowed doesn't produce the right return value.
Either 0 or -1 is, but 0 is much more common and works well when
seq allocation retries.
I believe this doesn't matter as the initial allocation is always
sufficient, this is just a correctness patch.
Miscellanea:
o Don't use strlen, use *ptr to determine if a string
should be emitted like all the other tests here
o Delete unnecessary return statements
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The return value of seq_printf() is soon to be removed. Remove the
checks from seq_printf() in favor of seq_has_overflowed().
Link: http://lkml.kernel.org/r/20141104142236.GA10239@salvia
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: netfilter-devel@vger.kernel.org
Cc: coreteam@netfilter.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Florian Westphal