Currently, if the user add a stateful object with the name size exceed
NFT_OBJ_MAXNAMELEN - 1 (i.e. 31), we truncate it down to 31 silently.
This is not friendly, furthermore, this will cause duplicated stateful
objects when the first 31 characters of the name is same. So limit the
stateful object's name size to NFT_OBJ_MAXNAMELEN - 1.
After apply this patch, error message will be printed out like this:
# name_32=$(printf "%0.sQ" {1..32})
# nft add counter filter $name_32
<cmdline>:1:1-52: Error: Could not process rule: Numerical result out
of range
add counter filter QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Also this patch cleans up the codes which missing the name size limit
validation in nftables.
Fixes: e50092404c ("netfilter: nf_tables: add stateful objects")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Some basic expressions are built into nf_tables.ko, such as nft_cmp,
nft_lookup, nft_range and so on. But these basic expressions' init
routine is a little ugly, too many goto errX labels, and we forget
to call nft_range_module_exit in the exit routine, although it is
harmless.
Acctually, the init and exit routines of these basic expressions
are same, i.e. do nft_register_expr in the init routine and do
nft_unregister_expr in the exit routine.
So it's better to arrange them into an array and deal with them
together.
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
When nft_expr_clone failed, a series of problems will happen:
1. module refcnt will leak, we call __module_get at the beginning but
we forget to put it back if ops->clone returns fail
2. memory will be leaked, if clone fail, we just return NULL and forget
to free the alloced element
3. set->nelems will become incorrect when set->size is specified. If
clone fail, we should decrease the set->nelems
Now this patch fixes these problems. And fortunately, clone fail will
only happen on counter expression when memory is exhausted.
Fixes: 086f332167 ("netfilter: nf_tables: add clone interface to expression operations")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
When CONFIG_NFT_SET_HASH is not enabled and I input the following rule:
"nft add rule filter output flow table test {ip daddr counter }", kernel
panic happened on my system:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [< (null)>] (null)
[...]
Call Trace:
[<ffffffffa0590466>] ? nft_dynset_eval+0x56/0x100 [nf_tables]
[<ffffffffa05851bb>] nft_do_chain+0xfb/0x4e0 [nf_tables]
[<ffffffffa0432f01>] ? nf_conntrack_tuple_taken+0x61/0x210 [nf_conntrack]
[<ffffffffa0459ea6>] ? get_unique_tuple+0x136/0x560 [nf_nat]
[<ffffffffa043bca1>] ? __nf_ct_ext_add_length+0x111/0x130 [nf_conntrack]
[<ffffffffa045a357>] ? nf_nat_setup_info+0x87/0x3b0 [nf_nat]
[<ffffffff81761e27>] ? ipt_do_table+0x327/0x610
[<ffffffffa045a6d7>] ? __nf_nat_alloc_null_binding+0x57/0x80 [nf_nat]
[<ffffffffa059f21f>] nft_ipv4_output+0xaf/0xd0 [nf_tables_ipv4]
[<ffffffff81702515>] nf_iterate+0x55/0x60
[<ffffffff81702593>] nf_hook_slow+0x73/0xd0
Because in rbtree type set, ops->update is not implemented. So just keep
it simple, in such case, report -EOPNOTSUPP to the user space.
Fixes: 22fe54d5fe ("netfilter: nf_tables: add support for dynamic set updates")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
With HZ=100 element timeout in dynamic sets (i.e. flow tables) is 10 times
higher than configured.
Add proper conversion to/from jiffies, when interacting with userspace.
I tested this on Linux 4.8.1, and it applies cleanly to current nf and
nf-next trees.
Fixes: 22fe54d5fe ("netfilter: nf_tables: add support for dynamic set updates")
Signed-off-by: Anders K. Pedersen <akp@cohaesio.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The dynset expression matches if we can fit a new entry into the set.
If there is no room for it, then it breaks the rule evaluation.
This patch introduces the inversion flag so you can add rules to
explicitly drop packets that don't fit into the set. For example:
# nft filter input flow table xyz size 4 { ip saddr timeout 120s counter } overflow drop
This is useful to provide a replacement for connlimit.
For the rule above, every new entry uses the IPv4 address as key in the
set, this entry gets a timeout of 120 seconds that gets refresh on every
packet seen. If we get new flow and our set already contains 4 entries
already, then this packet is dropped.
You can already express this in positive logic, assuming default policy
to drop:
# nft filter input flow table xyz size 4 { ip saddr timeout 10s counter } accept
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
nla_data() is now aligned on a 64-bit area.
A temporary version (nla_put_be64_32bit()) is added for nla_put_net64().
This function is removed in the next patch.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With the conversion of the counter expressions to make it percpu, we
need to clone the percpu memory area, otherwise we crash when using
counters from flow tables.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Support instantiating stateful expressions based on a template that
are associated with dynamically created set entries. The expressions
are evaluated when adding or updating the set element.
This allows to maintain per flow state using the existing set
infrastructure and expression types, with arbitrary definitions of
a flow.
Usage is currently restricted to anonymous sets, meaning only a single
binding can exist, since the desired semantics of multiple independant
bindings haven't been defined so far.
Examples (userspace syntax is still WIP):
1. Limit the rate of new SSH connections per host, similar to iptables
hashlimit:
flow ip saddr timeout 60s \
limit 10/second \
accept
2. Account network traffic between each set of /24 networks:
flow ip saddr & 255.255.255.0 . ip daddr & 255.255.255.0 \
counter
3. Account traffic to each host per user:
flow skuid . ip daddr \
counter
4. Account traffic for each combination of source address and TCP flags:
flow ip saddr . tcp flags \
counter
The resulting set content after a Xmas-scan look like this:
{
192.168.122.1 . fin | psh | urg : counter packets 1001 bytes 40040,
192.168.122.1 . ack : counter packets 74 bytes 3848,
192.168.122.1 . psh | ack : counter packets 35 bytes 3144
}
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add helper functions to parse and dump register values in netlink attributes.
These helpers will later be changed to take care of translation between the
old 128 bit and the new 32 bit register numbers.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Replace the array of registers passed to expressions by a struct nft_regs,
containing the verdict as a seperate member, which aliases to the
NFT_REG_VERDICT register.
This is needed to seperate the verdict from the data registers completely,
so their size can be changed.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Change nft_validate_input_register() to not only validate the input
register number, but also the length of the load, and rename it to
nft_validate_register_load() to reflect that change.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add a new "dynset" expression for dynamic set updates.
A new set op ->update() is added which, for non existant elements,
invokes an initialization callback and inserts the new element.
For both new or existing elements the extenstion pointer is returned
to the caller to optionally perform timer updates or other actions.
Element removal is not supported so far, however that seems to be a
rather exotic need and can be added later on.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Liping Zhang