Relax the checking that was introduced in 97840cb6 ("netfilter:
nfnetlink: fix insufficient validation in nfnetlink_bind") when the
subscription bitmask is used. Existing userspace code code may request
to listen to all of the existing netlink groups by setting an all to one
subscription group bitmask. Netlink already validates subscription via
setsockopt() for us.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Make sure there is enough room for the nfnetlink header in the
netlink messages that are part of the batch. There is a similar
check in netlink_rcv_skb().
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Actually after netlink_skb_clone() is called, the nskb and
skb will point to the same thing, but they are used just like
they are different, sometimes this is confusing, so i think
there is no necessary to keep nskb anymore.
Signed-off-by: NDuan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: NPablo Neira Ayuso <pablo@soleta.eu>

Netlink families can exist in multiple namespaces, and for the most
part multicast subscriptions are per network namespace. Thus it only
makes sense to have bind/unbind notifications per network namespace.

To achieve this, pass the network namespace of a given client socket
to the bind/unbind functions.

Also do this in generic netlink, and there also make sure that any
bind for multicast groups that only exist in init_net is rejected.
This isn't really a problem if it is accepted since a client in a
different namespace will never receive any notifications from such
a group, but it can confuse the family if not rejected (it's also
possible to silently (without telling the family) accept it, but it
would also have to be ignored on unbind so families that take any
kind of action on bind/unbind won't do unnecessary work for invalid
clients like that.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make sure the netlink group exists, otherwise you can trigger an out
of bound array memory access from the netlink_bind() path. This splat
can only be triggered only by superuser.

[  180.203600] UBSan: Undefined behaviour in ../net/netfilter/nfnetlink.c:467:28
[  180.204249] index 9 is out of range for type 'int [9]'
[  180.204697] CPU: 0 PID: 1771 Comm: trinity-main Not tainted 3.18.0-rc4-mm1+ #122
[  180.205365] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org
+04/01/2014
[  180.206498]  0000000000000018 0000000000000000 0000000000000009 ffff88007bdf7da8
[  180.207220]  ffffffff82b0ef5f 0000000000000092 ffffffff845ae2e0 ffff88007bdf7db8
[  180.207887]  ffffffff8199e489 ffff88007bdf7e18 ffffffff8199ea22 0000003900000000
[  180.208639] Call Trace:
[  180.208857] dump_stack (lib/dump_stack.c:52)
[  180.209370] ubsan_epilogue (lib/ubsan.c:174)
[  180.209849] __ubsan_handle_out_of_bounds (lib/ubsan.c:400)
[  180.210512] nfnetlink_bind (net/netfilter/nfnetlink.c:467)
[  180.210986] netlink_bind (net/netlink/af_netlink.c:1483)
[  180.211495] SYSC_bind (net/socket.c:1541)

Moreover, define the missing nf_tables and nf_acct multicast groups too.
Reported-by: NAndrey Ryabinin <a.ryabinin@samsung.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This allows us to access the original content of the batch from
the commit and the abort paths.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

We have to wait until the full batch has been processed to deliver the
netlink error messages to userspace. Otherwise, we may deliver
duplicated errors to userspace in case that we need to abort and replay
the transaction if any of the required modules needs to be autoloaded.

A simple way to reproduce this (assumming nft_meta is not loaded) with
the following test file:

 add table filter
 add chain filter test
 add chain bad test                 # intentional wrong unexistent table
 add rule filter test meta mark 0

Then, when trying to load the batch:

 # nft -f test
 test:4:1-19: Error: Could not process rule: No such file or directory
 add chain bad test
 ^^^^^^^^^^^^^^^^^^^
 test:4:1-19: Error: Could not process rule: No such file or directory
 add chain bad test
 ^^^^^^^^^^^^^^^^^^^

The error is reported twice, once when the batch is aborted due to
missing nft_meta and another when it is fully processed.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This bug manifests when calling the nft command line tool without
nf_tables kernel support.

kernel message:
[   44.071555] Netfilter messages via NETLINK v0.30.
[   44.072253] BUG: unable to handle kernel NULL pointer dereference at 0000000000000119
[   44.072264] IP: [<ffffffff8171db1f>] netlink_getsockbyportid+0xf/0x70
[   44.072272] PGD 7f2b74067 PUD 7f2b73067 PMD 0
[   44.072277] Oops: 0000 [#1] SMP
[...]
[   44.072369] Call Trace:
[   44.072373]  [<ffffffff8171fd81>] netlink_unicast+0x91/0x200
[   44.072377]  [<ffffffff817206c9>] netlink_ack+0x99/0x110
[   44.072381]  [<ffffffffa004b951>] nfnetlink_rcv+0x3c1/0x408 [nfnetlink]
[   44.072385]  [<ffffffff8171fde3>] netlink_unicast+0xf3/0x200
[   44.072389]  [<ffffffff817201ef>] netlink_sendmsg+0x2ff/0x740
[   44.072394]  [<ffffffff81044752>] ? __mmdrop+0x62/0x90
[   44.072398]  [<ffffffff816dafdb>] sock_sendmsg+0x8b/0xc0
[   44.072403]  [<ffffffff812f1af5>] ? copy_user_enhanced_fast_string+0x5/0x10
[   44.072406]  [<ffffffff816dbb6c>] ? move_addr_to_kernel+0x2c/0x50
[   44.072410]  [<ffffffff816db423>] ___sys_sendmsg+0x3c3/0x3d0
[   44.072415]  [<ffffffff811301ba>] ? handle_mm_fault+0xa9a/0xc60
[   44.072420]  [<ffffffff811362d6>] ? mmap_region+0x166/0x5a0
[   44.072424]  [<ffffffff817da84c>] ? __do_page_fault+0x1dc/0x510
[   44.072428]  [<ffffffff812b8b2c>] ? apparmor_capable+0x1c/0x60
[   44.072435]  [<ffffffff817d6e9a>] ? _raw_spin_unlock_bh+0x1a/0x20
[   44.072439]  [<ffffffff816dfc86>] ? release_sock+0x106/0x150
[   44.072443]  [<ffffffff816dc212>] __sys_sendmsg+0x42/0x80
[   44.072446]  [<ffffffff816dc262>] SyS_sendmsg+0x12/0x20
[   44.072450]  [<ffffffff817df616>] system_call_fastpath+0x1a/0x1f
Signed-off-by: NDenys Fedoryshchenko <nuclearcat@nuclearcat.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nfnetlink.c: In function ‘nfnetlink_rcv’:
net/netfilter/nfnetlink.c:371:14: warning: unused variable ‘net’ [-Wunused-variable]
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is possible by passing a netlink socket to a more privileged
executable and then to fool that executable into writing to the socket
data that happens to be valid netlink message to do something that
privileged executable did not intend to do.

To keep this from happening replace bare capable and ns_capable calls
with netlink_capable, netlink_net_calls and netlink_ns_capable calls.
Which act the same as the previous calls except they verify that the
opener of the socket had the desired permissions as well.
Reported-by: NAndy Lutomirski <luto@amacapital.net>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Have the netlink per-protocol optional bind function return an int error code
rather than void to signal a failure.

This will enable netlink protocols to perform extra checks including
capabilities and permissions verifications when updating memberships in
multicast groups.

In netlink_bind() and netlink_setsockopt() the call to the per-protocol bind
function was moved above the multicast group update to prevent any access to
the multicast socket groups before checking with the per-protocol bind
function.  This will enable the per-protocol bind function to be used to check
permissions which could be denied before making them available, and to avoid
the messy job of undoing the addition should the per-protocol bind function
fail.

The netfilter subsystem seems to be the only one currently using the
per-protocol bind function.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove duplicity and simplify code flow by moving the rcu_read_unlock() above
the condition and let the flow control exit naturally at the end of the
function.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a lockdep_nfnl_is_held() function and a nfnl_dereference() macro for
RCU dereferences protected by a NFNL subsystem mutex.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Commit 0628b123 ("netfilter: nfnetlink: add batch support and use it
from nf_tables") introduced a bug leading to various crashes in netlink_ack
when netlink message with invalid nlmsg_len was sent by an unprivileged
user.
Signed-off-by: NJiri Benc <jbenc@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds a batch support to nfnetlink. Basically, it adds
two new control messages:

* NFNL_MSG_BATCH_BEGIN, that indicates the beginning of a batch,
  the nfgenmsg->res_id indicates the nfnetlink subsystem ID.

* NFNL_MSG_BATCH_END, that results in the invocation of the
  ss->commit callback function. If not specified or an error
  ocurred in the batch, the ss->abort function is invoked
  instead.

The end message represents the commit operation in nftables, the
lack of end message results in an abort. This patch also adds the
.call_batch function that is only called from the batch receival
path.

This patch adds atomic rule updates and dumps based on
bitmask generations. This allows to atomically commit a set of
rule-set updates incrementally without altering the internal
state of existing nf_tables expressions/matches/targets.

The idea consists of using a generation cursor of 1 bit and
a bitmask of 2 bits per rule. Assuming the gencursor is 0,
then the genmask (expressed as a bitmask) can be interpreted
as:

00 active in the present, will be active in the next generation.
01 inactive in the present, will be active in the next generation.
10 active in the present, will be deleted in the next generation.
 ^
 gencursor

Once you invoke the transition to the next generation, the global
gencursor is updated:

00 active in the present, will be active in the next generation.
01 active in the present, needs to zero its future, it becomes 00.
10 inactive in the present, delete now.
^
gencursor

If a dump is in progress and nf_tables enters a new generation,
the dump will stop and return -EBUSY to let userspace know that
it has to retry again. In order to invalidate dumps, a global
genctr counter is increased everytime nf_tables enters a new
generation.

This new operation can be used from the user-space utility
that controls the firewall, eg.

nft -f restore

The rule updates contained in `file' will be applied atomically.

cat file
-----
add filter INPUT ip saddr 1.1.1.1 counter accept #1
del filter INPUT ip daddr 2.2.2.2 counter drop   #2
-EOF-

Note that the rule 1 will be inactive until the transition to the
next generation, the rule 2 will be evicted in the next generation.

There is a penalty during the rule update due to the branch
misprediction in the packet matching framework. But that should be
quickly resolved once the iteration over the commit list that
contain rules that require updates is finished.

Event notification happens once the rule-set update has been
committed. So we skip notifications is case the rule-set update
is aborted, which can happen in case that the rule-set is tested
to apply correctly.

This patch squashed the following patches from Pablo:

* nf_tables: atomic rule updates and dumps
* nf_tables: get rid of per rule list_head for commits
* nf_tables: use per netns commit list
* nfnetlink: add batch support and use it from nf_tables
* nf_tables: all rule updates are transactional
* nf_tables: attach replacement rule after stale one
* nf_tables: do not allow deletion/replacement of stale rules
* nf_tables: remove unused NFTA_RULE_FLAGS
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Get rid of the confusing mix of pid and portid and use portid consistently
for all netlink related socket identities.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NHong Zhiguo <honkiko@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit c14b78e7 ("netfilter:
nfnetlink: add mutex per subsystem") building nefnetlink.o without
CONFIG_PROVE_RCU set, triggers this GCC warning:
    net/netfilter/nfnetlink.c:65:22: warning: ‘nfnl_get_lock’ defined but not used [-Wunused-function]

The cause of that warning is, in short, that rcu_lockdep_assert()
compiles away if CONFIG_PROVE_RCU is not set. Silence this warning by
open coding nfnl_get_lock() in the sole place it was called, which
allows to remove that function.
Signed-off-by: NPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This patch replaces the global lock to one lock per subsystem.
The per-subsystem lock avoids that processes operating
with different subsystems are synchronized.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Allow an unpriviled user who has created a user namespace, and then
created a network namespace to effectively use the new network
namespace, by reducing capable(CAP_NET_ADMIN) and
capable(CAP_NET_RAW) calls to be ns_capable(net->user_ns,
CAP_NET_ADMIN), or capable(net->user_ns, CAP_NET_RAW) calls.

Allow creation of af_key sockets.
Allow creation of llc sockets.
Allow creation of af_packet sockets.

Allow sending xfrm netlink control messages.

Allow binding to netlink multicast groups.
Allow sending to netlink multicast groups.
Allow adding and dropping netlink multicast groups.
Allow sending to all netlink multicast groups and port ids.

Allow reading the netfilter SO_IP_SET socket option.
Allow sending netfilter netlink messages.
Allow setting and getting ip_vs netfilter socket options.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch defines netlink_kernel_create as a wrapper function of
__netlink_kernel_create to hide the struct module *me parameter
(which seems to be THIS_MODULE in all existing netlink subsystems).

Suggested by David S. Miller.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

nfnetlink_rcv_msg() might call a NULL callback which will cause NULL pointer
dereference.
Signed-off-by: NTomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This patch adds a hook in the binding path of netlink.

This is used by ctnetlink to allow module autoloading for the case
in which one user executes:

 conntrack -E

So far, this resulted in nfnetlink loaded, but not
nf_conntrack_netlink.

I have received in the past many complains on this behaviour.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds the following structure:

struct netlink_kernel_cfg {
        unsigned int    groups;
        void            (*input)(struct sk_buff *skb);
        struct mutex    *cb_mutex;
};

That can be passed to netlink_kernel_create to set optional configurations
for netlink kernel sockets.

I've populated this structure by looking for NULL and zero parameters at the
existing code. The remaining parameters that always need to be set are still
left in the original interface.

That includes optional parameters for the netlink socket creation. This allows
easy extensibility of this interface in the future.

This patch also adapts all callers to use this new interface.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Bug added in commit 6b75e3e8 (netfilter: nfnetlink: add RCU in
nfnetlink_rcv_msg())
Signed-off-by: NTomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Use of "unsigned int" is preferred to bare "unsigned" in net tree.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove all #inclusions of asm/system.h preparatory to splitting and killing
it.  Performed with the following command:

perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`
Signed-off-by: NDavid Howells <dhowells@redhat.com>

commit a9b3cd7f (rcu: convert uses of rcu_assign_pointer(x, NULL) to
RCU_INIT_POINTER) did a lot of incorrect changes, since it did a
complete conversion of rcu_assign_pointer(x, y) to RCU_INIT_POINTER(x,
y).

We miss needed barriers, even on x86, when y is not NULL.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Stephen Hemminger <shemminger@vyatta.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Once upon a time netlink was not sync and we had to get the effective
capabilities from the skb that was being received.  Today we instead get
the capabilities from the current task.  This has rendered the entire
purpose of the hook moot as it is now functionally equivalent to the
capable() call.
Signed-off-by: NEric Paris <eparis@redhat.com>

When assigning a NULL value to an RCU protected pointer, no barrier
is needed. The rcu_assign_pointer, used to handle that but will soon
change to not handle the special case.

Convert all rcu_assign_pointer of NULL value.

//smpl
@@ expression P; @@

- rcu_assign_pointer(P, NULL)
+ RCU_INIT_POINTER(P, NULL)

// </smpl>
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Goal of this patch is to permit nfnetlink providers not mandate
nfnl_mutex being held while nfnetlink_rcv_msg() calls them.

If struct nfnl_callback contains a non NULL call_rcu(), then
nfnetlink_rcv_msg() will use it instead of call() field, holding
rcu_read_lock instead of nfnl_mutex
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Florian Westphal <fw@strlen.de>
CC: Eric Leblond <eric@regit.org>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Make sure all printk messages have a severity level.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

This patch fixes a bug that allows to lose events when reliable
event delivery mode is used, ie. if NETLINK_BROADCAST_SEND_ERROR
and NETLINK_RECV_NO_ENOBUFS socket options are set.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove unused headers in net/netfilter/nfnetlink.c
Signed-off-by: NZhitong Wang <zhitong.wangzt@alibaba-inc.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Make nfnl socket per-petns.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Signed-off-by: NPatrick McHardy <kaber@trash.net>

This patch removes the notify chain infrastructure and replace it
by a simple function pointer. This issue has been mentioned in the
mailing list several times: the use of the notify chain adds
too much overhead for something that is only used by ctnetlink.

This patch also changes nfnetlink_send(). It seems that gfp_any()
returns GFP_KERNEL for user-context request, like those via
ctnetlink, inside the RCU read-side section which is not valid.
Using GFP_KERNEL is also evil since netlink may schedule(),
this leads to "scheduling while atomic" bug reports.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This patch cleans up the message handling path in two aspects:

 * it uses NLMSG_LENGTH() instead of NLMSG_SPACE() like rtnetlink
does in this case to check if there is enough room for the
Netlink/nfnetlink headers. No need to check for the padding room.

 * it removes a redundant header size checking that has been
 already do at the beginning of the function.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

With this patch, nfnetlink returns -ENOMEM instead of -EPERM if we
fail to create the nfnetlink netlink socket during the module
loading. This is exactly what rtnetlink does in this case.

Ideally, it would be better if we propagate the error that has
happened in netlink_kernel_create(), however, this function still
does not implement this yet.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NPatrick McHardy <kaber@trash.net>