Eric Dumazet spotted that we have to check skb->head instead
of skb->data as skb->head points to the beginning of the
data area of the skbuff. Similarly, we have to initialize the
skb->head pointer, not skb->data in __alloc_skb_head.

After this fix, netlink crashes in the release path of the
sk_buff, so let's fix that as well.

This bug was introduced in (0ebd0ac5 net: add function to
allocate sk_buff head without data area).
Reported-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit f9c22888 (netlink:
implement memory mapped recvmsg) increamented skb->users
ref count twice for a dump op which does not look right.

Following patch fixes that.

CC: Patrick McHardy <kaber@trash.net>
Signed-off-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Depending of the kernel configuration (CONFIG_UIDGID_STRICT_TYPE_CHECKS), we can
get the following errors:

net/netlink/af_netlink.c: In function ‘netlink_queue_mmaped_skb’:
net/netlink/af_netlink.c:663:14: error: incompatible types when assigning to type ‘__u32’ from type ‘kuid_t’
net/netlink/af_netlink.c:664:14: error: incompatible types when assigning to type ‘__u32’ from type ‘kgid_t’
net/netlink/af_netlink.c: In function ‘netlink_ring_set_copied’:
net/netlink/af_netlink.c:693:14: error: incompatible types when assigning to type ‘__u32’ from type ‘kuid_t’
net/netlink/af_netlink.c:694:14: error: incompatible types when assigning to type ‘__u32’ from type ‘kgid_t’

We must use the helpers to get the uid and gid, and also take care of user_ns.

Fix suggested by Eric W. Biederman <ebiederm@xmission.com>.
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add flow control for memory mapped RX. Since user-space usually doesn't
invoke recvmsg() when using memory mapped I/O, flow control is performed
in netlink_poll(). Dumps are allowed to continue if at least half of the
ring frames are unused.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add support for mmap'ed recvmsg(). To allow the kernel to construct messages
into the mapped area, a dataless skb is allocated and the data pointer is
set to point into the ring frame. This means frames will be delivered to
userspace in order of allocation instead of order of transmission. This
usually doesn't matter since the order is either not determinable by
userspace or message creation/transmission is serialized. The only case
where this can have a visible difference is nfnetlink_queue. Userspace
can't assume mmap'ed messages have ordered IDs anymore and needs to check
this if using batched verdicts.

For non-mapped sockets, nothing changes.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add support for mmap'ed sendmsg() to netlink. Since the kernel validates
received messages before processing them, the code makes sure userspace
can't modify the message contents after invoking sendmsg(). To do that
only a single mapping of the TX ring is allowed to exist and the socket
must not be shared. If either of these two conditions does not hold, it
falls back to copying.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add helper functions for looking up mmap'ed frame headers, reading and
writing their status, allocating skbs with mmap'ed data areas and a poll
function.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add support for mmap'ed RX and TX ring setup and teardown based on the
af_packet.c code. The following patches will use this to add the real
mmap'ed receive and transmit functionality.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For mmap'ed I/O a netlink specific skb destructor needs to be invoked
after the final kfree_skb() to clean up state. This doesn't work currently
since the skb's ownership is transfered to the receiving socket using
skb_set_owner_r(), which orphans the skb, thereby invoking the destructor
prematurely.

Since netlink doesn't account skbs to the originating socket, there's no
need to orphan the skb. Add a netlink specific skb_set_owner_r() variant
that does not orphan the skb and use a netlink specific destructor to
call sock_rfree().
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Netlink doesn't account skbs to the sending socket, so the there's no
need to orphan the skb before trimming it.

Removing the skb_orphan() call is required for mmap'ed netlink, which uses
a netlink specific skb destructor that must not be invoked before the
final freeing of the skb.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Memory mapped netlink needs to store the receiving userspace socket
when sending from the kernel to userspace. Rename 'ssk' to 'sk' to
avoid confusion.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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>

Move a few declarations in a header.
Acked-by: NPavel Emelyanov <xemul@parallels.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: NAndrey Vagin <avagin@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I'm not sure why, but the hlist for each entry iterators were conceived

        list_for_each_entry(pos, head, member)

The hlist ones were greedy and wanted an extra parameter:

        hlist_for_each_entry(tpos, pos, head, member)

Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.

Besides the semantic patch, there was some manual work required:

 - Fix up the actual hlist iterators in linux/list.h
 - Fix up the declaration of other iterators based on the hlist ones.
 - A very small amount of places were using the 'node' parameter, this
 was modified to use 'obj->member' instead.
 - Coccinelle didn't handle the hlist_for_each_entry_safe iterator
 properly, so those had to be fixed up manually.

The semantic patch which is mostly the work of Peter Senna Tschudin is here:

@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;

type T;
expression a,c,d,e;
identifier b;
statement S;
@@

-T b;
    <+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
    ...+>

[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: NPeter Senna Tschudin <peter.senna@gmail.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

proc_net_remove is only used to remove proc entries
that under /proc/net,it's not a general function for
removing proc entries of netns. if we want to remove
some proc entries which under /proc/net/stat/, we still
need to call remove_proc_entry.

this patch use remove_proc_entry to replace proc_net_remove.
we can remove proc_net_remove after this patch.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Right now, some modules such as bonding use proc_create
to create proc entries under /proc/net/, and other modules
such as ipv4 use proc_net_fops_create.

It looks a little chaos.this patch changes all of
proc_net_fops_create to proc_create. we can remove
proc_net_fops_create after this patch.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Otherwise an out of bounds read could happen.
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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>

On some suspend/resume operations involving wimax device, we have
noticed some intermittent memory corruptions in netlink code.

Stéphane Marchesin tracked this corruption in netlink_update_listeners()
and suggested a patch.

It appears netlink_release() should use kfree_rcu() instead of kfree()
for the listeners structure as it may be used by other cpus using RCU
protection.

netlink_release() must set to NULL the listeners pointer when
it is about to be freed.

Also have to protect netlink_update_listeners() and
netlink_has_listeners() if listeners is NULL.

Add a nl_deref_protected() lockdep helper to properly document which
locks protects us.
Reported-by: NJonathan Kliegman <kliegs@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Stéphane Marchesin <marcheu@google.com>
Cc: Sam Leffler <sleffler@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I get a panic when I use ss -a and rmmod inet_diag at the
same time.

It's because netlink_dump uses inet_diag_dump which belongs to module
inet_diag.

I search the codes and find many modules have the same problem.  We
need to add a reference to the module which the cb->dump belongs to.

Thanks for all help from Stephen,Jan,Eric,Steffen and Pablo.

Change From v3:
change netlink_dump_start to inline,suggestion from Pablo and
Eric.

Change From v2:
delete netlink_dump_done,and call module_put in netlink_dump
and netlink_sock_destruct.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is a frequent mistake to confuse the netlink port identifier with a
process identifier.  Try to reduce this confusion by renaming fields
that hold port identifiers portid instead of pid.

I have carefully avoided changing the structures exported to
userspace to avoid changing the userspace API.

I have successfully built an allyesconfig kernel with this change.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: NStephen Hemminger <shemminger@vyatta.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>

Replace netlink_set_nonroot by one new field `flags' in
struct netlink_kernel_cfg that is passed to netlink_kernel_create.

This patch also renames NL_NONROOT_* to NL_CFG_F_NONROOT_* since
now the flags field in nl_table is generic (so we can add more
flags if needed in the future).

Also adjust all callers in the net-next tree to use these flags
instead of netlink_set_nonroot.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Passing uids and gids on NETLINK_CB from a process in one user
namespace to a process in another user namespace can result in the
wrong uid or gid being presented to userspace.  Avoid that problem by
passing kuids and kgids instead.

- define struct scm_creds for use in scm_cookie and netlink_skb_parms
  that holds uid and gid information in kuid_t and kgid_t.

- Modify scm_set_cred to fill out scm_creds by heand instead of using
  cred_to_ucred to fill out struct ucred.  This conversion ensures
  userspace does not get incorrect uid or gid values to look at.

- Modify scm_recv to convert from struct scm_creds to struct ucred
  before copying credential values to userspace.

- Modify __scm_send to populate struct scm_creds on in the scm_cookie,
  instead of just copying struct ucred from userspace.

- Modify netlink_sendmsg to copy scm_creds instead of struct ucred
  into the NETLINK_CB.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Non-root user-space processes can send Netlink messages to other
processes that are well-known for being subscribed to Netlink
asynchronous notifications. This allows ilegitimate non-root
process to send forged messages to Netlink subscribers.

The userspace process usually verifies the legitimate origin in
two ways:

a) Socket credentials. If UID != 0, then the message comes from
   some ilegitimate process and the message needs to be dropped.

b) Netlink portID. In general, portID == 0 means that the origin
   of the messages comes from the kernel. Thus, discarding any
   message not coming from the kernel.

However, ctnetlink sets the portID in event messages that has
been triggered by some user-space process, eg. conntrack utility.
So other processes subscribed to ctnetlink events, eg. conntrackd,
know that the event was triggered by some user-space action.

Neither of the two ways to discard ilegitimate messages coming
from non-root processes can help for ctnetlink.

This patch adds capability validation in case that dst_pid is set
in netlink_sendmsg(). This approach is aggressive since existing
applications using any Netlink bus to deliver messages between
two user-space processes will break. Note that the exception is
NETLINK_USERSOCK, since it is reserved for netlink-to-netlink
userspace communication.

Still, if anyone wants that his Netlink bus allows netlink-to-netlink
userspace, then they can set NL_NONROOT_SEND. However, by default,
I don't think it makes sense to allow to use NETLINK_ROUTE to
communicate two processes that are sending no matter what information
that is not related to link/neighbouring/routing. They should be using
NETLINK_USERSOCK instead for that.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pablo Neira Ayuso discovered that avahi and
potentially NetworkManager accept spoofed Netlink messages because of a
kernel bug.  The kernel passes all-zero SCM_CREDENTIALS ancillary data
to the receiver if the sender did not provide such data, instead of not
including any such data at all or including the correct data from the
peer (as it is the case with AF_UNIX).

This bug was introduced in commit 16e57262
(af_unix: dont send SCM_CREDENTIALS by default)

This patch forces passing credentials for netlink, as
before the regression.

Another fix would be to not add SCM_CREDENTIALS in
netlink messages if not provided by the sender, but it
might break some programs.

With help from Florian Weimer & Petr Matousek

This issue is designated as CVE-2012-3520
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Petr Matousek <pmatouse@redhat.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The sending socket of an skb is already available by it's port id
in the NETLINK_CB.  If you want to know more like to examine the
credentials on the sending socket you have to look up the sending
socket by it's port id and all of the needed functions and data
structures are static inside of af_netlink.c.  So do the simple
thing and pass the sending socket to the receivers in the NETLINK_CB.

I intend to use this to get the user namespace of the sending socket
in inet_diag so that I can report uids in the context of the process
who opened the socket, the same way I report uids in the contect
of the process who opens files.
Acked-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

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>

Need to consume_skb() instead of kfree_skb() in netlink_dump() and
netlink_unicast_kernel() to avoid false dropwatch positives.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

netlink_destroy_callback() move to avoid forward reference

CodingStyle cleanups
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When we need to clone skb, we dont drop a packet.
Call consume_skb() to not confuse dropwatch.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As soon as an skb is queued into socket receive_queue, another thread
can consume it, so we are not allowed to reference skb anymore, or risk
use after free.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch allows you to pass a data pointer that can be
accessed from the dump callback.

Netfilter is going to use this patch to provide filtered dumps
to user-space. This is specifically interesting in ctnetlink that
may handle lots of conntrack entries. We can save precious
cycles by skipping the conversion to TLV format of conntrack
entries that are not interesting for user-space.

More specifically, ctnetlink will include one operation to allow
to filter the dumping of conntrack entries by ctmark values.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Davem considers that the argument list of this interface is getting
out of control. This patch tries to address this issue following
his proposal:

struct netlink_dump_control c = { .dump = dump, .done = done, ... };

netlink_dump_start(..., &c);

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