'protocol' is a user-controlled value, so sanitize it after the bounds
check to avoid using it for speculative out-of-bounds access to arrays
indexed by it.

This addresses the following accesses detected with the help of smatch:

* net/netlink/af_netlink.c:654 __netlink_create() warn: potential
  spectre issue 'nlk_cb_mutex_keys' [w]

* net/netlink/af_netlink.c:654 __netlink_create() warn: potential
  spectre issue 'nlk_cb_mutex_key_strings' [w]

* net/netlink/af_netlink.c:685 netlink_create() warn: potential spectre
  issue 'nl_table' [w] (local cap)

Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NJeremy Cline <jcline@redhat.com>
Reviewed-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On i386 nlk->ngroups might be 32 or 0. Which leads to UB, resulting in
hang during boot.
Check for 0 ngroups and use (unsigned long long) as a type to shift.

Fixes: 7acf9d42 ("netlink: Do not subscribe to non-existent groups").
Reported-by: Nkernel test robot <rong.a.chen@intel.com>
Signed-off-by: NDmitry Safonov <dima@arista.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make ABI more strict about subscribing to group > ngroups.
Code doesn't check for that and it looks bogus.
(one can subscribe to non-existing group)
Still, it's possible to bind() to all possible groups with (-1)

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: netdev@vger.kernel.org
Signed-off-by: NDmitry Safonov <dima@arista.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The poll() changes were not well thought out, and completely
unexplained.  They also caused a huge performance regression, because
"->poll()" was no longer a trivial file operation that just called down
to the underlying file operations, but instead did at least two indirect
calls.

Indirect calls are sadly slow now with the Spectre mitigation, but the
performance problem could at least be largely mitigated by changing the
"->get_poll_head()" operation to just have a per-file-descriptor pointer
to the poll head instead.  That gets rid of one of the new indirections.

But that doesn't fix the new complexity that is completely unwarranted
for the regular case.  The (undocumented) reason for the poll() changes
was some alleged AIO poll race fixing, but we don't make the common case
slower and more complex for some uncommon special case, so this all
really needs way more explanations and most likely a fundamental
redesign.

[ This revert is a revert of about 30 different commits, not reverted
  individually because that would just be unnecessarily messy  - Linus ]

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Variants of proc_create{,_data} that directly take a struct seq_operations
and deal with network namespaces in ->open and ->release.  All callers of
proc_create + seq_open_net converted over, and seq_{open,release}_net are
removed entirely.
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Making sure the headers line up properly with the actual value output of the command
`cat /proc/net/netlink`

Before the patch:
<sk       Eth Pid    Groups   Rmem     Wmem     Dump     Locks     Drops     Inode
<ffff8cd2c2f7b000 0   909    00000550 0        0        0 2        0        18946

After the patch:
>sk               Eth Pid        Groups   Rmem     Wmem     Dump  Locks    Drops    Inode
>0000000033203952 0   897        00000113 0        0        0     2        0        14906
Signed-off-by: NBo YU <tsu.yubo@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzbot reported :

BUG: KMSAN: uninit-value in ffs arch/x86/include/asm/bitops.h:432 [inline]
BUG: KMSAN: uninit-value in netlink_sendmsg+0xb26/0x1310 net/netlink/af_netlink.c:1851

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Synchronous pernet_operations are not allowed anymore.
All are asynchronous. So, drop the structure member.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

KMSAN reports use of uninitialized memory in the case when |alen| is
smaller than sizeof(struct sockaddr_nl), and therefore |nladdr| isn't
fully copied from the userspace.
Signed-off-by: NAlexander Potapenko <glider@google.com>
Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Reviewed-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Before, if cb->start() failed, the module reference would never be put,
because cb->cb_running is intentionally false at this point. Users are
generally annoyed by this because they can no longer unload modules that
leak references. Also, it may be possible to tediously wrap a reference
counter back to zero, especially since module.c still uses atomic_inc
instead of refcount_inc.

This patch expands the error path to simply call module_put if
cb->start() fails.

Fixes: 41c87425 ("netlink: do not set cb_running if dump's start() errs")
Signed-off-by: NJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pernet_operations init just allocated net memory,
and they obviously can be executed in parallel in any
others.

v3: New
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: NAndrei Vagin <avagin@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The methods of netlink_net_ops create and destroy "netlink"
file, which are not interesting for foreigh pernet_operations.
So, netlink_net_ops may safely be made async.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: NAndrei Vagin <avagin@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Changes since v1:
Added changes in these files:
    drivers/infiniband/hw/usnic/usnic_transport.c
    drivers/staging/lustre/lnet/lnet/lib-socket.c
    drivers/target/iscsi/iscsi_target_login.c
    drivers/vhost/net.c
    fs/dlm/lowcomms.c
    fs/ocfs2/cluster/tcp.c
    security/tomoyo/network.c

Before:
All these functions either return a negative error indicator,
or store length of sockaddr into "int *socklen" parameter
and return zero on success.

"int *socklen" parameter is awkward. For example, if caller does not
care, it still needs to provide on-stack storage for the value
it does not need.

None of the many FOO_getname() functions of various protocols
ever used old value of *socklen. They always just overwrite it.

This change drops this parameter, and makes all these functions, on success,
return length of sockaddr. It's always >= 0 and can be differentiated
from an error.

Tests in callers are changed from "if (err)" to "if (err < 0)", where needed.

rpc_sockname() lost "int buflen" parameter, since its only use was
to be passed to kernel_getsockname() as &buflen and subsequently
not used in any way.

Userspace API is not changed.

    text    data     bss      dec     hex filename
30108430 2633624  873672 33615726 200ef6e vmlinux.before.o
30108109 2633612  873672 33615393 200ee21 vmlinux.o
Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com>
CC: David S. Miller <davem@davemloft.net>
CC: linux-kernel@vger.kernel.org
CC: netdev@vger.kernel.org
CC: linux-bluetooth@vger.kernel.org
CC: linux-decnet-user@lists.sourceforge.net
CC: linux-wireless@vger.kernel.org
CC: linux-rdma@vger.kernel.org
CC: linux-sctp@vger.kernel.org
CC: linux-nfs@vger.kernel.org
CC: linux-x25@vger.kernel.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move up the extack reset/initialization in netlink_rcv_skb, so that
those 'goto ack' will not skip it. Otherwise, later on netlink_ack
may use the uninitialized extack and cause kernel crash.

Fixes: cbbdf843 ("netlink: extack needs to be reset each time through loop")
Reported-by: syzbot+03bee3680a37466775e7@syzkaller.appspotmail.com
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

/proc has been ignoring struct file_operations::owner field for 10 years.
Specifically, it started with commit 786d7e16
("Fix rmmod/read/write races in /proc entries"). Notice the chunk where
inode->i_fop is initialized with proxy struct file_operations for
regular files:

	-               if (de->proc_fops)
	-                       inode->i_fop = de->proc_fops;
	+               if (de->proc_fops) {
	+                       if (S_ISREG(inode->i_mode))
	+                               inode->i_fop = &proc_reg_file_ops;
	+                       else
	+                               inode->i_fop = de->proc_fops;
	+               }

VFS stopped pinning module at this point.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzbot triggered the WARN_ON in netlink_ack testing the bad_attr value.
The problem is that netlink_rcv_skb loops over the skb repeatedly invoking
the callback and without resetting the extack leaving potentially stale
data. Initializing each time through avoids the WARN_ON.

Fixes: 2d4bc933 ("netlink: extended ACK reporting")
Reported-by: syzbot+315fa6766d0f7c359327@syzkaller.appspotmail.com
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, a nlmon link inside a child namespace can observe systemwide
netlink activity.  Filter the traffic so that nlmon can only sniff
netlink messages from its own netns.

Test case:

    vpnns -- bash -c "ip link add nlmon0 type nlmon; \
                      ip link set nlmon0 up; \
                      tcpdump -i nlmon0 -q -w /tmp/nlmon.pcap -U" &
    sudo ip xfrm state add src 10.1.1.1 dst 10.1.1.2 proto esp \
        spi 0x1 mode transport \
        auth sha1 0x6162633132330000000000000000000000000000 \
        enc aes 0x00000000000000000000000000000000
    grep --binary abc123 /tmp/nlmon.pcap
Signed-off-by: NKevin Cernekee <cernekee@chromium.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Both netlink_add_tap() and netlink_remove_tap() are
called in process context, no need to bother spinlock.

Note, in fact, currently we always hold RTNL when calling
these two functions, so we don't need any other lock at
all, but keeping this lock doesn't harm anything.

Cc: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

nlmon device is not supposed to capture netlink events from
other netns, so instead of filtering events, we can simply
make netlink tap itself per netns.

Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Most callers of rhashtable_walk_start don't care about a resize event
which is indicated by a return value of -EAGAIN. So calls to
rhashtable_walk_start are wrapped wih code to ignore -EAGAIN. Something
like this is common:

       ret = rhashtable_walk_start(rhiter);
       if (ret && ret != -EAGAIN)
               goto out;

Since zero and -EAGAIN are the only possible return values from the
function this check is pointless. The condition never evaluates to true.

This patch changes rhashtable_walk_start to return void. This simplifies
code for the callers that ignore -EAGAIN. For the few cases where the
caller cares about the resize event, particularly where the table can be
walked in mulitple parts for netlink or seq file dump, the function
rhashtable_walk_start_check has been added that returns -EAGAIN on a
resize event.
Signed-off-by: NTom Herbert <tom@quantonium.net>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

netlink_skb_destructor() is actually defined before the first usage
in the file, so remove the unnecessary forward declaration.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The way people generally use netlink_dump is that they fill in the skb
as much as possible, breaking when nla_put returns an error. Then, they
get called again and start filling out the next skb, and again, and so
forth. The mechanism at work here is the ability for the iterative
dumping function to detect when the skb is filled up and not fill it
past the brim, waiting for a fresh skb for the rest of the data.

However, if the attributes are small and nicely packed, it is possible
that a dump callback function successfully fills in attributes until the
skb is of size 4080 (libmnl's default page-sized receive buffer size).
The dump function completes, satisfied, and then, if it happens to be
that this is actually the last skb, and no further ones are to be sent,
then netlink_dump will add on the NLMSG_DONE part:

  nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);

It is very important that netlink_dump does this, of course. However, in
this example, that call to nlmsg_put_answer will fail, because the
previous filling by the dump function did not leave it enough room. And
how could it possibly have done so? All of the nla_put variety of
functions simply check to see if the skb has enough tailroom,
independent of the context it is in.

In order to keep the important assumptions of all netlink dump users, it
is therefore important to give them an skb that has this end part of the
tail already reserved, so that the call to nlmsg_put_answer does not
fail. Otherwise, library authors are forced to find some bizarre sized
receive buffer that has a large modulo relative to the common sizes of
messages received, which is ugly and buggy.

This patch thus saves the NLMSG_DONE for an additional message, for the
case that things are dangerously close to the brim. This requires
keeping track of the errno from ->dump() across calls.
Signed-off-by: NJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The NLMSGERR API already carries data (eg, a cookie) on the success path.
Allow a message string to be returned as well.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It seems that it's possible to toggle NETLINK_F_EXT_ACK
through setsockopt() while another thread/CPU is building
a message inside netlink_ack(), which could then trigger
the WARN_ON()s I added since if it goes from being turned
off to being turned on between allocating and filling the
message, the skb could end up being too small.

Avoid this whole situation by storing the value of this
flag in a separate variable and using that throughout the
function instead.

Fixes: 2d4bc933 ("netlink: extended ACK reporting")
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When netlink_ack() reports an allocation error to the sending
socket, there's no need to look up the sending socket since
it's available in the SKB's CB. Use that instead of going to
the trouble of looking it up.

Note that the pointer is only available since Eric Biederman's
commit 3fbc2905 ("netlink: Make the sending netlink socket availabe in NETLINK_CB")
which is far newer than the original lookup code (Oct 2003)
(though the field was called 'ssk' in that commit and only got
renamed to 'sk' later, I'd actually argue 'ssk' was better - or
perhaps it should've been 'source_sk' - since there are so many
different 'sk's involved.)
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It turns out that multiple places can call netlink_dump(), which means
it's still possible to dereference partially initialized values in
dump() that were the result of a faulty returned start().

This fixes the issue by calling start() _before_ setting cb_running to
true, so that there's no chance at all of hitting the dump() function
through any indirect paths.

It also moves the call to start() to be when the mutex is held. This has
the nice side effect of serializing invocations to start(), which is
likely desirable anyway. It also prevents any possible other races that
might come out of this logic.

In testing this with several different pieces of tricky code to trigger
these issues, this commit fixes all avenues that I'm aware of.
Signed-off-by: NJason A. Donenfeld <Jason@zx2c4.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Drivers that use the start method for netlink dumping rely on dumpit not
being called if start fails. For example, ila_xlat.c allocates memory
and assigns it to cb->args[0] in its start() function. It might fail to
do that and return -ENOMEM instead. However, even when returning an
error, dumpit will be called, which, in the example above, quickly
dereferences the memory in cb->args[0], which will OOPS the kernel. This
is but one example of how this goes wrong.

Since start() has always been a function with an int return type, it
therefore makes sense to use it properly, rather than ignoring it. This
patch thus returns early and does not call dumpit() when start() fails.
Signed-off-by: NJason A. Donenfeld <Jason@zx2c4.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now there is no lock protecting nlk ngroups/groups' accessing in
netlink bind and getname. It's safe from nlk groups' setting in
netlink_release, but not from netlink_realloc_groups called by
netlink_setsockopt.

netlink_lock_table is needed in both netlink bind and getname when
accessing nlk groups.
Acked-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ChunYu found a netlink use-after-free issue by syzkaller:

[28448.842981] BUG: KASAN: use-after-free in __nla_put+0x37/0x40 at addr ffff8807185e2378
[28448.969918] Call Trace:
[...]
[28449.117207]  __nla_put+0x37/0x40
[28449.132027]  nla_put+0xf5/0x130
[28449.146261]  sk_diag_fill.isra.4.constprop.5+0x5a0/0x750 [netlink_diag]
[28449.176608]  __netlink_diag_dump+0x25a/0x700 [netlink_diag]
[28449.202215]  netlink_diag_dump+0x176/0x240 [netlink_diag]
[28449.226834]  netlink_dump+0x488/0xbb0
[28449.298014]  __netlink_dump_start+0x4e8/0x760
[28449.317924]  netlink_diag_handler_dump+0x261/0x340 [netlink_diag]
[28449.413414]  sock_diag_rcv_msg+0x207/0x390
[28449.432409]  netlink_rcv_skb+0x149/0x380
[28449.467647]  sock_diag_rcv+0x2d/0x40
[28449.484362]  netlink_unicast+0x562/0x7b0
[28449.564790]  netlink_sendmsg+0xaa8/0xe60
[28449.661510]  sock_sendmsg+0xcf/0x110
[28449.865631]  __sys_sendmsg+0xf3/0x240
[28450.000964]  SyS_sendmsg+0x32/0x50
[28450.016969]  do_syscall_64+0x25c/0x6c0
[28450.154439]  entry_SYSCALL64_slow_path+0x25/0x25

It was caused by no protection between nlk groups' free in netlink_release
and nlk groups' accessing in sk_diag_dump_groups. The similar issue also
exists in netlink_seq_show().

This patch is to defer nlk groups' free in deferred_put_nlk_sk.
Reported-by: NChunYu Wang <chunwang@redhat.com>
Acked-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

This patch uses refcount_inc_not_zero() instead of
atomic_inc_not_zero_hint() due to absense of a _hint()
version of refcount API. If the hint() version must
be used, we might need to revisit API.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It seems like a historic accident that these return unsigned char *,
and in many places that means casts are required, more often than not.

Make these functions (skb_put, __skb_put and pskb_put) return void *
and remove all the casts across the tree, adding a (u8 *) cast only
where the unsigned char pointer was used directly, all done with the
following spatch:

    @@
    expression SKB, LEN;
    typedef u8;
    identifier fn = { skb_put, __skb_put };
    @@
    - *(fn(SKB, LEN))
    + *(u8 *)fn(SKB, LEN)

    @@
    expression E, SKB, LEN;
    identifier fn = { skb_put, __skb_put };
    type T;
    @@
    - E = ((T *)(fn(SKB, LEN)))
    + E = fn(SKB, LEN)

which actually doesn't cover pskb_put since there are only three
users overall.

A handful of stragglers were converted manually, notably a macro in
drivers/isdn/i4l/isdn_bsdcomp.c and, oddly enough, one of the many
instances in net/bluetooth/hci_sock.c. In the former file, I also
had to fix one whitespace problem spatch introduced.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A common pattern with skb_put() is to just want to memcpy()
some data into the new space, introduce skb_put_data() for
this.

An spatch similar to the one for skb_put_zero() converts many
of the places using it:

    @@
    identifier p, p2;
    expression len, skb, data;
    type t, t2;
    @@
    (
    -p = skb_put(skb, len);
    +p = skb_put_data(skb, data, len);
    |
    -p = (t)skb_put(skb, len);
    +p = skb_put_data(skb, data, len);
    )
    (
    p2 = (t2)p;
    -memcpy(p2, data, len);
    |
    -memcpy(p, data, len);
    )

    @@
    type t, t2;
    identifier p, p2;
    expression skb, data;
    @@
    t *p;
    ...
    (
    -p = skb_put(skb, sizeof(t));
    +p = skb_put_data(skb, data, sizeof(t));
    |
    -p = (t *)skb_put(skb, sizeof(t));
    +p = skb_put_data(skb, data, sizeof(t));
    )
    (
    p2 = (t2)p;
    -memcpy(p2, data, sizeof(*p));
    |
    -memcpy(p, data, sizeof(*p));
    )

    @@
    expression skb, len, data;
    @@
    -memcpy(skb_put(skb, len), data, len);
    +skb_put_data(skb, data, len);

(again, manually post-processed to retain some comments)
Reviewed-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The NETLINK_F_LISTEN_ALL_NSID otion enables to listen all netns that have a
nsid assigned into the netns where the netlink socket is opened.
The nsid is sent as metadata to userland, but the existence of this nsid is
checked only for netns that are different from the socket netns. Thus, if
no nsid is assigned to the socket netns, NETNSA_NSID_NOT_ASSIGNED is
reported to the userland. This value is confusing and useless.
After this patch, only valid nsid are sent to userland.
Reported-by: NFlavio Leitner <fbl@sysclose.org>
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that we have extended error reporting and a new message format for
netlink ACK messages, also extend this to be able to return arbitrary
cookie data on success.

This will allow, for example, nl80211 to not send an extra message for
cookies identifying newly created objects, but return those directly
in the ACK message.

The cookie data size is currently limited to 20 bytes (since Jamal
talked about using SHA1 for identifiers.)

Thanks to Jamal Hadi Salim for bringing up this idea during the
discussions.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Reviewed-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add the base infrastructure and UAPI for netlink extended ACK
reporting. All "manual" calls to netlink_ack() pass NULL for now and
thus don't get extended ACK reporting.

Big thanks goes to Pablo Neira Ayuso for not only bringing up the
whole topic at netconf (again) but also coming up with the nlattr
passing trick and various other ideas.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Reviewed-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

cb_running is reported in /proc/self/net/netlink and it is reported by
the ss tool, when it gets information from the proc files.

sock_diag is a new interface which is used instead of proc files, so it
looks reasonable that this interface has to report no less information
about sockets than proc files.

We use these flags to dump and restore netlink sockets.
Signed-off-by: NAndrei Vagin <avagin@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On Tue, Mar 14, 2017 at 10:44:10AM +0100, Dmitry Vyukov wrote:
>
> Yes, please.
> Disregarding some reports is not a good way long term.

Please try this patch.

---8<---
Subject: netlink: Annotate nlk cb_mutex by protocol

Currently all occurences of nlk->cb_mutex are annotated by lockdep
as a single class.  This causes a false lcokdep cycle involving
genl and crypto_user.

This patch fixes it by dividing cb_mutex into individual classes
based on the netlink protocol.  As genl and crypto_user do not
use the same netlink protocol this breaks the false dependency
loop.
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>