<feed xmlns='http://www.w3.org/2005/Atom'>
<title>user/sven/linux.git/include, branch v4.19.60</title>
<subtitle>Linux Kernel
</subtitle>
<id>https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v4.19.60</id>
<link rel='self' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v4.19.60'/>
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<updated>2019-07-21T07:03:11Z</updated>
<entry>
<title>linux/kernel.h: fix overflow for DIV_ROUND_UP_ULL</title>
<updated>2019-07-21T07:03:11Z</updated>
<author>
<name>Vinod Koul</name>
<email>vkoul@kernel.org</email>
</author>
<published>2019-06-28T19:07:21Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=2656ee5a5ad59300bbe183d0833867a582910dcc'/>
<id>urn:sha1:2656ee5a5ad59300bbe183d0833867a582910dcc</id>
<content type='text'>
[ Upstream commit 8f9fab480c7a87b10bb5440b5555f370272a5d59 ]

DIV_ROUND_UP_ULL adds the two arguments and then invokes
DIV_ROUND_DOWN_ULL.  But on a 32bit system the addition of two 32 bit
values can overflow.  DIV_ROUND_DOWN_ULL does it correctly and stashes
the addition into a unsigned long long so cast the result to unsigned
long long here to avoid the overflow condition.

[akpm@linux-foundation.org: DIV_ROUND_UP_ULL must be an rval]
Link: http://lkml.kernel.org/r/20190625100518.30753-1-vkoul@kernel.org
Signed-off-by: Vinod Koul &lt;vkoul@kernel.org&gt;
Reviewed-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Bjorn Andersson &lt;bjorn.andersson@linaro.org&gt;
Cc: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>drivers: base: cacheinfo: Ensure cpu hotplug work is done before Intel RDT</title>
<updated>2019-07-21T07:03:03Z</updated>
<author>
<name>James Morse</name>
<email>james.morse@arm.com</email>
</author>
<published>2019-06-24T17:36:56Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=079d7f16a9738f8ea8a71671f5481f9b5049da3a'/>
<id>urn:sha1:079d7f16a9738f8ea8a71671f5481f9b5049da3a</id>
<content type='text'>
commit 83b44fe343b5abfcb1b2261289bd0cfcfcfd60a8 upstream.

The cacheinfo structures are alloced/freed by cpu online/offline
callbacks. Originally these were only used by sysfs to expose the
cache topology to user space. Without any in-kernel dependencies
CPUHP_AP_ONLINE_DYN was an appropriate choice.

resctrl has started using these structures to identify CPUs that
share a cache. It updates its 'domain' structures from cpu
online/offline callbacks. These depend on the cacheinfo structures
(resctrl_online_cpu()-&gt;domain_add_cpu()-&gt;get_cache_id()-&gt;
 get_cpu_cacheinfo()).
These also run as CPUHP_AP_ONLINE_DYN.

Now that there is an in-kernel dependency, move the cacheinfo
work earlier so we know its done before resctrl's CPUHP_AP_ONLINE_DYN
work runs.

Fixes: 2264d9c74dda1 ("x86/intel_rdt: Build structures for each resource based on cache topology")
Cc: &lt;stable@vger.kernel.org&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: Reinette Chatre &lt;reinette.chatre@intel.com&gt;
Signed-off-by: James Morse &lt;james.morse@arm.com&gt;
Link: https://lore.kernel.org/r/20190624173656.202407-1-james.morse@arm.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>nilfs2: do not use unexported cpu_to_le32()/le32_to_cpu() in uapi header</title>
<updated>2019-07-21T07:03:02Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>yamada.masahiro@socionext.com</email>
</author>
<published>2019-07-12T03:52:18Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=68048dce650eda36076793f4f894e2d019dcc4a7'/>
<id>urn:sha1:68048dce650eda36076793f4f894e2d019dcc4a7</id>
<content type='text'>
commit c32cc30c0544f13982ee0185d55f4910319b1a79 upstream.

cpu_to_le32/le32_to_cpu is defined in include/linux/byteorder/generic.h,
which is not exported to user-space.

UAPI headers must use the ones prefixed with double-underscore.

Detected by compile-testing exported headers:

  include/linux/nilfs2_ondisk.h: In function `nilfs_checkpoint_set_snapshot':
  include/linux/nilfs2_ondisk.h:536:17: error: implicit declaration of function `cpu_to_le32' [-Werror=implicit-function-declaration]
    cp-&gt;cp_flags = cpu_to_le32(le32_to_cpu(cp-&gt;cp_flags) |  \
                   ^
  include/linux/nilfs2_ondisk.h:552:1: note: in expansion of macro `NILFS_CHECKPOINT_FNS'
   NILFS_CHECKPOINT_FNS(SNAPSHOT, snapshot)
   ^~~~~~~~~~~~~~~~~~~~
  include/linux/nilfs2_ondisk.h:536:29: error: implicit declaration of function `le32_to_cpu' [-Werror=implicit-function-declaration]
    cp-&gt;cp_flags = cpu_to_le32(le32_to_cpu(cp-&gt;cp_flags) |  \
                               ^
  include/linux/nilfs2_ondisk.h:552:1: note: in expansion of macro `NILFS_CHECKPOINT_FNS'
   NILFS_CHECKPOINT_FNS(SNAPSHOT, snapshot)
   ^~~~~~~~~~~~~~~~~~~~
  include/linux/nilfs2_ondisk.h: In function `nilfs_segment_usage_set_clean':
  include/linux/nilfs2_ondisk.h:622:19: error: implicit declaration of function `cpu_to_le64' [-Werror=implicit-function-declaration]
    su-&gt;su_lastmod = cpu_to_le64(0);
                     ^~~~~~~~~~~

Link: http://lkml.kernel.org/r/20190605053006.14332-1-yamada.masahiro@socionext.com
Fixes: e63e88bc53ba ("nilfs2: move ioctl interface and disk layout to uapi separately")
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Acked-by: Ryusuke Konishi &lt;konishi.ryusuke@gmail.com&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Greg KH &lt;gregkh@linuxfoundation.org&gt;
Cc: Joe Perches &lt;joe@perches.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[4.9+]
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>VMCI: Fix integer overflow in VMCI handle arrays</title>
<updated>2019-07-14T06:11:21Z</updated>
<author>
<name>Vishnu DASA</name>
<email>vdasa@vmware.com</email>
</author>
<published>2019-05-24T15:13:10Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=d202b5adccfb093c4859d67ec74d5f3fb9fcfc54'/>
<id>urn:sha1:d202b5adccfb093c4859d67ec74d5f3fb9fcfc54</id>
<content type='text'>
commit 1c2eb5b2853c9f513690ba6b71072d8eb65da16a upstream.

The VMCI handle array has an integer overflow in
vmci_handle_arr_append_entry when it tries to expand the array. This can be
triggered from a guest, since the doorbell link hypercall doesn't impose a
limit on the number of doorbell handles that a VM can create in the
hypervisor, and these handles are stored in a handle array.

In this change, we introduce a mandatory max capacity for handle
arrays/lists to avoid excessive memory usage.

Signed-off-by: Vishnu Dasa &lt;vdasa@vmware.com&gt;
Reviewed-by: Adit Ranadive &lt;aditr@vmware.com&gt;
Reviewed-by: Jorgen Hansen &lt;jhansen@vmware.com&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>ALSA: usb-audio: Fix parse of UAC2 Extension Units</title>
<updated>2019-07-14T06:11:16Z</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2019-07-04T14:31:12Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=87c3262b00d88063d266b31752054e7b03a49102'/>
<id>urn:sha1:87c3262b00d88063d266b31752054e7b03a49102</id>
<content type='text'>
commit ca95c7bf3d29716916baccdc77c3c2284b703069 upstream.

Extension Unit (XU) is used to have a compatible layout with
Processing Unit (PU) on UAC1, and the usb-audio driver code assumed it
for parsing the descriptors.  Meanwhile, on UAC2, XU became slightly
incompatible with PU; namely, XU has a one-byte bmControls bitmap
while PU has two bytes bmControls bitmap.  This incompatibility
results in the read of a wrong address for the last iExtension field,
which ended up with an incorrect string for the mixer element name, as
recently reported for Focusrite Scarlett 18i20 device.

This patch corrects this misalignment by introducing a couple of new
macros and calling them depending on the descriptor type.

Fixes: 23caaf19b11e ("ALSA: usb-mixer: Add support for Audio Class v2.0")
Reported-by: Stefan Sauer &lt;ensonic@hora-obscura.de&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>ip6_tunnel: allow not to count pkts on tstats by passing dev as NULL</title>
<updated>2019-07-14T06:11:14Z</updated>
<author>
<name>Xin Long</name>
<email>lucien.xin@gmail.com</email>
</author>
<published>2019-06-17T13:34:14Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=740b2ac495187f33e7ad7c216382ef171150d358'/>
<id>urn:sha1:740b2ac495187f33e7ad7c216382ef171150d358</id>
<content type='text'>
[ Upstream commit 6f6a8622057c92408930c31698394fae1557b188 ]

A similar fix to Patch "ip_tunnel: allow not to count pkts on tstats by
setting skb's dev to NULL" is also needed by ip6_tunnel.

Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>bpf: fix bpf_jit_limit knob for PAGE_SIZE &gt;= 64K</title>
<updated>2019-07-10T07:53:47Z</updated>
<author>
<name>Daniel Borkmann</name>
<email>daniel@iogearbox.net</email>
</author>
<published>2018-12-11T11:14:12Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=54e8cf41b20b9e9952c7e563794efcbc5d47e891'/>
<id>urn:sha1:54e8cf41b20b9e9952c7e563794efcbc5d47e891</id>
<content type='text'>
[ Upstream commit fdadd04931c2d7cd294dc5b2b342863f94be53a3 ]

Michael and Sandipan report:

  Commit ede95a63b5 introduced a bpf_jit_limit tuneable to limit BPF
  JIT allocations. At compile time it defaults to PAGE_SIZE * 40000,
  and is adjusted again at init time if MODULES_VADDR is defined.

  For ppc64 kernels, MODULES_VADDR isn't defined, so we're stuck with
  the compile-time default at boot-time, which is 0x9c400000 when
  using 64K page size. This overflows the signed 32-bit bpf_jit_limit
  value:

  root@ubuntu:/tmp# cat /proc/sys/net/core/bpf_jit_limit
  -1673527296

  and can cause various unexpected failures throughout the network
  stack. In one case `strace dhclient eth0` reported:

  setsockopt(5, SOL_SOCKET, SO_ATTACH_FILTER, {len=11, filter=0x105dd27f8},
             16) = -1 ENOTSUPP (Unknown error 524)

  and similar failures can be seen with tools like tcpdump. This doesn't
  always reproduce however, and I'm not sure why. The more consistent
  failure I've seen is an Ubuntu 18.04 KVM guest booted on a POWER9
  host would time out on systemd/netplan configuring a virtio-net NIC
  with no noticeable errors in the logs.

Given this and also given that in near future some architectures like
arm64 will have a custom area for BPF JIT image allocations we should
get rid of the BPF_JIT_LIMIT_DEFAULT fallback / default entirely. For
4.21, we have an overridable bpf_jit_alloc_exec(), bpf_jit_free_exec()
so therefore add another overridable bpf_jit_alloc_exec_limit() helper
function which returns the possible size of the memory area for deriving
the default heuristic in bpf_jit_charge_init().

Like bpf_jit_alloc_exec() and bpf_jit_free_exec(), the new
bpf_jit_alloc_exec_limit() assumes that module_alloc() is the default
JIT memory provider, and therefore in case archs implement their custom
module_alloc() we use MODULES_{END,_VADDR} for limits and otherwise for
vmalloc_exec() cases like on ppc64 we use VMALLOC_{END,_START}.

Additionally, for archs supporting large page sizes, we should change
the sysctl to be handled as long to not run into sysctl restrictions
in future.

Fixes: ede95a63b5e8 ("bpf: add bpf_jit_limit knob to restrict unpriv allocations")
Reported-by: Sandipan Das &lt;sandipan@linux.ibm.com&gt;
Reported-by: Michael Roth &lt;mdroth@linux.vnet.ibm.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Tested-by: Michael Roth &lt;mdroth@linux.vnet.ibm.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>ip6: fix skb leak in ip6frag_expire_frag_queue()</title>
<updated>2019-07-10T07:53:46Z</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2019-05-03T15:24:44Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=a8891c5e2251ebe2084f824f867ea657460b14ab'/>
<id>urn:sha1:a8891c5e2251ebe2084f824f867ea657460b14ab</id>
<content type='text'>
[ Upstream commit 47d3d7fdb10a21c223036b58bd70ffdc24a472c4 ]

Since ip6frag_expire_frag_queue() now pulls the head skb
from frag queue, we should no longer use skb_get(), since
this leads to an skb leak.

Stefan Bader initially reported a problem in 4.4.stable [1] caused
by the skb_get(), so this patch should also fix this issue.

296583.091021] kernel BUG at /build/linux-6VmqmP/linux-4.4.0/net/core/skbuff.c:1207!
[296583.091734] Call Trace:
[296583.091749]  [&lt;ffffffff81740e50&gt;] __pskb_pull_tail+0x50/0x350
[296583.091764]  [&lt;ffffffff8183939a&gt;] _decode_session6+0x26a/0x400
[296583.091779]  [&lt;ffffffff817ec719&gt;] __xfrm_decode_session+0x39/0x50
[296583.091795]  [&lt;ffffffff818239d0&gt;] icmpv6_route_lookup+0xf0/0x1c0
[296583.091809]  [&lt;ffffffff81824421&gt;] icmp6_send+0x5e1/0x940
[296583.091823]  [&lt;ffffffff81753238&gt;] ? __netif_receive_skb+0x18/0x60
[296583.091838]  [&lt;ffffffff817532b2&gt;] ? netif_receive_skb_internal+0x32/0xa0
[296583.091858]  [&lt;ffffffffc0199f74&gt;] ? ixgbe_clean_rx_irq+0x594/0xac0 [ixgbe]
[296583.091876]  [&lt;ffffffffc04eb260&gt;] ? nf_ct_net_exit+0x50/0x50 [nf_defrag_ipv6]
[296583.091893]  [&lt;ffffffff8183d431&gt;] icmpv6_send+0x21/0x30
[296583.091906]  [&lt;ffffffff8182b500&gt;] ip6_expire_frag_queue+0xe0/0x120
[296583.091921]  [&lt;ffffffffc04eb27f&gt;] nf_ct_frag6_expire+0x1f/0x30 [nf_defrag_ipv6]
[296583.091938]  [&lt;ffffffff810f3b57&gt;] call_timer_fn+0x37/0x140
[296583.091951]  [&lt;ffffffffc04eb260&gt;] ? nf_ct_net_exit+0x50/0x50 [nf_defrag_ipv6]
[296583.091968]  [&lt;ffffffff810f5464&gt;] run_timer_softirq+0x234/0x330
[296583.091982]  [&lt;ffffffff8108a339&gt;] __do_softirq+0x109/0x2b0

Fixes: d4289fcc9b16 ("net: IP6 defrag: use rbtrees for IPv6 defrag")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reported-by: Stefan Bader &lt;stefan.bader@canonical.com&gt;
Cc: Peter Oskolkov &lt;posk@google.com&gt;
Cc: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>futex: Update comments and docs about return values of arch futex code</title>
<updated>2019-07-03T11:14:49Z</updated>
<author>
<name>Will Deacon</name>
<email>will.deacon@arm.com</email>
</author>
<published>2019-04-10T10:51:54Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=a319c8ff4f09cae9936385a9297b1b29165e2d8c'/>
<id>urn:sha1:a319c8ff4f09cae9936385a9297b1b29165e2d8c</id>
<content type='text'>
commit 427503519739e779c0db8afe876c1b33f3ac60ae upstream.

The architecture implementations of 'arch_futex_atomic_op_inuser()' and
'futex_atomic_cmpxchg_inatomic()' are permitted to return only -EFAULT,
-EAGAIN or -ENOSYS in the case of failure.

Update the comments in the asm-generic/ implementation and also a stray
reference in the robust futex documentation.

Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>bpf: fix unconnected udp hooks</title>
<updated>2019-07-03T11:14:48Z</updated>
<author>
<name>Daniel Borkmann</name>
<email>daniel@iogearbox.net</email>
</author>
<published>2019-06-06T23:48:57Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=613bc37f74c9b2249acbe1a5a80867547f13611a'/>
<id>urn:sha1:613bc37f74c9b2249acbe1a5a80867547f13611a</id>
<content type='text'>
commit 983695fa676568fc0fe5ddd995c7267aabc24632 upstream.

Intention of cgroup bind/connect/sendmsg BPF hooks is to act transparently
to applications as also stated in original motivation in 7828f20e3779 ("Merge
branch 'bpf-cgroup-bind-connect'"). When recently integrating the latter
two hooks into Cilium to enable host based load-balancing with Kubernetes,
I ran into the issue that pods couldn't start up as DNS got broken. Kubernetes
typically sets up DNS as a service and is thus subject to load-balancing.

Upon further debugging, it turns out that the cgroupv2 sendmsg BPF hooks API
is currently insufficient and thus not usable as-is for standard applications
shipped with most distros. To break down the issue we ran into with a simple
example:

  # cat /etc/resolv.conf
  nameserver 147.75.207.207
  nameserver 147.75.207.208

For the purpose of a simple test, we set up above IPs as service IPs and
transparently redirect traffic to a different DNS backend server for that
node:

  # cilium service list
  ID   Frontend            Backend
  1    147.75.207.207:53   1 =&gt; 8.8.8.8:53
  2    147.75.207.208:53   1 =&gt; 8.8.8.8:53

The attached BPF program is basically selecting one of the backends if the
service IP/port matches on the cgroup hook. DNS breaks here, because the
hooks are not transparent enough to applications which have built-in msg_name
address checks:

  # nslookup 1.1.1.1
  ;; reply from unexpected source: 8.8.8.8#53, expected 147.75.207.207#53
  ;; reply from unexpected source: 8.8.8.8#53, expected 147.75.207.208#53
  ;; reply from unexpected source: 8.8.8.8#53, expected 147.75.207.207#53
  [...]
  ;; connection timed out; no servers could be reached

  # dig 1.1.1.1
  ;; reply from unexpected source: 8.8.8.8#53, expected 147.75.207.207#53
  ;; reply from unexpected source: 8.8.8.8#53, expected 147.75.207.208#53
  ;; reply from unexpected source: 8.8.8.8#53, expected 147.75.207.207#53
  [...]

  ; &lt;&lt;&gt;&gt; DiG 9.11.3-1ubuntu1.7-Ubuntu &lt;&lt;&gt;&gt; 1.1.1.1
  ;; global options: +cmd
  ;; connection timed out; no servers could be reached

For comparison, if none of the service IPs is used, and we tell nslookup
to use 8.8.8.8 directly it works just fine, of course:

  # nslookup 1.1.1.1 8.8.8.8
  1.1.1.1.in-addr.arpa	name = one.one.one.one.

In order to fix this and thus act more transparent to the application,
this needs reverse translation on recvmsg() side. A minimal fix for this
API is to add similar recvmsg() hooks behind the BPF cgroups static key
such that the program can track state and replace the current sockaddr_in{,6}
with the original service IP. From BPF side, this basically tracks the
service tuple plus socket cookie in an LRU map where the reverse NAT can
then be retrieved via map value as one example. Side-note: the BPF cgroups
static key should be converted to a per-hook static key in future.

Same example after this fix:

  # cilium service list
  ID   Frontend            Backend
  1    147.75.207.207:53   1 =&gt; 8.8.8.8:53
  2    147.75.207.208:53   1 =&gt; 8.8.8.8:53

Lookups work fine now:

  # nslookup 1.1.1.1
  1.1.1.1.in-addr.arpa    name = one.one.one.one.

  Authoritative answers can be found from:

  # dig 1.1.1.1

  ; &lt;&lt;&gt;&gt; DiG 9.11.3-1ubuntu1.7-Ubuntu &lt;&lt;&gt;&gt; 1.1.1.1
  ;; global options: +cmd
  ;; Got answer:
  ;; -&gt;&gt;HEADER&lt;&lt;- opcode: QUERY, status: NXDOMAIN, id: 51550
  ;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

  ;; OPT PSEUDOSECTION:
  ; EDNS: version: 0, flags:; udp: 512
  ;; QUESTION SECTION:
  ;1.1.1.1.                       IN      A

  ;; AUTHORITY SECTION:
  .                       23426   IN      SOA     a.root-servers.net. nstld.verisign-grs.com. 2019052001 1800 900 604800 86400

  ;; Query time: 17 msec
  ;; SERVER: 147.75.207.207#53(147.75.207.207)
  ;; WHEN: Tue May 21 12:59:38 UTC 2019
  ;; MSG SIZE  rcvd: 111

And from an actual packet level it shows that we're using the back end
server when talking via 147.75.207.20{7,8} front end:

  # tcpdump -i any udp
  [...]
  12:59:52.698732 IP foo.42011 &gt; google-public-dns-a.google.com.domain: 18803+ PTR? 1.1.1.1.in-addr.arpa. (38)
  12:59:52.698735 IP foo.42011 &gt; google-public-dns-a.google.com.domain: 18803+ PTR? 1.1.1.1.in-addr.arpa. (38)
  12:59:52.701208 IP google-public-dns-a.google.com.domain &gt; foo.42011: 18803 1/0/0 PTR one.one.one.one. (67)
  12:59:52.701208 IP google-public-dns-a.google.com.domain &gt; foo.42011: 18803 1/0/0 PTR one.one.one.one. (67)
  [...]

In order to be flexible and to have same semantics as in sendmsg BPF
programs, we only allow return codes in [1,1] range. In the sendmsg case
the program is called if msg-&gt;msg_name is present which can be the case
in both, connected and unconnected UDP.

The former only relies on the sockaddr_in{,6} passed via connect(2) if
passed msg-&gt;msg_name was NULL. Therefore, on recvmsg side, we act in similar
way to call into the BPF program whenever a non-NULL msg-&gt;msg_name was
passed independent of sk-&gt;sk_state being TCP_ESTABLISHED or not. Note
that for TCP case, the msg-&gt;msg_name is ignored in the regular recvmsg
path and therefore not relevant.

For the case of ip{,v6}_recv_error() paths, picked up via MSG_ERRQUEUE,
the hook is not called. This is intentional as it aligns with the same
semantics as in case of TCP cgroup BPF hooks right now. This might be
better addressed in future through a different bpf_attach_type such
that this case can be distinguished from the regular recvmsg paths,
for example.

Fixes: 1cedee13d25a ("bpf: Hooks for sys_sendmsg")
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Andrey Ignatov &lt;rdna@fb.com&gt;
Acked-by: Martin KaFai Lau &lt;kafai@fb.com&gt;
Acked-by: Martynas Pumputis &lt;m@lambda.lt&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
</feed>
