linux-stable.git/net/core, branch linux-5.6.y

__netif_receive_skb_core: pass skb by reference

2020-06-03T06:22:42+00:00

[ Upstream commit c0bbbdc32febd4f034ecbf3ea17865785b2c0652 ]

__netif_receive_skb_core may change the skb pointer passed into it (e.g.
in rx_handler). The original skb may be freed as a result of this
operation.

The callers of __netif_receive_skb_core may further process original skb
by using pt_prev pointer returned by __netif_receive_skb_core thus
leading to unpleasant effects.

The solution is to pass skb by reference into __netif_receive_skb_core.

v2: Added Fixes tag and comment regarding ppt_prev and skb invariant.

Fixes: 88eb1944e18c ("net: core: propagate SKB lists through packet_type lookup")
Signed-off-by: Boris Sukholitko 
Acked-by: Edward Cree 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

flow_dissector: Drop BPF flow dissector prog ref on netns cleanup

2020-05-27T15:48:29+00:00

commit 5cf65922bb15279402e1e19b5ee8c51d618fa51f upstream.

When attaching a flow dissector program to a network namespace with
bpf(BPF_PROG_ATTACH, ...) we grab a reference to bpf_prog.

If netns gets destroyed while a flow dissector is still attached, and there
are no other references to the prog, we leak the reference and the program
remains loaded.

Leak can be reproduced by running flow dissector tests from selftests/bpf:

  # bpftool prog list
  # ./test_flow_dissector.sh
  ...
  selftests: test_flow_dissector [PASS]
  # bpftool prog list
  4: flow_dissector  name _dissect  tag e314084d332a5338  gpl
          loaded_at 2020-05-20T18:50:53+0200  uid 0
          xlated 552B  jited 355B  memlock 4096B  map_ids 3,4
          btf_id 4
  #

Fix it by detaching the flow dissector program when netns is going away.

Fixes: d58e468b1112 ("flow_dissector: implements flow dissector BPF hook")
Signed-off-by: Jakub Sitnicki 
Signed-off-by: Alexei Starovoitov 
Reviewed-by: Stanislav Fomichev 
Link: https://lore.kernel.org/bpf/20200521083435.560256-1-jakub@cloudflare.com
Signed-off-by: Greg Kroah-Hartman

bpf, sockmap: msg_pop_data can incorrecty set an sge length

2020-05-20T06:22:14+00:00

[ Upstream commit 3e104c23816220919ea1b3fd93fabe363c67c484 ]

When sk_msg_pop() is called where the pop operation is working on
the end of a sge element and there is no additional trailing data
and there _is_ data in front of pop, like the following case,

   |____________a_____________|__pop__|

We have out of order operations where we incorrectly set the pop
variable so that instead of zero'ing pop we incorrectly leave it
untouched, effectively. This can cause later logic to shift the
buffers around believing it should pop extra space. The result is
we have 'popped' more data then we expected potentially breaking
program logic.

It took us a while to hit this case because typically we pop headers
which seem to rarely be at the end of a scatterlist elements but
we can't rely on this.

Fixes: 7246d8ed4dcce ("bpf: helper to pop data from messages")
Signed-off-by: John Fastabend 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Jakub Sitnicki 
Acked-by: Martin KaFai Lau 
Link: https://lore.kernel.org/bpf/158861288359.14306.7654891716919968144.stgit@john-Precision-5820-Tower
Signed-off-by: Sasha Levin

netprio_cgroup: Fix unlimited memory leak of v2 cgroups

2020-05-20T06:22:04+00:00

[ Upstream commit 090e28b229af92dc5b40786ca673999d59e73056 ]

If systemd is configured to use hybrid mode which enables the use of
both cgroup v1 and v2, systemd will create new cgroup on both the default
root (v2) and netprio_cgroup hierarchy (v1) for a new session and attach
task to the two cgroups. If the task does some network thing then the v2
cgroup can never be freed after the session exited.

One of our machines ran into OOM due to this memory leak.

In the scenario described above when sk_alloc() is called
cgroup_sk_alloc() thought it's in v2 mode, so it stores
the cgroup pointer in sk->sk_cgrp_data and increments
the cgroup refcnt, but then sock_update_netprioidx()
thought it's in v1 mode, so it stores netprioidx value
in sk->sk_cgrp_data, so the cgroup refcnt will never be freed.

Currently we do the mode switch when someone writes to the ifpriomap
cgroup control file. The easiest fix is to also do the switch when
a task is attached to a new cgroup.

Fixes: bd1060a1d671 ("sock, cgroup: add sock->sk_cgroup")
Reported-by: Yang Yingliang 
Tested-by: Yang Yingliang 
Signed-off-by: Zefan Li 
Acked-by: Tejun Heo 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net: fix a potential recursive NETDEV_FEAT_CHANGE

2020-05-20T06:22:01+00:00

[ Upstream commit dd912306ff008891c82cd9f63e8181e47a9cb2fb ]

syzbot managed to trigger a recursive NETDEV_FEAT_CHANGE event
between bonding master and slave. I managed to find a reproducer
for this:

  ip li set bond0 up
  ifenslave bond0 eth0
  brctl addbr br0
  ethtool -K eth0 lro off
  brctl addif br0 bond0
  ip li set br0 up

When a NETDEV_FEAT_CHANGE event is triggered on a bonding slave,
it captures this and calls bond_compute_features() to fixup its
master's and other slaves' features. However, when syncing with
its lower devices by netdev_sync_lower_features() this event is
triggered again on slaves when the LRO feature fails to change,
so it goes back and forth recursively until the kernel stack is
exhausted.

Commit 17b85d29e82c intentionally lets __netdev_update_features()
return -1 for such a failure case, so we have to just rely on
the existing check inside netdev_sync_lower_features() and skip
NETDEV_FEAT_CHANGE event only for this specific failure case.

Fixes: fd867d51f889 ("net/core: generic support for disabling netdev features down stack")
Reported-by: syzbot+e73ceacfd8560cc8a3ca@syzkaller.appspotmail.com
Reported-by: syzbot+c2fb6f9ddcea95ba49b5@syzkaller.appspotmail.com
Cc: Jarod Wilson 
Cc: Nikolay Aleksandrov 
Cc: Josh Poimboeuf 
Cc: Jann Horn 
Reviewed-by: Jay Vosburgh 
Signed-off-by: Cong Wang 
Acked-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

drop_monitor: work around gcc-10 stringop-overflow warning

2020-05-20T06:21:58+00:00

[ Upstream commit dc30b4059f6e2abf3712ab537c8718562b21c45d ]

The current gcc-10 snapshot produces a false-positive warning:

net/core/drop_monitor.c: In function 'trace_drop_common.constprop':
cc1: error: writing 8 bytes into a region of size 0 [-Werror=stringop-overflow=]
In file included from net/core/drop_monitor.c:23:
include/uapi/linux/net_dropmon.h:36:8: note: at offset 0 to object 'entries' with size 4 declared here
   36 |  __u32 entries;
      |        ^~~~~~~

I reported this in the gcc bugzilla, but in case it does not get
fixed in the release, work around it by using a temporary variable.

Fixes: 9a8afc8d3962 ("Network Drop Monitor: Adding drop monitor implementation & Netlink protocol")
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94881
Signed-off-by: Arnd Bergmann 
Acked-by: Neil Horman 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

neigh: send protocol value in neighbor create notification

2020-05-14T05:59:15+00:00

[ Upstream commit 38212bb31fe923d0a2c6299bd2adfbb84cddef2a ]

When a new neighbor entry has been added, event is generated but it does not
include protocol, because its value is assigned after the event notification
routine has run, so move protocol assignment code earlier.

Fixes: df9b0e30d44c ("neighbor: Add protocol attribute")
Cc: David Ahern 
Signed-off-by: Roman Mashak 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

devlink: fix return value after hitting end in region read

2020-05-14T05:59:14+00:00

[ Upstream commit 610a9346c138b9c2c93d38bf5f3728e74ae9cbd5 ]

Commit d5b90e99e1d5 ("devlink: report 0 after hitting end in region read")
fixed region dump, but region read still returns a spurious error:

$ devlink region read netdevsim/netdevsim1/dummy snapshot 0 addr 0 len 128
0000000000000000 a6 f4 c4 1c 21 35 95 a6 9d 34 c3 5b 87 5b 35 79
0000000000000010 f3 a0 d7 ee 4f 2f 82 7f c6 dd c4 f6 a5 c3 1b ae
0000000000000020 a4 fd c8 62 07 59 48 03 70 3b c7 09 86 88 7f 68
0000000000000030 6f 45 5d 6d 7d 0e 16 38 a9 d0 7a 4b 1e 1e 2e a6
0000000000000040 e6 1d ae 06 d6 18 00 85 ca 62 e8 7e 11 7e f6 0f
0000000000000050 79 7e f7 0f f3 94 68 bd e6 40 22 85 b6 be 6f b1
0000000000000060 af db ef 5e 34 f0 98 4b 62 9a e3 1b 8b 93 fc 17
devlink answers: Invalid argument
0000000000000070 61 e8 11 11 66 10 a5 f7 b1 ea 8d 40 60 53 ed 12

This is a minimal fix, I'll follow up with a restructuring
so we don't have two checks for the same condition.

Fixes: fdd41ec21e15 ("devlink: Return right error code in case of errors for region read")
Signed-off-by: Jakub Kicinski 
Reviewed-by: Jacob Keller 
Reviewed-by: Jiri Pirko 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

devlink: Fix reporter's recovery condition

2020-05-14T05:59:14+00:00

[ Upstream commit bea0c5c942d3b4e9fb6ed45f6a7de74c6b112437 ]

Devlink health core conditions the reporter's recovery with the
expiration of the grace period. This is not relevant for the first
recovery. Explicitly demand that the grace period will only apply to
recoveries other than the first.

Fixes: c8e1da0bf923 ("devlink: Add health report functionality")
Signed-off-by: Aya Levin 
Reviewed-by: Moshe Shemesh 
Reviewed-by: Jiri Pirko 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

cgroup, netclassid: remove double cond_resched

2020-05-10T08:32:53+00:00

commit 526f3d96b8f83b1b13d73bd0b5c79cc2c487ec8e upstream.

Commit 018d26fcd12a ("cgroup, netclassid: periodically release file_lock
on classid") added a second cond_resched to write_classid indirectly by
update_classid_task. Remove the one in write_classid.

Signed-off-by: Jiri Slaby 
Cc: Dmitry Yakunin 
Cc: Konstantin Khlebnikov 
Cc: David S. Miller 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman