linux-stable.git/net, branch v5.4.49

net: core: device_rename: Use rwsem instead of a seqcount

2020-06-24T15:50:52+00:00

[ Upstream commit 11d6011c2cf29f7c8181ebde6c8bc0c4d83adcd7 ]

Sequence counters write paths are critical sections that must never be
preempted, and blocking, even for CONFIG_PREEMPTION=n, is not allowed.

Commit 5dbe7c178d3f ("net: fix kernel deadlock with interface rename and
netdev name retrieval.") handled a deadlock, observed with
CONFIG_PREEMPTION=n, where the devnet_rename seqcount read side was
infinitely spinning: it got scheduled after the seqcount write side
blocked inside its own critical section.

To fix that deadlock, among other issues, the commit added a
cond_resched() inside the read side section. While this will get the
non-preemptible kernel eventually unstuck, the seqcount reader is fully
exhausting its slice just spinning -- until TIF_NEED_RESCHED is set.

The fix is also still broken: if the seqcount reader belongs to a
real-time scheduling policy, it can spin forever and the kernel will
livelock.

Disabling preemption over the seqcount write side critical section will
not work: inside it are a number of GFP_KERNEL allocations and mutex
locking through the drivers/base/ :: device_rename() call chain.

>From all the above, replace the seqcount with a rwsem.

Fixes: 5dbe7c178d3f (net: fix kernel deadlock with interface rename and netdev name retrieval.)
Fixes: 30e6c9fa93cf (net: devnet_rename_seq should be a seqcount)
Fixes: c91f6df2db49 (sockopt: Change getsockopt() of SO_BINDTODEVICE to return an interface name)
Cc: 
Reported-by: kbuild test robot  [ v1 missing up_read() on error exit ]
Reported-by: Dan Carpenter  [ v1 missing up_read() on error exit ]
Signed-off-by: Ahmed S. Darwish 
Reviewed-by: Sebastian Andrzej Siewior 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

sched/rt, net: Use CONFIG_PREEMPTION.patch

2020-06-24T15:50:52+00:00

[ Upstream commit 2da2b32fd9346009e9acdb68c570ca8d3966aba7 ]

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.

Update the comment to use CONFIG_PREEMPTION.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Thomas Gleixner 
Acked-by: David S. Miller 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/20191015191821.11479-22-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

bpf: Fix memlock accounting for sock_hash

2020-06-24T15:50:44+00:00

[ Upstream commit 60e5ca8a64bad8f3e2e20a1e57846e497361c700 ]

Add missed bpf_map_charge_init() in sock_hash_alloc() and
correspondingly bpf_map_charge_finish() on ENOMEM.

It was found accidentally while working on unrelated selftest that
checks "map->memory.pages > 0" is true for all map types.

Before:
	# bpftool m l
	...
	3692: sockhash  name m_sockhash  flags 0x0
		key 4B  value 4B  max_entries 8  memlock 0B

After:
	# bpftool m l
	...
	84: sockmap  name m_sockmap  flags 0x0
		key 4B  value 4B  max_entries 8  memlock 4096B

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Andrey Ignatov 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20200612000857.2881453-1-rdna@fb.com
Signed-off-by: Sasha Levin

xdp: Fix xsk_generic_xmit errno

2020-06-24T15:50:44+00:00

[ Upstream commit aa2cad0600ed2ca6a0ab39948d4db1666b6c962b ]

Propagate sock_alloc_send_skb error code, not set it to
EAGAIN unconditionally, when fail to allocate skb, which
might cause that user space unnecessary loops.

Fixes: 35fcde7f8deb ("xsk: support for Tx")
Signed-off-by: Li RongQing 
Signed-off-by: Daniel Borkmann 
Acked-by: Björn Töpel 
Link: https://lore.kernel.org/bpf/1591852266-24017-1-git-send-email-lirongqing@baidu.com
Signed-off-by: Sasha Levin

net/filter: Permit reading NET in load_bytes_relative when MAC not set

2020-06-24T15:50:43+00:00

[ Upstream commit 0f5d82f187e1beda3fe7295dfc500af266a5bd80 ]

Added a check in the switch case on start_header that checks for
the existence of the header, and in the case that MAC is not set
and the caller requests for MAC, -EFAULT. If the caller requests
for NET then MAC's existence is completely ignored.

There is no function to check NET header's existence and as far
as cgroup_skb/egress is concerned it should always be set.

Removed for ptr >= the start of header, considering offset is
bounded unsigned and should always be true. len <= end - mac is
redundant to ptr + len <= end.

Fixes: 3eee1f75f2b9 ("bpf: fix bpf_skb_load_bytes_relative pkt length check")
Signed-off-by: YiFei Zhu 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Stanislav Fomichev 
Link: https://lore.kernel.org/bpf/76bb820ddb6a95f59a772ecbd8c8a336f646b362.1591812755.git.zhuyifei@google.com
Signed-off-by: Sasha Levin

bpf, sockhash: Synchronize delete from bucket list on map free

2020-06-24T15:50:42+00:00

[ Upstream commit 75e68e5bf2c7fa9d3e874099139df03d5952a3e1 ]

We can end up modifying the sockhash bucket list from two CPUs when a
sockhash is being destroyed (sock_hash_free) on one CPU, while a socket
that is in the sockhash is unlinking itself from it on another CPU
it (sock_hash_delete_from_link).

This results in accessing a list element that is in an undefined state as
reported by KASAN:

| ==================================================================
| BUG: KASAN: wild-memory-access in sock_hash_free+0x13c/0x280
| Write of size 8 at addr dead000000000122 by task kworker/2:1/95
|
| CPU: 2 PID: 95 Comm: kworker/2:1 Not tainted 5.7.0-rc7-02961-ge22c35ab0038-dirty #691
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
| Workqueue: events bpf_map_free_deferred
| Call Trace:
|  dump_stack+0x97/0xe0
|  ? sock_hash_free+0x13c/0x280
|  __kasan_report.cold+0x5/0x40
|  ? mark_lock+0xbc1/0xc00
|  ? sock_hash_free+0x13c/0x280
|  kasan_report+0x38/0x50
|  ? sock_hash_free+0x152/0x280
|  sock_hash_free+0x13c/0x280
|  bpf_map_free_deferred+0xb2/0xd0
|  ? bpf_map_charge_finish+0x50/0x50
|  ? rcu_read_lock_sched_held+0x81/0xb0
|  ? rcu_read_lock_bh_held+0x90/0x90
|  process_one_work+0x59a/0xac0
|  ? lock_release+0x3b0/0x3b0
|  ? pwq_dec_nr_in_flight+0x110/0x110
|  ? rwlock_bug.part.0+0x60/0x60
|  worker_thread+0x7a/0x680
|  ? _raw_spin_unlock_irqrestore+0x4c/0x60
|  kthread+0x1cc/0x220
|  ? process_one_work+0xac0/0xac0
|  ? kthread_create_on_node+0xa0/0xa0
|  ret_from_fork+0x24/0x30
| ==================================================================

Fix it by reintroducing spin-lock protected critical section around the
code that removes the elements from the bucket on sockhash free.

To do that we also need to defer processing of removed elements, until out
of atomic context so that we can unlink the socket from the map when
holding the sock lock.

Fixes: 90db6d772f74 ("bpf, sockmap: Remove bucket->lock from sock_{hash|map}_free")
Reported-by: Eric Dumazet 
Signed-off-by: Jakub Sitnicki 
Signed-off-by: Alexei Starovoitov 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20200607205229.2389672-3-jakub@cloudflare.com
Signed-off-by: Sasha Levin

bpf/sockmap: Fix kernel panic at __tcp_bpf_recvmsg

2020-06-24T15:50:42+00:00

[ Upstream commit 487082fb7bd2a32b66927d2b22e3a81b072b44f0 ]

When user application calls read() with MSG_PEEK flag to read data
of bpf sockmap socket, kernel panic happens at
__tcp_bpf_recvmsg+0x12c/0x350. sk_msg is not removed from ingress_msg
queue after read out under MSG_PEEK flag is set. Because it's not
judged whether sk_msg is the last msg of ingress_msg queue, the next
sk_msg may be the head of ingress_msg queue, whose memory address of
sg page is invalid. So it's necessary to add check codes to prevent
this problem.

[20759.125457] BUG: kernel NULL pointer dereference, address:
0000000000000008
[20759.132118] CPU: 53 PID: 51378 Comm: envoy Tainted: G            E
5.4.32 #1
[20759.140890] Hardware name: Inspur SA5212M4/YZMB-00370-109, BIOS
4.1.12 06/18/2017
[20759.149734] RIP: 0010:copy_page_to_iter+0xad/0x300
[20759.270877] __tcp_bpf_recvmsg+0x12c/0x350
[20759.276099] tcp_bpf_recvmsg+0x113/0x370
[20759.281137] inet_recvmsg+0x55/0xc0
[20759.285734] __sys_recvfrom+0xc8/0x130
[20759.290566] ? __audit_syscall_entry+0x103/0x130
[20759.296227] ? syscall_trace_enter+0x1d2/0x2d0
[20759.301700] ? __audit_syscall_exit+0x1e4/0x290
[20759.307235] __x64_sys_recvfrom+0x24/0x30
[20759.312226] do_syscall_64+0x55/0x1b0
[20759.316852] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: dihu 
Signed-off-by: Alexei Starovoitov 
Acked-by: John Fastabend 
Acked-by: Jakub Sitnicki 
Link: https://lore.kernel.org/bpf/20200605084625.9783-1-anny.hu@linux.alibaba.com
Signed-off-by: Sasha Levin

rxrpc: Adjust /proc/net/rxrpc/calls to display call->debug_id not user_ID

2020-06-24T15:50:37+00:00

[ Upstream commit 32f71aa497cfb23d37149c2ef16ad71fce2e45e2 ]

The user ID value isn't actually much use - and leaks a kernel pointer or a
userspace value - so replace it with the call debug ID, which appears in trace
points.

Signed-off-by: David Howells 
Signed-off-by: Sasha Levin

net: sunrpc: Fix off-by-one issues in 'rpc_ntop6'

2020-06-24T15:50:35+00:00

[ Upstream commit 118917d696dc59fd3e1741012c2f9db2294bed6f ]

Fix off-by-one issues in 'rpc_ntop6':
 - 'snprintf' returns the number of characters which would have been
   written if enough space had been available, excluding the terminating
   null byte. Thus, a return value of 'sizeof(scopebuf)' means that the
   last character was dropped.
 - 'strcat' adds a terminating null byte to the string, thus if len ==
   buflen, the null byte is written past the end of the buffer.

Signed-off-by: Fedor Tokarev 
Signed-off-by: Anna Schumaker 
Signed-off-by: Sasha Levin

bpf, sockhash: Fix memory leak when unlinking sockets in sock_hash_free

2020-06-24T15:50:19+00:00

[ Upstream commit 33a7c831565c43a7ee2f38c7df4c4a40e1dfdfed ]

When sockhash gets destroyed while sockets are still linked to it, we will
walk the bucket lists and delete the links. However, we are not freeing the
list elements after processing them, leaking the memory.

The leak can be triggered by close()'ing a sockhash map when it still
contains sockets, and observed with kmemleak:

  unreferenced object 0xffff888116e86f00 (size 64):
    comm "race_sock_unlin", pid 223, jiffies 4294731063 (age 217.404s)
    hex dump (first 32 bytes):
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
      81 de e8 41 00 00 00 00 c0 69 2f 15 81 88 ff ff  ...A.....i/.....
    backtrace:
      [<00000000dd089ebb>] sock_hash_update_common+0x4ca/0x760
      [<00000000b8219bd5>] sock_hash_update_elem+0x1d2/0x200
      [<000000005e2c23de>] __do_sys_bpf+0x2046/0x2990
      [<00000000d0084618>] do_syscall_64+0xad/0x9a0
      [<000000000d96f263>] entry_SYSCALL_64_after_hwframe+0x49/0xb3

Fix it by freeing the list element when we're done with it.

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Jakub Sitnicki 
Signed-off-by: Alexei Starovoitov 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20200607205229.2389672-2-jakub@cloudflare.com
Signed-off-by: Sasha Levin