linux-stable.git/net/ipv4, branch v6.2.5

tcp: tcp_check_req() can be called from process context

2023-03-11T12:50:34+00:00

[ Upstream commit 580f98cc33a260bb8c6a39ae2921b29586b84fdf ]

This is a follow up of commit 0a375c822497 ("tcp: tcp_rtx_synack()
can be called from process context").

Frederick Lawler reported another "__this_cpu_add() in preemptible"
warning caused by the same reason.

In my former patch I took care of tcp_rtx_synack()
but forgot that tcp_check_req() also contained some SNMP updates.

Note that some parts of tcp_check_req() always run in BH context,
I added a comment to clarify this.

Fixes: 8336886f786f ("tcp: TCP Fast Open Server - support TFO listeners")
Link: https://lore.kernel.org/netdev/8cd33923-a21d-397c-e46b-2a068c287b03@cloudflare.com/T/
Signed-off-by: Eric Dumazet 
Reported-by: Frederick Lawler 
Tested-by: Frederick Lawler 
Link: https://lore.kernel.org/r/20230227083336.4153089-1-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

netfilter: x_tables: fix percpu counter block leak on error path when creating new netns

2023-03-11T12:50:30+00:00

[ Upstream commit 0af8c09c896810879387decfba8c942994bb61f5 ]

Here is the stack where we allocate percpu counter block:

  +-< __alloc_percpu
    +-< xt_percpu_counter_alloc
      +-< find_check_entry # {arp,ip,ip6}_tables.c
        +-< translate_table

And it can be leaked on this code path:

  +-> ip6t_register_table
    +-> translate_table # allocates percpu counter block
    +-> xt_register_table # fails

there is no freeing of the counter block on xt_register_table fail.
Note: xt_percpu_counter_free should be called to free it like we do in
do_replace through cleanup_entry helper (or in __ip6t_unregister_table).

Probability of hitting this error path is low AFAICS (xt_register_table
can only return ENOMEM here, as it is not replacing anything, as we are
creating new netns, and it is hard to imagine that all previous
allocations succeeded and after that one in xt_register_table failed).
But it's worth fixing even the rare leak.

Fixes: 71ae0dff02d7 ("netfilter: xtables: use percpu rule counters")
Signed-off-by: Pavel Tikhomirov 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: ebtables: fix table blob use-after-free

2023-03-11T12:50:30+00:00

[ Upstream commit e58a171d35e32e6e8c37cfe0e8a94406732a331f ]

We are not allowed to return an error at this point.
Looking at the code it looks like ret is always 0 at this
point, but its not.

t = find_table_lock(net, repl->name, &ret, &ebt_mutex);

... this can return a valid table, with ret != 0.

This bug causes update of table->private with the new
blob, but then frees the blob right away in the caller.

Syzbot report:

BUG: KASAN: vmalloc-out-of-bounds in __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168
Read of size 4 at addr ffffc90005425000 by task kworker/u4:4/74
Workqueue: netns cleanup_net
Call Trace:
 kasan_report+0xbf/0x1f0 mm/kasan/report.c:517
 __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168
 ebt_unregister_table+0x35/0x40 net/bridge/netfilter/ebtables.c:1372
 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169
 cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613
...

ip(6)tables appears to be ok (ret should be 0 at this point) but make
this more obvious.

Fixes: c58dd2dd443c ("netfilter: Can't fail and free after table replacement")
Reported-by: syzbot+f61594de72d6705aea03@syzkaller.appspotmail.com
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

inet: fix fast path in __inet_hash_connect()

2023-03-10T08:29:09+00:00

[ Upstream commit 21cbd90a6fab7123905386985e3e4a80236b8714 ]

__inet_hash_connect() has a fast path taken if sk_head(&tb->owners) is
equal to the sk parameter.
sk_head() returns the hlist_entry() with respect to the sk_node field.
However entries in the tb->owners list are inserted with respect to the
sk_bind_node field with sk_add_bind_node().
Thus the check would never pass and the fast path never execute.

This fast path has never been executed or tested as this bug seems
to be present since commit 1da177e4c3f4 ("Linux-2.6.12-rc2"), thus
remove it to reduce code complexity.

Signed-off-by: Pietro Borrello 
Reviewed-by: Kuniyuki Iwashima 
Reviewed-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20230112-inet_hash_connect_bind_head-v3-1-b591fd212b93@diag.uniroma1.it
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

txhash: fix sk->sk_txrehash default

2023-02-08T09:07:11+00:00

This code fix a bug that sk->sk_txrehash gets its default enable
value from sysctl_txrehash only when the socket is a TCP listener.

We should have sysctl_txrehash to set the default sk->sk_txrehash,
no matter TCP, nor listerner/connector.

Tested by following packetdrill:
  0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
  +0 socket(..., SOCK_DGRAM, IPPROTO_UDP) = 4
  // SO_TXREHASH == 74, default to sysctl_txrehash == 1
  +0 getsockopt(3, SOL_SOCKET, 74, [1], [4]) = 0
  +0 getsockopt(4, SOL_SOCKET, 74, [1], [4]) = 0

Fixes: 26859240e4ee ("txhash: Add socket option to control TX hash rethink behavior")
Signed-off-by: Kevin Yang 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2023-01-28T07:32:03+00:00

Daniel Borkmann says:

====================
bpf 2023-01-27

We've added 10 non-merge commits during the last 9 day(s) which contain
a total of 10 files changed, 170 insertions(+), 59 deletions(-).

The main changes are:

1) Fix preservation of register's parent/live fields when copying
   range-info, from Eduard Zingerman.

2) Fix an off-by-one bug in bpf_mem_cache_idx() to select the right
   cache, from Hou Tao.

3) Fix stack overflow from infinite recursion in sock_map_close(),
   from Jakub Sitnicki.

4) Fix missing btf_put() in register_btf_id_dtor_kfuncs()'s error path,
   from Jiri Olsa.

5) Fix a splat from bpf_setsockopt() via lsm_cgroup/socket_sock_rcv_skb,
   from Kui-Feng Lee.

6) Fix bpf_send_signal[_thread]() helpers to hold a reference on the task,
   from Yonghong Song.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpf: Fix the kernel crash caused by bpf_setsockopt().
  selftests/bpf: Cover listener cloning with progs attached to sockmap
  selftests/bpf: Pass BPF skeleton to sockmap_listen ops tests
  bpf, sockmap: Check for any of tcp_bpf_prots when cloning a listener
  bpf, sockmap: Don't let sock_map_{close,destroy,unhash} call itself
  bpf: Add missing btf_put to register_btf_id_dtor_kfuncs
  selftests/bpf: Verify copy_register_state() preserves parent/live fields
  bpf: Fix to preserve reg parent/live fields when copying range info
  bpf: Fix a possible task gone issue with bpf_send_signal[_thread]() helpers
  bpf: Fix off-by-one error in bpf_mem_cache_idx()
====================

Link: https://lore.kernel.org/r/20230127215820.4993-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski

bpf, sockmap: Check for any of tcp_bpf_prots when cloning a listener

2023-01-25T05:32:55+00:00

A listening socket linked to a sockmap has its sk_prot overridden. It
points to one of the struct proto variants in tcp_bpf_prots. The variant
depends on the socket's family and which sockmap programs are attached.

A child socket cloned from a TCP listener initially inherits their sk_prot.
But before cloning is finished, we restore the child's proto to the
listener's original non-tcp_bpf_prots one. This happens in
tcp_create_openreq_child -> tcp_bpf_clone.

Today, in tcp_bpf_clone we detect if the child's proto should be restored
by checking only for the TCP_BPF_BASE proto variant. This is not
correct. The sk_prot of listening socket linked to a sockmap can point to
to any variant in tcp_bpf_prots.

If the listeners sk_prot happens to be not the TCP_BPF_BASE variant, then
the child socket unintentionally is left if the inherited sk_prot by
tcp_bpf_clone.

This leads to issues like infinite recursion on close [1], because the
child state is otherwise not set up for use with tcp_bpf_prot operations.

Adjust the check in tcp_bpf_clone to detect all of tcp_bpf_prots variants.

Note that it wouldn't be sufficient to check the socket state when
overriding the sk_prot in tcp_bpf_update_proto in order to always use the
TCP_BPF_BASE variant for listening sockets. Since commit
b8b8315e39ff ("bpf, sockmap: Remove unhash handler for BPF sockmap usage")
it is possible for a socket to transition to TCP_LISTEN state while already
linked to a sockmap, e.g. connect() -> insert into map ->
connect(AF_UNSPEC) -> listen().

[1]: https://lore.kernel.org/all/00000000000073b14905ef2e7401@google.com/

Fixes: e80251555f0b ("tcp_bpf: Don't let child socket inherit parent protocol ops on copy")
Reported-by: syzbot+04c21ed96d861dccc5cd@syzkaller.appspotmail.com
Signed-off-by: Jakub Sitnicki 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/r/20230113-sockmap-fix-v2-2-1e0ee7ac2f90@cloudflare.com
Signed-off-by: Alexei Starovoitov

ipv4: prevent potential spectre v1 gadget in fib_metrics_match()

2023-01-24T05:37:39+00:00

if (!type)
        continue;
    if (type > RTAX_MAX)
        return false;
    ...
    fi_val = fi->fib_metrics->metrics[type - 1];

@type being used as an array index, we need to prevent
cpu speculation or risk leaking kernel memory content.

Fixes: 5f9ae3d9e7e4 ("ipv4: do metrics match when looking up and deleting a route")
Signed-off-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20230120133140.3624204-1-edumazet@google.com
Signed-off-by: Jakub Kicinski

ipv4: prevent potential spectre v1 gadget in ip_metrics_convert()

2023-01-24T05:37:25+00:00

if (!type)
		continue;
	if (type > RTAX_MAX)
		return -EINVAL;
	...
	metrics[type - 1] = val;

@type being used as an array index, we need to prevent
cpu speculation or risk leaking kernel memory content.

Fixes: 6cf9dfd3bd62 ("net: fib: move metrics parsing to a helper")
Signed-off-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20230120133040.3623463-1-edumazet@google.com
Signed-off-by: Jakub Kicinski

tcp: fix rate_app_limited to default to 1

2023-01-20T13:23:35+00:00

The initial default value of 0 for tp->rate_app_limited was incorrect,
since a flow is indeed application-limited until it first sends
data. Fixing the default to be 1 is generally correct but also
specifically will help user-space applications avoid using the initial
tcpi_delivery_rate value of 0 that persists until the connection has
some non-zero bandwidth sample.

Fixes: eb8329e0a04d ("tcp: export data delivery rate")
Suggested-by: Yuchung Cheng 
Signed-off-by: David Morley 
Signed-off-by: Neal Cardwell 
Tested-by: David Morley 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller