linux.git/include/net, branch v6.5-rc4

tcp: Reduce chance of collisions in inet6_hashfn().

2023-07-24T23:52:37+00:00

For both IPv4 and IPv6 incoming TCP connections are tracked in a hash
table with a hash over the source & destination addresses and ports.
However, the IPv6 hash is insufficient and can lead to a high rate of
collisions.

The IPv6 hash used an XOR to fit everything into the 96 bits for the
fast jenkins hash, meaning it is possible for an external entity to
ensure the hash collides, thus falling back to a linear search in the
bucket, which is slow.

We take the approach of hash the full length of IPv6 address in
__ipv6_addr_jhash() so that all users can benefit from a more secure
version.

While this may look like it adds overhead, the reality of modern CPUs
means that this is unmeasurable in real world scenarios.

In simulating with llvm-mca, the increase in cycles for the hashing
code was ~16 cycles on Skylake (from a base of ~155), and an extra ~9
on Nehalem (base of ~173).

In commit dd6d2910c5e0 ("netfilter: conntrack: switch to siphash")
netfilter switched from a jenkins hash to a siphash, but even the faster
hsiphash is a more significant overhead (~20-30%) in some preliminary
testing.  So, in this patch, we keep to the more conservative approach to
ensure we don't add much overhead per SYN.

In testing, this results in a consistently even spread across the
connection buckets.  In both testing and real-world scenarios, we have
not found any measurable performance impact.

Fixes: 08dcdbf6a7b9 ("ipv6: use a stronger hash for tcp")
Signed-off-by: Stewart Smith 
Signed-off-by: Samuel Mendoza-Jonas 
Suggested-by: Eric Dumazet 
Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20230721222410.17914-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski

vxlan: calculate correct header length for GPE

2023-07-24T08:37:32+00:00

VXLAN-GPE does not add an extra inner Ethernet header. Take that into
account when calculating header length.

This causes problems in skb_tunnel_check_pmtu, where incorrect PMTU is
cached.

In the collect_md mode (which is the only mode that VXLAN-GPE
supports), there's no magic auto-setting of the tunnel interface MTU.
It can't be, since the destination and thus the underlying interface
may be different for each packet.

So, the administrator is responsible for setting the correct tunnel
interface MTU. Apparently, the administrators are capable enough to
calculate that the maximum MTU for VXLAN-GPE is (their_lower_MTU - 36).
They set the tunnel interface MTU to 1464. If you run a TCP stream over
such interface, it's then segmented according to the MTU 1464, i.e.
producing 1514 bytes frames. Which is okay, this still fits the lower
MTU.

However, skb_tunnel_check_pmtu (called from vxlan_xmit_one) uses 50 as
the header size and thus incorrectly calculates the frame size to be
1528. This leads to ICMP too big message being generated (locally),
PMTU of 1450 to be cached and the TCP stream to be resegmented.

The fix is to use the correct actual header size, especially for
skb_tunnel_check_pmtu calculation.

Fixes: e1e5314de08ba ("vxlan: implement GPE")
Signed-off-by: Jiri Benc 
Reviewed-by: Simon Horman 
Signed-off-by: David S. Miller

Merge tag 'for-net-2023-07-20' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth

2023-07-20T19:57:55+00:00

Luiz Augusto von Dentz says:

====================
bluetooth pull request for net:

 - Fix building with coredump disabled
 - Fix use-after-free in hci_remove_adv_monitor
 - Use RCU for hci_conn_params and iterate safely in hci_sync
 - Fix locking issues on ISO and SCO
 - Fix bluetooth on Intel Macbook 2014

* tag 'for-net-2023-07-20' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth:
  Bluetooth: MGMT: Use correct address for memcpy()
  Bluetooth: btusb: Fix bluetooth on Intel Macbook 2014
  Bluetooth: SCO: fix sco_conn related locking and validity issues
  Bluetooth: hci_conn: return ERR_PTR instead of NULL when there is no link
  Bluetooth: hci_sync: Avoid use-after-free in dbg for hci_remove_adv_monitor()
  Bluetooth: coredump: fix building with coredump disabled
  Bluetooth: ISO: fix iso_conn related locking and validity issues
  Bluetooth: hci_event: call disconnect callback before deleting conn
  Bluetooth: use RCU for hci_conn_params and iterate safely in hci_sync
====================

Link: https://lore.kernel.org/r/20230720190201.446469-1-luiz.dentz@gmail.com
Signed-off-by: Jakub Kicinski

tcp: annotate data-races around tp->notsent_lowat

2023-07-20T19:34:18+00:00

tp->notsent_lowat can be read locklessly from do_tcp_getsockopt()
and tcp_poll().

Fixes: c9bee3b7fdec ("tcp: TCP_NOTSENT_LOWAT socket option")
Signed-off-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20230719212857.3943972-10-edumazet@google.com
Signed-off-by: Jakub Kicinski

tcp: annotate data-races around tp->keepalive_probes

2023-07-20T19:34:18+00:00

do_tcp_getsockopt() reads tp->keepalive_probes while another cpu
might change its value.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20230719212857.3943972-6-edumazet@google.com
Signed-off-by: Jakub Kicinski

tcp: annotate data-races around tp->keepalive_intvl

2023-07-20T19:34:18+00:00

do_tcp_getsockopt() reads tp->keepalive_intvl while another cpu
might change its value.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20230719212857.3943972-5-edumazet@google.com
Signed-off-by: Jakub Kicinski

tcp: annotate data-races around tp->keepalive_time

2023-07-20T19:34:18+00:00

do_tcp_getsockopt() reads tp->keepalive_time while another cpu
might change its value.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20230719212857.3943972-4-edumazet@google.com
Signed-off-by: Jakub Kicinski

Bluetooth: coredump: fix building with coredump disabled

2023-07-20T18:25:24+00:00

The btmtk driver uses an IS_ENABLED() check to conditionally compile
the coredump support, but this fails to build because the hdev->dump
member is in an #ifdef:

drivers/bluetooth/btmtk.c: In function 'btmtk_process_coredump':
drivers/bluetooth/btmtk.c:386:30: error: 'struct hci_dev' has no member named 'dump'
  386 |   schedule_delayed_work(&hdev->dump.dump_timeout,
      |                              ^~

The struct member doesn't really make a huge difference in the total size,
so just remove the #ifdef around it to avoid adding similar checks
around each user.

Fixes: 872f8c253cb9e ("Bluetooth: btusb: mediatek: add MediaTek devcoredump support")
Fixes: 9695ef876fd12 ("Bluetooth: Add support for hci devcoredump")
Signed-off-by: Arnd Bergmann 
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: use RCU for hci_conn_params and iterate safely in hci_sync

2023-07-20T18:25:24+00:00

hci_update_accept_list_sync iterates over hdev->pend_le_conns and
hdev->pend_le_reports, and waits for controller events in the loop body,
without holding hdev lock.

Meanwhile, these lists and the items may be modified e.g. by
le_scan_cleanup. This can invalidate the list cursor or any other item
in the list, resulting to invalid behavior (eg use-after-free).

Use RCU for the hci_conn_params action lists. Since the loop bodies in
hci_sync block and we cannot use RCU or hdev->lock for the whole loop,
copy list items first and then iterate on the copy. Only the flags field
is written from elsewhere, so READ_ONCE/WRITE_ONCE should guarantee we
read valid values.

Free params everywhere with hci_conn_params_free so the cleanup is
guaranteed to be done properly.

This fixes the following, which can be triggered e.g. by BlueZ new
mgmt-tester case "Add + Remove Device Nowait - Success", or by changing
hci_le_set_cig_params to always return false, and running iso-tester:

==================================================================
BUG: KASAN: slab-use-after-free in hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2536 net/bluetooth/hci_sync.c:2723 net/bluetooth/hci_sync.c:2841)
Read of size 8 at addr ffff888001265018 by task kworker/u3:0/32

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
Workqueue: hci0 hci_cmd_sync_work
Call Trace:

dump_stack_lvl (./arch/x86/include/asm/irqflags.h:134 lib/dump_stack.c:107)
print_report (mm/kasan/report.c:320 mm/kasan/report.c:430)
? __virt_addr_valid (./include/linux/mmzone.h:1915 ./include/linux/mmzone.h:2011 arch/x86/mm/physaddr.c:65)
? hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2536 net/bluetooth/hci_sync.c:2723 net/bluetooth/hci_sync.c:2841)
kasan_report (mm/kasan/report.c:538)
? hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2536 net/bluetooth/hci_sync.c:2723 net/bluetooth/hci_sync.c:2841)
hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2536 net/bluetooth/hci_sync.c:2723 net/bluetooth/hci_sync.c:2841)
? __pfx_hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2780)
? mutex_lock (kernel/locking/mutex.c:282)
? __pfx_mutex_lock (kernel/locking/mutex.c:282)
? __pfx_mutex_unlock (kernel/locking/mutex.c:538)
? __pfx_update_passive_scan_sync (net/bluetooth/hci_sync.c:2861)
hci_cmd_sync_work (net/bluetooth/hci_sync.c:306)
process_one_work (./arch/x86/include/asm/preempt.h:27 kernel/workqueue.c:2399)
worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2538)
? __pfx_worker_thread (kernel/workqueue.c:2480)
kthread (kernel/kthread.c:376)
? __pfx_kthread (kernel/kthread.c:331)
ret_from_fork (arch/x86/entry/entry_64.S:314)


Allocated by task 31:
kasan_save_stack (mm/kasan/common.c:46)
kasan_set_track (mm/kasan/common.c:52)
__kasan_kmalloc (mm/kasan/common.c:374 mm/kasan/common.c:383)
hci_conn_params_add (./include/linux/slab.h:580 ./include/linux/slab.h:720 net/bluetooth/hci_core.c:2277)
hci_connect_le_scan (net/bluetooth/hci_conn.c:1419 net/bluetooth/hci_conn.c:1589)
hci_connect_cis (net/bluetooth/hci_conn.c:2266)
iso_connect_cis (net/bluetooth/iso.c:390)
iso_sock_connect (net/bluetooth/iso.c:899)
__sys_connect (net/socket.c:2003 net/socket.c:2020)
__x64_sys_connect (net/socket.c:2027)
do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)

Freed by task 15:
kasan_save_stack (mm/kasan/common.c:46)
kasan_set_track (mm/kasan/common.c:52)
kasan_save_free_info (mm/kasan/generic.c:523)
__kasan_slab_free (mm/kasan/common.c:238 mm/kasan/common.c:200 mm/kasan/common.c:244)
__kmem_cache_free (mm/slub.c:1807 mm/slub.c:3787 mm/slub.c:3800)
hci_conn_params_del (net/bluetooth/hci_core.c:2323)
le_scan_cleanup (net/bluetooth/hci_conn.c:202)
process_one_work (./arch/x86/include/asm/preempt.h:27 kernel/workqueue.c:2399)
worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2538)
kthread (kernel/kthread.c:376)
ret_from_fork (arch/x86/entry/entry_64.S:314)
==================================================================

Fixes: e8907f76544f ("Bluetooth: hci_sync: Make use of hci_cmd_sync_queue set 3")
Signed-off-by: Pauli Virtanen 
Signed-off-by: Luiz Augusto von Dentz

llc: Check netns in llc_estab_match() and llc_listener_match().

2023-07-20T08:46:28+00:00

We will remove this restriction in llc_rcv() in the following patch,
which means that the protocol handler must be aware of netns.

        if (!net_eq(dev_net(dev), &init_net))
                goto drop;

llc_rcv() fetches llc_type_handlers[llc_pdu_type(skb) - 1] and calls it
if not NULL.

If the PDU type is LLC_DEST_CONN, llc_conn_handler() is called to pass
skb to corresponding sockets.  Then, we must look up a proper socket in
the same netns with skb->dev.

llc_conn_handler() calls __llc_lookup() to look up a established or
litening socket by __llc_lookup_established() and llc_lookup_listener().

Both functions iterate on a list and call llc_estab_match() or
llc_listener_match() to check if the socket is the correct destination.
However, these functions do not check netns.

Also, bind() and connect() call llc_establish_connection(), which
finally calls __llc_lookup_established(), to check if there is a
conflicting socket.

Let's test netns in llc_estab_match() and llc_listener_match().

Signed-off-by: Kuniyuki Iwashima 
Signed-off-by: Paolo Abeni