Eric Dumazet
8ffd74f354
genetlink: hold RCU in genlmsg_mcast()
...
[ Upstream commit 56440d7ec28d60f8da3bfa09062b3368ff9b16db ]
While running net selftests with CONFIG_PROVE_RCU_LIST=y I saw
one lockdep splat [1].
genlmsg_mcast() uses for_each_net_rcu(), and must therefore hold RCU.
Instead of letting all callers guard genlmsg_multicast_allns()
with a rcu_read_lock()/rcu_read_unlock() pair, do it in genlmsg_mcast().
This also means the @flags parameter is useless, we need to always use
GFP_ATOMIC.
[1]
[10882.424136] =============================
[10882.424166] WARNING: suspicious RCU usage
[10882.424309] 6.12.0-rc2-virtme #1156 Not tainted
[10882.424400] -----------------------------
[10882.424423] net/netlink/genetlink.c:1940 RCU-list traversed in non-reader section!!
[10882.424469]
other info that might help us debug this:
[10882.424500]
rcu_scheduler_active = 2, debug_locks = 1
[10882.424744] 2 locks held by ip/15677:
[10882.424791] #0 : ffffffffb6b491b0 (cb_lock){++++}-{3:3}, at: genl_rcv (net/netlink/genetlink.c:1219)
[10882.426334] #1 : ffffffffb6b49248 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg (net/netlink/genetlink.c:61 net/netlink/genetlink.c:57 net/netlink/genetlink.c:1209)
[10882.426465]
stack backtrace:
[10882.426805] CPU: 14 UID: 0 PID: 15677 Comm: ip Not tainted 6.12.0-rc2-virtme #1156
[10882.426919] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[10882.427046] Call Trace:
[10882.427131] <TASK>
[10882.427244] dump_stack_lvl (lib/dump_stack.c:123)
[10882.427335] lockdep_rcu_suspicious (kernel/locking/lockdep.c:6822)
[10882.427387] genlmsg_multicast_allns (net/netlink/genetlink.c:1940 (discriminator 7) net/netlink/genetlink.c:1977 (discriminator 7))
[10882.427436] l2tp_tunnel_notify.constprop.0 (net/l2tp/l2tp_netlink.c:119) l2tp_netlink
[10882.427683] l2tp_nl_cmd_tunnel_create (net/l2tp/l2tp_netlink.c:253) l2tp_netlink
[10882.427748] genl_family_rcv_msg_doit (net/netlink/genetlink.c:1115)
[10882.427834] genl_rcv_msg (net/netlink/genetlink.c:1195 net/netlink/genetlink.c:1210)
[10882.427877] ? __pfx_l2tp_nl_cmd_tunnel_create (net/l2tp/l2tp_netlink.c:186) l2tp_netlink
[10882.427927] ? __pfx_genl_rcv_msg (net/netlink/genetlink.c:1201)
[10882.427959] netlink_rcv_skb (net/netlink/af_netlink.c:2551)
[10882.428069] genl_rcv (net/netlink/genetlink.c:1220)
[10882.428095] netlink_unicast (net/netlink/af_netlink.c:1332 net/netlink/af_netlink.c:1357)
[10882.428140] netlink_sendmsg (net/netlink/af_netlink.c:1901)
[10882.428210] ____sys_sendmsg (net/socket.c:729 (discriminator 1) net/socket.c:744 (discriminator 1) net/socket.c:2607 (discriminator 1))
Fixes: 33f72e6f0c67 ("l2tp : multicast notification to the registered listeners")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: James Chapman <jchapman@katalix.com>
Cc: Tom Parkin <tparkin@katalix.com>
Cc: Johannes Berg <johannes.berg@intel.com>
Link: https://patch.msgid.link/20241011171217.3166614-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-23 23:21:59 +01:00
James Chapman
3cf4e3f975
l2tp: fix lockdep splat
...
[ Upstream commit 86a41ea9fd79ddb6145cb8ebf5aeafceabca6f7d ]
When l2tp tunnels use a socket provided by userspace, we can hit
lockdep splats like the below when data is transmitted through another
(unrelated) userspace socket which then gets routed over l2tp.
This issue was previously discussed here:
https://lore.kernel.org/netdev/87sfialu2n.fsf@cloudflare.com/
The solution is to have lockdep treat socket locks of l2tp tunnel
sockets separately than those of standard INET sockets. To do so, use
a different lockdep subclass where lock nesting is possible.
============================================
WARNING: possible recursive locking detected
6.10.0+ #34 Not tainted
--------------------------------------------
iperf3/771 is trying to acquire lock:
ffff8881027601d8 (slock-AF_INET/1){+.-.}-{2:2}, at: l2tp_xmit_skb+0x243/0x9d0
but task is already holding lock:
ffff888102650d98 (slock-AF_INET/1){+.-.}-{2:2}, at: tcp_v4_rcv+0x1848/0x1e10
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(slock-AF_INET/1);
lock(slock-AF_INET/1);
*** DEADLOCK ***
May be due to missing lock nesting notation
10 locks held by iperf3/771:
#0 : ffff888102650258 (sk_lock-AF_INET){+.+.}-{0:0}, at: tcp_sendmsg+0x1a/0x40
#1 : ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: __ip_queue_xmit+0x4b/0xbc0
#2 : ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x17a/0x1130
#3 : ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x28b/0x9f0
#4 : ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: ip_local_deliver_finish+0xf9/0x260
#5 : ffff888102650d98 (slock-AF_INET/1){+.-.}-{2:2}, at: tcp_v4_rcv+0x1848/0x1e10
#6 : ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: __ip_queue_xmit+0x4b/0xbc0
#7 : ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x17a/0x1130
#8 : ffffffff822ac1e0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0xcc/0x1450
#9 : ffff888101f33258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_queue_xmit+0x513/0x1450
stack backtrace:
CPU: 2 UID: 0 PID: 771 Comm: iperf3 Not tainted 6.10.0+ #34
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Call Trace:
<IRQ>
dump_stack_lvl+0x69/0xa0
dump_stack+0xc/0x20
__lock_acquire+0x135d/0x2600
? srso_alias_return_thunk+0x5/0xfbef5
lock_acquire+0xc4/0x2a0
? l2tp_xmit_skb+0x243/0x9d0
? __skb_checksum+0xa3/0x540
_raw_spin_lock_nested+0x35/0x50
? l2tp_xmit_skb+0x243/0x9d0
l2tp_xmit_skb+0x243/0x9d0
l2tp_eth_dev_xmit+0x3c/0xc0
dev_hard_start_xmit+0x11e/0x420
sch_direct_xmit+0xc3/0x640
__dev_queue_xmit+0x61c/0x1450
? ip_finish_output2+0xf4c/0x1130
ip_finish_output2+0x6b6/0x1130
? srso_alias_return_thunk+0x5/0xfbef5
? __ip_finish_output+0x217/0x380
? srso_alias_return_thunk+0x5/0xfbef5
__ip_finish_output+0x217/0x380
ip_output+0x99/0x120
__ip_queue_xmit+0xae4/0xbc0
? srso_alias_return_thunk+0x5/0xfbef5
? srso_alias_return_thunk+0x5/0xfbef5
? tcp_options_write.constprop.0+0xcb/0x3e0
ip_queue_xmit+0x34/0x40
__tcp_transmit_skb+0x1625/0x1890
__tcp_send_ack+0x1b8/0x340
tcp_send_ack+0x23/0x30
__tcp_ack_snd_check+0xa8/0x530
? srso_alias_return_thunk+0x5/0xfbef5
tcp_rcv_established+0x412/0xd70
tcp_v4_do_rcv+0x299/0x420
tcp_v4_rcv+0x1991/0x1e10
ip_protocol_deliver_rcu+0x50/0x220
ip_local_deliver_finish+0x158/0x260
ip_local_deliver+0xc8/0xe0
ip_rcv+0xe5/0x1d0
? __pfx_ip_rcv+0x10/0x10
__netif_receive_skb_one_core+0xce/0xe0
? process_backlog+0x28b/0x9f0
__netif_receive_skb+0x34/0xd0
? process_backlog+0x28b/0x9f0
process_backlog+0x2cb/0x9f0
__napi_poll.constprop.0+0x61/0x280
net_rx_action+0x332/0x670
? srso_alias_return_thunk+0x5/0xfbef5
? find_held_lock+0x2b/0x80
? srso_alias_return_thunk+0x5/0xfbef5
? srso_alias_return_thunk+0x5/0xfbef5
handle_softirqs+0xda/0x480
? __dev_queue_xmit+0xa2c/0x1450
do_softirq+0xa1/0xd0
</IRQ>
<TASK>
__local_bh_enable_ip+0xc8/0xe0
? __dev_queue_xmit+0xa2c/0x1450
__dev_queue_xmit+0xa48/0x1450
? ip_finish_output2+0xf4c/0x1130
ip_finish_output2+0x6b6/0x1130
? srso_alias_return_thunk+0x5/0xfbef5
? __ip_finish_output+0x217/0x380
? srso_alias_return_thunk+0x5/0xfbef5
__ip_finish_output+0x217/0x380
ip_output+0x99/0x120
__ip_queue_xmit+0xae4/0xbc0
? srso_alias_return_thunk+0x5/0xfbef5
? srso_alias_return_thunk+0x5/0xfbef5
? tcp_options_write.constprop.0+0xcb/0x3e0
ip_queue_xmit+0x34/0x40
__tcp_transmit_skb+0x1625/0x1890
tcp_write_xmit+0x766/0x2fb0
? __entry_text_end+0x102ba9/0x102bad
? srso_alias_return_thunk+0x5/0xfbef5
? __might_fault+0x74/0xc0
? srso_alias_return_thunk+0x5/0xfbef5
__tcp_push_pending_frames+0x56/0x190
tcp_push+0x117/0x310
tcp_sendmsg_locked+0x14c1/0x1740
tcp_sendmsg+0x28/0x40
inet_sendmsg+0x5d/0x90
sock_write_iter+0x242/0x2b0
vfs_write+0x68d/0x800
? __pfx_sock_write_iter+0x10/0x10
ksys_write+0xc8/0xf0
__x64_sys_write+0x3d/0x50
x64_sys_call+0xfaf/0x1f50
do_syscall_64+0x6d/0x140
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f4d143af992
Code: c3 8b 07 85 c0 75 24 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> e9 01 cc ff ff 41 54 b8 02 00 00 0
RSP: 002b:00007ffd65032058 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f4d143af992
RDX: 0000000000000025 RSI: 00007f4d143f3bcc RDI: 0000000000000005
RBP: 00007f4d143f2b28 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4d143f3bcc
R13: 0000000000000005 R14: 0000000000000000 R15: 00007ffd650323f0
</TASK>
Fixes: 0b2c59720e65 ("l2tp: close all race conditions in l2tp_tunnel_register()")
Suggested-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot+6acef9e0a4d1f46c83d4@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=6acef9e0a4d1f46c83d4
CC: gnault@redhat.com
CC: cong.wang@bytedance.com
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Link: https://patch.msgid.link/20240806160626.1248317-1-jchapman@katalix.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-23 23:20:22 +01:00
David Bauer
94ef599d29
net l2tp: drop flow hash on forward
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[ Upstream commit 42f853b42899d9b445763b55c3c8adc72be0f0e1 ]
Drop the flow-hash of the skb when forwarding to the L2TP netdev.
This avoids the L2TP qdisc from using the flow-hash from the outer
packet, which is identical for every flow within the tunnel.
This does not affect every platform but is specific for the ethernet
driver. It depends on the platform including L4 information in the
flow-hash.
One such example is the Mediatek Filogic MT798x family of networking
processors.
Fixes: d9e31d17ceba ("l2tp: Add L2TP ethernet pseudowire support")
Acked-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David Bauer <mail@david-bauer.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240424171110.13701-1-mail@david-bauer.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-19 11:32:42 +01:00
Gavrilov Ilia
60b65d0d74
l2tp: fix incorrect parameter validation in the pppol2tp_getsockopt() function
...
[ Upstream commit 955e9876ba4ee26eeaab1b13517f5b2c88e73d55 ]
The 'len' variable can't be negative when assigned the result of
'min_t' because all 'min_t' parameters are cast to unsigned int,
and then the minimum one is chosen.
To fix the logic, check 'len' as read from 'optlen',
where the types of relevant variables are (signed) int.
Fixes: 3557baabf280 ("[L2TP]: PPP over L2TP driver core")
Reviewed-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-19 08:44:50 +01:00
Tom Parkin
2f73a67792
l2tp: pass correct message length to ip6_append_data
...
commit 359e54a93ab43d32ee1bff3c2f9f10cb9f6b6e79 upstream.
l2tp_ip6_sendmsg needs to avoid accounting for the transport header
twice when splicing more data into an already partially-occupied skbuff.
To manage this, we check whether the skbuff contains data using
skb_queue_empty when deciding how much data to append using
ip6_append_data.
However, the code which performed the calculation was incorrect:
ulen = len + skb_queue_empty(&sk->sk_write_queue) ? transhdrlen : 0;
...due to C operator precedence, this ends up setting ulen to
transhdrlen for messages with a non-zero length, which results in
corrupted packets on the wire.
Add parentheses to correct the calculation in line with the original
intent.
Fixes: 9d4c75800f61 ("ipv4, ipv6: Fix handling of transhdrlen in __ip{,6}_append_data()")
Cc: David Howells <dhowells@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240220122156.43131-1-tparkin@katalix.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-18 22:25:37 +01:00
Gabriel2392
7ed7ee9edf
Import A536BXXU9EXDC
2024-06-15 16:02:09 -03:00
Eric Dumazet