[ Upstream commit 405df89dd5 ]
We noticed some rare sk_buffs were stepping past the queue when system was
under memory pressure. The general theory is to skip enqueueing
sk_buffs when its not necessary which is the normal case with a system
that is properly provisioned for the task, no memory pressure and enough
cpu assigned.
But, if we can't allocate memory due to an ENOMEM error when enqueueing
the sk_buff into the sockmap receive queue we push it onto a delayed
workqueue to retry later. When a new sk_buff is received we then check
if that queue is empty. However, there is a problem with simply checking
the queue length. When a sk_buff is being processed from the ingress queue
but not yet on the sockmap msg receive queue its possible to also recv
a sk_buff through normal path. It will check the ingress queue which is
zero and then skip ahead of the pkt being processed.
Previously we used sock lock from both contexts which made the problem
harder to hit, but not impossible.
To fix instead of popping the skb from the queue entirely we peek the
skb from the queue and do the copy there. This ensures checks to the
queue length are non-zero while skb is being processed. Then finally
when the entire skb has been copied to user space queue or another
socket we pop it off the queue. This way the queue length check allows
bypassing the queue only after the list has been completely processed.
To reproduce issue we run NGINX compliance test with sockmap running and
observe some flakes in our testing that we attributed to this issue.
Fixes: 04919bed94 ("tcp: Introduce tcp_read_skb()")
Suggested-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: William Findlay <will@isovalent.com>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20230523025618.113937-5-john.fastabend@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 29173d07f7 ]
Sk_buffs are fed into sockmap verdict programs either from a strparser
(when the user might want to decide how framing of skb is done by attaching
another parser program) or directly through tcp_read_sock. The
tcp_read_sock is the preferred method for performance when the BPF logic is
a stream parser.
The flow for Cilium's common use case with a stream parser is,
tcp_read_sock()
sk_psock_verdict_recv
ret = bpf_prog_run_pin_on_cpu()
sk_psock_verdict_apply(sock, skb, ret)
// if system is under memory pressure or app is slow we may
// need to queue skb. Do this queuing through ingress_skb and
// then kick timer to wake up handler
skb_queue_tail(ingress_skb, skb)
schedule_work(work);
The work queue is wired up to sk_psock_backlog(). This will then walk the
ingress_skb skb list that holds our sk_buffs that could not be handled,
but should be OK to run at some later point. However, its possible that
the workqueue doing this work still hits an error when sending the skb.
When this happens the skbuff is requeued on a temporary 'state' struct
kept with the workqueue. This is necessary because its possible to
partially send an skbuff before hitting an error and we need to know how
and where to restart when the workqueue runs next.
Now for the trouble, we don't rekick the workqueue. This can cause a
stall where the skbuff we just cached on the state variable might never
be sent. This happens when its the last packet in a flow and no further
packets come along that would cause the system to kick the workqueue from
that side.
To fix we could do simple schedule_work(), but while under memory pressure
it makes sense to back off some instead of continue to retry repeatedly. So
instead to fix convert schedule_work to schedule_delayed_work and add
backoff logic to reschedule from backlog queue on errors. Its not obvious
though what a good backoff is so use '1'.
To test we observed some flakes whil running NGINX compliance test with
sockmap we attributed these failed test to this bug and subsequent issue.
>From on list discussion. This commit
bec217197b41("skmsg: Schedule psock work if the cached skb exists on the psock")
was intended to address similar race, but had a couple cases it missed.
Most obvious it only accounted for receiving traffic on the local socket
so if redirecting into another socket we could still get an sk_buff stuck
here. Next it missed the case where copied=0 in the recv() handler and
then we wouldn't kick the scheduler. Also its sub-optimal to require
userspace to kick the internal mechanisms of sockmap to wake it up and
copy data to user. It results in an extra syscall and requires the app
to actual handle the EAGAIN correctly.
Fixes: 04919bed94 ("tcp: Introduce tcp_read_skb()")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: William Findlay <will@isovalent.com>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20230523025618.113937-3-john.fastabend@gmail.com
Stable-dep-of: 405df89dd5 ("bpf, sockmap: Improved check for empty queue")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6648e61322 ]
Fix NULL pointer data-races in sk_psock_skb_ingress_enqueue() which
syzbot reported [1].
[1]
BUG: KCSAN: data-race in sk_psock_drop / sk_psock_skb_ingress_enqueue
write to 0xffff88814b3278b8 of 8 bytes by task 10724 on cpu 1:
sk_psock_stop_verdict net/core/skmsg.c:1257 [inline]
sk_psock_drop+0x13e/0x1f0 net/core/skmsg.c:843
sk_psock_put include/linux/skmsg.h:459 [inline]
sock_map_close+0x1a7/0x260 net/core/sock_map.c:1648
unix_release+0x4b/0x80 net/unix/af_unix.c:1048
__sock_release net/socket.c:659 [inline]
sock_close+0x68/0x150 net/socket.c:1421
__fput+0x2c1/0x660 fs/file_table.c:422
__fput_sync+0x44/0x60 fs/file_table.c:507
__do_sys_close fs/open.c:1556 [inline]
__se_sys_close+0x101/0x1b0 fs/open.c:1541
__x64_sys_close+0x1f/0x30 fs/open.c:1541
do_syscall_64+0xd3/0x1d0
entry_SYSCALL_64_after_hwframe+0x6d/0x75
read to 0xffff88814b3278b8 of 8 bytes by task 10713 on cpu 0:
sk_psock_data_ready include/linux/skmsg.h:464 [inline]
sk_psock_skb_ingress_enqueue+0x32d/0x390 net/core/skmsg.c:555
sk_psock_skb_ingress_self+0x185/0x1e0 net/core/skmsg.c:606
sk_psock_verdict_apply net/core/skmsg.c:1008 [inline]
sk_psock_verdict_recv+0x3e4/0x4a0 net/core/skmsg.c:1202
unix_read_skb net/unix/af_unix.c:2546 [inline]
unix_stream_read_skb+0x9e/0xf0 net/unix/af_unix.c:2682
sk_psock_verdict_data_ready+0x77/0x220 net/core/skmsg.c:1223
unix_stream_sendmsg+0x527/0x860 net/unix/af_unix.c:2339
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x140/0x180 net/socket.c:745
____sys_sendmsg+0x312/0x410 net/socket.c:2584
___sys_sendmsg net/socket.c:2638 [inline]
__sys_sendmsg+0x1e9/0x280 net/socket.c:2667
__do_sys_sendmsg net/socket.c:2676 [inline]
__se_sys_sendmsg net/socket.c:2674 [inline]
__x64_sys_sendmsg+0x46/0x50 net/socket.c:2674
do_syscall_64+0xd3/0x1d0
entry_SYSCALL_64_after_hwframe+0x6d/0x75
value changed: 0xffffffff83d7feb0 -> 0x0000000000000000
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10713 Comm: syz-executor.4 Tainted: G W 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Prior to this, commit 4cd12c6065 ("bpf, sockmap: Fix NULL pointer
dereference in sk_psock_verdict_data_ready()") fixed one NULL pointer
similarly due to no protection of saved_data_ready. Here is another
different caller causing the same issue because of the same reason. So
we should protect it with sk_callback_lock read lock because the writer
side in the sk_psock_drop() uses "write_lock_bh(&sk->sk_callback_lock);".
To avoid errors that could happen in future, I move those two pairs of
lock into the sk_psock_data_ready(), which is suggested by John Fastabend.
Fixes: 604326b41a ("bpf, sockmap: convert to generic sk_msg interface")
Reported-by: syzbot+aa8c8ec2538929f18f2d@syzkaller.appspotmail.com
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=aa8c8ec2538929f18f2d
Link: https://lore.kernel.org/all/20240329134037.92124-1-kerneljasonxing@gmail.com
Link: https://lore.kernel.org/bpf/20240404021001.94815-1-kerneljasonxing@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 809e4dc71a upstream.
strp_done is only called when psock->progs.stream_parser is not NULL,
but stream_parser was set to NULL by sk_psock_stop_strp(), called
by sk_psock_drop() earlier. So, strp_done can never be called.
Introduce SK_PSOCK_RX_ENABLED to mark whether there is strp on psock.
Change the condition for calling strp_done from judging whether
stream_parser is set to judging whether this flag is set. This flag is
only set once when strp_init() succeeds, and will never be cleared later.
Fixes: c0d95d3380 ("bpf, sockmap: Re-evaluate proto ops when psock is removed from sockmap")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20230804073740.194770-3-xukuohai@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit a351d6087b ]
When redirecting, we use sk_msg_to_ingress() to get the BPF_F_INGRESS
flag from the msg->flags. If apply_bytes is used and it is larger than
the current data being processed, sk_psock_msg_verdict() will not be
called when sendmsg() is called again. At this time, the msg->flags is 0,
and we lost the BPF_F_INGRESS flag.
So we need to save the BPF_F_INGRESS flag in sk_psock and use it when
redirection.
Fixes: 8934ce2fd0 ("bpf: sockmap redirect ingress support")
Signed-off-by: Pengcheng Yang <yangpc@wangsu.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/1669718441-2654-3-git-send-email-yangpc@wangsu.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 8bbabb3fdd ]
Stanislav reported a lockdep warning, which is caused by the
cancel_work_sync() called inside sock_map_close(), as analyzed
below by Jakub:
psock->work.func = sk_psock_backlog()
ACQUIRE psock->work_mutex
sk_psock_handle_skb()
skb_send_sock()
__skb_send_sock()
sendpage_unlocked()
kernel_sendpage()
sock->ops->sendpage = inet_sendpage()
sk->sk_prot->sendpage = tcp_sendpage()
ACQUIRE sk->sk_lock
tcp_sendpage_locked()
RELEASE sk->sk_lock
RELEASE psock->work_mutex
sock_map_close()
ACQUIRE sk->sk_lock
sk_psock_stop()
sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED)
cancel_work_sync()
__cancel_work_timer()
__flush_work()
// wait for psock->work to finish
RELEASE sk->sk_lock
We can move the cancel_work_sync() out of the sock lock protection,
but still before saved_close() was called.
Fixes: 799aa7f98d ("skmsg: Avoid lock_sock() in sk_psock_backlog()")
Reported-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20221102043417.279409-1-xiyou.wangcong@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d8616ee2af ]
During TCP sockmap redirect pressure test, the following warning is triggered:
WARNING: CPU: 3 PID: 2145 at net/core/stream.c:205 sk_stream_kill_queues+0xbc/0xd0
CPU: 3 PID: 2145 Comm: iperf Kdump: loaded Tainted: G W 5.10.0+ #9
Call Trace:
inet_csk_destroy_sock+0x55/0x110
inet_csk_listen_stop+0xbb/0x380
tcp_close+0x41b/0x480
inet_release+0x42/0x80
__sock_release+0x3d/0xa0
sock_close+0x11/0x20
__fput+0x9d/0x240
task_work_run+0x62/0x90
exit_to_user_mode_prepare+0x110/0x120
syscall_exit_to_user_mode+0x27/0x190
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The reason we observed is that:
When the listener is closing, a connection may have completed the three-way
handshake but not accepted, and the client has sent some packets. The child
sks in accept queue release by inet_child_forget()->inet_csk_destroy_sock(),
but psocks of child sks have not released.
To fix, add sock_map_destroy to release psocks.
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220524075311.649153-1-wangyufen@huawei.com
Stable-dep-of: 8bbabb3fdd ("bpf, sock_map: Move cancel_work_sync() out of sock lock")
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 2a0133723f upstream.
Syzkaller reports refcount bug as follows:
------------[ cut here ]------------
refcount_t: saturated; leaking memory.
WARNING: CPU: 1 PID: 3605 at lib/refcount.c:19 refcount_warn_saturate+0xf4/0x1e0 lib/refcount.c:19
Modules linked in:
CPU: 1 PID: 3605 Comm: syz-executor208 Not tainted 5.18.0-syzkaller-03023-g7e062cda7d90 #0
<TASK>
__refcount_add_not_zero include/linux/refcount.h:163 [inline]
__refcount_inc_not_zero include/linux/refcount.h:227 [inline]
refcount_inc_not_zero include/linux/refcount.h:245 [inline]
sk_psock_get+0x3bc/0x410 include/linux/skmsg.h:439
tls_data_ready+0x6d/0x1b0 net/tls/tls_sw.c:2091
tcp_data_ready+0x106/0x520 net/ipv4/tcp_input.c:4983
tcp_data_queue+0x25f2/0x4c90 net/ipv4/tcp_input.c:5057
tcp_rcv_state_process+0x1774/0x4e80 net/ipv4/tcp_input.c:6659
tcp_v4_do_rcv+0x339/0x980 net/ipv4/tcp_ipv4.c:1682
sk_backlog_rcv include/net/sock.h:1061 [inline]
__release_sock+0x134/0x3b0 net/core/sock.c:2849
release_sock+0x54/0x1b0 net/core/sock.c:3404
inet_shutdown+0x1e0/0x430 net/ipv4/af_inet.c:909
__sys_shutdown_sock net/socket.c:2331 [inline]
__sys_shutdown_sock net/socket.c:2325 [inline]
__sys_shutdown+0xf1/0x1b0 net/socket.c:2343
__do_sys_shutdown net/socket.c:2351 [inline]
__se_sys_shutdown net/socket.c:2349 [inline]
__x64_sys_shutdown+0x50/0x70 net/socket.c:2349
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
</TASK>
During SMC fallback process in connect syscall, kernel will
replaces TCP with SMC. In order to forward wakeup
smc socket waitqueue after fallback, kernel will sets
clcsk->sk_user_data to origin smc socket in
smc_fback_replace_callbacks().
Later, in shutdown syscall, kernel will calls
sk_psock_get(), which treats the clcsk->sk_user_data
as psock type, triggering the refcnt warning.
So, the root cause is that smc and psock, both will use
sk_user_data field. So they will mismatch this field
easily.
This patch solves it by using another bit(defined as
SK_USER_DATA_PSOCK) in PTRMASK, to mark whether
sk_user_data points to a psock object or not.
This patch depends on a PTRMASK introduced in commit f1ff5ce2cd
("net, sk_msg: Clear sk_user_data pointer on clone if tagged").
For there will possibly be more flags in the sk_user_data field,
this patch also refactor sk_user_data flags code to be more generic
to improve its maintainability.
Reported-and-tested-by: syzbot+5f26f85569bd179c18ce@syzkaller.appspotmail.com
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Wen Gu <guwen@linux.alibaba.com>
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 938d3480b9 ]
If tcp_bpf_sendmsg is running during a tear down operation we may enqueue
data on the ingress msg queue while tear down is trying to free it.
sk1 (redirect sk2) sk2
------------------- ---------------
tcp_bpf_sendmsg()
tcp_bpf_send_verdict()
tcp_bpf_sendmsg_redir()
bpf_tcp_ingress()
sock_map_close()
lock_sock()
lock_sock() ... blocking
sk_psock_stop
sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
release_sock(sk);
lock_sock()
sk_mem_charge()
get_page()
sk_psock_queue_msg()
sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED);
drop_sk_msg()
release_sock()
While drop_sk_msg(), the msg has charged memory form sk by sk_mem_charge
and has sg pages need to put. To fix we use sk_msg_free() and then kfee()
msg.
This issue can cause the following info:
WARNING: CPU: 0 PID: 9202 at net/core/stream.c:205 sk_stream_kill_queues+0xc8/0xe0
Call Trace:
<IRQ>
inet_csk_destroy_sock+0x55/0x110
tcp_rcv_state_process+0xe5f/0xe90
? sk_filter_trim_cap+0x10d/0x230
? tcp_v4_do_rcv+0x161/0x250
tcp_v4_do_rcv+0x161/0x250
tcp_v4_rcv+0xc3a/0xce0
ip_protocol_deliver_rcu+0x3d/0x230
ip_local_deliver_finish+0x54/0x60
ip_local_deliver+0xfd/0x110
? ip_protocol_deliver_rcu+0x230/0x230
ip_rcv+0xd6/0x100
? ip_local_deliver+0x110/0x110
__netif_receive_skb_one_core+0x85/0xa0
process_backlog+0xa4/0x160
__napi_poll+0x29/0x1b0
net_rx_action+0x287/0x300
__do_softirq+0xff/0x2fc
do_softirq+0x79/0x90
</IRQ>
WARNING: CPU: 0 PID: 531 at net/ipv4/af_inet.c:154 inet_sock_destruct+0x175/0x1b0
Call Trace:
<TASK>
__sk_destruct+0x24/0x1f0
sk_psock_destroy+0x19b/0x1c0
process_one_work+0x1b3/0x3c0
? process_one_work+0x3c0/0x3c0
worker_thread+0x30/0x350
? process_one_work+0x3c0/0x3c0
kthread+0xe6/0x110
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x22/0x30
</TASK>
Fixes: 9635720b7c ("bpf, sockmap: Fix memleak on ingress msg enqueue")
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220304081145.2037182-2-wangyufen@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 7303524e04 ]
If sockmap enable strparser, there are lose offset info in
sk_psock_skb_ingress(). If the length determined by parse_msg function is not
skb->len, the skb will be converted to sk_msg multiple times, and userspace
app will get the data multiple times.
Fix this by get the offset and length from strp_msg. And as Cong suggested,
add one bit in skb->_sk_redir to distinguish enable or disable strparser.
Fixes: 604326b41a ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Liu Jian <liujian56@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20211029141216.211899-1-liujian56@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
If backlog handler is running during a tear down operation we may enqueue
data on the ingress msg queue while tear down is trying to free it.
sk_psock_backlog()
sk_psock_handle_skb()
skb_psock_skb_ingress()
sk_psock_skb_ingress_enqueue()
sk_psock_queue_msg(psock,msg)
spin_lock(ingress_lock)
sk_psock_zap_ingress()
_sk_psock_purge_ingerss_msg()
_sk_psock_purge_ingress_msg()
-- free ingress_msg list --
spin_unlock(ingress_lock)
spin_lock(ingress_lock)
list_add_tail(msg,ingress_msg) <- entry on list with no one
left to free it.
spin_unlock(ingress_lock)
To fix we only enqueue from backlog if the ENABLED bit is set. The tear
down logic clears the bit with ingress_lock set so we wont enqueue the
msg in the last step.
Fixes: 799aa7f98d ("skmsg: Avoid lock_sock() in sk_psock_backlog()")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210727160500.1713554-4-john.fastabend@gmail.com
Trivial conflict in net/netfilter/nf_tables_api.c.
Duplicate fix in tools/testing/selftests/net/devlink_port_split.py
- take the net-next version.
skmsg, and L4 bpf - keep the bpf code but remove the flags
and err params.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch introduces a function wrapper to call the sk_error_report
callback. That will prepare to add additional handling whenever
sk_error_report is called, for example to trace socket errors.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I tried to reuse sk_msg_wait_data() for different protocols,
but it turns out it can not be simply reused. For example,
UDP actually uses two queues to receive skb:
udp_sk(sk)->reader_queue and sk->sk_receive_queue. So we have
to check both of them to know whether we have received any
packet.
Also, UDP does not lock the sock during BH Rx path, it makes
no sense for its ->recvmsg() to lock the sock. It is always
possible for ->recvmsg() to be called before packets actually
arrive in the receive queue, we just use best effort to make
it accurate here.
Fixes: 1f5be6b3b0 ("udp: Implement udp_bpf_recvmsg() for sockmap")
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210615021342.7416-2-xiyou.wangcong@gmail.com
'err' and 'flags' are not used, we can just get rid of them.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <song@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210517022348.50555-1-xiyou.wangcong@gmail.com
Alexei Starovoitov says:
====================
pull-request: bpf-next 2021-04-23
The following pull-request contains BPF updates for your *net-next* tree.
We've added 69 non-merge commits during the last 22 day(s) which contain
a total of 69 files changed, 3141 insertions(+), 866 deletions(-).
The main changes are:
1) Add BPF static linker support for extern resolution of global, from Andrii.
2) Refine retval for bpf_get_task_stack helper, from Dave.
3) Add a bpf_snprintf helper, from Florent.
4) A bunch of miscellaneous improvements from many developers.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
MAINTAINERS
- keep Chandrasekar
drivers/net/ethernet/mellanox/mlx5/core/en_main.c
- simple fix + trust the code re-added to param.c in -next is fine
include/linux/bpf.h
- trivial
include/linux/ethtool.h
- trivial, fix kdoc while at it
include/linux/skmsg.h
- move to relevant place in tcp.c, comment re-wrapped
net/core/skmsg.c
- add the sk = sk // sk = NULL around calls
net/tipc/crypto.c
- trivial
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In '4da6a196f93b1' we fixed a potential unhash loop caused when
a TLS socket in a sockmap was removed from the sockmap. This
happened because the unhash operation on the TLS ctx continued
to point at the sockmap implementation of unhash even though the
psock has already been removed. The sockmap unhash handler when a
psock is removed does the following,
void sock_map_unhash(struct sock *sk)
{
void (*saved_unhash)(struct sock *sk);
struct sk_psock *psock;
rcu_read_lock();
psock = sk_psock(sk);
if (unlikely(!psock)) {
rcu_read_unlock();
if (sk->sk_prot->unhash)
sk->sk_prot->unhash(sk);
return;
}
[...]
}
The unlikely() case is there to handle the case where psock is detached
but the proto ops have not been updated yet. But, in the above case
with TLS and removed psock we never fixed sk_prot->unhash() and unhash()
points back to sock_map_unhash resulting in a loop. To fix this we added
this bit of code,
static inline void sk_psock_restore_proto(struct sock *sk,
struct sk_psock *psock)
{
sk->sk_prot->unhash = psock->saved_unhash;
This will set the sk_prot->unhash back to its saved value. This is the
correct callback for a TLS socket that has been removed from the sock_map.
Unfortunately, this also overwrites the unhash pointer for all psocks.
We effectively break sockmap unhash handling for any future socks.
Omitting the unhash operation will leave stale entries in the map if
a socket transition through unhash, but does not do close() op.
To fix set unhash correctly before calling into tls_update. This way the
TLS enabled socket will point to the saved unhash() handler.
Fixes: 4da6a196f9 ("bpf: Sockmap/tls, during free we may call tcp_bpf_unhash() in loop")
Reported-by: Cong Wang <xiyou.wangcong@gmail.com>
Reported-by: Lorenz Bauer <lmb@cloudflare.com>
Suggested-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/161731441904.68884.15593917809745631972.stgit@john-XPS-13-9370
Although these two functions are only used by TCP, they are not
specific to TCP at all, both operate on skmsg and ingress_msg,
so fit in net/core/skmsg.c very well.
And we will need them for non-TCP, so rename and move them to
skmsg.c and export them to modules.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210331023237.41094-13-xiyou.wangcong@gmail.com
Currently sockmap calls into each protocol to update the struct
proto and replace it. This certainly won't work when the protocol
is implemented as a module, for example, AF_UNIX.
Introduce a new ops sk->sk_prot->psock_update_sk_prot(), so each
protocol can implement its own way to replace the struct proto.
This also helps get rid of symbol dependencies on CONFIG_INET.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210331023237.41094-11-xiyou.wangcong@gmail.com
Reusing BPF_SK_SKB_STREAM_VERDICT is possible but its name is
confusing and more importantly we still want to distinguish them
from user-space. So we can just reuse the stream verdict code but
introduce a new type of eBPF program, skb_verdict. Users are not
allowed to attach stream_verdict and skb_verdict programs to the
same map.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210331023237.41094-10-xiyou.wangcong@gmail.com
The RCU callback sk_psock_destroy() only queues work psock->gc,
so we can just switch to rcu work to simplify the code.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210331023237.41094-6-xiyou.wangcong@gmail.com
We do not have to lock the sock to avoid losing sk_socket,
instead we can purge all the ingress queues when we close
the socket. Sending or receiving packets after orphaning
socket makes no sense.
We do purge these queues when psock refcnt reaches zero but
here we want to purge them explicitly in sock_map_close().
There are also some nasty race conditions on testing bit
SK_PSOCK_TX_ENABLED and queuing/canceling the psock work,
we can expand psock->ingress_lock a bit to protect them too.
As noticed by John, we still have to lock the psock->work,
because the same work item could be running concurrently on
different CPU's.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210331023237.41094-5-xiyou.wangcong@gmail.com
Currently we rely on lock_sock to protect ingress_msg,
it is too big for this, we can actually just use a spinlock
to protect this list like protecting other skb queues.
__tcp_bpf_recvmsg() is still special because of peeking,
it still has to use lock_sock.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210331023237.41094-3-xiyou.wangcong@gmail.com
These two eBPF programs are tied to BPF_SK_SKB_STREAM_PARSER
and BPF_SK_SKB_STREAM_VERDICT, rename them to reflect the fact
they are only used for TCP. And save the name 'skb_verdict' for
general use later.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Lorenz Bauer <lmb@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210223184934.6054-6-xiyou.wangcong@gmail.com
Currently TCP_SKB_CB() is hard-coded in skmsg code, it certainly
does not work for any other non-TCP protocols. We can move them to
skb ext, but it introduces a memory allocation on fast path.
Fortunately, we only need to a word-size to store all the information,
because the flags actually only contains 1 bit so can be just packed
into the lowest bit of the "pointer", which is stored as unsigned
long.
Inside struct sk_buff, '_skb_refdst' can be reused because skb dst is
no longer needed after ->sk_data_ready() so we can just drop it.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210223184934.6054-5-xiyou.wangcong@gmail.com
struct sk_psock_parser is embedded in sk_psock, it is
unnecessary as skb verdict also uses ->saved_data_ready.
We can simply fold these fields into sk_psock, and get rid
of ->enabled.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210223184934.6054-3-xiyou.wangcong@gmail.com
As suggested by John, clean up sockmap related Kconfigs:
Reduce the scope of CONFIG_BPF_STREAM_PARSER down to TCP stream
parser, to reflect its name.
Make the rest sockmap code simply depend on CONFIG_BPF_SYSCALL
and CONFIG_INET, the latter is still needed at this point because
of TCP/UDP proto update. And leave CONFIG_NET_SOCK_MSG untouched,
as it is used by non-sockmap cases.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Lorenz Bauer <lmb@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210223184934.6054-2-xiyou.wangcong@gmail.com
sk_psock_destroy() is a RCU callback, I can't see any reason why
it could be used outside.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jakub Sitnicki <jakub@cloudflare.com>
Cc: Lorenz Bauer <lmb@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210127221501.46866-1-xiyou.wangcong@gmail.com
Currently, we often run with a nop parser namely one that just does
this, 'return skb->len'. This happens when either our verdict program
can handle streaming data or it is only looking at socket data such
as IP addresses and other metadata associated with the flow. The second
case is common for a L3/L4 proxy for instance.
So lets allow loading programs without the parser then we can skip
the stream parser logic and avoid having to add a BPF program that
is effectively a nop.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/160239297866.8495.13345662302749219672.stgit@john-Precision-5820-Tower
Initializing psock->sk_proto and other saved callbacks is only
done in sk_psock_update_proto, after sk_psock_init has returned.
The logic for this is difficult to follow, and needlessly complex.
Instead, initialize psock->sk_proto whenever we allocate a new
psock. Additionally, assert the following invariants:
* The SK has no ULP: ULP does it's own finagling of sk->sk_prot
* sk_user_data is unused: we need it to store sk_psock
Protect our access to sk_user_data with sk_callback_lock, which
is what other users like reuseport arrays, etc. do.
The result is that an sk_psock is always fully initialized, and
that psock->sk_proto is always the "original" struct proto.
The latter allows us to use psock->sk_proto when initializing
IPv6 TCP / UDP callbacks for sockmap.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200821102948.21918-2-lmb@cloudflare.com
The sockmap code currently ignores the value of attach_bpf_fd when
detaching a program. This is contrary to the usual behaviour of
checking that attach_bpf_fd represents the currently attached
program.
Ensure that attach_bpf_fd is indeed the currently attached
program. It turns out that all sockmap selftests already do this,
which indicates that this is unlikely to cause breakage.
Fixes: 604326b41a ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200629095630.7933-5-lmb@cloudflare.com
KTLS uses a stream parser to collect TLS messages and send them to
the upper layer tls receive handler. This ensures the tls receiver
has a full TLS header to parse when it is run. However, when a
socket has BPF_SK_SKB_STREAM_VERDICT program attached before KTLS
is enabled we end up with two stream parsers running on the same
socket.
The result is both try to run on the same socket. First the KTLS
stream parser runs and calls read_sock() which will tcp_read_sock
which in turn calls tcp_rcv_skb(). This dequeues the skb from the
sk_receive_queue. When this is done KTLS code then data_ready()
callback which because we stacked KTLS on top of the bpf stream
verdict program has been replaced with sk_psock_start_strp(). This
will in turn kick the stream parser again and eventually do the
same thing KTLS did above calling into tcp_rcv_skb() and dequeuing
a skb from the sk_receive_queue.
At this point the data stream is broke. Part of the stream was
handled by the KTLS side some other bytes may have been handled
by the BPF side. Generally this results in either missing data
or more likely a "Bad Message" complaint from the kTLS receive
handler as the BPF program steals some bytes meant to be in a
TLS header and/or the TLS header length is no longer correct.
We've already broke the idealized model where we can stack ULPs
in any order with generic callbacks on the TX side to handle this.
So in this patch we do the same thing but for RX side. We add
a sk_psock_strp_enabled() helper so TLS can learn a BPF verdict
program is running and add a tls_sw_has_ctx_rx() helper so BPF
side can learn there is a TLS ULP on the socket.
Then on BPF side we omit calling our stream parser to avoid
breaking the data stream for the KTLS receiver. Then on the
KTLS side we call BPF_SK_SKB_STREAM_VERDICT once the KTLS
receiver is done with the packet but before it posts the
msg to userspace. This gives us symmetry between the TX and
RX halfs and IMO makes it usable again. On the TX side we
process packets in this order BPF -> TLS -> TCP and on
the receive side in the reverse order TCP -> TLS -> BPF.
Discovered while testing OpenSSL 3.0 Alpha2.0 release.
Fixes: d829e9c411 ("tls: convert to generic sk_msg interface")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/159079361946.5745.605854335665044485.stgit@john-Precision-5820-Tower
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In bpf_tcp_ingress we used apply_bytes to subtract bytes from sg.size
which is used to track total bytes in a message. But this is not
correct because apply_bytes is itself modified in the main loop doing
the mem_charge.
Then at the end of this we have sg.size incorrectly set and out of
sync with actual sk values. Then we can get a splat if we try to
cork the data later and again try to redirect the msg to ingress. To
fix instead of trying to track msg.size do the easy thing and include
it as part of the sk_msg_xfer logic so that when the msg is moved the
sg.size is always correct.
To reproduce the below users will need ingress + cork and hit an
error path that will then try to 'free' the skmsg.
[ 173.699981] BUG: KASAN: null-ptr-deref in sk_msg_free_elem+0xdd/0x120
[ 173.699987] Read of size 8 at addr 0000000000000008 by task test_sockmap/5317
[ 173.700000] CPU: 2 PID: 5317 Comm: test_sockmap Tainted: G I 5.7.0-rc1+ #43
[ 173.700005] Hardware name: Dell Inc. Precision 5820 Tower/002KVM, BIOS 1.9.2 01/24/2019
[ 173.700009] Call Trace:
[ 173.700021] dump_stack+0x8e/0xcb
[ 173.700029] ? sk_msg_free_elem+0xdd/0x120
[ 173.700034] ? sk_msg_free_elem+0xdd/0x120
[ 173.700042] __kasan_report+0x102/0x15f
[ 173.700052] ? sk_msg_free_elem+0xdd/0x120
[ 173.700060] kasan_report+0x32/0x50
[ 173.700070] sk_msg_free_elem+0xdd/0x120
[ 173.700080] __sk_msg_free+0x87/0x150
[ 173.700094] tcp_bpf_send_verdict+0x179/0x4f0
[ 173.700109] tcp_bpf_sendpage+0x3ce/0x5d0
Fixes: 604326b41a ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/158861290407.14306.5327773422227552482.stgit@john-Precision-5820-Tower
The init, close and unhash handlers from TCP sockmap are generic,
and can be reused by UDP sockmap. Move the helpers into the sockmap code
base and expose them. This requires tcp_bpf_get_proto and tcp_bpf_clone to
be conditional on BPF_STREAM_PARSER.
The moved functions are unmodified, except that sk_psock_unlink is
renamed to sock_map_unlink to better match its behaviour.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200309111243.6982-6-lmb@cloudflare.com
Only update psock->saved_* if psock->sk_proto has not been initialized
yet. This allows us to get rid of tcp_bpf_reinit_sk_prot.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200309111243.6982-3-lmb@cloudflare.com
The sock map code checks that a socket does not have an active upper
layer protocol before inserting it into the map. This requires casting
via inet_csk, which isn't valid for UDP sockets.
Guard checks for ULP by checking inet_sk(sk)->is_icsk first.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200309111243.6982-2-lmb@cloudflare.com
sk_msg and ULP frameworks override protocol callbacks pointer in
sk->sk_prot, while tcp accesses it locklessly when cloning the listening
socket, that is with neither sk_lock nor sk_callback_lock held.
Once we enable use of listening sockets with sockmap (and hence sk_msg),
there will be shared access to sk->sk_prot if socket is getting cloned
while being inserted/deleted to/from the sockmap from another CPU:
Read side:
tcp_v4_rcv
sk = __inet_lookup_skb(...)
tcp_check_req(sk)
inet_csk(sk)->icsk_af_ops->syn_recv_sock
tcp_v4_syn_recv_sock
tcp_create_openreq_child
inet_csk_clone_lock
sk_clone_lock
READ_ONCE(sk->sk_prot)
Write side:
sock_map_ops->map_update_elem
sock_map_update_elem
sock_map_update_common
sock_map_link_no_progs
tcp_bpf_init
tcp_bpf_update_sk_prot
sk_psock_update_proto
WRITE_ONCE(sk->sk_prot, ops)
sock_map_ops->map_delete_elem
sock_map_delete_elem
__sock_map_delete
sock_map_unref
sk_psock_put
sk_psock_drop
sk_psock_restore_proto
tcp_update_ulp
WRITE_ONCE(sk->sk_prot, proto)
Mark the shared access with READ_ONCE/WRITE_ONCE annotations.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200218171023.844439-2-jakub@cloudflare.com
There is no need to clear psock->sk_proto when restoring socket protocol
callbacks in sk->sk_prot. The psock is about to get detached from the sock
and eventually destroyed. At worst we will restore the protocol callbacks
and the write callback twice.
This makes reasoning about psock state easier. Once psock is initialized,
we can count on psock->sk_proto always being set.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200217121530.754315-3-jakub@cloudflare.com
We don't need a fallback for when the socket is not using ULP.
tcp_update_ulp handles this case exactly the same as we do in
sk_psock_restore_proto. Get rid of the duplicated code.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200217121530.754315-2-jakub@cloudflare.com
When sockmap sock with TLS enabled is removed we cleanup bpf/psock state
and call tcp_update_ulp() to push updates to TLS ULP on top. However, we
don't push the write_space callback up and instead simply overwrite the
op with the psock stored previous op. This may or may not be correct so
to ensure we don't overwrite the TLS write space hook pass this field to
the ULP and have it fixup the ctx.
This completes a previous fix that pushed the ops through to the ULP
but at the time missed doing this for write_space, presumably because
write_space TLS hook was added around the same time.
Fixes: 95fa145479 ("bpf: sockmap/tls, close can race with map free")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/bpf/20200111061206.8028-4-john.fastabend@gmail.com
When a sockmap is free'd and a socket in the map is enabled with tls
we tear down the bpf context on the socket, the psock struct and state,
and then call tcp_update_ulp(). The tcp_update_ulp() call is to inform
the tls stack it needs to update its saved sock ops so that when the tls
socket is later destroyed it doesn't try to call the now destroyed psock
hooks.
This is about keeping stacked ULPs in good shape so they always have
the right set of stacked ops.
However, recently unhash() hook was removed from TLS side. But, the
sockmap/bpf side is not doing any extra work to update the unhash op
when is torn down instead expecting TLS side to manage it. So both
TLS and sockmap believe the other side is managing the op and instead
no one updates the hook so it continues to point at tcp_bpf_unhash().
When unhash hook is called we call tcp_bpf_unhash() which detects the
psock has already been destroyed and calls sk->sk_prot_unhash() which
calls tcp_bpf_unhash() yet again and so on looping and hanging the core.
To fix have sockmap tear down logic fixup the stale pointer.
Fixes: 5d92e631b8 ("net/tls: partially revert fix transition through disconnect with close")
Reported-by: syzbot+83979935eb6304f8cd46@syzkaller.appspotmail.com
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/bpf/20200111061206.8028-2-john.fastabend@gmail.com
TLS 1.3 started using the entry at the end of the SG array
for chaining-in the single byte content type entry. This mostly
works:
[ E E E E E E . . ]
^ ^
start end
E < content type
/
[ E E E E E E C . ]
^ ^
start end
(Where E denotes a populated SG entry; C denotes a chaining entry.)
If the array is full, however, the end will point to the start:
[ E E E E E E E E ]
^
start
end
And we end up overwriting the start:
E < content type
/
[ C E E E E E E E ]
^
start
end
The sg array is supposed to be a circular buffer with start and
end markers pointing anywhere. In case where start > end
(i.e. the circular buffer has "wrapped") there is an extra entry
reserved at the end to chain the two halves together.
[ E E E E E E . . l ]
(Where l is the reserved entry for "looping" back to front.
As suggested by John, let's reserve another entry for chaining
SG entries after the main circular buffer. Note that this entry
has to be pointed to by the end entry so its position is not fixed.
Examples of full messages:
[ E E E E E E E E . l ]
^ ^
start end
<---------------.
[ E E . E E E E E E l ]
^ ^
end start
Now the end will always point to an unused entry, so TLS 1.3
can always use it.
Fixes: 130b392c6c ("net: tls: Add tls 1.3 support")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
One conflict in the BPF samples Makefile, some fixes in 'net' whilst
we were converting over to Makefile.target rules in 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
sk_msg_trim() tries to only update curr pointer if it falls into
the trimmed region. The logic, however, does not take into the
account pointer wrapping that sk_msg_iter_var_prev() does nor
(as John points out) the fact that msg->sg is a ring buffer.
This means that when the message was trimmed completely, the new
curr pointer would have the value of MAX_MSG_FRAGS - 1, which is
neither smaller than any other value, nor would it actually be
correct.
Special case the trimming to 0 length a little bit and rework
the comparison between curr and end to take into account wrapping.
This bug caused the TLS code to not copy all of the message, if
zero copy filled in fewer sg entries than memcopy would need.
Big thanks to Alexander Potapenko for the non-KMSAN reproducer.
v2:
- take into account that msg->sg is a ring buffer (John).
Link: https://lore.kernel.org/netdev/20191030160542.30295-1-jakub.kicinski@netronome.com/ (v1)
Fixes: d829e9c411 ("tls: convert to generic sk_msg interface")
Reported-by: syzbot+f8495bff23a879a6d0bd@syzkaller.appspotmail.com
Reported-by: syzbot+6f50c99e8f6194bf363f@syzkaller.appspotmail.com
Co-developed-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Don't use bool array in struct sk_msg_sg, save 12 bytes.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
