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net: tls: wait for async completion on last message

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When asynchronous encryption is used KTLS sends out the final data at
proto->close time. This becomes problematic when the task calling
close() receives a signal. In this case it can happen that
tcp_sendmsg_locked() called at close time returns -ERESTARTSYS and the
final data is not sent.

The described situation happens when KTLS is used in conjunction with
io_uring, as io_uring uses task_work_add() to add work to the current
userspace task. A discussion of the problem along with a reproducer can
be found in [1] and [2]

Fix this by waiting for the asynchronous encryption to be completed on
the final message. With this there is no data left to be sent at close
time.

[1] https://lore.kernel.org/all/20231010141932.GD3114228@pengutronix.de/
[2] https://lore.kernel.org/all/20240315100159.3898944-1-s.hauer@pengutronix.de/

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Link: https://patch.msgid.link/20240904-ktls-wait-async-v1-1-a62892833110@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Sascha Hauer 2024-09-04 14:17:41 +02:00 committed by Jakub Kicinski
parent 7ab50d5e88
commit 54001d0f2f
1 changed files with 1 additions and 1 deletions
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2
net/tls/tls_sw.c
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@ -1201,7 +1201,7 @@ trim_sgl:
if (!num_async) {
goto send_end;
} else if (num_zc) {
} else if (num_zc || eor) {
int err;
/* Wait for pending encryptions to get completed */