net: tls: wait for async completion on last message

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/[email protected]/
[2] https://lore.kernel.org/all/[email protected]/

Signed-off-by: Sascha Hauer <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

0 files changed, 0 insertions, 0 deletions