Re: [PATCH v2 net-next] net/tls: allow MSG_CMSG_COMPAT in sendmsg

On Fri, 2020-08-07 at 10:26 +0200, Rouven Czerwinski wrote:

On Thu, 2020-08-06 at 11:46 -0700, Jakub Kicinski wrote:

quoted

On Thu,  6 Aug 2020 08:49:06 +0200 Rouven Czerwinski wrote:

quoted

Trying to use ktls on a system with 32-bit userspace and 64-bit
kernel
results in a EOPNOTSUPP message during sendmsg:

  setsockopt(3, SOL_TLS, TLS_TX, …, 40) = 0
  sendmsg(3, …, msg_flags=0}, 0) = -1 EOPNOTSUPP (Operation not
supported)

The tls_sw implementation does strict flag checking and does not
allow
the MSG_CMSG_COMPAT flag, which is set if the message comes in
through
the compat syscall.

This patch adds MSG_CMSG_COMPAT to the flag check to allow the
usage of
the TLS SW implementation on systems using the compat syscall
path.

Note that the same check is present in the sendmsg path for the
TLS
device implementation, however the flag hasn't been added there
for
lack
of testing hardware.

Signed-off-by: Rouven Czerwinski <redacted>

I don't know much about the compat stuff, I trust our cmsg handling
is
fine?

Just to be sure - did you run tools/testing/selftests/net/tls ?

After some pains to get this to correctly compile I have two failing
tests, both for multi_chunk_sendfile:

root@192:~ /usr/lib/kselftest/net/tls
[==========] Running 93 tests from 4 test cases.
…
[ RUN      ] tls.12.multi_chunk_sendfile
multi_chunk_sendfile: Test terminated by timeout
[     FAIL ] tls.12.multi_chunk_sendfile
…
[ RUN      ] tls.13.multi_chunk_sendfile
multi_chunk_sendfile: Test terminated by timeout
[     FAIL ] tls.13.multi_chunk_sendfile
…
[==========] 91 / 93 tests passed.
[  FAILED  ]

I just tested on my x86_64 workstation and these specific tests fail
there too, do they only work on 5.8? They were added in 5.8, but I am
running 5.7.11 here. It looks like these failures are not
MSG_CMSG_COMPAT related.

Pooja Trivedi do you have an idea?

Regards,
Rouven