[PATCH net 0/2] net: psp: avoid conflicts with skb->decrypted and sk_validate_xmit_skb()

[Daniel Zahka <daniel.zahka@gmail.com>]

Sashiko's review of commit da630d1da2b1 ("netdevsim: psp: drop tx key
ops") [1] showed that there is a hazard between psp and offloaded tls,
where both can clobber what the other set in the sk_validate_xmit_skb
callback.

It was discussed further on the mailing list [2], and it was pointed out
that there are conflicts with psp and non-offloaded tls both using the
skb->decrypted bit.

The simplest fix is to make psp and tls mutually exclusive. This series
goes a bit further and makes psp exclusive with all TCP ULPs. The PSP
implementation that we have is not designed to be used with any TCP ULP,
so don't allow a socket to have state for both.

[1]: https://sashiko.dev/#/patchset/20260903-psp-prep-v1-0-d47e9c4c375d%40gmail.com 
[2]: https://lore.kernel.org/netdev/20260903-psp-prep-v1-0-d47e9c4c375d@gmail.com/

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
---
Daniel Zahka (2):
      net: psp: avoid conflicts with skb->decrypted and sk_validate_xmit_skb()
      selftests: drv-net: psp: test PSP and TCP ULP mutual exclusion

 include/net/sock.h                         | 11 +++++++
 net/core/sock.c                            |  7 +++++
 net/ipv4/tcp_ulp.c                         |  4 +++
 net/psp/psp_sock.c                         |  4 +++
 tools/testing/selftests/drivers/net/config |  1 +
 tools/testing/selftests/drivers/net/psp.py | 46 ++++++++++++++++++++++++++++++
 6 files changed, 73 insertions(+)
---
base-commit: 78445023439506ebd83b86d40b1e428a3b309d4a
change-id: 20260909-psp-ktls-fix-47aa27d955f2

Best regards,
-- 
Daniel Zahka <daniel.zahka@gmail.com>