linux/net/tls
Maxim Mikityanskiy 94ce3b64c6 net/tls: Use RCU API to access tls_ctx->netdev
Currently, tls_device_down synchronizes with tls_device_resync_rx using
RCU, however, the pointer to netdev is stored using WRITE_ONCE and
loaded using READ_ONCE.

Although such approach is technically correct (rcu_dereference is
essentially a READ_ONCE, and rcu_assign_pointer uses WRITE_ONCE to store
NULL), using special RCU helpers for pointers is more valid, as it
includes additional checks and might change the implementation
transparently to the callers.

Mark the netdev pointer as __rcu and use the correct RCU helpers to
access it. For non-concurrent access pass the right conditions that
guarantee safe access (locks taken, refcount value). Also use the
correct helper in mlx5e, where even READ_ONCE was missing.

The transition to RCU exposes existing issues, fixed by this commit:

1. bond_tls_device_xmit could read netdev twice, and it could become
NULL the second time, after the NULL check passed.

2. Drivers shouldn't stop processing the last packet if tls_device_down
just set netdev to NULL, before tls_dev_del was called. This prevents a
possible packet drop when transitioning to the fallback software mode.

Fixes: 89df6a8104 ("net/bonding: Implement TLS TX device offload")
Fixes: c55dcdd435 ("net/tls: Fix use-after-free after the TLS device goes down and up")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Link: https://lore.kernel.org/r/20220810081602.1435800-1-maximmi@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-10 22:58:43 -07:00
..
Kconfig net/tls: Select SOCK_RX_QUEUE_MAPPING from TLS_DEVICE 2021-02-11 19:08:06 -08:00
Makefile tls: rx: async: hold onto the input skb 2022-07-18 11:24:11 +01:00
tls_device_fallback.c net/tls: Use RCU API to access tls_ctx->netdev 2022-08-10 22:58:43 -07:00
tls_device.c net/tls: Use RCU API to access tls_ctx->netdev 2022-08-10 22:58:43 -07:00
tls_main.c tls: rx: do not use the standard strparser 2022-07-26 14:38:51 -07:00
tls_proc.c tls: rx: add counter for NoPad violations 2022-07-11 19:48:33 -07:00
tls_strp.c tls: rx: device: don't try to copy too much on detach 2022-08-10 22:53:25 -07:00
tls_sw.c tls: rx: fix the false positive warning 2022-07-28 21:50:00 -07:00
tls_toe.c tls: create an internal header 2022-07-08 18:38:45 -07:00
tls.h tls: rx: do not use the standard strparser 2022-07-26 14:38:51 -07:00
trace.c net/tls: add tracing for device/offload events 2019-10-05 16:29:00 -07:00
trace.h net/tls: add device decrypted trace point 2019-10-05 16:29:00 -07:00