tree 5953b30c4717eff8003934a9f513c51d6a9641ed
parent 1e6a3b41cf2a104877e60027b389d1c91d742d9b
author Ahmed S. Darwish <a.darwish@linutronix.de> 1615892189 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1618382525 +0200

net: xfrm: Localize sequence counter per network namespace

[ Upstream commit e88add19f68191448427a6e4eb059664650a837f ]

A sequence counter write section must be serialized or its internal
state can get corrupted. The "xfrm_state_hash_generation" seqcount is
global, but its write serialization lock (net->xfrm.xfrm_state_lock) is
instantiated per network namespace. The write protection is thus
insufficient.

To provide full protection, localize the sequence counter per network
namespace instead. This should be safe as both the seqcount read and
write sections access data exclusively within the network namespace. It
also lays the foundation for transforming "xfrm_state_hash_generation"
data type from seqcount_t to seqcount_LOCKNAME_t in further commits.

Fixes: b65e3d7be06f ("xfrm: state: add sequence count to detect hash resizes")
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>