stable inclusion
from stable-5.10.30
commit 0224432a8fc183b88dcaade4d7e25d455b72f528
bugzilla: 51791

--------------------------------

[ Upstream commit e88add19 ]

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: b65e3d7b ("xfrm: state: add sequence count to detect hash resizes")
Signed-off-by: NAhmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: NSteffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: N  Weilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>