rxrpc: Fix race between conn bundle lookup and bundle removal [ZDI-CAN-15975]

stable inclusion
from stable-v5.10.157
commit 3535c632e6d16c98f76e615da8dc0cb2750c66cc
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I6VK2H
CVE: CVE-2023-2006

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3535c632e6d16c98f76e615da8dc0cb2750c66cc



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[ Upstream commit 3bcd6c7e ]

After rxrpc_unbundle_conn() has removed a connection from a bundle, it
checks to see if there are any conns with available channels and, if not,
removes and attempts to destroy the bundle.

Whilst it does check after grabbing client_bundles_lock that there are no
connections attached, this races with rxrpc_look_up_bundle() retrieving the
bundle, but not attaching a connection for the connection to be attached
later.

There is therefore a window in which the bundle can get destroyed before we
manage to attach a new connection to it.

Fix this by adding an "active" counter to struct rxrpc_bundle:

 (1) rxrpc_connect_call() obtains an active count by prepping/looking up a
     bundle and ditches it before returning.

 (2) If, during rxrpc_connect_call(), a connection is added to the bundle,
     this obtains an active count, which is held until the connection is
     discarded.

 (3) rxrpc_deactivate_bundle() is created to drop an active count on a
     bundle and destroy it when the active count reaches 0.  The active
     count is checked inside client_bundles_lock() to prevent a race with
     rxrpc_look_up_bundle().

 (4) rxrpc_unbundle_conn() then calls rxrpc_deactivate_bundle().

Fixes: 245500d8 ("rxrpc: Rewrite the client connection manager")
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-15975
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by:  <zdi-disclosures@trendmicro.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:
	net/rxrpc/ar-internal.h
	net/rxrpc/conn_client.c

Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Reviewed-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Wang Weiyang <wangweiyang2@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>