tipc: force a dst refcount before doing decryption

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: tipc: force a dst refcount before doing decryption As it says in commit 3bc07321ccc2 ("xfrm: Force a dst refcount before entering the xfrm type handlers"): "Crypto requests might return asynchronous. In this case we leave the rcu protected region, so force a refcount on the skb's destination entry before we enter the xfrm type input/output handlers." On TIPC decryption path it has the same problem, and skb_dst_force() should be called before doing decryption to avoid a possible crash. Shuang reported this issue when this warning is triggered: [] WARNING: include/net/dst.h:337 tipc_sk_rcv+0x1055/0x1ea0 [tipc] [] Kdump: loaded Tainted: G W --------- - - 4.18.0-496.el8.x86_64+debug [] Workqueue: crypto cryptd_queue_worker [] RIP: 0010:tipc_sk_rcv+0x1055/0x1ea0 [tipc] [] Call Trace: [] tipc_sk_mcast_rcv+0x548/0xea0 [tipc] [] tipc_rcv+0xcf5/0x1060 [tipc] [] tipc_aead_decrypt_done+0x215/0x2e0 [tipc] [] cryptd_aead_crypt+0xdb/0x190 [] cryptd_queue_worker+0xed/0x190 [] process_one_work+0x93d/0x17e0

References

• https://git.kernel.org/stable/c/3eb1b39627892c4e26cb0162b75725aa5fcc60c8
• https://git.kernel.org/stable/c/692803b39a36e63ac73208e0a3769ae6a2f9bc76
• https://git.kernel.org/stable/c/623c90d86a61e3780f682b32928af469c66ec4c2
• https://git.kernel.org/stable/c/b57a4a2dc8746cea58a922ebe31b6aa629d69d93
• https://git.kernel.org/stable/c/6808b41371670c51feea14f63ade211e78100930
• https://git.kernel.org/stable/c/2ebe8f840c7450ecbfca9d18ac92e9ce9155e269