xprtrdma: treat all calls not a bcall when bc_serv is NULL

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: xprtrdma: treat all calls not a bcall when bc_serv is NULL When a rdma server returns a fault format reply, nfs v3 client may treats it as a bcall when bc service is not exist. The debug message at rpcrdma_bc_receive_call are, [56579.837169] RPC: rpcrdma_bc_receive_call: callback XID 00000001, length=20 [56579.837174] RPC: rpcrdma_bc_receive_call: 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04 After that, rpcrdma_bc_receive_call will meets NULL pointer as, [ 226.057890] BUG: unable to handle kernel NULL pointer dereference at 00000000000000c8 ... [ 226.058704] RIP: 0010:_raw_spin_lock+0xc/0x20 ... [ 226.059732] Call Trace: [ 226.059878] rpcrdma_bc_receive_call+0x138/0x327 [rpcrdma] [ 226.060011] __ib_process_cq+0x89/0x170 [ib_core] [ 226.060092] ib_cq_poll_work+0x26/0x80 [ib_core] [ 226.060257] process_one_work+0x1a7/0x360 [ 226.060367] ? create_worker+0x1a0/0x1a0 [ 226.060440] worker_thread+0x30/0x390 [ 226.060500] ? create_worker+0x1a0/0x1a0 [ 226.060574] kthread+0x116/0x130 [ 226.060661] ? kthread_flush_work_fn+0x10/0x10 [ 226.060724] ret_from_fork+0x35/0x40 ...

References

• https://git.kernel.org/stable/c/8e3943c50764dc7c5f25911970c3ff062ec1f18c
• https://git.kernel.org/stable/c/998d35a2aff4b81a1c784f3aa45cd3afff6814c1
• https://git.kernel.org/stable/c/da99331fa62131a38a0947a8204c5208de7b0454
• https://git.kernel.org/stable/c/8dbae5affbdbf524b48000f9d357925bb001e5f4
• https://git.kernel.org/stable/c/a3fc8051ee061e31db13e2fe011e8e0b71a7f815
• https://git.kernel.org/stable/c/90c4f73104016748533a5707ecd15930fbeff402
• https://git.kernel.org/stable/c/91784f3d77b73885e1b2e6b59d3cbf0de0a1126a
• https://git.kernel.org/stable/c/11270e7ca268e8d61b5d9e5c3a54bd1550642c9c