CVE-2021-47290

In the Linux kernel, the following vulnerability has been resolved: scsi:
target: Fix NULL dereference on XCOPY completion CPU affinity control added
with commit 39ae3edda325 (“scsi: target: core: Make completion affinity
configurable”) makes target_complete_cmd() queue work on a CPU based on
se_tpg->se_tpg_wwn->cmd_compl_affinity state. LIO’s EXTENDED COPY worker is
a special case in that read/write cmds are dispatched using the global
xcopy_pt_tpg, which carries a NULL se_tpg_wwn pointer following
initialization in target_xcopy_setup_pt(). The NULL
xcopy_pt_tpg->se_tpg_wwn pointer is dereferenced on completion of any
EXTENDED COPY initiated read/write cmds. E.g using the libiscsi
SCSI.ExtendedCopy.Simple test: BUG: kernel NULL pointer dereference,
address: 00000000000001a8 RIP: 0010:target_complete_cmd+0x9d/0x130
[target_core_mod] Call Trace: fd_execute_rw+0x148/0x42a [target_core_file]
? __dynamic_pr_debug+0xa7/0xe0 ? target_check_reservation+0x5b/0x940
[target_core_mod] __target_execute_cmd+0x1e/0x90 [target_core_mod]
transport_generic_new_cmd+0x17c/0x330 [target_core_mod]
target_xcopy_issue_pt_cmd+0x9/0x60 [target_core_mod]
target_xcopy_read_source.isra.7+0x10b/0x1b0 [target_core_mod] ?
target_check_fua+0x40/0x40 [target_core_mod] ?
transport_complete_task_attr+0x130/0x130 [target_core_mod]
target_xcopy_do_work+0x61f/0xc00 [target_core_mod] This fix makes
target_complete_cmd() queue work on se_cmd->cpuid if se_tpg_wwn is NULL.