Bug 1224884 (CVE-2021-47290)

Summary: VUL-0: CVE-2021-47290: kernel: scsi: target: Fix NULL dereference on XCOPY completion
Product: [Novell Products] SUSE Security Incidents Reporter: SMASH SMASH <smash_bz>
Component: IncidentsAssignee: Security Team bot <security-team>
Status: RESOLVED INVALID QA Contact: Security Team bot <security-team>
Severity: Normal    
Priority: P3 - Medium CC: carlos.lopez, mhocko
Version: unspecified   
Target Milestone: ---   
Hardware: Other   
OS: Other   
URL: https://smash.suse.de/issue/406923/
Whiteboard: CVSSv3.1:SUSE:CVE-2021-47290:5.5:(AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Found By: Security Response Team Services Priority:
Business Priority: Blocker: ---
Marketing QA Status: --- IT Deployment: ---

Description SMASH SMASH 2024-05-22 10:07:01 UTC
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.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-47290
https://www.cve.org/CVERecord?id=CVE-2021-47290
https://git.kernel.org/stable/c/a47fa41381a09e5997afd762664db4f5f6657e03
https://git.kernel.org/stable/c/e7732c5a19a15a62b0b23fd683a639b0483e1f40
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2021/CVE-2021-47290.mbox
Comment 2 Michal Hocko 2024-05-23 16:24:17 UTC
Nothing to be done
Comment 3 Carlos López 2024-05-28 11:32:51 UTC
Nothing to do, closing.