| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2021-47290: scsi: target: Fix NULL dereference on XCOPY completion |
| |
| Description |
| =========== |
| |
| 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. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47290 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.13 with commit 39ae3edda325e9cf9e978c9788affe88231f3b34 and fixed in 5.13.6 with commit e7732c5a19a15a62b0b23fd683a639b0483e1f40 |
| Issue introduced in 5.13 with commit 39ae3edda325e9cf9e978c9788affe88231f3b34 and fixed in 5.14 with commit a47fa41381a09e5997afd762664db4f5f6657e03 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2021-47290 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/target/target_core_transport.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/e7732c5a19a15a62b0b23fd683a639b0483e1f40 |
| https://git.kernel.org/stable/c/a47fa41381a09e5997afd762664db4f5f6657e03 |
