| 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-2023-52849: cxl/mem: Fix shutdown order |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| cxl/mem: Fix shutdown order |
| |
| Ira reports that removing cxl_mock_mem causes a crash with the following |
| trace: |
| |
| BUG: kernel NULL pointer dereference, address: 0000000000000044 |
| [..] |
| RIP: 0010:cxl_region_decode_reset+0x7f/0x180 [cxl_core] |
| [..] |
| Call Trace: |
| <TASK> |
| cxl_region_detach+0xe8/0x210 [cxl_core] |
| cxl_decoder_kill_region+0x27/0x40 [cxl_core] |
| cxld_unregister+0x29/0x40 [cxl_core] |
| devres_release_all+0xb8/0x110 |
| device_unbind_cleanup+0xe/0x70 |
| device_release_driver_internal+0x1d2/0x210 |
| bus_remove_device+0xd7/0x150 |
| device_del+0x155/0x3e0 |
| device_unregister+0x13/0x60 |
| devm_release_action+0x4d/0x90 |
| ? __pfx_unregister_port+0x10/0x10 [cxl_core] |
| delete_endpoint+0x121/0x130 [cxl_core] |
| devres_release_all+0xb8/0x110 |
| device_unbind_cleanup+0xe/0x70 |
| device_release_driver_internal+0x1d2/0x210 |
| bus_remove_device+0xd7/0x150 |
| device_del+0x155/0x3e0 |
| ? lock_release+0x142/0x290 |
| cdev_device_del+0x15/0x50 |
| cxl_memdev_unregister+0x54/0x70 [cxl_core] |
| |
| This crash is due to the clearing out the cxl_memdev's driver context |
| (@cxlds) before the subsystem is done with it. This is ultimately due to |
| the region(s), that this memdev is a member, being torn down and expecting |
| to be able to de-reference @cxlds, like here: |
| |
| static int cxl_region_decode_reset(struct cxl_region *cxlr, int count) |
| ... |
| if (cxlds->rcd) |
| goto endpoint_reset; |
| ... |
| |
| Fix it by keeping the driver context valid until memdev-device |
| unregistration, and subsequently the entire stack of related |
| dependencies, unwinds. |
| |
| The Linux kernel CVE team has assigned CVE-2023-52849 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.15 with commit 9cc238c7a526dba9ee8c210fa2828886fc65db66 and fixed in 5.15.139 with commit 20bd0198bebdd706bd4614b3933ef70d7c19618f |
| Issue introduced in 5.15 with commit 9cc238c7a526dba9ee8c210fa2828886fc65db66 and fixed in 6.1.63 with commit 7c7371b41a14e86f53e7dbe5baa7b1d3e0ab324b |
| Issue introduced in 5.15 with commit 9cc238c7a526dba9ee8c210fa2828886fc65db66 and fixed in 6.5.12 with commit cad22a757029c3a1985c221a2d4a6491ad4035ae |
| Issue introduced in 5.15 with commit 9cc238c7a526dba9ee8c210fa2828886fc65db66 and fixed in 6.6.2 with commit 0ca074f7d788627a4e0b047ca5fbdb5fc567220c |
| Issue introduced in 5.15 with commit 9cc238c7a526dba9ee8c210fa2828886fc65db66 and fixed in 6.7 with commit 88d3917f82ed4215a2154432c26de1480a61b209 |
| Issue introduced in 5.14.8 with commit 964a9834492210f48b360baa9e20a9eedf4d08ff |
| |
| 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-2023-52849 |
| 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/cxl/core/memdev.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/20bd0198bebdd706bd4614b3933ef70d7c19618f |
| https://git.kernel.org/stable/c/7c7371b41a14e86f53e7dbe5baa7b1d3e0ab324b |
| https://git.kernel.org/stable/c/cad22a757029c3a1985c221a2d4a6491ad4035ae |
| https://git.kernel.org/stable/c/0ca074f7d788627a4e0b047ca5fbdb5fc567220c |
| https://git.kernel.org/stable/c/88d3917f82ed4215a2154432c26de1480a61b209 |
