ghsa-pqqv-8xrg-2jg9
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
cxl/port: Fix delete_endpoint() vs parent unregistration race
The CXL subsystem, at cxl_mem ->probe() time, establishes a lineage of ports (struct cxl_port objects) between an endpoint and the root of a CXL topology. Each port including the endpoint port is attached to the cxl_port driver.
Given that setup, it follows that when either any port in that lineage goes through a cxl_port ->remove() event, or the memdev goes through a cxl_mem ->remove() event. The hierarchy below the removed port, or the entire hierarchy if the memdev is removed needs to come down.
The delete_endpoint() callback is careful to check whether it is being called to tear down the hierarchy, or if it is only being called to teardown the memdev because an ancestor port is going through ->remove().
That care needs to take the device_lock() of the endpoint's parent. Which requires 2 bugs to be fixed:
1/ A reference on the parent is needed to prevent use-after-free scenarios like this signature:
BUG: spinlock bad magic on CPU#0, kworker/u56:0/11
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20230524-3.fc38 05/24/2023
Workqueue: cxl_port detach_memdev [cxl_core]
RIP: 0010:spin_bug+0x65/0xa0
Call Trace:
do_raw_spin_lock+0x69/0xa0
__mutex_lock+0x695/0xb80
delete_endpoint+0xad/0x150 [cxl_core]
devres_release_all+0xb8/0x110
device_unbind_cleanup+0xe/0x70
device_release_driver_internal+0x1d2/0x210
detach_memdev+0x15/0x20 [cxl_core]
process_one_work+0x1e3/0x4c0
worker_thread+0x1dd/0x3d0
2/ In the case of RCH topologies, the parent device that needs to be locked is not always @port->dev as returned by cxl_mem_find_port(), use endpoint->dev.parent instead.
{
"affected": [],
"aliases": [
"CVE-2023-52771"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-21T16:15:16Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncxl/port: Fix delete_endpoint() vs parent unregistration race\n\nThe CXL subsystem, at cxl_mem -\u003eprobe() time, establishes a lineage of\nports (struct cxl_port objects) between an endpoint and the root of a\nCXL topology. Each port including the endpoint port is attached to the\ncxl_port driver.\n\nGiven that setup, it follows that when either any port in that lineage\ngoes through a cxl_port -\u003eremove() event, or the memdev goes through a\ncxl_mem -\u003eremove() event. The hierarchy below the removed port, or the\nentire hierarchy if the memdev is removed needs to come down.\n\nThe delete_endpoint() callback is careful to check whether it is being\ncalled to tear down the hierarchy, or if it is only being called to\nteardown the memdev because an ancestor port is going through\n-\u003eremove().\n\nThat care needs to take the device_lock() of the endpoint\u0027s parent.\nWhich requires 2 bugs to be fixed:\n\n1/ A reference on the parent is needed to prevent use-after-free\n scenarios like this signature:\n\n BUG: spinlock bad magic on CPU#0, kworker/u56:0/11\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20230524-3.fc38 05/24/2023\n Workqueue: cxl_port detach_memdev [cxl_core]\n RIP: 0010:spin_bug+0x65/0xa0\n Call Trace:\n do_raw_spin_lock+0x69/0xa0\n __mutex_lock+0x695/0xb80\n delete_endpoint+0xad/0x150 [cxl_core]\n devres_release_all+0xb8/0x110\n device_unbind_cleanup+0xe/0x70\n device_release_driver_internal+0x1d2/0x210\n detach_memdev+0x15/0x20 [cxl_core]\n process_one_work+0x1e3/0x4c0\n worker_thread+0x1dd/0x3d0\n\n2/ In the case of RCH topologies, the parent device that needs to be\n locked is not always @port-\u003edev as returned by cxl_mem_find_port(), use\n endpoint-\u003edev.parent instead.",
"id": "GHSA-pqqv-8xrg-2jg9",
"modified": "2024-11-06T00:31:53Z",
"published": "2024-05-21T18:31:20Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-52771"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/37179fcc916bce8c3cc7b36d67ef814cce55142b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6b2e428e673b3f55965674a426c40922e91388aa"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8d2ad999ca3c64cb08cf6a58d227b9d9e746d708"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.