ghsa-3m8v-mqfw-xp3g
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
PCI: s390: Fix use-after-free of PCI resources with per-function hotplug
On s390 PCI functions may be hotplugged individually even when they belong to a multi-function device. In particular on an SR-IOV device VFs may be removed and later re-added.
In commit a50297cf8235 ("s390/pci: separate zbus creation from scanning") it was missed however that struct pci_bus and struct zpci_bus's resource list retained a reference to the PCI functions MMIO resources even though those resources are released and freed on hot-unplug. These stale resources may subsequently be claimed when the PCI function re-appears resulting in use-after-free.
One idea of fixing this use-after-free in s390 specific code that was investigated was to simply keep resources around from the moment a PCI function first appeared until the whole virtual PCI bus created for a multi-function device disappears. The problem with this however is that due to the requirement of artificial MMIO addreesses (address cookies) extra logic is then needed to keep the address cookies compatible on re-plug. At the same time the MMIO resources semantically belong to the PCI function so tying their lifecycle to the function seems more logical.
Instead a simpler approach is to remove the resources of an individually hot-unplugged PCI function from the PCI bus's resource list while keeping the resources of other PCI functions on the PCI bus untouched.
This is done by introducing pci_bus_remove_resource() to remove an individual resource. Similarly the resource also needs to be removed from the struct zpci_bus's resource list. It turns out however, that there is really no need to add the MMIO resources to the struct zpci_bus's resource list at all and instead we can simply use the zpci_bar_struct's resource pointer directly.
{
"affected": [],
"aliases": [
"CVE-2023-53123"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-05-02T16:15:31Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nPCI: s390: Fix use-after-free of PCI resources with per-function hotplug\n\nOn s390 PCI functions may be hotplugged individually even when they\nbelong to a multi-function device. In particular on an SR-IOV device VFs\nmay be removed and later re-added.\n\nIn commit a50297cf8235 (\"s390/pci: separate zbus creation from\nscanning\") it was missed however that struct pci_bus and struct\nzpci_bus\u0027s resource list retained a reference to the PCI functions MMIO\nresources even though those resources are released and freed on\nhot-unplug. These stale resources may subsequently be claimed when the\nPCI function re-appears resulting in use-after-free.\n\nOne idea of fixing this use-after-free in s390 specific code that was\ninvestigated was to simply keep resources around from the moment a PCI\nfunction first appeared until the whole virtual PCI bus created for\na multi-function device disappears. The problem with this however is\nthat due to the requirement of artificial MMIO addreesses (address\ncookies) extra logic is then needed to keep the address cookies\ncompatible on re-plug. At the same time the MMIO resources semantically\nbelong to the PCI function so tying their lifecycle to the function\nseems more logical.\n\nInstead a simpler approach is to remove the resources of an individually\nhot-unplugged PCI function from the PCI bus\u0027s resource list while\nkeeping the resources of other PCI functions on the PCI bus untouched.\n\nThis is done by introducing pci_bus_remove_resource() to remove an\nindividual resource. Similarly the resource also needs to be removed\nfrom the struct zpci_bus\u0027s resource list. It turns out however, that\nthere is really no need to add the MMIO resources to the struct\nzpci_bus\u0027s resource list at all and instead we can simply use the\nzpci_bar_struct\u0027s resource pointer directly.",
"id": "GHSA-3m8v-mqfw-xp3g",
"modified": "2025-05-02T18:31:37Z",
"published": "2025-05-02T18:31:37Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-53123"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/437bb839e36cc9f35adc6d2a2bf113b7a0fc9985"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a2410d0c3d2d714ed968a135dfcbed6aa3ff7027"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ab909509850b27fd39b8ba99e44cda39dbc3858c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b99ebf4b62774e690e73a551cf5fbf6f219bdd96"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
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