ghsa-m3r4-hpjv-ph84
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
powerpc/pseries: Fix use after free in remove_phb_dynamic()
In remove_phb_dynamic() we use &phb->io_resource, after we've called device_unregister(&host_bridge->dev). But the unregister may have freed phb, because pcibios_free_controller_deferred() is the release function for the host_bridge.
If there are no outstanding references when we call device_unregister() then phb will be freed out from under us.
This has gone mainly unnoticed, but with slub_debug and page_poison enabled it can lead to a crash:
PID: 7574 TASK: c0000000d492cb80 CPU: 13 COMMAND: "drmgr" #0 [c0000000e4f075a0] crash_kexec at c00000000027d7dc #1 [c0000000e4f075d0] oops_end at c000000000029608 #2 [c0000000e4f07650] __bad_page_fault at c0000000000904b4 #3 [c0000000e4f076c0] do_bad_slb_fault at c00000000009a5a8 #4 [c0000000e4f076f0] data_access_slb_common_virt at c000000000008b30 Data SLB Access [380] exception frame: R0: c000000000167250 R1: c0000000e4f07a00 R2: c000000002a46100 R3: c000000002b39ce8 R4: 00000000000000c0 R5: 00000000000000a9 R6: 3894674d000000c0 R7: 0000000000000000 R8: 00000000000000ff R9: 0000000000000100 R10: 6b6b6b6b6b6b6b6b R11: 0000000000008000 R12: c00000000023da80 R13: c0000009ffd38b00 R14: 0000000000000000 R15: 000000011c87f0f0 R16: 0000000000000006 R17: 0000000000000003 R18: 0000000000000002 R19: 0000000000000004 R20: 0000000000000005 R21: 000000011c87ede8 R22: 000000011c87c5a8 R23: 000000011c87d3a0 R24: 0000000000000000 R25: 0000000000000001 R26: c0000000e4f07cc8 R27: c00000004d1cc400 R28: c0080000031d00e8 R29: c00000004d23d800 R30: c00000004d1d2400 R31: c00000004d1d2540 NIP: c000000000167258 MSR: 8000000000009033 OR3: c000000000e9f474 CTR: 0000000000000000 LR: c000000000167250 XER: 0000000020040003 CCR: 0000000024088420 MQ: 0000000000000000 DAR: 6b6b6b6b6b6b6ba3 DSISR: c0000000e4f07920 Syscall Result: fffffffffffffff2 [NIP : release_resource+56] [LR : release_resource+48] #5 [c0000000e4f07a00] release_resource at c000000000167258 (unreliable) #6 [c0000000e4f07a30] remove_phb_dynamic at c000000000105648 #7 [c0000000e4f07ab0] dlpar_remove_slot at c0080000031a09e8 [rpadlpar_io] #8 [c0000000e4f07b50] remove_slot_store at c0080000031a0b9c [rpadlpar_io] #9 [c0000000e4f07be0] kobj_attr_store at c000000000817d8c #10 [c0000000e4f07c00] sysfs_kf_write at c00000000063e504 #11 [c0000000e4f07c20] kernfs_fop_write_iter at c00000000063d868 #12 [c0000000e4f07c70] new_sync_write at c00000000054339c #13 [c0000000e4f07d10] vfs_write at c000000000546624 #14 [c0000000e4f07d60] ksys_write at c0000000005469f4 #15 [c0000000e4f07db0] system_call_exception at c000000000030840 #16 [c0000000e4f07e10] system_call_vectored_common at c00000000000c168
To avoid it, we can take a reference to the host_bridge->dev until we're done using phb. Then when we drop the reference the phb will be freed.
{
"affected": [],
"aliases": [
"CVE-2022-49196"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-02-26T07:00:56Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/pseries: Fix use after free in remove_phb_dynamic()\n\nIn remove_phb_dynamic() we use \u0026phb-\u003eio_resource, after we\u0027ve called\ndevice_unregister(\u0026host_bridge-\u003edev). But the unregister may have freed\nphb, because pcibios_free_controller_deferred() is the release function\nfor the host_bridge.\n\nIf there are no outstanding references when we call device_unregister()\nthen phb will be freed out from under us.\n\nThis has gone mainly unnoticed, but with slub_debug and page_poison\nenabled it can lead to a crash:\n\n PID: 7574 TASK: c0000000d492cb80 CPU: 13 COMMAND: \"drmgr\"\n #0 [c0000000e4f075a0] crash_kexec at c00000000027d7dc\n #1 [c0000000e4f075d0] oops_end at c000000000029608\n #2 [c0000000e4f07650] __bad_page_fault at c0000000000904b4\n #3 [c0000000e4f076c0] do_bad_slb_fault at c00000000009a5a8\n #4 [c0000000e4f076f0] data_access_slb_common_virt at c000000000008b30\n Data SLB Access [380] exception frame:\n R0: c000000000167250 R1: c0000000e4f07a00 R2: c000000002a46100\n R3: c000000002b39ce8 R4: 00000000000000c0 R5: 00000000000000a9\n R6: 3894674d000000c0 R7: 0000000000000000 R8: 00000000000000ff\n R9: 0000000000000100 R10: 6b6b6b6b6b6b6b6b R11: 0000000000008000\n R12: c00000000023da80 R13: c0000009ffd38b00 R14: 0000000000000000\n R15: 000000011c87f0f0 R16: 0000000000000006 R17: 0000000000000003\n R18: 0000000000000002 R19: 0000000000000004 R20: 0000000000000005\n R21: 000000011c87ede8 R22: 000000011c87c5a8 R23: 000000011c87d3a0\n R24: 0000000000000000 R25: 0000000000000001 R26: c0000000e4f07cc8\n R27: c00000004d1cc400 R28: c0080000031d00e8 R29: c00000004d23d800\n R30: c00000004d1d2400 R31: c00000004d1d2540\n NIP: c000000000167258 MSR: 8000000000009033 OR3: c000000000e9f474\n CTR: 0000000000000000 LR: c000000000167250 XER: 0000000020040003\n CCR: 0000000024088420 MQ: 0000000000000000 DAR: 6b6b6b6b6b6b6ba3\n DSISR: c0000000e4f07920 Syscall Result: fffffffffffffff2\n [NIP : release_resource+56]\n [LR : release_resource+48]\n #5 [c0000000e4f07a00] release_resource at c000000000167258 (unreliable)\n #6 [c0000000e4f07a30] remove_phb_dynamic at c000000000105648\n #7 [c0000000e4f07ab0] dlpar_remove_slot at c0080000031a09e8 [rpadlpar_io]\n #8 [c0000000e4f07b50] remove_slot_store at c0080000031a0b9c [rpadlpar_io]\n #9 [c0000000e4f07be0] kobj_attr_store at c000000000817d8c\n #10 [c0000000e4f07c00] sysfs_kf_write at c00000000063e504\n #11 [c0000000e4f07c20] kernfs_fop_write_iter at c00000000063d868\n #12 [c0000000e4f07c70] new_sync_write at c00000000054339c\n #13 [c0000000e4f07d10] vfs_write at c000000000546624\n #14 [c0000000e4f07d60] ksys_write at c0000000005469f4\n #15 [c0000000e4f07db0] system_call_exception at c000000000030840\n #16 [c0000000e4f07e10] system_call_vectored_common at c00000000000c168\n\nTo avoid it, we can take a reference to the host_bridge-\u003edev until we\u0027re\ndone using phb. Then when we drop the reference the phb will be freed.",
"id": "GHSA-m3r4-hpjv-ph84",
"modified": "2025-03-04T18:33:26Z",
"published": "2025-03-04T18:33:26Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49196"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/33d39efb61a84e055ca2386157d39ebbdf6b7d31"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/403f9e0bc5535a0a5184d1352fa3a70e6ffacb6f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/895ca4ae1f72e0a0160ab162723e59c9f265ec93"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fe2640bd7a62f1f7c3f55fbda31084085075bc30"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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.