CVE-2024-39479

CVE Details

Release Date:

2024-07-05

Description

In the Linux kernel, the following vulnerability has been resolved:\ndrm/i915/hwmon: Get rid of devm\nWhen both hwmon and hwmon drvdata (on which hwmon depends) are device\nmanaged resources, the expectation, on device unbind, is that hwmon will be\nreleased before drvdata. However, in i915 there are two separate code\npaths, which both release either drvdata or hwmon and either can be\nreleased before the other. These code paths (for device unbind) are as\nfollows (see also the bug referenced below):\nCall Trace:\nrelease_nodes+0x11/0x70\ndevres_release_group+0xb2/0x110\ncomponent_unbind_all+0x8d/0xa0\ncomponent_del+0xa5/0x140\nintel_pxp_tee_component_fini+0x29/0x40 [i915]\nintel_pxp_fini+0x33/0x80 [i915]\ni915_driver_remove+0x4c/0x120 [i915]\ni915_pci_remove+0x19/0x30 [i915]\npci_device_remove+0x32/0xa0\ndevice_release_driver_internal+0x19c/0x200\nunbind_store+0x9c/0xb0\nand\nCall Trace:\nrelease_nodes+0x11/0x70\ndevres_release_all+0x8a/0xc0\ndevice_unbind_cleanup+0x9/0x70\ndevice_release_driver_internal+0x1c1/0x200\nunbind_store+0x9c/0xb0\nThis means that in i915, if use devm, we cannot gurantee that hwmon will\nalways be released before drvdata. Which means that we have a uaf if hwmon\nsysfs is accessed when drvdata has been released but hwmon hasn't.\nThe only way out of this seems to be do get rid of devm_ and release/free\neverything explicitly during device unbind.\nv2: Change commit message and other minor code changes\nv3: Cleanup from i915_hwmon_register on error (Armin Wolf)\nv4: Eliminate potential static analyzer warning (Rodrigo)\nEliminate fetch_and_zero (Jani)\nv5: Restore previous logic for ddat_gt->hwmon_dev error return (Andi)

See more information about CVE-2024-39479 from MITRE CVE dictionary and NIST NVD

CVSS Scoring

NOTE: The following CVSS v3.1 metrics and score provided are preliminary and subject to review.

Base Score:	4.4	CVSS Vector:	CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Attack Vector:	Local network	Attack Complexity:	Low
Privileges Required:	High	User Interaction:	None
Scope:	Unchanged	Confidentiality Impact:	None
Integrity Impact:	None	Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 9 (kernel)	ELSA-2024-9315	2024-11-14