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In the Linux kernel, the following vulnerability has been...

Moderate severity Unreviewed Published May 21, 2024 to the GitHub Advisory Database • Updated Jan 31, 2025

Package

No package listed— Suggest a package

Affected versions

Unknown

Patched versions

Unknown

Description

In the Linux kernel, the following vulnerability has been resolved:

drm/bridge: lt8912b: Fix crash on bridge detach

The lt8912b driver, in its bridge detach function, calls
drm_connector_unregister() and drm_connector_cleanup().

drm_connector_unregister() should be called only for connectors
explicitly registered with drm_connector_register(), which is not the
case in lt8912b.

The driver's drm_connector_funcs.destroy hook is set to
drm_connector_cleanup().

Thus the driver should not call either drm_connector_unregister() nor
drm_connector_cleanup() in its lt8912_bridge_detach(), as they cause a
crash on bridge detach:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Mem abort info:
ESR = 0x0000000096000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
CM = 0, WnR = 0, TnD = 0, TagAccess = 0
GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=00000000858f3000
[0000000000000000] pgd=0800000085918003, p4d=0800000085918003, pud=0800000085431003, pmd=0000000000000000
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in: tidss(-) display_connector lontium_lt8912b tc358768 panel_lvds panel_simple drm_dma_helper drm_kms_helper drm drm_panel_orientation_quirks
CPU: 3 PID: 462 Comm: rmmod Tainted: G W 6.5.0-rc2+ #2
Hardware name: Toradex Verdin AM62 on Verdin Development Board (DT)
pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : drm_connector_cleanup+0x78/0x2d4 [drm]
lr : lt8912_bridge_detach+0x54/0x6c [lontium_lt8912b]
sp : ffff800082ed3a90
x29: ffff800082ed3a90 x28: ffff0000040c1940 x27: 0000000000000000
x26: 0000000000000000 x25: dead000000000122 x24: dead000000000122
x23: dead000000000100 x22: ffff000003fb6388 x21: 0000000000000000
x20: 0000000000000000 x19: ffff000003fb6260 x18: fffffffffffe56e8
x17: 0000000000000000 x16: 0010000000000000 x15: 0000000000000038
x14: 0000000000000000 x13: ffff800081914b48 x12: 000000000000040e
x11: 000000000000015a x10: ffff80008196ebb8 x9 : ffff800081914b48
x8 : 00000000ffffefff x7 : ffff0000040c1940 x6 : ffff80007aa649d0
x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff80008159e008
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
drm_connector_cleanup+0x78/0x2d4 [drm]
lt8912_bridge_detach+0x54/0x6c [lontium_lt8912b]
drm_bridge_detach+0x44/0x84 [drm]
drm_encoder_cleanup+0x40/0xb8 [drm]
drmm_encoder_alloc_release+0x1c/0x30 [drm]
drm_managed_release+0xac/0x148 [drm]
drm_dev_put.part.0+0x88/0xb8 [drm]
devm_drm_dev_init_release+0x14/0x24 [drm]
devm_action_release+0x14/0x20
release_nodes+0x5c/0x90
devres_release_all+0x8c/0xe0
device_unbind_cleanup+0x18/0x68
device_release_driver_internal+0x208/0x23c
driver_detach+0x4c/0x94
bus_remove_driver+0x70/0xf4
driver_unregister+0x30/0x60
platform_driver_unregister+0x14/0x20
tidss_platform_driver_exit+0x18/0xb2c [tidss]
__arm64_sys_delete_module+0x1a0/0x2b4
invoke_syscall+0x48/0x110
el0_svc_common.constprop.0+0x60/0x10c
do_el0_svc_compat+0x1c/0x40
el0_svc_compat+0x40/0xac
el0t_32_sync_handler+0xb0/0x138
el0t_32_sync+0x194/0x198
Code: 9104a276 f2fbd5b7 aa0203e1 91008af8 (f85c0420)

References

Published by the National Vulnerability Database May 21, 2024
Published to the GitHub Advisory Database May 21, 2024
Last updated Jan 31, 2025

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(5th percentile)

Weaknesses

CVE ID

CVE-2023-52856

GHSA ID

GHSA-3qr9-g9f2-22xh

Source code

No known source code

Dependabot alerts are not supported on this advisory because it does not have a package from a supported ecosystem with an affected and fixed version.

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