Описание
In the Linux kernel, the following vulnerability has been resolved:
drm/display/dp_mst: Add protection against 0 vcpi
When releasing a timeslot there is a slight chance we may end up
with the wrong payload mask due to overflow if the delayed_destroy_work
ends up coming into play after a DP 2.1 monitor gets disconnected
which causes vcpi to become 0 then we try to make the payload =
~BIT(vcpi - 1) which is a negative shift. VCPI id should never
really be 0 hence skip changing the payload mask if VCPI is 0.
Otherwise it leads to
<7> [515.287237] xe 0000:03:00.0: [drm:drm_dp_mst_get_port_malloc
[drm_display_helper]] port ffff888126ce9000 (3)
<4> [515.287267] -----------[ cut here ]-----------
<3> [515.287268] UBSAN: shift-out-of-bounds in
../drivers/gpu/drm/display/drm_dp_mst_topology.c:4575:36
<3> [515.287271] shift exponent -1 is negative
<4> [515.287275] CPU: 7 UID: 0 PID: 3108 Comm: kworker/u64:33 Tainted: G
S U 6.17.0-rc6-lgci-xe-xe-3795-3e79699fa1b216e92+ #1 PREEMPT(voluntary)
<4> [515.287279] Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER
<4> [515.287279] Hardware name: ASUS System Product Name/PRIME Z790-P
WIFI, BIOS 1645 03/15/2024
<4> [515.287281] Workqueue: drm_dp_mst_wq drm_dp_delayed_destroy_work
[drm_display_helper]
<4> [515.287303] Call Trace:
<4> [515.287304]
<4> [515.287306] dump_stack_lvl+0xc1/0xf0
<4> [515.287313] dump_stack+0x10/0x20
<4> [515.287316] __ubsan_handle_shift_out_of_bounds+0x133/0x2e0
<4> [515.287324] ? drm_atomic_get_private_obj_state+0x186/0x1d0
<4> [515.287333] drm_dp_atomic_release_time_slots.cold+0x17/0x3d
[drm_display_helper]
<4> [515.287355] mst_connector_atomic_check+0x159/0x180 [xe]
<4> [515.287546] drm_atomic_helper_check_modeset+0x4d9/0xfa0
<4> [515.287550] ? __ww_mutex_lock.constprop.0+0x6f/0x1a60
<4> [515.287562] intel_atomic_check+0x119/0x2b80 [xe]
<4> [515.287740] ? find_held_lock+0x31/0x90
<4> [515.287747] ? lock_release+0xce/0x2a0
<4> [515.287754] drm_atomic_check_only+0x6a2/0xb40
<4> [515.287758] ? drm_atomic_add_affected_connectors+0x12b/0x140
<4> [515.287765] drm_atomic_commit+0x6e/0xf0
<4> [515.287766] ? _pfx__drm_printfn_info+0x10/0x10
<4> [515.287774] drm_client_modeset_commit_atomic+0x25c/0x2b0
<4> [515.287794] drm_client_modeset_commit_locked+0x60/0x1b0
<4> [515.287795] ? mutex_lock_nested+0x1b/0x30
<4> [515.287801] drm_client_modeset_commit+0x26/0x50
<4> [515.287804] __drm_fb_helper_restore_fbdev_mode_unlocked+0xdc/0x110
<4> [515.287810] drm_fb_helper_hotplug_event+0x120/0x140
<4> [515.287814] drm_fbdev_client_hotplug+0x28/0xd0
<4> [515.287819] drm_client_hotplug+0x6c/0xf0
<4> [515.287824] drm_client_dev_hotplug+0x9e/0xd0
<4> [515.287829] drm_kms_helper_hotplug_event+0x1a/0x30
<4> [515.287834] drm_dp_delayed_destroy_work+0x3df/0x410
[drm_display_helper]
<4> [515.287861] process_one_work+0x22b/0x6f0
<4> [515.287874] worker_thread+0x1e8/0x3d0
<4> [515.287879] ? __pfx_worker_thread+0x10/0x10
<4> [515.287882] kthread+0x11c/0x250
<4> [515.287886] ? __pfx_kthread+0x10/0x10
<4> [515.287890] ret_from_fork+0x2d7/0x310
<4> [515.287894] ? __pfx_kthread+0x10/0x10
<4> [515.287897] ret_from_fork_asm+0x1a/0x30
A flaw was found in the Linux kernel's DisplayPort Multi-Stream Transport (MST) subsystem. When a DisplayPort 2.1 monitor is disconnected, a timing issue can cause the Virtual Channel Packet Interval (VCPI) value to become zero. Subsequent operations attempting to use this zero value in a bit shift can lead to a "shift-out-of-bounds" error, potentially resulting in system instability or a denial of service.
Отчет
A shift-out-of-bounds condition in the DRM DisplayPort MST path can occur when delayed_destroy_work runs after a DP 2.1 monitor disconnect and payload vcpi becomes 0. The code then evaluates BIT(vcpi - 1), which creates a negative shift exponent and triggers UBSAN. For the CVSS the PR:N because physical hotplug triggering does not require an authenticated local user account, although it requires physical access to the display path. The issue is not network reachable and is tied to DisplayPort MST hotplug or disconnect behavior. Impact is mainly denial of service or display stack disruption, with higher availability impact only on systems where UBSAN or warning conditions can panic the kernel.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred |
Показывать по
Дополнительная информация
Статус:
EPSS
4.2 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: drm/display/dp_mst: Add protection against 0 vcpi When releasing a timeslot there is a slight chance we may end up with the wrong payload mask due to overflow if the delayed_destroy_work ends up coming into play after a DP 2.1 monitor gets disconnected which causes vcpi to become 0 then we try to make the payload = ~BIT(vcpi - 1) which is a negative shift. VCPI id should never really be 0 hence skip changing the payload mask if VCPI is 0. Otherwise it leads to <7> [515.287237] xe 0000:03:00.0: [drm:drm_dp_mst_get_port_malloc [drm_display_helper]] port ffff888126ce9000 (3) <4> [515.287267] -----------[ cut here ]----------- <3> [515.287268] UBSAN: shift-out-of-bounds in ../drivers/gpu/drm/display/drm_dp_mst_topology.c:4575:36 <3> [515.287271] shift exponent -1 is negative <4> [515.287275] CPU: 7 UID: 0 PID: 3108 Comm: kworker/u64:33 Tainted: G S U 6.17.0-rc6-lgci-xe-xe-3795-3e79699fa1b216e92+ #1 PREEMPT(voluntary) <4...
In the Linux kernel, the following vulnerability has been resolved: drm/display/dp_mst: Add protection against 0 vcpi When releasing a timeslot there is a slight chance we may end up with the wrong payload mask due to overflow if the delayed_destroy_work ends up coming into play after a DP 2.1 monitor gets disconnected which causes vcpi to become 0 then we try to make the payload = ~BIT(vcpi - 1) which is a negative shift. VCPI id should never really be 0 hence skip changing the payload mask if VCPI is 0. Otherwise it leads to <7> [515.287237] xe 0000:03:00.0: [drm:drm_dp_mst_get_port_malloc [drm_display_helper]] port ffff888126ce9000 (3) <4> [515.287267] -----------[ cut here ]----------- <3> [515.287268] UBSAN: shift-out-of-bounds in ../drivers/gpu/drm/display/drm_dp_mst_topology.c:4575:36 <3> [515.287271] shift exponent -1 is negative <4> [515.287275] CPU: 7 UID: 0 PID: 3108 Comm: kworker/u64:33 Tainted: G S U 6.17.0-rc6-lgci-xe-xe-3795-3e79699fa1b216e92+ #1 PREEMPT(voluntary) <4
In the Linux kernel, the following vulnerability has been resolved: d ...
In the Linux kernel, the following vulnerability has been resolved: drm/display/dp_mst: Add protection against 0 vcpi When releasing a timeslot there is a slight chance we may end up with the wrong payload mask due to overflow if the delayed_destroy_work ends up coming into play after a DP 2.1 monitor gets disconnected which causes vcpi to become 0 then we try to make the payload = ~BIT(vcpi - 1) which is a negative shift. VCPI id should never really be 0 hence skip changing the payload mask if VCPI is 0. Otherwise it leads to <7> [515.287237] xe 0000:03:00.0: [drm:drm_dp_mst_get_port_malloc [drm_display_helper]] port ffff888126ce9000 (3) <4> [515.287267] -----------[ cut here ]----------- <3> [515.287268] UBSAN: shift-out-of-bounds in ../drivers/gpu/drm/display/drm_dp_mst_topology.c:4575:36 <3> [515.287271] shift exponent -1 is negative <4> [515.287275] CPU: 7 UID: 0 PID: 3108 Comm: kworker/u64:33 Tainted: G S U 6.17.0-rc6-lgci-xe-xe-3795-3e79699fa1b216e92+ #1 PREEMPT(voluntary)...
EPSS
4.2 Medium
CVSS3