Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
drm/i915/sseu: fix max_subslices array-index-out-of-bounds access
It seems that commit bc3c5e0809ae (“drm/i915/sseu: Don’t try to store EU mask internally in UAPI format”) exposed a potential out-of-bounds access, reported by UBSAN as following on a laptop with a gen 11 i915 card:
UBSAN: array-index-out-of-bounds in drivers/gpu/drm/i915/gt/intel_sseu.c:65:27
index 6 is out of range for type ‘u16 [6]’
CPU: 2 PID: 165 Comm: systemd-udevd Not tainted 6.2.0-9-generic #9-Ubuntu
Hardware name: Dell Inc. XPS 13 9300/077Y9N, BIOS 1.11.0 03/22/2022
Call Trace:
According to the definition of sseu_dev_info, eu_mask->hsw is limited to a maximum of GEN_MAX_SS_PER_HSW_SLICE (6) sub-slices, but gen11_sseu_info_init() can potentially set 8 sub-slices, in the !IS_JSL_EHL(gt->i915) case.
Fix this by reserving up to 8 slots for max_subslices in the eu_mask struct.
(cherry picked from commit 3cba09a6ac86ea1d456909626eb2685596c07822)
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 8.4 ELS , CentOS 8.5 ELS
- Affected packages:
- kernel @ 5.14.0 (+2 more)
In the Linux kernel, the following vulnerability has been resolved:
drm/i915/sseu: fix max_subslices array-index-out-of-bounds access
It seems that commit bc3c5e0809ae (“drm/i915/sseu: Don’t try to store EU mask internally in UAPI format”) exposed a potential out-of-bounds access, reported by UBSAN as following on a laptop with a gen 11 i915 card:
UBSAN: array-index-out-of-bounds in drivers/gpu/drm/i915/gt/intel_sseu.c:65:27
index 6 is out of range for type ‘u16 [6]’
CPU: 2 PID: 165 Comm: systemd-udevd Not tainted 6.2.0-9-generic #9-Ubuntu
Hardware name: Dell Inc. XPS 13 9300/077Y9N, BIOS 1.11.0 03/22/2022
Call Trace:
According to the definition of sseu_dev_info, eu_mask->hsw is limited to a maximum of GEN_MAX_SS_PER_HSW_SLICE (6) sub-slices, but gen11_sseu_info_init() can potentially set 8 sub-slices, in the !IS_JSL_EHL(gt->i915) case.
Fix this by reserving up to 8 slots for max_subslices in the eu_mask struct.
(cherry picked from commit 3cba09a6ac86ea1d456909626eb2685596c07822)