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CVE-2024-46813
drm/amd/display: Check link_index before accessing dc->links[]
Published 2024-09-27 (2 years ago) by the Linux kernel CNA. Subsystem drivers/gpu. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2024-46813 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | fixed | 6.10.9-1 | Update the kernel and reboot. Fixed in 6.10.9-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 6.10.9-1 | Update the kernel and reboot. Fixed in 6.10.9-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 6.10.9-1 | Update the kernel and reboot. Fixed in 6.10.9-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
[WHY & HOW] dc->links[] has max size of MAX_LINKS and NULL is return when trying to access with out-of-bound index. This fixes 3 OVERRUN and 1 RESOURCE_LEAK issues reported by Coverity.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
drivers/gpu/drm/amd/display/dc/core/dc_link_exports.c
- What this is
- AMD DISPLAY COREMAINTAINERS section matched on drivers/gpu/drm/amd/display/ · amd-gfx@lists.freedesktop.org · Supported
Show whether Debian builds this, per release
Not established. This site could not find the build rule for the affected file in the kernel trees Debian ships, so it has no answer about whether Debian compiles this code. Read that as unknown, never as absent.
- bookworm, trixie, forky, sid?
- ?
- not established - no Makefile entry for the affected file
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS
Signals
- Published
- 2024-09-27 (2 years ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.26%, higher than 15.9% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/gpu
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 4.15 | 6.6.87 | 032c5407a608 |
| 4.15 | 6.10.9 | ac04759b4a00 |
| 4.15 | 6.11 | 8aa2864044b9 |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The vulnerable code is in the amdgpu DC display driver, reached during local driver probe and subsequently exercised through the local DRM device node (/dev/dri/card*) via atomic ioctl HDCP operations. There is no network-facing path to dc_get_link_at_index().
- AC:LAttack complexity, low
- On an affected platform (DCN3.1-class hardware with 4 USB4 DPIA links plus a VBIOS reporting enough connector indices to push link_count past MAX_LINKS) the out-of-bounds access occurs deterministically on every driver load, and the subsequent use of the corrupted ddc.handle is reached reliably by enabling HDCP. No unpredictable memory-layout or timing condition must be won.
- PR:LPrivileges required, low
- The out-of-bounds read and type-confused write occur during unprivileged driver initialization, and the corrupted HDCP DDC handle is subsequently dereferenced through the Content Protection connector property, which a local user with access to /dev/dri can set via the DRM atomic ioctl. No root or CAP_SYS_ADMIN is required.
- UI:NUser interaction, none
- The out-of-bounds indexing happens automatically at driver probe with no victim action, and the follow-on HDCP DDC path is driven entirely by the attacker's own DRM ioctls.
- S:UScope, unchanged
- The out-of-bounds access and the resulting corruption are confined to kernel memory within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.
- C:HConfidentiality impact, high
- The out-of-bounds read pulls adjacent struct dc members (link_srv, current_state, res_pool, clk_mgr) and treats them as a struct dc_link, so subsequent field reads and the HDCP DDC read_dpcd/read_i2c calls interpret arbitrary kernel memory as link state, and the resulting memory corruption can be leveraged for further information disclosure.
- I:HIntegrity impact, high
- The type-confused pointer is written through (link->priv = aconnector, link->psr_settings.* = ...), corrupting a live kernel object such as struct link_service or dc_state that contains function pointers, giving a memory-corruption primitive exploitable for control-flow hijacking.
- A:HAvailability impact, high
- Dereferencing an out-of-bounds pointer read as a struct dc_link, and corrupting adjacent live kernel structures, reliably produces a kernel oops/panic and leaves the display subsystem in an inconsistent state.