Cloudanix VulnDB

CVE-2021-46980

None

CVSS

—

EPSS

0.2%

Published

Feb 28, 2024

CISA due date

—

Cloudanix analysis

Monitor only SSVC: Track

A bug in the Linux kernel's handling of certain USB-C chargers can cause the computer to crash when the charger offers more power options than the code expected.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Moderate
Impact
Denial Of Service
Component
OS kernel
Class
Buffer Overflow
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

Out-of-bounds array access in ucsi_psy_get_voltage_now when an RDO object position exceeds the four PDOs fetched into the src_pdos array, triggered by PD sources advertising up to seven PDOs.

Why it matters to the business

Kernel crash and system instability on Linux devices when connected to certain USB-C power adapters that negotiate contracts using PDO indices five through seven.

How an attack unfolds

An attacker supplies a PD-capable source advertising five or more PDOs; the PPM negotiates a contract on PDO index greater than four; subsequent power-supply property queries invoke rdo_index on the undersized array, causing an out-of-bounds read and kernel panic.

How to fix it

Apply the upstream fix that performs two GET_PDOS commands to store up to seven PDOs in con->src_pdos; update to a kernel containing commit 4dbc6a4ef06d or later equivalent.

How to confirm the fix worked

Confirm kernel source contains the two-call GET_PDOS retrieval logic; test attachment of a five-PDO PD adapter and verify absence of UBSAN array-bounds or BRK exceptions in ucsi_psy_get_prop.

Typical attack path

  1. Connect a USB-C PD source advertising five or more PDOs
  2. Allow the PPM to negotiate a power contract selecting PDO index > 4
  3. Trigger power_supply_changed or uevent that calls ucsi_psy_get_prop
  4. ucsi_psy_get_voltage_now performs out-of-bounds access via rdo_index into src_pdos

How to detect it

Search kernel logs for BRK exceptions or UBSAN array-bounds violations at ucsi_psy_get_prop+0x208, power_supply_uevent, or power_supply_changed_work; correlate with USB-C PD connection events.

  • ucsi_psy_get_prop+0x208
  • Unexpected kernel BRK exception at EL1
  • Internal error: BRK handler: f2005512
  • power_supply_changed_work+0x174

What your security team should do

  • Prioritize kernel updates containing the PDO retrieval fix on all Linux systems exposing USB-C PD
  • Monitor for kernel oops or panic logs referencing ucsi_psy_get_prop
  • Limit exposure by disabling USB-C PD when feasible until patched

The record

In the Linux kernel, the following vulnerability has been resolved: usb: typec: ucsi: Retrieve all the PDOs instead of just the first 4 commit 4dbc6a4ef06d ("usb: typec: ucsi: save power data objects in PD mode") introduced retrieval of the PDOs when connected to a PD-capable source. But only the first 4 PDOs are received since that is the maximum number that can be fetched at a time given the MESSAGE_IN length limitation (16 bytes). However, as per the PD spec a connected source may advertise up to a maximum of 7 PDOs. If such a source is connected it's possible the PPM could have negotiated a power contract with one of the PDOs at index greater than 4, and would be reflected in the request data object's (RDO) object position field. This would result in an out-of-bounds access when the rdo_index() is used to index into the src_pdos array in ucsi_psy_get_voltage_now(). With the help of the UBSAN -fsanitize=array-bounds checker enabled this exact issue is revealed when connecting to a PD source adapter that advertise 5 PDOs and the PPM enters a contract having selected the 5th one. [ 151.545106][ T70] Unexpected kernel BRK exception at EL1 [ 151.545112][ T70] Internal error: BRK handler: f2005512 [#1] PREEMPT SMP ... [ 151.545499][ T70] pc : ucsi_psy_get_prop+0x208/0x20c [ 151.545507][ T70] lr : power_supply_show_property+0xc0/0x328 ... [ 151.545542][ T70] Call trace: [ 151.545544][ T70] ucsi_psy_get_prop+0x208/0x20c [ 151.545546][ T70] power_supply_uevent+0x1a4/0x2f0 [ 151.545550][ T70] dev_uevent+0x200/0x384 [ 151.545555][ T70] kobject_uevent_env+0x1d4/0x7e8 [ 151.545557][ T70] power_supply_changed_work+0x174/0x31c [ 151.545562][ T70] process_one_work+0x244/0x6f0 [ 151.545564][ T70] worker_thread+0x3e0/0xa64 We can resolve this by instead retrieving and storing up to the maximum of 7 PDOs in the con->src_pdos array. This would involve two calls to the GET_PDOS command.

Affected packages

Ecosystem Package Introduced Fixed
Debian:11 linux 0 5.10.38-1
Debian:12 linux 0 5.10.38-1
Debian:13 linux 0 5.10.38-1
SUSE:Enterprise Storage 7.1 kernel-64kb 0 5.3.18-150300.59.158.1
SUSE:Enterprise Storage 7.1 kernel-default 0 5.3.18-150300.59.158.1
SUSE:Enterprise Storage 7.1 kernel-default-base 0 5.3.18-150300.59.158.1.150300.18.92.5
SUSE:Enterprise Storage 7.1 kernel-docs 0 5.3.18-150300.59.158.1
SUSE:Enterprise Storage 7.1 kernel-obs-build 0 5.3.18-150300.59.158.1
SUSE:Enterprise Storage 7.1 kernel-preempt 0 5.3.18-150300.59.158.1
SUSE:Enterprise Storage 7.1 kernel-source 0 5.3.18-150300.59.158.1
SUSE:Enterprise Storage 7.1 kernel-syms 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise High Availability Extension 15 SP3 kernel-default 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS kernel-64kb 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS kernel-default 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS kernel-default-base 0 5.3.18-150300.59.158.1.150300.18.92.5
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS kernel-docs 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS kernel-obs-build 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS kernel-preempt 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS kernel-source 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS kernel-syms 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Live Patching 15 SP3 kernel-default 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Live Patching 15 SP3 kernel-livepatch-SLE15-SP3_Update_43 0 1-150300.7.3.5
SUSE:Linux Enterprise Micro 5.1 kernel-default 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Micro 5.1 kernel-default-base 0 5.3.18-150300.59.158.1.150300.18.92.5
SUSE:Linux Enterprise Micro 5.1 kernel-rt 0 5.3.18-150300.166.1
SUSE:Linux Enterprise Micro 5.1 kernel-source-rt 0 5.3.18-150300.166.1
SUSE:Linux Enterprise Micro 5.2 kernel-default 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Micro 5.2 kernel-default-base 0 5.3.18-150300.59.158.1.150300.18.92.5
SUSE:Linux Enterprise Micro 5.2 kernel-rt 0 5.3.18-150300.166.1
SUSE:Linux Enterprise Micro 5.2 kernel-source-rt 0 5.3.18-150300.166.1
SUSE:Linux Enterprise Server 15 SP3-LTSS kernel-64kb 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Server 15 SP3-LTSS kernel-default 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Server 15 SP3-LTSS kernel-default-base 0 5.3.18-150300.59.158.1.150300.18.92.5
SUSE:Linux Enterprise Server 15 SP3-LTSS kernel-docs 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Server 15 SP3-LTSS kernel-obs-build 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Server 15 SP3-LTSS kernel-preempt 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Server 15 SP3-LTSS kernel-source 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Server 15 SP3-LTSS kernel-syms 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Server 15 SP3-LTSS kernel-zfcpdump 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP3 kernel-default 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP3 kernel-default-base 0 5.3.18-150300.59.158.1.150300.18.92.5
SUSE:Linux Enterprise Server for SAP Applications 15 SP3 kernel-docs 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP3 kernel-obs-build 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP3 kernel-preempt 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP3 kernel-source 0 5.3.18-150300.59.158.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP3 kernel-syms 0 5.3.18-150300.59.158.1
Ubuntu:16.04:LTS linux-hwe-edge 0 No fix
Ubuntu:18.04:LTS linux-aws-5.0 0 No fix
Ubuntu:18.04:LTS linux-aws-5.3 0 No fix
Ubuntu:18.04:LTS linux-azure 0 No fix
Ubuntu:18.04:LTS linux-azure-5.3 0 No fix
Ubuntu:18.04:LTS linux-azure-edge 0 No fix
Ubuntu:18.04:LTS linux-gcp 0 No fix
Ubuntu:18.04:LTS linux-gcp-5.3 0 No fix
Ubuntu:18.04:LTS linux-gke-4.15 0 No fix
Ubuntu:18.04:LTS linux-gke-5.4 0 No fix
Ubuntu:18.04:LTS linux-gkeop-5.4 0 No fix
Ubuntu:18.04:LTS linux-hwe 0 No fix
Ubuntu:18.04:LTS linux-hwe-edge 0 No fix
Ubuntu:18.04:LTS linux-oem 0 No fix
Ubuntu:18.04:LTS linux-oracle-5.0 0 No fix
Ubuntu:18.04:LTS linux-oracle-5.3 0 No fix
Ubuntu:20.04:LTS linux 0 5.4.0-9.12
Ubuntu:20.04:LTS linux-aws 0 5.4.0-1005.5
Ubuntu:20.04:LTS linux-aws-5.11 0 No fix
Ubuntu:20.04:LTS linux-aws-5.13 0 No fix
Ubuntu:20.04:LTS linux-aws-5.15 0 5.15.0-1014.18~20.04.1
Ubuntu:20.04:LTS linux-aws-5.8 0 No fix
Ubuntu:20.04:LTS linux-azure 0 5.4.0-1006.6
Ubuntu:20.04:LTS linux-azure-5.11 0 No fix
Ubuntu:20.04:LTS linux-azure-5.13 0 No fix
Ubuntu:20.04:LTS linux-azure-5.15 0 5.15.0-1007.8~20.04.1
Ubuntu:20.04:LTS linux-azure-5.8 0 No fix
Ubuntu:20.04:LTS linux-azure-fde 0 No fix
Ubuntu:20.04:LTS linux-azure-fde-5.15 0 5.15.0-1019.24~20.04.1.1
Ubuntu:20.04:LTS linux-bluefield 0 5.4.0-1007.10
Ubuntu:20.04:LTS linux-gcp 0 5.4.0-1005.5
Ubuntu:20.04:LTS linux-gcp-5.11 0 No fix
Ubuntu:20.04:LTS linux-gcp-5.13 0 No fix
Ubuntu:20.04:LTS linux-gcp-5.15 0 5.15.0-1006.9~20.04.1
Ubuntu:20.04:LTS linux-gcp-5.8 0 No fix
Ubuntu:20.04:LTS linux-gke 0 No fix
Ubuntu:20.04:LTS linux-gke-5.15 0 No fix
Ubuntu:20.04:LTS linux-gkeop 0 5.4.0-1008.9
Ubuntu:20.04:LTS linux-gkeop-5.15 0 5.15.0-1003.5~20.04.2
Ubuntu:20.04:LTS linux-hwe-5.11 0 No fix
Ubuntu:20.04:LTS linux-hwe-5.13 0 No fix
Ubuntu:20.04:LTS linux-hwe-5.15 0 5.15.0-33.34~20.04.1
Ubuntu:20.04:LTS linux-hwe-5.8 0 No fix
Ubuntu:20.04:LTS linux-ibm 0 5.4.0-1003.4
Ubuntu:20.04:LTS linux-ibm-5.15 0 5.15.0-1033.36~20.04.1
Ubuntu:20.04:LTS linux-intel-5.13 0 No fix
Ubuntu:20.04:LTS linux-intel-iotg-5.15 0 5.15.0-1003.5~20.04.1
Ubuntu:20.04:LTS linux-iot 0 5.4.0-1001.3
Ubuntu:20.04:LTS linux-kvm 0 5.4.0-1004.4
Ubuntu:20.04:LTS linux-lowlatency-hwe-5.15 0 5.15.0-33.34~20.04.1
Ubuntu:20.04:LTS linux-oem-5.10 0 No fix
Ubuntu:20.04:LTS linux-oem-5.13 0 No fix
Ubuntu:20.04:LTS linux-oem-5.14 0 No fix
Ubuntu:20.04:LTS linux-oem-5.6 0 No fix
Ubuntu:20.04:LTS linux-oracle 0 5.4.0-1005.5
Ubuntu:20.04:LTS linux-oracle-5.11 0 No fix
Ubuntu:20.04:LTS linux-oracle-5.13 0 No fix
Ubuntu:20.04:LTS linux-oracle-5.15 0 5.15.0-1007.9~20.04.1
Ubuntu:20.04:LTS linux-oracle-5.8 0 No fix
Ubuntu:20.04:LTS linux-raspi 0 5.4.0-1007.7
Ubuntu:20.04:LTS linux-raspi2 0 No fix
Ubuntu:20.04:LTS linux-riscv 0 No fix
Ubuntu:20.04:LTS linux-riscv-5.11 0 No fix
Ubuntu:20.04:LTS linux-riscv-5.15 0 5.15.0-1015.17~20.04.1
Ubuntu:20.04:LTS linux-riscv-5.8 0 No fix
Ubuntu:20.04:LTS linux-xilinx-zynqmp 0 5.4.0-1020.24
Ubuntu:22.04:LTS linux 0 5.13.0-19.19
Ubuntu:22.04:LTS linux-allwinner-5.19 0 No fix
Ubuntu:22.04:LTS linux-aws 0 5.13.0-1005.6
Ubuntu:22.04:LTS linux-aws-5.19 0 No fix
Ubuntu:22.04:LTS linux-aws-6.2 0 No fix
Ubuntu:22.04:LTS linux-aws-6.5 0 6.5.0-1008.8~22.04.1
Ubuntu:22.04:LTS linux-azure 0 5.13.0-1006.7
Ubuntu:22.04:LTS linux-azure-5.19 0 No fix
Ubuntu:22.04:LTS linux-azure-6.2 0 No fix
Ubuntu:22.04:LTS linux-azure-6.5 0 6.5.0-1007.7~22.04.1
Ubuntu:22.04:LTS linux-azure-fde 0 5.15.0-1019.24.1
Ubuntu:22.04:LTS linux-azure-fde-5.19 0 No fix
Ubuntu:22.04:LTS linux-azure-fde-6.2 0 No fix
Ubuntu:22.04:LTS linux-gcp 0 5.13.0-1005.6
Ubuntu:22.04:LTS linux-gcp-5.19 0 No fix
Ubuntu:22.04:LTS linux-gcp-6.2 0 No fix
Ubuntu:22.04:LTS linux-gcp-6.5 0 6.5.0-1010.10~22.04.3
Ubuntu:22.04:LTS linux-gke 0 5.15.0-1002.2
Ubuntu:22.04:LTS linux-gkeop 0 5.15.0-1001.2
Ubuntu:22.04:LTS linux-hwe-5.19 0 No fix
Ubuntu:22.04:LTS linux-hwe-6.2 0 No fix
Ubuntu:22.04:LTS linux-hwe-6.5 0 6.5.0-14.14~22.04.1
Ubuntu:22.04:LTS linux-ibm 0 5.15.0-1002.2
Ubuntu:22.04:LTS linux-intel-iotg 0 5.15.0-1004.6
Ubuntu:22.04:LTS linux-kvm 0 5.13.0-1004.4
Ubuntu:22.04:LTS linux-lowlatency 0 5.15.0-22.22
Ubuntu:22.04:LTS linux-lowlatency-hwe-5.19 0 No fix
Ubuntu:22.04:LTS linux-lowlatency-hwe-6.2 0 No fix
Ubuntu:22.04:LTS linux-lowlatency-hwe-6.5 0 6.5.0-14.14.1~22.04.1
Ubuntu:22.04:LTS linux-nvidia 0 5.15.0-1005.5
Ubuntu:22.04:LTS linux-nvidia-6.2 0 No fix
Ubuntu:22.04:LTS linux-nvidia-6.5 0 6.5.0-1004.4
Ubuntu:22.04:LTS linux-nvidia-6.8 0 6.8.0-1008.8~22.04.1
Ubuntu:22.04:LTS linux-oem-5.17 0 No fix
Ubuntu:22.04:LTS linux-oem-6.0 0 No fix
Ubuntu:22.04:LTS linux-oem-6.1 0 No fix
Ubuntu:22.04:LTS linux-oem-6.5 0 6.5.0-1003.3
Ubuntu:22.04:LTS linux-oracle 0 5.13.0-1008.10
Ubuntu:22.04:LTS linux-oracle-6.5 0 6.5.0-1013.13~22.04.4
Ubuntu:22.04:LTS linux-raspi 0 5.13.0-1008.9
Ubuntu:22.04:LTS linux-riscv 0 No fix
Ubuntu:22.04:LTS linux-riscv-5.19 0 No fix
Ubuntu:22.04:LTS linux-riscv-6.5 0 6.5.0-17.17.1.1~22.04.1
Ubuntu:22.04:LTS linux-starfive-5.19 0 No fix
Ubuntu:22.04:LTS linux-starfive-6.2 0 No fix
Ubuntu:22.04:LTS linux-starfive-6.5 0 6.5.0-1007.8~22.04.1
Ubuntu:22.04:LTS linux-xilinx-zynqmp 0 5.15.0-1022.26
Ubuntu:24.04:LTS linux 0 6.5.0-9.9
Ubuntu:24.04:LTS linux-aws 0 6.5.0-1008.8
Ubuntu:24.04:LTS linux-azure 0 6.5.0-1007.7
Ubuntu:24.04:LTS linux-gcp 0 6.5.0-1007.7
Ubuntu:24.04:LTS linux-gke 0 6.8.0-1003.5
Ubuntu:24.04:LTS linux-gkeop 0 6.8.0-1001.3
Ubuntu:24.04:LTS linux-ibm 0 6.5.0-1009.9
Ubuntu:24.04:LTS linux-lowlatency 0 6.5.0-9.9.1
Ubuntu:24.04:LTS linux-nvidia 0 6.8.0-1007.7
Ubuntu:24.04:LTS linux-nvidia-lowlatency 0 6.8.0-1009.9.1
Ubuntu:24.04:LTS linux-oem-6.8 0 6.8.0-1003.3
Ubuntu:24.04:LTS linux-oracle 0 6.5.0-1010.10
Ubuntu:24.04:LTS linux-raspi 0 6.5.0-1005.7
Ubuntu:24.04:LTS linux-riscv 0 6.5.0-9.9.1
Ubuntu:Pro:16.04:LTS linux-hwe-edge 0 No fix
Ubuntu:Pro:18.04:LTS linux-aws-5.0 0 No fix
Ubuntu:Pro:18.04:LTS linux-aws-5.3 0 No fix
Ubuntu:Pro:18.04:LTS linux-azure 0 No fix
Ubuntu:Pro:18.04:LTS linux-azure-5.3 0 No fix
Ubuntu:Pro:18.04:LTS linux-azure-edge 0 No fix
Ubuntu:Pro:18.04:LTS linux-gcp 0 No fix
Ubuntu:Pro:18.04:LTS linux-gcp-5.3 0 No fix
Ubuntu:Pro:18.04:LTS linux-gke-4.15 0 No fix
Ubuntu:Pro:18.04:LTS linux-gke-5.4 0 No fix
Ubuntu:Pro:18.04:LTS linux-gkeop-5.4 0 No fix
Ubuntu:Pro:18.04:LTS linux-hwe 0 No fix
Ubuntu:Pro:18.04:LTS linux-hwe-edge 0 No fix
Ubuntu:Pro:18.04:LTS linux-oem 0 No fix
Ubuntu:Pro:18.04:LTS linux-oracle-5.0 0 No fix
Ubuntu:Pro:18.04:LTS linux-oracle-5.3 0 No fix
Ubuntu:Pro:20.04:LTS linux-aws-5.11 0 No fix
Ubuntu:Pro:20.04:LTS linux-aws-5.13 0 No fix
Ubuntu:Pro:20.04:LTS linux-aws-5.8 0 No fix
Ubuntu:Pro:20.04:LTS linux-azure-5.11 0 No fix
Ubuntu:Pro:20.04:LTS linux-azure-5.13 0 No fix
Ubuntu:Pro:20.04:LTS linux-azure-5.8 0 No fix
Ubuntu:Pro:20.04:LTS linux-azure-fde 0 No fix
Ubuntu:Pro:20.04:LTS linux-gcp-5.11 0 No fix
Ubuntu:Pro:20.04:LTS linux-gcp-5.13 0 No fix
Ubuntu:Pro:20.04:LTS linux-gcp-5.8 0 No fix
Ubuntu:Pro:20.04:LTS linux-gke 0 No fix

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