CVE-2024-46693 soc: qcom: pmic_glink: Fix race during initialization

2024-09-1305:29:22

Linux

www.cve.org

linux kernel

vulnerability resolved

stephen boyd

pmic_glink child drivers

null pointer dereference

timeline

protection domain registry

commit related.

EPSS

Percentile

5.1%

JSON

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

soc: qcom: pmic_glink: Fix race during initialization

As pointed out by Stephen Boyd it is possible that during initialization
of the pmic_glink child drivers, the protection-domain notifiers fires,
and the associated work is scheduled, before the client registration
returns and as a result the local “client” pointer has been initialized.

The outcome of this is a NULL pointer dereference as the “client”
pointer is blindly dereferenced.

Timeline provided by Stephen:
CPU0 CPU1

ucsi->client = NULL;
devm_pmic_glink_register_client()
client->pdr_notify(client->priv, pg->client_state)
pmic_glink_ucsi_pdr_notify()
schedule_work(&ucsi->register_work)
<schedule away>
pmic_glink_ucsi_register()
ucsi_register()
pmic_glink_ucsi_read_version()
pmic_glink_ucsi_read()
pmic_glink_ucsi_read()
pmic_glink_send(ucsi->client)
<client is NULL BAD>
ucsi->client = client // Too late!

This code is identical across the altmode, battery manager and usci
child drivers.

Resolve this by splitting the allocation of the “client” object and the
registration thereof into two operations.

This only happens if the protection domain registry is populated at the
time of registration, which by the introduction of commit ‘1ebcde047c54
(“soc: qcom: add pd-mapper implementation”)’ became much more likely.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/power/supply/qcom_battmgr.c",
      "drivers/soc/qcom/pmic_glink.c",
      "drivers/soc/qcom/pmic_glink_altmode.c",
      "drivers/usb/typec/ucsi/ucsi_glink.c",
      "include/linux/soc/qcom/pmic_glink.h"
    ],
    "versions": [
      {
        "version": "58ef4ece1e41",
        "lessThan": "1efdbf5323c9",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "58ef4ece1e41",
        "lessThan": "943b0e7cc646",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "58ef4ece1e41",
        "lessThan": "3568affcddd6",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/power/supply/qcom_battmgr.c",
      "drivers/soc/qcom/pmic_glink.c",
      "drivers/soc/qcom/pmic_glink_altmode.c",
      "drivers/usb/typec/ucsi/ucsi_glink.c",
      "include/linux/soc/qcom/pmic_glink.h"
    ],
    "versions": [
      {
        "version": "6.3",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "6.3",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.49",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.10.8",
        "lessThanOrEqual": "6.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.11",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]