CVE-2021-47276 ftrace: Do not blindly read the ip address in ftrace_bug()

2024-05-2114:20:04

Linux

github.com

linux kernel

vulnerability

ftrace_bug

6.6 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

13.1%

JSON

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

ftrace: Do not blindly read the ip address in ftrace_bug()

It was reported that a bug on arm64 caused a bad ip address to be used for
updating into a nop in ftrace_init(), but the error path (rightfully)
returned -EINVAL and not -EFAULT, as the bug caused more than one error to
occur. But because -EINVAL was returned, the ftrace_bug() tried to report
what was at the location of the ip address, and read it directly. This
caused the machine to panic, as the ip was not pointing to a valid memory
address.

Instead, read the ip address with copy_from_kernel_nofault() to safely
access the memory, and if it faults, report that the address faulted,
otherwise report what was in that location.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "kernel/trace/ftrace.c"
    ],
    "versions": [
      {
        "version": "05736a427f7e",
        "lessThan": "0bc62e398bbd",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "05736a427f7e",
        "lessThan": "4aedc2bc2b32",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "05736a427f7e",
        "lessThan": "acf671ba79c1",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "05736a427f7e",
        "lessThan": "862dcc14f280",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "05736a427f7e",
        "lessThan": "7e4e824b109f",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "05736a427f7e",
        "lessThan": "97524384762c",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "05736a427f7e",
        "lessThan": "3e4ddeb68751",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "05736a427f7e",
        "lessThan": "6c14133d2d3f",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "kernel/trace/ftrace.c"
    ],
    "versions": [
      {
        "version": "2.6.28",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "2.6.28",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.4.273",
        "lessThanOrEqual": "4.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.9.273",
        "lessThanOrEqual": "4.9.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.14.237",
        "lessThanOrEqual": "4.14.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.19.195",
        "lessThanOrEqual": "4.19.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.126",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.44",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.12.11",
        "lessThanOrEqual": "5.12.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.13",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]