CVE-2022-48929 bpf: Fix crash due to out of bounds access into reg2btf_ids.

2024-08-2203:31:22

Linux

www.cve.org

linux kernel

vulnerability

bpf

crash

out of bounds access

reg2btf_ids

kfunc support

verifier

reg type

btf_vmlinux

btf id

kernel function

type flag composition

kernel crash

EPSS

Percentile

5.0%

JSON

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

bpf: Fix crash due to out of bounds access into reg2btf_ids.

When commit e6ac2450d6de (“bpf: Support bpf program calling kernel function”) added
kfunc support, it defined reg2btf_ids as a cheap way to translate the verifier
reg type to the appropriate btf_vmlinux BTF ID, however
commit c25b2ae13603 (“bpf: Replace PTR_TO_XXX_OR_NULL with PTR_TO_XXX | PTR_MAYBE_NULL”)
moved the __BPF_REG_TYPE_MAX from the last member of bpf_reg_type enum to after
the base register types, and defined other variants using type flag
composition. However, now, the direct usage of reg->type to index into
reg2btf_ids may no longer fall into __BPF_REG_TYPE_MAX range, and hence lead to
out of bounds access and kernel crash on dereference of bad pointer.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "kernel/bpf/btf.c"
    ],
    "versions": [
      {
        "version": "e8efe8369944",
        "lessThan": "8c39925e98d4",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "931e56be527f",
        "lessThan": "f0ce1bc9e023",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c25b2ae13603",
        "lessThan": "45ce4b4f9009",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "kernel/bpf/btf.c"
    ],
    "versions": [
      {
        "version": "5.15.15",
        "lessThan": "5.15.37",
        "status": "affected",
        "versionType": "custom"
      },
      {
        "version": "5.16.1",
        "lessThan": "5.16.12",
        "status": "affected",
        "versionType": "custom"
      }
    ]
  }
]