ghsa-8vqp-74w3-mg32
Vulnerability from github
Published
2024-10-21 15:32
Modified
2024-10-23 21:30
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Details

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

bpf: Zero former ARG_PTR_TO_{LONG,INT} args in case of error

For all non-tracing helpers which formerly had ARG_PTR_TO_{LONG,INT} as input arguments, zero the value for the case of an error as otherwise it could leak memory. For tracing, it is not needed given CAP_PERFMON can already read all kernel memory anyway hence bpf_get_func_arg() and bpf_get_func_ret() is skipped in here.

Also, the MTU helpers mtu_len pointer value is being written but also read. Technically, the MEM_UNINIT should not be there in order to always force init. Removing MEM_UNINIT needs more verifier rework though: MEM_UNINIT right now implies two things actually: i) write into memory, ii) memory does not have to be initialized. If we lift MEM_UNINIT, it then becomes: i) read into memory, ii) memory must be initialized. This means that for bpf__check_mtu() we're readding the issue we're trying to fix, that is, it would then be able to write back into things like .rodata BPF maps. Follow-up work will rework the MEM_UNINIT semantics such that the intent can be better expressed. For now just clear the mtu_len on error path which can be lifted later again.

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{
   affected: [],
   aliases: [
      "CVE-2024-47728",
   ],
   database_specific: {
      cwe_ids: [
         "CWE-459",
      ],
      github_reviewed: false,
      github_reviewed_at: null,
      nvd_published_at: "2024-10-21T13:15:02Z",
      severity: "MODERATE",
   },
   details: "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Zero former ARG_PTR_TO_{LONG,INT} args in case of error\n\nFor all non-tracing helpers which formerly had ARG_PTR_TO_{LONG,INT} as input\narguments, zero the value for the case of an error as otherwise it could leak\nmemory. For tracing, it is not needed given CAP_PERFMON can already read all\nkernel memory anyway hence bpf_get_func_arg() and bpf_get_func_ret() is skipped\nin here.\n\nAlso, the MTU helpers mtu_len pointer value is being written but also read.\nTechnically, the MEM_UNINIT should not be there in order to always force init.\nRemoving MEM_UNINIT needs more verifier rework though: MEM_UNINIT right now\nimplies two things actually: i) write into memory, ii) memory does not have\nto be initialized. If we lift MEM_UNINIT, it then becomes: i) read into memory,\nii) memory must be initialized. This means that for bpf_*_check_mtu() we're\nreadding the issue we're trying to fix, that is, it would then be able to\nwrite back into things like .rodata BPF maps. Follow-up work will rework the\nMEM_UNINIT semantics such that the intent can be better expressed. For now\njust clear the *mtu_len on error path which can be lifted later again.",
   id: "GHSA-8vqp-74w3-mg32",
   modified: "2024-10-23T21:30:28Z",
   published: "2024-10-21T15:32:26Z",
   references: [
      {
         type: "ADVISORY",
         url: "https://nvd.nist.gov/vuln/detail/CVE-2024-47728",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/4b3786a6c5397dc220b1483d8e2f4867743e966f",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/594a9f5a8d2de2573a856e506f77ba7dd2cefc6a",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/599d15b6d03356a97bff7a76155c5604c42a2962",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/8397bf78988f3ae9dbebb0200189a62a57264980",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/a634fa8e480ac2423f86311a602f6295df2c8ed0",
      },
   ],
   schema_version: "1.4.0",
   severity: [
      {
         score: "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
         type: "CVSS_V3",
      },
   ],
}


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