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GHSA-8VCH-C6PW-5CHH

Vulnerability from github – Published: 2024-04-03 15:30 – Updated: 2024-11-05 18:31
VLAI
Details

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

powerpc/kasan: Fix addr error caused by page alignment

In kasan_init_region, when k_start is not page aligned, at the begin of for loop, k_cur = k_start & PAGE_MASK is less than k_start, and then va = block + k_cur - k_start is less than block, the addr va is invalid, because the memory address space from va to block is not alloced by memblock_alloc, which will not be reserved by memblock_reserve later, it will be used by other places.

As a result, memory overwriting occurs.

for example: int __init __weak kasan_init_region(void start, size_t size) { [...] / if say block(dcd97000) k_start(feef7400) k_end(feeff3fe) / block = memblock_alloc(k_end - k_start, PAGE_SIZE); [...] for (k_cur = k_start & PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) { / at the begin of for loop * block(dcd97000) va(dcd96c00) k_cur(feef7000) k_start(feef7400) * va(dcd96c00) is less than block(dcd97000), va is invalid / void va = block + k_cur - k_start; [...] } [...] }

Therefore, page alignment is performed on k_start before memblock_alloc() to ensure the validity of the VA address.

Severity
4.4 (Medium)
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2024-26712"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-04-03T15:15:53Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/kasan: Fix addr error caused by page alignment\n\nIn kasan_init_region, when k_start is not page aligned, at the begin of\nfor loop, k_cur = k_start \u0026 PAGE_MASK is less than k_start, and then\n`va = block + k_cur - k_start` is less than block, the addr va is invalid,\nbecause the memory address space from va to block is not alloced by\nmemblock_alloc, which will not be reserved by memblock_reserve later, it\nwill be used by other places.\n\nAs a result, memory overwriting occurs.\n\nfor example:\nint __init __weak kasan_init_region(void *start, size_t size)\n{\n[...]\n\t/* if say block(dcd97000) k_start(feef7400) k_end(feeff3fe) */\n\tblock = memblock_alloc(k_end - k_start, PAGE_SIZE);\n\t[...]\n\tfor (k_cur = k_start \u0026 PAGE_MASK; k_cur \u003c k_end; k_cur += PAGE_SIZE) {\n\t\t/* at the begin of for loop\n\t\t * block(dcd97000) va(dcd96c00) k_cur(feef7000) k_start(feef7400)\n\t\t * va(dcd96c00) is less than block(dcd97000), va is invalid\n\t\t */\n\t\tvoid *va = block + k_cur - k_start;\n\t\t[...]\n\t}\n[...]\n}\n\nTherefore, page alignment is performed on k_start before\nmemblock_alloc() to ensure the validity of the VA address.",
  "id": "GHSA-8vch-c6pw-5chh",
  "modified": "2024-11-05T18:31:58Z",
  "published": "2024-04-03T15:30:43Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26712"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0516c06b19dc64807c10e01bb99b552bdf2d7dbe"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0c09912dd8387e228afcc5e34ac5d79b1e3a1058"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/230e89b5ad0a33f530a2a976b3e5e4385cb27882"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2738e0aa2fb24a7ab9c878d912dc2b239738c6c6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4a7aee96200ad281a5cc4cf5c7a2e2a49d2b97b0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/70ef2ba1f4286b2b73675aeb424b590c92d57b25"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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