{
  "id": "CVE-2024-26712",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2024-04-03T15:15:53.590",
  "lastModified": "2024-11-21T09:02:53.947",
  "vulnStatus": "Awaiting Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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 & 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 & PAGE_MASK; k_cur < 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."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: powerpc/kasan: corrige el error de direcci\u00f3n causado por la alineaci\u00f3n de la p\u00e1gina En kasan_init_region, cuando k_start no est\u00e1 alineado con la p\u00e1gina, al comienzo del bucle for, k_cur = k_start y PAGE_MASK es menor que k_start. y luego `va = block + k_cur - k_start` es menor que block, la direcci\u00f3n va no es v\u00e1lida, porque memblock_alloc no asigna el espacio de direcciones de memoria de va al bloque, que no ser\u00e1 reservado por memblock_reserve m\u00e1s adelante, se utilizar\u00e1 por otros lugares. Como resultado, se produce una sobrescritura de la memoria. por ejemplo: 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 &amp; PAGE_MASK; k_cur &lt; k_end; k_cur += PAGE_SIZE) { /* al comienzo del bucle for * block(dcd97000) va(dcd96c00) k_cur(feef7000) k_start(feef7400) * va (dcd96c00) es menor que block(dcd97000), va no es v\u00e1lido */ void *va = block + k_cur - k_start; [...] } [...] } Por lo tanto, la alineaci\u00f3n de la p\u00e1gina se realiza en k_start antes de memblock_alloc() para garantizar la validez de la direcci\u00f3n VA."
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 4.4,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "HIGH",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 0.8,
        "impactScore": 3.6
      }
    ]
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0516c06b19dc64807c10e01bb99b552bdf2d7dbe",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/0c09912dd8387e228afcc5e34ac5d79b1e3a1058",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/230e89b5ad0a33f530a2a976b3e5e4385cb27882",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2738e0aa2fb24a7ab9c878d912dc2b239738c6c6",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4a7aee96200ad281a5cc4cf5c7a2e2a49d2b97b0",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/70ef2ba1f4286b2b73675aeb424b590c92d57b25",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/0516c06b19dc64807c10e01bb99b552bdf2d7dbe",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/0c09912dd8387e228afcc5e34ac5d79b1e3a1058",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/230e89b5ad0a33f530a2a976b3e5e4385cb27882",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/2738e0aa2fb24a7ab9c878d912dc2b239738c6c6",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/4a7aee96200ad281a5cc4cf5c7a2e2a49d2b97b0",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/70ef2ba1f4286b2b73675aeb424b590c92d57b25",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ]
}