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CVE-2024-49869

Estado: AnalizadaAlta (7.8)—

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

btrfs: send: fix buffer overflow detection when copying path to cache entry

Starting with commit c0247d289e73 ("btrfs: send: annotate struct name_cache_entry with __counted_by()") we annotated the variable length array "name" from the name_cache_entry structure with __counted_by() to improve overflow detection. However that alone was not correct, because the length of that array does not match the "name_len" field - it matches that plus 1 to include the NUL string terminator, so that makes a fortified kernel think there's an overflow and report a splat like this:

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Fix this by not storing the NUL string terminator since we don't actually need it for name cache entries, this way "name_len" corresponds to the actual size of the "name" array. This requires marking the "name" array field with __nonstring and using memcpy() instead of strcpy() as recommended by the guidelines at:

Detalles técnicos trazas, registros y código del informe original
  strcpy: detected buffer overflow: 20 byte write of buffer size 19
  WARNING: CPU: 3 PID: 3310 at __fortify_report+0x45/0x50
  CPU: 3 UID: 0 PID: 3310 Comm: btrfs Not tainted 6.11.0-prnet #1
  Hardware name: CompuLab Ltd.  sbc-ihsw/Intense-PC2 (IPC2), BIOS IPC2_3.330.7 X64 03/15/2018
  RIP: 0010:__fortify_report+0x45/0x50
  Code: 48 8b 34 (...)
  RSP: 0018:ffff97ebc0d6f650 EFLAGS: 00010246
  RAX: 7749924ef60fa600 RBX: ffff8bf5446a521a RCX: 0000000000000027
  RDX: 00000000ffffdfff RSI: ffff97ebc0d6f548 RDI: ffff8bf84e7a1cc8
  RBP: ffff8bf548574080 R08: ffffffffa8c40e10 R09: 0000000000005ffd
  R10: 0000000000000004 R11: ffffffffa8c70e10 R12: ffff8bf551eef400
  R13: 0000000000000000 R14: 0000000000000013 R15: 00000000000003a8
  FS:  00007fae144de8c0(0000) GS:ffff8bf84e780000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007fae14691690 CR3: 00000001027a2003 CR4: 00000000001706f0
  Call Trace:
   <TASK>
   ? __warn+0x12a/0x1d0
   ? __fortify_report+0x45/0x50
   ? report_bug+0x154/0x1c0
   ? handle_bug+0x42/0x70
   ? exc_invalid_op+0x1a/0x50
   ? asm_exc_invalid_op+0x1a/0x20
   ? __fortify_report+0x45/0x50
   __fortify_panic+0x9/0x10
  __get_cur_name_and_parent+0x3bc/0x3c0
   get_cur_path+0x207/0x3b0
   send_extent_data+0x709/0x10d0
   ? find_parent_nodes+0x22df/0x25d0
   ? mas_nomem+0x13/0x90
   ? mtree_insert_range+0xa5/0x110
   ? btrfs_lru_cache_store+0x5f/0x1e0
   ? iterate_extent_inodes+0x52d/0x5a0
   process_extent+0xa96/0x11a0
   ? __pfx_lookup_backref_cache+0x10/0x10
   ? __pfx_store_backref_cache+0x10/0x10
   ? __pfx_iterate_backrefs+0x10/0x10
   ? __pfx_check_extent_item+0x10/0x10
   changed_cb+0x6fa/0x930
   ? tree_advance+0x362/0x390
   ? memcmp_extent_buffer+0xd7/0x160
   send_subvol+0xf0a/0x1520
   btrfs_ioctl_send+0x106b/0x11d0
   ? __pfx___clone_root_cmp_sort+0x10/0x10
   _btrfs_ioctl_send+0x1ac/0x240
   btrfs_ioctl+0x75b/0x850
   __se_sys_ioctl+0xca/0x150
   do_syscall_64+0x85/0x160
   ? __count_memcg_events+0x69/0x100
   ? handle_mm_fault+0x1327/0x15c0
   ? __se_sys_rt_sigprocmask+0xf1/0x180
   ? syscall_exit_to_user_mode+0x75/0xa0
   ? do_syscall_64+0x91/0x160
   ? do_user_addr_fault+0x21d/0x630
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
  RIP: 0033:0x7fae145eeb4f
  Code: 00 48 89 (...)
  RSP: 002b:00007ffdf1cb09b0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fae145eeb4f
  RDX: 00007ffdf1cb0ad0 RSI: 0000000040489426 RDI: 0000000000000004
  RBP: 00000000000078fe R08: 00007fae144006c0 R09: 00007ffdf1cb0927
  R10: 0000000000000008 R11: 0000000000000246 R12: 00007ffdf1cb1ce8
  R13: 0000000000000003 R14: 000055c499fab2e0 R15: 0000000000000004
   </TASK>

   https://github.com/KSPP/linux/issues/90

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

CWE-120 (buffer overflow) en código de kernel local (AV:L, PR:L) sin UI. Aunque el problema es una verificación de desbordamiento, la vulnerabilidad subyacente permitiría escalada local.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Tecnologías afectadas (1)

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2024-49869",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2024-49869",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2024-10-22T13:47:11.699189Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "c0247d289e73e18f6ddb0895de30c09770fbed95",
              "lessThan": "843738ede6cb8b959fb22591fcbabe8b456d7216",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c0247d289e73e18f6ddb0895de30c09770fbed95",
              "lessThan": "96c6ca71572a3556ed0c37237305657ff47174b7",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/btrfs/send.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.11",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.11.3",
              "versionType": "semver",
              "lessThanOrEqual": "6.11.*"
            },
            {
              "status": "unaffected",
              "version": "6.12",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/btrfs/send.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2024-10-21T18:15:08.340",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/843738ede6cb8b959fb22591fcbabe8b456d7216",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/96c6ca71572a3556ed0c37237305657ff47174b7",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-120"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: send: fix buffer overflow detection when copying path to cache entry\n\nStarting with commit c0247d289e73 (\"btrfs: send: annotate struct\nname_cache_entry with __counted_by()\") we annotated the variable length\narray \"name\" from the name_cache_entry structure with __counted_by() to\nimprove overflow detection. However that alone was not correct, because\nthe length of that array does not match the \"name_len\" field - it matches\nthat plus 1 to include the NUL string terminator, so that makes a\nfortified kernel think there's an overflow and report a splat like this:\n\n  strcpy: detected buffer overflow: 20 byte write of buffer size 19\n  WARNING: CPU: 3 PID: 3310 at __fortify_report+0x45/0x50\n  CPU: 3 UID: 0 PID: 3310 Comm: btrfs Not tainted 6.11.0-prnet #1\n  Hardware name: CompuLab Ltd.  sbc-ihsw/Intense-PC2 (IPC2), BIOS IPC2_3.330.7 X64 03/15/2018\n  RIP: 0010:__fortify_report+0x45/0x50\n  Code: 48 8b 34 (...)\n  RSP: 0018:ffff97ebc0d6f650 EFLAGS: 00010246\n  RAX: 7749924ef60fa600 RBX: ffff8bf5446a521a RCX: 0000000000000027\n  RDX: 00000000ffffdfff RSI: ffff97ebc0d6f548 RDI: ffff8bf84e7a1cc8\n  RBP: ffff8bf548574080 R08: ffffffffa8c40e10 R09: 0000000000005ffd\n  R10: 0000000000000004 R11: ffffffffa8c70e10 R12: ffff8bf551eef400\n  R13: 0000000000000000 R14: 0000000000000013 R15: 00000000000003a8\n  FS:  00007fae144de8c0(0000) GS:ffff8bf84e780000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 00007fae14691690 CR3: 00000001027a2003 CR4: 00000000001706f0\n  Call Trace:\n   <TASK>\n   ? __warn+0x12a/0x1d0\n   ? __fortify_report+0x45/0x50\n   ? report_bug+0x154/0x1c0\n   ? handle_bug+0x42/0x70\n   ? exc_invalid_op+0x1a/0x50\n   ? asm_exc_invalid_op+0x1a/0x20\n   ? __fortify_report+0x45/0x50\n   __fortify_panic+0x9/0x10\n  __get_cur_name_and_parent+0x3bc/0x3c0\n   get_cur_path+0x207/0x3b0\n   send_extent_data+0x709/0x10d0\n   ? find_parent_nodes+0x22df/0x25d0\n   ? mas_nomem+0x13/0x90\n   ? mtree_insert_range+0xa5/0x110\n   ? btrfs_lru_cache_store+0x5f/0x1e0\n   ? iterate_extent_inodes+0x52d/0x5a0\n   process_extent+0xa96/0x11a0\n   ? __pfx_lookup_backref_cache+0x10/0x10\n   ? __pfx_store_backref_cache+0x10/0x10\n   ? __pfx_iterate_backrefs+0x10/0x10\n   ? __pfx_check_extent_item+0x10/0x10\n   changed_cb+0x6fa/0x930\n   ? tree_advance+0x362/0x390\n   ? memcmp_extent_buffer+0xd7/0x160\n   send_subvol+0xf0a/0x1520\n   btrfs_ioctl_send+0x106b/0x11d0\n   ? __pfx___clone_root_cmp_sort+0x10/0x10\n   _btrfs_ioctl_send+0x1ac/0x240\n   btrfs_ioctl+0x75b/0x850\n   __se_sys_ioctl+0xca/0x150\n   do_syscall_64+0x85/0x160\n   ? __count_memcg_events+0x69/0x100\n   ? handle_mm_fault+0x1327/0x15c0\n   ? __se_sys_rt_sigprocmask+0xf1/0x180\n   ? syscall_exit_to_user_mode+0x75/0xa0\n   ? do_syscall_64+0x91/0x160\n   ? do_user_addr_fault+0x21d/0x630\n  entry_SYSCALL_64_after_hwframe+0x76/0x7e\n  RIP: 0033:0x7fae145eeb4f\n  Code: 00 48 89 (...)\n  RSP: 002b:00007ffdf1cb09b0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010\n  RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fae145eeb4f\n  RDX: 00007ffdf1cb0ad0 RSI: 0000000040489426 RDI: 0000000000000004\n  RBP: 00000000000078fe R08: 00007fae144006c0 R09: 00007ffdf1cb0927\n  R10: 0000000000000008 R11: 0000000000000246 R12: 00007ffdf1cb1ce8\n  R13: 0000000000000003 R14: 000055c499fab2e0 R15: 0000000000000004\n   </TASK>\n\nFix this by not storing the NUL string terminator since we don't actually\nneed it for name cache entries, this way \"name_len\" corresponds to the\nactual size of the \"name\" array. This requires marking the \"name\" array\nfield with __nonstring and using memcpy() instead of strcpy() as\nrecommended by the guidelines at:\n\n   https://github.com/KSPP/linux/issues/90"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: btrfs: send: corrige la detección de desbordamiento de búfer al copiar la ruta a la entrada de caché A partir de el commit c0247d289e73 (\"btrfs: send: annotate struct name_cache_entry with __counted_by()\"), anotamos la matriz de longitud variable \"name\" de la estructura name_cache_entry con __counted_by() para mejorar la detección de desbordamiento. Sin embargo, eso solo no era correcto, porque la longitud de esa matriz no coincide con el campo \"name_len\" - coincide con eso más 1 para incluir el terminador de cadena NUL, por lo que hace que un kernel fortificado piense que hay un desbordamiento e informe un splat como este: strcpy: desbordamiento de búfer detectado: escritura de 20 bytes de tamaño de búfer 19 ADVERTENCIA: CPU: 3 PID: 3310 en __fortify_report+0x45/0x50 CPU: 3 UID: 0 PID: 3310 Comm: btrfs No contaminado 6.11.0-prnet #1 Nombre del hardware: CompuLab Ltd. sbc-ihsw/Intense-PC2 (IPC2), BIOS IPC2_3.330.7 X64 15/03/2018 RIP: 0010:__fortify_report+0x45/0x50 Código: 48 8b 34 (...) RSP: 0018:ffff97ebc0d6f650 EFLAGS: 00010246 RAX: 7749924ef60fa600 RBX: ffff8bf5446a521a RCX: 0000000000000027 RDX: 00000000ffffdfff RSI: ffff97ebc0d6f548 RDI: ffff8bf84e7a1cc8 RBP: ffff8bf548574080 R08: ffffffffa8c40e10 R09: 0000000000005ffd R10: 0000000000000004 R11: ffffffffa8c70e10 R12: ffff8bf551eef400 R13: 0000000000000000 R14: 0000000000000013 R15: 000000000000003a8 FS: 00007fae144de8c0(0000) GS:ffff8bf84e780000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fae14691690 CR3: 00000001027a2003 CR4: 00000000001706f0 Seguimiento de llamadas:  ? __warn+0x12a/0x1d0 ? __fortify_report+0x45/0x50 ? report_bug+0x154/0x1c0 ? handle_bug+0x42/0x70 ? exc_invalid_op+0x1a/0x50 ? asm_exc_invalid_op+0x1a/0x20 ? __fortify_report+0x45/0x50 __fortify_panic+0x9/0x10 __get_cur_name_and_parent_+0x3bc/0x3c0 get_cur_path+0x207/0x3b0 send_extent_data+0x709/0x10d0 ? find_parent_nodes+0x22df/0x25d0 ? mas_nomem+0x13/0x90 ? mtree_insert_range+0xa5/0x110 ? btrfs_lru_cache_store+0x5f/0x1e0 ? iterate_extent_inodes+0x52d/0x5a0 process_extent+0xa96/0x11a0 ? __pfx_lookup_backref_cache+0x10/0x10 ? __pfx_store_backref_cache+0x10/0x10 ? __pfx_iterate_backrefs+0x10/0x10 ? __pfx_check_extent_item+0x10/0x10 changed_cb+0x6fa/0x930 ? tree_advance+0x362/0x390 ? __pfx___clone_root_cmp_sort+0x10/0x10 _btrfs_ioctl_send+0x1ac/0x240 btrfs_ioctl+0x75b/0x850 __se_sys_ioctl+0xca/0x150 do_syscall_64+0x85/0x160 ? __count_memcg_events+0x69/0x100 ? handle_mm_fault+0x1327/0x15c0 ? __se_sys_rt_sigprocmask+0xf1/0x180 ? syscall_exit_to_user_mode+0x75/0xa0 ? do_syscall_64+0x91/0x160 ? do_user_addr_fault+0x21d/0x630 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7fae145eeb4f Código: 00 48 89 (...) RSP: 002b:00007ffdf1cb09b0 EFLAGS: 00000246 ORIG_RAX: 000000000000010 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fae145eeb4f RDX: 00007ffdf1cb0ad0 RSI: 0000000040489426 RDI: 0000000000000004 RBP: 00000000000078fe R08: 00007fae144006c0 R09: 00007ffdf1cb0927 R10: 0000000000000008 R11: 0000000000000246 R12: 00007ffdf1cb1ce8 R13: 000000000000003 R14: 000055c499fab2e0 R15: 000000000000004  Solucione esto al no almacenar el terminador de cadena NUL ya que en realidad no lo necesitamos para las entradas de caché de nombres, de esta manera \"name_len\" corresponde al tamaño real de la matriz \"name\". Esto requiere marcar el campo de matriz \"nombre\" con __nonstring y usar memcpy() en lugar de strcpy() como lo recomiendan las pautas en: https://github.com/KSPP/linux/issues/90"
    }
  ],
  "lastModified": "2026-06-17T08:00:37.350",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "54D9C704-D679-41A7-9C40-10A6B1E7FFE9",
              "versionEndExcluding": "6.11.3",
              "versionStartIncluding": "6.11"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}