fkie_cve-2024-49882
Vulnerability from fkie_nvd
Published
2024-10-21 18:15
Modified
2025-11-03 23:16
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ext4: fix double brelse() the buffer of the extents path In ext4_ext_try_to_merge_up(), set path[1].p_bh to NULL after it has been released, otherwise it may be released twice. An example of what triggers this is as follows: split2 map split1 |--------|-------|--------| ext4_ext_map_blocks ext4_ext_handle_unwritten_extents ext4_split_convert_extents // path->p_depth == 0 ext4_split_extent // 1. do split1 ext4_split_extent_at |ext4_ext_insert_extent | ext4_ext_create_new_leaf | ext4_ext_grow_indepth | le16_add_cpu(&neh->eh_depth, 1) | ext4_find_extent | // return -ENOMEM |// get error and try zeroout |path = ext4_find_extent | path->p_depth = 1 |ext4_ext_try_to_merge | ext4_ext_try_to_merge_up | path->p_depth = 0 | brelse(path[1].p_bh) ---> not set to NULL here |// zeroout success // 2. update path ext4_find_extent // 3. do split2 ext4_split_extent_at ext4_ext_insert_extent ext4_ext_create_new_leaf ext4_ext_grow_indepth le16_add_cpu(&neh->eh_depth, 1) ext4_find_extent path[0].p_bh = NULL; path->p_depth = 1 read_extent_tree_block ---> return err // path[1].p_bh is still the old value ext4_free_ext_path ext4_ext_drop_refs // path->p_depth == 1 brelse(path[1].p_bh) ---> brelse a buffer twice Finally got the following WARRNING when removing the buffer from lru: ============================================ VFS: brelse: Trying to free free buffer WARNING: CPU: 2 PID: 72 at fs/buffer.c:1241 __brelse+0x58/0x90 CPU: 2 PID: 72 Comm: kworker/u19:1 Not tainted 6.9.0-dirty #716 RIP: 0010:__brelse+0x58/0x90 Call Trace: <TASK> __find_get_block+0x6e7/0x810 bdev_getblk+0x2b/0x480 __ext4_get_inode_loc+0x48a/0x1240 ext4_get_inode_loc+0xb2/0x150 ext4_reserve_inode_write+0xb7/0x230 __ext4_mark_inode_dirty+0x144/0x6a0 ext4_ext_insert_extent+0x9c8/0x3230 ext4_ext_map_blocks+0xf45/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] ============================================
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/230ee0535d01478bad9a3037292043f39b9be10bPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/32bbb59e3f18facd7201bef110010bf35819b8c3Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/68a69cf60660c73990c1875f94a5551600b04775Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7633407ca4ab8be2916ab214eb44ccebc6a50e1aPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/78bbc3d15b6f443acb26e94418c445bac940d414Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b6c29c8f3d7cb67b505f3b2f6c242d52298d1f2ePatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d4574bda63906bf69660e001470bfe1a0ac524ae
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dcaa6c31134c0f515600111c38ed7750003e1b9cPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f9fd47c9d9548f9e47fa60098eab99dde175401d
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *


To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "3B73A13A-D7BE-4035-BEF2-2821D9D5CB6D",
              "versionEndExcluding": "5.10.227",
              "versionStartIncluding": "3.7",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "4D51C05D-455B-4D8D-89E7-A58E140B864C",
              "versionEndExcluding": "5.15.168",
              "versionStartIncluding": "5.11",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "D01BD22E-ACD1-4618-9D01-6116570BE1EE",
              "versionEndExcluding": "6.1.113",
              "versionStartIncluding": "5.16",
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            },
            {
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              "matchCriteriaId": "E90B9576-56C4-47BC-AAB0-C5B2D438F5D0",
              "versionEndExcluding": "6.6.55",
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              "versionEndExcluding": "6.10.14",
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            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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          "negate": false,
          "operator": "OR"
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      ]
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix double brelse() the buffer of the extents path\n\nIn ext4_ext_try_to_merge_up(), set path[1].p_bh to NULL after it has been\nreleased, otherwise it may be released twice. An example of what triggers\nthis is as follows:\n\n  split2    map    split1\n|--------|-------|--------|\n\next4_ext_map_blocks\n ext4_ext_handle_unwritten_extents\n  ext4_split_convert_extents\n   // path-\u003ep_depth == 0\n   ext4_split_extent\n     // 1. do split1\n     ext4_split_extent_at\n       |ext4_ext_insert_extent\n       |  ext4_ext_create_new_leaf\n       |    ext4_ext_grow_indepth\n       |      le16_add_cpu(\u0026neh-\u003eeh_depth, 1)\n       |    ext4_find_extent\n       |      // return -ENOMEM\n       |// get error and try zeroout\n       |path = ext4_find_extent\n       |  path-\u003ep_depth = 1\n       |ext4_ext_try_to_merge\n       |  ext4_ext_try_to_merge_up\n       |    path-\u003ep_depth = 0\n       |    brelse(path[1].p_bh)  ---\u003e not set to NULL here\n       |// zeroout success\n     // 2. update path\n     ext4_find_extent\n     // 3. do split2\n     ext4_split_extent_at\n       ext4_ext_insert_extent\n         ext4_ext_create_new_leaf\n           ext4_ext_grow_indepth\n             le16_add_cpu(\u0026neh-\u003eeh_depth, 1)\n           ext4_find_extent\n             path[0].p_bh = NULL;\n             path-\u003ep_depth = 1\n             read_extent_tree_block  ---\u003e return err\n             // path[1].p_bh is still the old value\n             ext4_free_ext_path\n               ext4_ext_drop_refs\n                 // path-\u003ep_depth == 1\n                 brelse(path[1].p_bh)  ---\u003e brelse a buffer twice\n\nFinally got the following WARRNING when removing the buffer from lru:\n\n============================================\nVFS: brelse: Trying to free free buffer\nWARNING: CPU: 2 PID: 72 at fs/buffer.c:1241 __brelse+0x58/0x90\nCPU: 2 PID: 72 Comm: kworker/u19:1 Not tainted 6.9.0-dirty #716\nRIP: 0010:__brelse+0x58/0x90\nCall Trace:\n \u003cTASK\u003e\n __find_get_block+0x6e7/0x810\n bdev_getblk+0x2b/0x480\n __ext4_get_inode_loc+0x48a/0x1240\n ext4_get_inode_loc+0xb2/0x150\n ext4_reserve_inode_write+0xb7/0x230\n __ext4_mark_inode_dirty+0x144/0x6a0\n ext4_ext_insert_extent+0x9c8/0x3230\n ext4_ext_map_blocks+0xf45/0x2dc0\n ext4_map_blocks+0x724/0x1700\n ext4_do_writepages+0x12d6/0x2a70\n[...]\n============================================"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ext4: corregir el doble brelse() del b\u00fafer de la ruta de las extensiones En ext4_ext_try_to_merge_up(), establezca path[1].p_bh en NULL despu\u00e9s de que se haya liberado, de lo contrario, puede liberarse dos veces. Un ejemplo de lo que desencadena esto es el siguiente: split2 map split1 |--------|-------|--------| ext4_ext_map_blocks ext4_ext_handle_unwritten_extents ext4_split_convert_extents // path-\u0026gt;p_depth == 0 ext4_split_extent // 1. hacer split1 ext4_split_extent_at |ext4_ext_insert_extent | ext4_ext_create_new_leaf | ext4_ext_grow_indepth | le16_add_cpu(\u0026amp;neh-\u0026gt;eh_depth, 1) | ext4_find_extent | // devuelve -ENOMEM |// obtiene el error e intenta poner a cero |path = ext4_find_extent | path-\u0026gt;p_depth = 1 |ext4_ext_try_to_merge | ext4_ext_try_to_merge_up | path-\u0026gt;p_depth = 0 | brelse(path[1].p_bh) ---\u0026gt; no establecido en NULL aqu\u00ed |// puesta a cero exitosa // 2. actualizar ruta ext4_find_extent // 3. hacer split2 ext4_split_extent_at ext4_ext_insert_extent ext4_ext_create_new_leaf ext4_ext_grow_indepth le16_add_cpu(\u0026amp;neh-\u0026gt;eh_depth, 1) ext4_find_extent path[0].p_bh = NULL; path-\u0026gt;p_depth = 1 read_extent_tree_block ---\u0026gt; return err // path[1].p_bh sigue siendo el valor anterior ext4_free_ext_path ext4_ext_drop_refs // path-\u0026gt;p_depth == 1 brelse(path[1].p_bh) ---\u0026gt; brelse un buffer dos veces Finalmente obtuve la siguiente ADVERTENCIA al eliminar el buffer de lru: =============================================== VFS: brelse: Intentando liberar b\u00fafer libre ADVERTENCIA: CPU: 2 PID: 72 en fs/buffer.c:1241 __brelse+0x58/0x90 CPU: 2 PID: 72 Comm: kworker/u19:1 No contaminado 6.9.0-dirty #716 RIP: 0010:__brelse+0x58/0x90 Seguimiento de llamadas:  __find_get_block+0x6e7/0x810 bdev_getblk+0x2b/0x480 __ext4_get_inode_loc+0x48a/0x1240 ext4_get_inode_loc+0xb2/0x150 ext4_reserve_inode_write+0xb7/0x230 __ext4_mark_inode_dirty+0x144/0x6a0 ext4_ext_insert_extent+0x9c8/0x3230 ext4_ext_map_blocks+0xf45/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] ============================================"
    }
  ],
  "id": "CVE-2024-49882",
  "lastModified": "2025-11-03T23:16:28.410",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2024-10-21T18:15:10.790",
  "references": [
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      "url": "https://git.kernel.org/stable/c/7633407ca4ab8be2916ab214eb44ccebc6a50e1a"
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    },
    {
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      "url": "https://git.kernel.org/stable/c/d4574bda63906bf69660e001470bfe1a0ac524ae"
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    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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      "url": "https://git.kernel.org/stable/c/f9fd47c9d9548f9e47fa60098eab99dde175401d"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
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      "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html"
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  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-415"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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