cve-2024-42305
Vulnerability from cvelistv5
Published
2024-08-17 09:09
Modified
2024-12-19 09:16
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ext4: check dot and dotdot of dx_root before making dir indexed Syzbot reports a issue as follows: ============================================ BUG: unable to handle page fault for address: ffffed11022e24fe PGD 23ffee067 P4D 23ffee067 PUD 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 0 PID: 5079 Comm: syz-executor306 Not tainted 6.10.0-rc5-g55027e689933 #0 Call Trace: <TASK> make_indexed_dir+0xdaf/0x13c0 fs/ext4/namei.c:2341 ext4_add_entry+0x222a/0x25d0 fs/ext4/namei.c:2451 ext4_rename fs/ext4/namei.c:3936 [inline] ext4_rename2+0x26e5/0x4370 fs/ext4/namei.c:4214 [...] ============================================ The immediate cause of this problem is that there is only one valid dentry for the block to be split during do_split, so split==0 results in out of bounds accesses to the map triggering the issue. do_split unsigned split dx_make_map count = 1 split = count/2 = 0; continued = hash2 == map[split - 1].hash; ---> map[4294967295] The maximum length of a filename is 255 and the minimum block size is 1024, so it is always guaranteed that the number of entries is greater than or equal to 2 when do_split() is called. But syzbot's crafted image has no dot and dotdot in dir, and the dentry distribution in dirblock is as follows: bus dentry1 hole dentry2 free |xx--|xx-------------|...............|xx-------------|...............| 0 12 (8+248)=256 268 256 524 (8+256)=264 788 236 1024 So when renaming dentry1 increases its name_len length by 1, neither hole nor free is sufficient to hold the new dentry, and make_indexed_dir() is called. In make_indexed_dir() it is assumed that the first two entries of the dirblock must be dot and dotdot, so bus and dentry1 are left in dx_root because they are treated as dot and dotdot, and only dentry2 is moved to the new leaf block. That's why count is equal to 1. Therefore add the ext4_check_dx_root() helper function to add more sanity checks to dot and dotdot before starting the conversion to avoid the above issue.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/19e13b4d7f0303186fcc891aba8d0de7c8fdbda8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/42d420517072028fb0eb852c358056b7717ba5aa
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/50ea741def587a64e08879ce6c6a30131f7111e7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8afe06ed3be7a874b3cd82ef5f8959aca8d6429a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9d241b7a39af192d1bb422714a458982c7cc67a2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/abb411ac991810c0bcbe51c2e76d2502bf611b5c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b80575ffa98b5bb3a5d4d392bfe4c2e03e9557db
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cdd345321699042ece4a9d2e70754d2397d378c5
Impacted products
Vendor Product Version
Linux Linux Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
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   Linux Linux Version: 2.6.19
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                "id": "CVE-2024-42305",
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: check dot and dotdot of dx_root before making dir indexed\n\nSyzbot reports a issue as follows:\n============================================\nBUG: unable to handle page fault for address: ffffed11022e24fe\nPGD 23ffee067 P4D 23ffee067 PUD 0\nOops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI\nCPU: 0 PID: 5079 Comm: syz-executor306 Not tainted 6.10.0-rc5-g55027e689933 #0\nCall Trace:\n \u003cTASK\u003e\n make_indexed_dir+0xdaf/0x13c0 fs/ext4/namei.c:2341\n ext4_add_entry+0x222a/0x25d0 fs/ext4/namei.c:2451\n ext4_rename fs/ext4/namei.c:3936 [inline]\n ext4_rename2+0x26e5/0x4370 fs/ext4/namei.c:4214\n[...]\n============================================\n\nThe immediate cause of this problem is that there is only one valid dentry\nfor the block to be split during do_split, so split==0 results in out of\nbounds accesses to the map triggering the issue.\n\n    do_split\n      unsigned split\n      dx_make_map\n       count = 1\n      split = count/2 = 0;\n      continued = hash2 == map[split - 1].hash;\n       ---\u003e map[4294967295]\n\nThe maximum length of a filename is 255 and the minimum block size is 1024,\nso it is always guaranteed that the number of entries is greater than or\nequal to 2 when do_split() is called.\n\nBut syzbot\u0027s crafted image has no dot and dotdot in dir, and the dentry\ndistribution in dirblock is as follows:\n\n  bus     dentry1          hole           dentry2           free\n|xx--|xx-------------|...............|xx-------------|...............|\n0   12 (8+248)=256  268     256     524 (8+256)=264 788     236     1024\n\nSo when renaming dentry1 increases its name_len length by 1, neither hole\nnor free is sufficient to hold the new dentry, and make_indexed_dir() is\ncalled.\n\nIn make_indexed_dir() it is assumed that the first two entries of the\ndirblock must be dot and dotdot, so bus and dentry1 are left in dx_root\nbecause they are treated as dot and dotdot, and only dentry2 is moved\nto the new leaf block. That\u0027s why count is equal to 1.\n\nTherefore add the ext4_check_dx_root() helper function to add more sanity\nchecks to dot and dotdot before starting the conversion to avoid the above\nissue."
        }
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    "cveId": "CVE-2024-42305",
    "datePublished": "2024-08-17T09:09:11.296Z",
    "dateReserved": "2024-07-30T07:40:12.273Z",
    "dateUpdated": "2024-12-19T09:16:03.235Z",
    "state": "PUBLISHED"
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    "nvd": "{\"cve\":{\"id\":\"CVE-2024-42305\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-08-17T09:15:10.690\",\"lastModified\":\"2024-08-19T12:59:59.177\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\next4: check dot and dotdot of dx_root before making dir indexed\\n\\nSyzbot reports a issue as follows:\\n============================================\\nBUG: unable to handle page fault for address: ffffed11022e24fe\\nPGD 23ffee067 P4D 23ffee067 PUD 0\\nOops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI\\nCPU: 0 PID: 5079 Comm: syz-executor306 Not tainted 6.10.0-rc5-g55027e689933 #0\\nCall Trace:\\n \u003cTASK\u003e\\n make_indexed_dir+0xdaf/0x13c0 fs/ext4/namei.c:2341\\n ext4_add_entry+0x222a/0x25d0 fs/ext4/namei.c:2451\\n ext4_rename fs/ext4/namei.c:3936 [inline]\\n ext4_rename2+0x26e5/0x4370 fs/ext4/namei.c:4214\\n[...]\\n============================================\\n\\nThe immediate cause of this problem is that there is only one valid dentry\\nfor the block to be split during do_split, so split==0 results in out of\\nbounds accesses to the map triggering the issue.\\n\\n    do_split\\n      unsigned split\\n      dx_make_map\\n       count = 1\\n      split = count/2 = 0;\\n      continued = hash2 == map[split - 1].hash;\\n       ---\u003e map[4294967295]\\n\\nThe maximum length of a filename is 255 and the minimum block size is 1024,\\nso it is always guaranteed that the number of entries is greater than or\\nequal to 2 when do_split() is called.\\n\\nBut syzbot\u0027s crafted image has no dot and dotdot in dir, and the dentry\\ndistribution in dirblock is as follows:\\n\\n  bus     dentry1          hole           dentry2           free\\n|xx--|xx-------------|...............|xx-------------|...............|\\n0   12 (8+248)=256  268     256     524 (8+256)=264 788     236     1024\\n\\nSo when renaming dentry1 increases its name_len length by 1, neither hole\\nnor free is sufficient to hold the new dentry, and make_indexed_dir() is\\ncalled.\\n\\nIn make_indexed_dir() it is assumed that the first two entries of the\\ndirblock must be dot and dotdot, so bus and dentry1 are left in dx_root\\nbecause they are treated as dot and dotdot, and only dentry2 is moved\\nto the new leaf block. That\u0027s why count is equal to 1.\\n\\nTherefore add the ext4_check_dx_root() helper function to add more sanity\\nchecks to dot and dotdot before starting the conversion to avoid the above\\nissue.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ext4: verifique el punto y el punto de dx_root antes de indexar el directorio Syzbot informa un problema de la siguiente manera: =================== ========================= ERROR: no se puede manejar el error de p\u00e1gina para la direcci\u00f3n: ffffed11022e24fe PGD 23ffee067 P4D 23ffee067 PUD 0 Ups: Ups: 0000 [#1 ] PREEMPT SMP KASAN PTI CPU: 0 PID: 5079 Comm: syz-executor306 No contaminado 6.10.0-rc5-g55027e689933 #0 Seguimiento de llamada:  make_indexed_dir+0xdaf/0x13c0 fs/ext4/namei.c:2341 ext4_add_entry+0x222 un /0x25d0 fs/ext4/namei.c:2451 ext4_rename fs/ext4/namei.c:3936 [en l\u00ednea] text4_rename2+0x26e5/0x4370 fs/ext4/namei.c:4214 [...] ======= ====================================== La causa inmediata de este problema es que s\u00f3lo hay una v\u00e1lida dentry para que el bloque se divida durante do_split, por lo que split==0 da como resultado accesos fuera de los l\u00edmites al mapa que desencadenan el problema. do_split divisi\u00f3n sin signo dx_make_map recuento = 1 divisi\u00f3n = recuento/2 = 0; contin\u00faa = hash2 == mapa[dividido - 1].hash; ---\u0026gt; map[4294967295] La longitud m\u00e1xima de un nombre de archivo es 255 y el tama\u00f1o m\u00ednimo de bloque es 1024, por lo que siempre se garantiza que el n\u00famero de entradas sea mayor o igual a 2 cuando se llama a do_split(). Pero la imagen manipulada por syzbot no tiene punto ni puntopunto en el directorio, y la distribuci\u00f3n de dentry en dirblock es la siguiente: bus dentry1 agujero dentry2 gratis |xx--|xx-------------|... ............|xx-------------|...............| 0 12 (8+248)=256 268 256 524 (8+256)=264 788 236 1024 Entonces, cuando se cambia el nombre de dentry1 se aumenta la longitud de name_len en 1, ni el agujero ni el espacio libre son suficientes para contener el nuevo dentry, y make_indexed_dir() es llamado. En make_indexed_dir() se supone que las dos primeras entradas del bloque de directorios deben ser punto y puntopunto, por lo que bus y dentry1 se dejan en dx_root porque se tratan como punto y puntodot, y solo dentry2 se mueve al nuevo bloque de hoja. Es por eso que el recuento es igual a 1. Por lo tanto, agregue la funci\u00f3n auxiliar ext4_check_dx_root() para agregar m\u00e1s controles de cordura a los puntos y puntos antes de comenzar la conversi\u00f3n para evitar el problema anterior.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/19e13b4d7f0303186fcc891aba8d0de7c8fdbda8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/42d420517072028fb0eb852c358056b7717ba5aa\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/50ea741def587a64e08879ce6c6a30131f7111e7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/8afe06ed3be7a874b3cd82ef5f8959aca8d6429a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9d241b7a39af192d1bb422714a458982c7cc67a2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/abb411ac991810c0bcbe51c2e76d2502bf611b5c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b80575ffa98b5bb3a5d4d392bfe4c2e03e9557db\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cdd345321699042ece4a9d2e70754d2397d378c5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2024-42305\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2024-09-10T16:10:19.161352Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2024-09-11T12:42:23.520Z\"}}], \"cna\": {\"title\": \"ext4: check dot and dotdot of dx_root before making dir indexed\", \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"ac27a0ec112a089f1a5102bc8dffc79c8c815571\", \"lessThan\": \"b80575ffa98b5bb3a5d4d392bfe4c2e03e9557db\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"ac27a0ec112a089f1a5102bc8dffc79c8c815571\", \"lessThan\": \"19e13b4d7f0303186fcc891aba8d0de7c8fdbda8\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"ac27a0ec112a089f1a5102bc8dffc79c8c815571\", \"lessThan\": \"42d420517072028fb0eb852c358056b7717ba5aa\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"ac27a0ec112a089f1a5102bc8dffc79c8c815571\", \"lessThan\": \"8afe06ed3be7a874b3cd82ef5f8959aca8d6429a\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"ac27a0ec112a089f1a5102bc8dffc79c8c815571\", \"lessThan\": \"abb411ac991810c0bcbe51c2e76d2502bf611b5c\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"ac27a0ec112a089f1a5102bc8dffc79c8c815571\", \"lessThan\": \"9d241b7a39af192d1bb422714a458982c7cc67a2\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"ac27a0ec112a089f1a5102bc8dffc79c8c815571\", \"lessThan\": \"cdd345321699042ece4a9d2e70754d2397d378c5\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"ac27a0ec112a089f1a5102bc8dffc79c8c815571\", \"lessThan\": \"50ea741def587a64e08879ce6c6a30131f7111e7\", \"versionType\": \"git\"}], \"programFiles\": [\"fs/ext4/namei.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"2.6.19\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"2.6.19\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"4.19.320\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"4.19.*\"}, {\"status\": \"unaffected\", \"version\": \"5.4.282\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.4.*\"}, {\"status\": \"unaffected\", \"version\": \"5.10.224\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.10.*\"}, {\"status\": \"unaffected\", \"version\": \"5.15.165\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.15.*\"}, {\"status\": \"unaffected\", \"version\": \"6.1.103\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.1.*\"}, {\"status\": \"unaffected\", \"version\": \"6.6.44\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.6.*\"}, {\"status\": \"unaffected\", \"version\": \"6.10.3\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.10.*\"}, {\"status\": \"unaffected\", \"version\": \"6.11\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"fs/ext4/namei.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/b80575ffa98b5bb3a5d4d392bfe4c2e03e9557db\"}, {\"url\": \"https://git.kernel.org/stable/c/19e13b4d7f0303186fcc891aba8d0de7c8fdbda8\"}, {\"url\": \"https://git.kernel.org/stable/c/42d420517072028fb0eb852c358056b7717ba5aa\"}, {\"url\": \"https://git.kernel.org/stable/c/8afe06ed3be7a874b3cd82ef5f8959aca8d6429a\"}, {\"url\": \"https://git.kernel.org/stable/c/abb411ac991810c0bcbe51c2e76d2502bf611b5c\"}, {\"url\": \"https://git.kernel.org/stable/c/9d241b7a39af192d1bb422714a458982c7cc67a2\"}, {\"url\": \"https://git.kernel.org/stable/c/cdd345321699042ece4a9d2e70754d2397d378c5\"}, {\"url\": \"https://git.kernel.org/stable/c/50ea741def587a64e08879ce6c6a30131f7111e7\"}], \"x_generator\": {\"engine\": \"bippy-5f407fcff5a0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\next4: check dot and dotdot of dx_root before making dir indexed\\n\\nSyzbot reports a issue as follows:\\n============================================\\nBUG: unable to handle page fault for address: ffffed11022e24fe\\nPGD 23ffee067 P4D 23ffee067 PUD 0\\nOops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI\\nCPU: 0 PID: 5079 Comm: syz-executor306 Not tainted 6.10.0-rc5-g55027e689933 #0\\nCall Trace:\\n \u003cTASK\u003e\\n make_indexed_dir+0xdaf/0x13c0 fs/ext4/namei.c:2341\\n ext4_add_entry+0x222a/0x25d0 fs/ext4/namei.c:2451\\n ext4_rename fs/ext4/namei.c:3936 [inline]\\n ext4_rename2+0x26e5/0x4370 fs/ext4/namei.c:4214\\n[...]\\n============================================\\n\\nThe immediate cause of this problem is that there is only one valid dentry\\nfor the block to be split during do_split, so split==0 results in out of\\nbounds accesses to the map triggering the issue.\\n\\n    do_split\\n      unsigned split\\n      dx_make_map\\n       count = 1\\n      split = count/2 = 0;\\n      continued = hash2 == map[split - 1].hash;\\n       ---\u003e map[4294967295]\\n\\nThe maximum length of a filename is 255 and the minimum block size is 1024,\\nso it is always guaranteed that the number of entries is greater than or\\nequal to 2 when do_split() is called.\\n\\nBut syzbot\u0027s crafted image has no dot and dotdot in dir, and the dentry\\ndistribution in dirblock is as follows:\\n\\n  bus     dentry1          hole           dentry2           free\\n|xx--|xx-------------|...............|xx-------------|...............|\\n0   12 (8+248)=256  268     256     524 (8+256)=264 788     236     1024\\n\\nSo when renaming dentry1 increases its name_len length by 1, neither hole\\nnor free is sufficient to hold the new dentry, and make_indexed_dir() is\\ncalled.\\n\\nIn make_indexed_dir() it is assumed that the first two entries of the\\ndirblock must be dot and dotdot, so bus and dentry1 are left in dx_root\\nbecause they are treated as dot and dotdot, and only dentry2 is moved\\nto the new leaf block. That\u0027s why count is equal to 1.\\n\\nTherefore add the ext4_check_dx_root() helper function to add more sanity\\nchecks to dot and dotdot before starting the conversion to avoid the above\\nissue.\"}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2024-12-19T09:16:03.235Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2024-42305\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2024-12-19T09:16:03.235Z\", \"dateReserved\": \"2024-07-30T07:40:12.273Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-08-17T09:09:11.296Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}


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