FKIE_CVE-2024-42305
Vulnerability from fkie_nvd - Published: 2024-08-17 09:15 - Updated: 2026-06-17 07:49
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
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | 2.6.19 | |
| linux | linux_kernel | 2.6.19 | |
| linux | linux_kernel | 2.6.19 | |
| linux | linux_kernel | 2.6.19 | |
| linux | linux_kernel | 2.6.19 | |
| linux | linux_kernel | 2.6.19 |
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],
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"versions": [
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},
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"version": "0",
"versionType": "semver"
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{
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"version": "4.19.320",
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},
{
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"status": "unaffected",
"version": "5.4.282",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.224",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.165",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.103",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.44",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.10.*",
"status": "unaffected",
"version": "6.10.3",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.11",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"affectedData": [
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"
}
],
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"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."
}
],
"id": "CVE-2024-42305",
"lastModified": "2026-06-17T07:49:13.373",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 5.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
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"source": "nvd@nist.gov",
"type": "Primary"
}
],
"ssvcV203": [
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"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2024-42305",
"options": [
{
"exploitation": "none"
},
{
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},
{
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}
],
"role": "CISA Coordinator",
"timestamp": "2024-09-10T16:10:19.161352Z",
"version": "2.0.3"
}
}
]
},
"published": "2024-08-17T09:15:10.690",
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{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"
},
{
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-265688.html"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Modified",
"weaknesses": [
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{
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"value": "CWE-125"
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],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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