fkie_cve-2024-46701
Vulnerability from fkie_nvd
Published
2024-09-13 07:15
Modified
2024-09-19 13:40
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
libfs: fix infinite directory reads for offset dir
After we switch tmpfs dir operations from simple_dir_operations to
simple_offset_dir_operations, every rename happened will fill new dentry
to dest dir's maple tree(&SHMEM_I(inode)->dir_offsets->mt) with a free
key starting with octx->newx_offset, and then set newx_offset equals to
free key + 1. This will lead to infinite readdir combine with rename
happened at the same time, which fail generic/736 in xfstests(detail show
as below).
1. create 5000 files(1 2 3...) under one dir
2. call readdir(man 3 readdir) once, and get one entry
3. rename(entry, "TEMPFILE"), then rename("TEMPFILE", entry)
4. loop 2~3, until readdir return nothing or we loop too many
times(tmpfs break test with the second condition)
We choose the same logic what commit 9b378f6ad48cf ("btrfs: fix infinite
directory reads") to fix it, record the last_index when we open dir, and
do not emit the entry which index >= last_index. The file->private_data
now used in offset dir can use directly to do this, and we also update
the last_index when we llseek the dir file.
[brauner: only update last_index after seek when offset is zero like Jan suggested]
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | 6.11 | |
| linux | linux_kernel | 6.11 | |
| linux | linux_kernel | 6.11 |
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"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibfs: fix infinite directory reads for offset dir\n\nAfter we switch tmpfs dir operations from simple_dir_operations to\nsimple_offset_dir_operations, every rename happened will fill new dentry\nto dest dir\u0027s maple tree(\u0026SHMEM_I(inode)-\u003edir_offsets-\u003emt) with a free\nkey starting with octx-\u003enewx_offset, and then set newx_offset equals to\nfree key + 1. This will lead to infinite readdir combine with rename\nhappened at the same time, which fail generic/736 in xfstests(detail show\nas below).\n\n1. create 5000 files(1 2 3...) under one dir\n2. call readdir(man 3 readdir) once, and get one entry\n3. rename(entry, \"TEMPFILE\"), then rename(\"TEMPFILE\", entry)\n4. loop 2~3, until readdir return nothing or we loop too many\n times(tmpfs break test with the second condition)\n\nWe choose the same logic what commit 9b378f6ad48cf (\"btrfs: fix infinite\ndirectory reads\") to fix it, record the last_index when we open dir, and\ndo not emit the entry which index \u003e= last_index. The file-\u003eprivate_data\nnow used in offset dir can use directly to do this, and we also update\nthe last_index when we llseek the dir file.\n\n[brauner: only update last_index after seek when offset is zero like Jan suggested]"
},
{
"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: libfs: arregla lecturas de directorio infinitas para el directorio offset Despu\u00e9s de cambiar las operaciones de directorio tmpfs de simple_dir_operations a simple_offset_dir_operations, cada cambio de nombre que se produzca llenar\u00e1 new dentry en el \u00e1rbol de maple del directorio de destino (\u0026amp;SHMEM_I(inode)-\u0026gt;dir_offsets-\u0026gt;mt) con una clave libre que comienza con octx-\u0026gt;newx_offset, y luego establece newx_offset igual a la clave libre + 1. Esto provocar\u00e1 una combinaci\u00f3n de lectura de directorio infinita con el cambio de nombre ocurrido al mismo tiempo, lo que falla generic/736 en xfstests (los detalles se muestran a continuaci\u00f3n). 1. crear 5000 archivos (1 2 3...) bajo un directorio 2. llamar a readdir(man 3 readdir) una vez, y obtener una entrada 3. renombrar(entrada, \"TEMPFILE\"), luego renombrar(\"TEMPFILE\", entrada) 4. repetir 2~3 veces, hasta que readdir no devuelva nada o repetimos demasiadas veces (tmpfs interrumpe la prueba con la segunda condici\u00f3n) Elegimos la misma l\u00f3gica que el commit 9b378f6ad48cf (\"btrfs: arregla lecturas infinitas de directorio\") para arreglarlo, registrar el last_index cuando abrimos el directorio, y no emitir la entrada cuyo \u00edndice \u0026gt;= last_index. El file-\u0026gt;private_data que ahora se usa en el directorio de desplazamiento se puede usar directamente para hacer esto, y tambi\u00e9n actualizamos el last_index cuando buscamos el archivo dir. [brauner: solo actualizamos last_index despu\u00e9s de la b\u00fasqueda cuando el desplazamiento es cero como sugiri\u00f3 Jan]"
}
],
"id": "CVE-2024-46701",
"lastModified": "2024-09-19T13:40:27.817",
"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,
"impactScore": 3.6,
"source": "nvd@nist.gov",
"type": "Primary"
}
]
},
"published": "2024-09-13T07:15:05.127",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/308b4fc2403b335894592ee9dc212a5e58bb309f"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
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"url": "https://git.kernel.org/stable/c/64a7ce76fb901bf9f9c36cf5d681328fc0fd4b5a"
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"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Analyzed",
"weaknesses": [
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"description": [
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"lang": "en",
"value": "CWE-835"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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