fkie_cve-2021-47638
Vulnerability from fkie_nvd
Published
2025-02-26 06:37
Modified
2025-10-01 20:15
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved:
ubifs: rename_whiteout: Fix double free for whiteout_ui->data
'whiteout_ui->data' will be freed twice if space budget fail for
rename whiteout operation as following process:
rename_whiteout
dev = kmalloc
whiteout_ui->data = dev
kfree(whiteout_ui->data) // Free first time
iput(whiteout)
ubifs_free_inode
kfree(ui->data) // Double free!
KASAN reports:
==================================================================
BUG: KASAN: double-free or invalid-free in ubifs_free_inode+0x4f/0x70
Call Trace:
kfree+0x117/0x490
ubifs_free_inode+0x4f/0x70 [ubifs]
i_callback+0x30/0x60
rcu_do_batch+0x366/0xac0
__do_softirq+0x133/0x57f
Allocated by task 1506:
kmem_cache_alloc_trace+0x3c2/0x7a0
do_rename+0x9b7/0x1150 [ubifs]
ubifs_rename+0x106/0x1f0 [ubifs]
do_syscall_64+0x35/0x80
Freed by task 1506:
kfree+0x117/0x490
do_rename.cold+0x53/0x8a [ubifs]
ubifs_rename+0x106/0x1f0 [ubifs]
do_syscall_64+0x35/0x80
The buggy address belongs to the object at ffff88810238bed8 which
belongs to the cache kmalloc-8 of size 8
==================================================================
Let ubifs_free_inode() free 'whiteout_ui->data'. BTW, delete unused
assignment 'whiteout_ui->data_len = 0', process 'ubifs_evict_inode()
-> ubifs_jnl_delete_inode() -> ubifs_jnl_write_inode()' doesn't need it
(because 'inc_nlink(whiteout)' won't be excuted by 'goto out_release',
and the nlink of whiteout inode is 0).
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 | * |
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nubifs: rename_whiteout: Fix double free for whiteout_ui-\u003edata\n\n\u0027whiteout_ui-\u003edata\u0027 will be freed twice if space budget fail for\nrename whiteout operation as following process:\n\nrename_whiteout\n dev = kmalloc\n whiteout_ui-\u003edata = dev\n kfree(whiteout_ui-\u003edata) // Free first time\n iput(whiteout)\n ubifs_free_inode\n kfree(ui-\u003edata)\t // Double free!\n\nKASAN reports:\n==================================================================\nBUG: KASAN: double-free or invalid-free in ubifs_free_inode+0x4f/0x70\nCall Trace:\n kfree+0x117/0x490\n ubifs_free_inode+0x4f/0x70 [ubifs]\n i_callback+0x30/0x60\n rcu_do_batch+0x366/0xac0\n __do_softirq+0x133/0x57f\n\nAllocated by task 1506:\n kmem_cache_alloc_trace+0x3c2/0x7a0\n do_rename+0x9b7/0x1150 [ubifs]\n ubifs_rename+0x106/0x1f0 [ubifs]\n do_syscall_64+0x35/0x80\n\nFreed by task 1506:\n kfree+0x117/0x490\n do_rename.cold+0x53/0x8a [ubifs]\n ubifs_rename+0x106/0x1f0 [ubifs]\n do_syscall_64+0x35/0x80\n\nThe buggy address belongs to the object at ffff88810238bed8 which\nbelongs to the cache kmalloc-8 of size 8\n==================================================================\n\nLet ubifs_free_inode() free \u0027whiteout_ui-\u003edata\u0027. BTW, delete unused\nassignment \u0027whiteout_ui-\u003edata_len = 0\u0027, process \u0027ubifs_evict_inode()\n-\u003e ubifs_jnl_delete_inode() -\u003e ubifs_jnl_write_inode()\u0027 doesn\u0027t need it\n(because \u0027inc_nlink(whiteout)\u0027 won\u0027t be excuted by \u0027goto out_release\u0027,\n and the nlink of whiteout inode is 0)."
},
{
"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ubifs: rename_whiteout: Se corrige la doble liberaci\u00f3n para whiteout_ui-\u0026gt;data \u0027whiteout_ui-\u0026gt;data\u0027 se liberar\u00e1 dos veces si el presupuesto de espacio falla para la operaci\u00f3n de cambio de nombre de whiteout como el siguiente proceso: rename_whiteout dev = kmalloc whiteout_ui-\u0026gt;data = dev kfree(whiteout_ui-\u0026gt;data) // Libera la primera vez iput(whiteout) ubifs_free_inode kfree(ui-\u0026gt;data) // \u00a1Doble liberaci\u00f3n! KASAN informa: ==================================================================== ERROR: KASAN: liberaci\u00f3n doble o liberaci\u00f3n no v\u00e1lida en ubifs_free_inode+0x4f/0x70 Seguimiento de llamadas: kfree+0x117/0x490 ubifs_free_inode+0x4f/0x70 [ubifs] i_callback+0x30/0x60 rcu_do_batch+0x366/0xac0 __do_softirq+0x133/0x57f Asignado por la tarea 1506: kmem_cache_alloc_trace+0x3c2/0x7a0 do_rename+0x9b7/0x1150 [ubifs] ubifs_rename+0x106/0x1f0 [ubifs] do_syscall_64+0x35/0x80 Liberado por la tarea 1506: kfree+0x117/0x490 do_rename.cold+0x53/0x8a [ubifs] ubifs_rename+0x106/0x1f0 [ubifs] do_syscall_64+0x35/0x80 La direcci\u00f3n con errores pertenece al objeto en ffff88810238bed8 que pertenece al cach\u00e9 kmalloc-8 de tama\u00f1o 8 ===================================================================== Deje que ubifs_free_inode() libere \u0027whiteout_ui-\u0026gt;data\u0027. Por cierto, elimine la asignaci\u00f3n no utilizada \u0027whiteout_ui-\u0026gt;data_len = 0\u0027, el proceso \u0027ubifs_evict_inode() -\u0026gt; ubifs_jnl_delete_inode() -\u0026gt; ubifs_jnl_write_inode()\u0027 no lo necesita (porque \u0027inc_nlink(whiteout)\u0027 no ser\u00e1 ejecutado por \u0027goto out_release\u0027, y el nlink del inodo whiteout es 0)."
}
],
"id": "CVE-2021-47638",
"lastModified": "2025-10-01T20:15:40.810",
"metrics": {
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"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",
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"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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"published": "2025-02-26T06:37:05.580",
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"value": "CWE-415"
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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.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- 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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