CVE-2021-47638

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2021-47638
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).

5.5 /10

CVSS v3 : MEDIUM

V3 Legend

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://git.kernel.org/stable/c/14276d38c89a170363e90b6ac0a53c3cf61b87fc Patch
https://git.kernel.org/stable/c/2ad07009c459e56ebdcc089d850d664660fdb742 Patch
https://git.kernel.org/stable/c/2b3236ecf96db7af5836e1366ce39ace8ce832fa Patch
https://git.kernel.org/stable/c/40a8f0d5e7b3999f096570edab71c345da812e3e Patch
https://git.kernel.org/stable/c/6d7a158a7363c1f6604aa47ae1a280a5c65123dd Patch
https://git.kernel.org/stable/c/8b3c7be16f3f4dfd6e15ac651484e59d3fa36274 Patch
https://git.kernel.org/stable/c/a90e2dbe66d2647ff95a0442ad2e86482d977fd8 Patch
https://git.kernel.org/stable/c/b9a937f096e608b3368c1abc920d4d640ba2c94f Patch
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
History

18 Mar 2025, 19:08

Type Values Removed Values Added
CPE cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Summary
  • (es) En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ubifs: rename_whiteout: Se corrige la doble liberación para whiteout_ui->data 'whiteout_ui->data' se liberará dos veces si el presupuesto de espacio falla para la operación de cambio de nombre de whiteout como el siguiente proceso: rename_whiteout dev = kmalloc whiteout_ui->data = dev kfree(whiteout_ui->data) // Libera la primera vez iput(whiteout) ubifs_free_inode kfree(ui->data) // ¡Doble liberación! KASAN informa: ==================================================================== ERROR: KASAN: liberación doble o liberación no válida 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 dirección con errores pertenece al objeto en ffff88810238bed8 que pertenece al caché kmalloc-8 de tamaño 8 ===================================================================== Deje que ubifs_free_inode() libere 'whiteout_ui->data'. Por cierto, elimine la asignación no utilizada 'whiteout_ui->data_len = 0', el proceso 'ubifs_evict_inode() -> ubifs_jnl_delete_inode() -> ubifs_jnl_write_inode()' no lo necesita (porque 'inc_nlink(whiteout)' no será ejecutado por 'goto out_release', y el nlink del inodo whiteout es 0).
CWE CWE-415
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 5.5
First Time Linux linux Kernel
Linux
References () https://git.kernel.org/stable/c/14276d38c89a170363e90b6ac0a53c3cf61b87fc - () https://git.kernel.org/stable/c/14276d38c89a170363e90b6ac0a53c3cf61b87fc - Patch
References () https://git.kernel.org/stable/c/2ad07009c459e56ebdcc089d850d664660fdb742 - () https://git.kernel.org/stable/c/2ad07009c459e56ebdcc089d850d664660fdb742 - Patch
References () https://git.kernel.org/stable/c/2b3236ecf96db7af5836e1366ce39ace8ce832fa - () https://git.kernel.org/stable/c/2b3236ecf96db7af5836e1366ce39ace8ce832fa - Patch
References () https://git.kernel.org/stable/c/40a8f0d5e7b3999f096570edab71c345da812e3e - () https://git.kernel.org/stable/c/40a8f0d5e7b3999f096570edab71c345da812e3e - Patch
References () https://git.kernel.org/stable/c/6d7a158a7363c1f6604aa47ae1a280a5c65123dd - () https://git.kernel.org/stable/c/6d7a158a7363c1f6604aa47ae1a280a5c65123dd - Patch
References () https://git.kernel.org/stable/c/8b3c7be16f3f4dfd6e15ac651484e59d3fa36274 - () https://git.kernel.org/stable/c/8b3c7be16f3f4dfd6e15ac651484e59d3fa36274 - Patch
References () https://git.kernel.org/stable/c/a90e2dbe66d2647ff95a0442ad2e86482d977fd8 - () https://git.kernel.org/stable/c/a90e2dbe66d2647ff95a0442ad2e86482d977fd8 - Patch
References () https://git.kernel.org/stable/c/b9a937f096e608b3368c1abc920d4d640ba2c94f - () https://git.kernel.org/stable/c/b9a937f096e608b3368c1abc920d4d640ba2c94f - Patch

26 Feb 2025, 06:37

Type Values Removed Values Added
New CVE
Information

Published : 2025-02-26 06:37

Updated : 2025-03-18 19:08

NVD link : CVE-2021-47638

Mitre link : CVE-2021-47638

CVE.ORG link : CVE-2021-47638

JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-415

Double Free