CVE-2024-47660

In the Linux kernel, the following vulnerability has been resolved: fsnotify: clear PARENT_WATCHED flags lazily In some setups directories can have many (usually negative) dentries. Hence __fsnotify_update_child_dentry_flags() function can take a significant amount of time. Since the bulk of this function happens under inode->i_lock this causes a significant contention on the lock when we remove the watch from the directory as the __fsnotify_update_child_dentry_flags() call from fsnotify_recalc_mask() races with __fsnotify_update_child_dentry_flags() calls from __fsnotify_parent() happening on children. This can lead upto softlockup reports reported by users. Fix the problem by calling fsnotify_update_children_dentry_flags() to set PARENT_WATCHED flags only when parent starts watching children. When parent stops watching children, clear false positive PARENT_WATCHED flags lazily in __fsnotify_parent() for each accessed child.

CVSS v3 4.7 MEDIUM

4.7^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.0 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity HIGH

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/172e422ffea20a89bfdc672741c1aad6fbb5044e	Patch
https://git.kernel.org/stable/c/3f3ef1d9f66b93913ce2171120d9226b55acd41d	Patch
https://git.kernel.org/stable/c/7ef1d2e240c32b1f337a37232d037b07e3919e1a	Patch
https://git.kernel.org/stable/c/d8c42405fc3507cc43ba7e4986a773c3fc633f6e	Patch
https://git.kernel.org/stable/c/f9a48bc3dd9099935751458a5bbbea4b7c28abc8	Patch
https://git.kernel.org/stable/c/fc1b1e135c3f72382f792e6c319fc088d5523ad5	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::::::::

History

No history.

Information

Published : 2024-10-09 14:15

Updated : 2024-10-23 17:00

NVD link : CVE-2024-47660

Mitre link : CVE-2024-47660

CVE.ORG link : CVE-2024-47660

JSON object : View

Products Affected

linux

linux_kernel

CWE

CWE-362

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

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Since the bulk of this function happens\nunder inode->i_lock this causes a significant contention on the lock\nwhen we remove the watch from the directory as the\n__fsnotify_update_child_dentry_flags() call from fsnotify_recalc_mask()\nraces with __fsnotify_update_child_dentry_flags() calls from\n__fsnotify_parent() happening on children. This can lead upto softlockup\nreports reported by users.\n\nFix the problem by calling fsnotify_update_children_dentry_flags() to\nset PARENT_WATCHED flags only when parent starts watching children.\n\nWhen parent stops watching children, clear false positive PARENT_WATCHED\nflags lazily in __fsnotify_parent() for each accessed child."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: fsnotify: borrar indicadores PARENT_WATCHED de forma diferida En algunas configuraciones, los directorios pueden tener muchas entradas (normalmente negativas). Por lo tanto, la funci\u00f3n __fsnotify_update_child_dentry_flags() puede tardar una cantidad significativa de tiempo. Dado que la mayor parte de esta funci\u00f3n se realiza en inode->i_lock, esto provoca una contenci\u00f3n significativa en el bloqueo cuando eliminamos la vigilancia del directorio, ya que la llamada __fsnotify_update_child_dentry_flags() desde fsnotify_recalc_mask() compite con las llamadas __fsnotify_update_child_dentry_flags() desde __fsnotify_parent() que ocurren en los hijos. Esto puede provocar informes de bloqueo suave informados por los usuarios. Solucione el problema llamando a fsnotify_update_children_dentry_flags() para establecer los indicadores PARENT_WATCHED solo cuando el padre comience a vigilar a los hijos. 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