Описание
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix invalid free tracking in ext4_xattr_move_to_block()
In ext4_xattr_move_to_block(), the value of the extended attribute
which we need to move to an external block may be allocated by
kvmalloc() if the value is stored in an external inode. So at the end
of the function the code tried to check if this was the case by
testing entry->e_value_inum.
However, at this point, the pointer to the xattr entry is no longer
valid, because it was removed from the original location where it had
been stored. So we could end up calling kvfree() on a pointer which
was not allocated by kvmalloc(); or we could also potentially leak
memory by not freeing the buffer when it should be freed. Fix this by
storing whether it should be freed in a separate variable.
A memory management flaw was found in the Linux kernel's ext4 filesystem extended attribute handling. In ext4_xattr_move_to_block(), when moving an extended attribute value to an external block, the code checks entry->e_value_inum to determine if the buffer was allocated via kvmalloc(). However, at cleanup time the xattr entry pointer is stale (already removed), leading to either calling kvfree() on an invalid pointer or leaking memory that should have been freed.
Отчет
This flaw affects ext4 filesystems using extended attributes stored in external inodes. The invalid free tracking occurs when moving large xattr values to separate blocks. While this can cause memory corruption or leaks, exploiting it requires specific filesystem operations on ext4 with large extended attributes, limiting practical attack scenarios.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Not affected | ||
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Fix deferred | ||
| Red Hat Enterprise Linux 8 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2024:2394 | 30.04.2024 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2024:2394 | 30.04.2024 |
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Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: ext4: fix invalid free tracking in ext4_xattr_move_to_block() In ext4_xattr_move_to_block(), the value of the extended attribute which we need to move to an external block may be allocated by kvmalloc() if the value is stored in an external inode. So at the end of the function the code tried to check if this was the case by testing entry->e_value_inum. However, at this point, the pointer to the xattr entry is no longer valid, because it was removed from the original location where it had been stored. So we could end up calling kvfree() on a pointer which was not allocated by kvmalloc(); or we could also potentially leak memory by not freeing the buffer when it should be freed. Fix this by storing whether it should be freed in a separate variable.
In the Linux kernel, the following vulnerability has been resolved: ext4: fix invalid free tracking in ext4_xattr_move_to_block() In ext4_xattr_move_to_block(), the value of the extended attribute which we need to move to an external block may be allocated by kvmalloc() if the value is stored in an external inode. So at the end of the function the code tried to check if this was the case by testing entry->e_value_inum. However, at this point, the pointer to the xattr entry is no longer valid, because it was removed from the original location where it had been stored. So we could end up calling kvfree() on a pointer which was not allocated by kvmalloc(); or we could also potentially leak memory by not freeing the buffer when it should be freed. Fix this by storing whether it should be freed in a separate variable.
In the Linux kernel, the following vulnerability has been resolved: e ...
In the Linux kernel, the following vulnerability has been resolved: ext4: fix invalid free tracking in ext4_xattr_move_to_block() In ext4_xattr_move_to_block(), the value of the extended attribute which we need to move to an external block may be allocated by kvmalloc() if the value is stored in an external inode. So at the end of the function the code tried to check if this was the case by testing entry->e_value_inum. However, at this point, the pointer to the xattr entry is no longer valid, because it was removed from the original location where it had been stored. So we could end up calling kvfree() on a pointer which was not allocated by kvmalloc(); or we could also potentially leak memory by not freeing the buffer when it should be freed. Fix this by storing whether it should be freed in a separate variable.
Уязвимость функции ext4_xattr_move_to_block() модуля fs/ext4/xattr.c файловой системы Ext4 ядра операционной системы Linux, позволяющая нарушителю вызвать отказ в обслуживании
EPSS
5.5 Medium
CVSS3