CVE-2024-49889 Information

Description

In the Linux kernel the following vulnerability has been resolved:

ext4: avoid use-after-free in ext4_ext_show_leaf()

In ext4_find_extent() path may be freed by error or be reallocated so using a previously saved ppath may have been freed and thus may trigger use-after-free as follows:

ext4_split_extent path = ppath; ext4_split_extent_at(ppath) path = ext4_find_extent(ppath) ext4_split_extent_at(ppath) // ext4_find_extent fails to free path // but zeroout succeeds ext4_ext_show_leaf(inode path) eh = path[depth].p_hdr // path use-after-free !!!

Similar to ext4_split_extent_at() we use ppath directly as an input to ext4_ext_show_leaf(). Fix a spelling error by the way.

Same problem in ext4_ext_handle_unwritten_extents(). Since ‘path’ is only used in ext4_ext_show_leaf() remove ‘path’ and use ppath directly.

This issue is triggered only when EXT_DEBUG is defined and therefore does not affect functionality.

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Reference

https://git.kernel.org/stable/c/b0cb4561fc4284d04e69c8a66c8504928ab2484e https://git.kernel.org/stable/c/4999fed877bb64e3e7f9ab9996de2ca983c41928 https://git.kernel.org/stable/c/2eba3b0cc5b8de624918d21f32b5b8db59a90b39 https://git.kernel.org/stable/c/34b2096380ba475771971a778a478661a791aa15 https://git.kernel.org/stable/c/8b114f2cc7dd5d36729d040b68432fbd0f0a8868 https://git.kernel.org/stable/c/d483c7cc1796bd6a80e7b3a8fd494996260f6b67 https://git.kernel.org/stable/c/4e2524ba2ca5f54bdbb9e5153bea00421ef653f5

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

7.8