Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
Low
Attack Vector
Local
0

CVE-2024-50015

Disclosure Date: October 21, 2024 •
CVE-2024-50015 CVSS v3 Base Score: 5.5
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

In the Linux kernel, the following vulnerability has been resolved:

ext4: dax: fix overflowing extents beyond inode size when partially writing

The dax_iomap_rw() does two things in each iteration: map written blocks
and copy user data to blocks. If the process is killed by user(See signal
handling in dax_iomap_iter()), the copied data will be returned and added
on inode size, which means that the length of written extents may exceed
the inode size, then fsck will fail. An example is given as:

dd if=/dev/urandom of=file bs=4M count=1
dax_iomap_rw
iomap_iter // round 1
ext4_iomap_begin

ext4_iomap_alloc // allocate 0~2M extents(written flag)

dax_iomap_iter // copy 2M data
iomap_iter // round 2
iomap_iter_advance

iter->pos += iter->processed // iter->pos = 2M

ext4_iomap_begin

ext4_iomap_alloc // allocate 2~4M extents(written flag)

dax_iomap_iter
fatal_signal_pending
done = iter->pos – iocb->ki_pos // done = 2M
ext4_handle_inode_extension
ext4_update_inode_size // inode size = 2M

fsck reports: Inode 13, i_size is 2097152, should be 4194304. Fix?

Fix the problem by truncating extents if the written length is smaller
than expected.

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CVSS V3 Severity and Metrics
Base Score:
5.5 Medium
Impact Score:
3.6
Exploitability Score:
1.8
Vector:
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector (AV):
Local
Attack Complexity (AC):
Low
Privileges Required (PR):
Low
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
None
Integrity (I):
None
Availability (A):
High

General Information

Offensive Application
Unknown
Utility Class
Unknown
Ports
Unknown
OS
Unknown
Vulnerable Versions
Linux f8a7c342326f
Linux not down converted
Prerequisites
Unknown
Discovered By
Unknown
PoC Author
Unknown
Metasploit Module
Unknown
Reporter
Unknown

Vendors

  • linux

Products

  • linux kernel
Technical Analysis