5.5

CVE-2024-39276

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

ext4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find()

Syzbot reports a warning as follows:

============================================
WARNING: CPU: 0 PID: 5075 at fs/mbcache.c:419 mb_cache_destroy+0x224/0x290
Modules linked in:
CPU: 0 PID: 5075 Comm: syz-executor199 Not tainted 6.9.0-rc6-gb947cc5bf6d7
RIP: 0010:mb_cache_destroy+0x224/0x290 fs/mbcache.c:419
Call Trace:
 <TASK>
 ext4_put_super+0x6d4/0xcd0 fs/ext4/super.c:1375
 generic_shutdown_super+0x136/0x2d0 fs/super.c:641
 kill_block_super+0x44/0x90 fs/super.c:1675
 ext4_kill_sb+0x68/0xa0 fs/ext4/super.c:7327
[...]
============================================

This is because when finding an entry in ext4_xattr_block_cache_find(), if
ext4_sb_bread() returns -ENOMEM, the ce's e_refcnt, which has already grown
in the __entry_find(), won't be put away, and eventually trigger the above
issue in mb_cache_destroy() due to reference count leakage.

So call mb_cache_entry_put() on the -ENOMEM error branch as a quick fix.

Verknüpft mit AI von unstrukturierten Daten zu bestehenden CPE der NVD
This information is available to logged-in users.
Data is provided by the National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 4.14.92 < 4.15
Linux ≫ Linux Kernel Version >= 4.19.14 < 4.19.316
Linux ≫ Linux Kernel Version >= 4.20.1 <= 5.4.278
Linux ≫ Linux Kernel Version >= 5.5 <= 5.15.161
Linux ≫ Linux Kernel Version >= 5.16 <= 6.1.94
Linux ≫ Linux Kernel Version >= 6.2 <= 6.6.34
Linux ≫ Linux Kernel Version >= 6.7 <= 6.9.5
Zu dieser CVE wurde keine CISA KEV oder CERT.AT-Warnung gefunden.
EPSS Metriken
Type Source Score Percentile
EPSS FIRST.org 0.01% 0.011
CVSS Metriken
Source Base Score Exploit Score Impact Score Vector string
134c704f-9b21-4f2e-91b3-4a467353bcc0 5.5 1.8 3.6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N