7.8

CVE-2021-47342

ext4: fix possible UAF when remounting r/o a mmp-protected file system

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

ext4: fix possible UAF when remounting r/o a mmp-protected file system

After commit 618f003199c6 ("ext4: fix memory leak in
ext4_fill_super"), after the file system is remounted read-only, there
is a race where the kmmpd thread can exit, causing sbi->s_mmp_tsk to
point at freed memory, which the call to ext4_stop_mmpd() can trip
over.

Fix this by only allowing kmmpd() to exit when it is stopped via
ext4_stop_mmpd().

Bug-Report-Link: <20210629143603.2166962-1-yebin10@huawei.com>
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version < 5.10.77
Linux ≫ Linux Kernel Version >= 5.11 < 5.13.3
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.25% 0.154
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 7.8 1.8 5.9
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE-416 Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

https://git.kernel.org/stable/c/61bb4a1c417e5b95d9edb4f887f131de32e419cb
Patch
https://git.kernel.org/stable/c/7ed572cdf11081f8f9e07abd4bea56a3f2c4edbd
Patch
https://git.kernel.org/stable/c/b663890d854403e566169f7e90aed5cd6ff64f6b
Patch