7.8

CVE-2021-47646

Revert "Revert "block, bfq: honor already-setup queue merges""

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

Revert "Revert "block, bfq: honor already-setup queue merges""

A crash [1] happened to be triggered in conjunction with commit
2d52c58b9c9b ("block, bfq: honor already-setup queue merges"). The
latter was then reverted by commit ebc69e897e17 ("Revert "block, bfq:
honor already-setup queue merges""). Yet, the reverted commit was not
the one introducing the bug. In fact, it actually triggered a UAF
introduced by a different commit, and now fixed by commit d29bd41428cf
("block, bfq: reset last_bfqq_created on group change").

So, there is no point in keeping commit 2d52c58b9c9b ("block, bfq:
honor already-setup queue merges") out. This commit restores it.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=214503
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version < 4.19.238
Linux ≫ Linux Kernel Version >= 4.20 < 5.4.189
Linux ≫ Linux Kernel Version >= 5.5 < 5.10.110
Linux ≫ Linux Kernel Version >= 5.11 < 5.15.33
Linux ≫ Linux Kernel Version >= 5.16 < 5.16.19
Linux ≫ Linux Kernel Version >= 5.17 < 5.17.2
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.25% 0.167
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
134c704f-9b21-4f2e-91b3-4a467353bcc0 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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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/15729ff8143f8135b03988a100a19e66d7cb7ecd
Patch
https://git.kernel.org/stable/c/4083925bd6dc89216d156474a8076feec904e607
Patch
https://git.kernel.org/stable/c/65d8a737452e88f251fe5d925371de6d606df613
Patch
https://git.kernel.org/stable/c/931aff627469a75c77b9fd3823146d0575afffd6
Patch
https://git.kernel.org/stable/c/abc2129e646af7b43025d90a071f83043f1ae76c
Patch
https://git.kernel.org/stable/c/cc051f497eac9d8a0d816cd4bffa3415f2724871
Patch
https://git.kernel.org/stable/c/f990f0985eda59d4f29fc83fcf300c92b1225d39
Patch