4.7

CVE-2022-49554

zsmalloc: fix races between asynchronous zspage free and page migration

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

zsmalloc: fix races between asynchronous zspage free and page migration

The asynchronous zspage free worker tries to lock a zspage's entire page
list without defending against page migration.  Since pages which haven't
yet been locked can concurrently migrate off the zspage page list while
lock_zspage() churns away, lock_zspage() can suffer from a few different
lethal races.

It can lock a page which no longer belongs to the zspage and unsafely
dereference page_private(), it can unsafely dereference a torn pointer to
the next page (since there's a data race), and it can observe a spurious
NULL pointer to the next page and thus not lock all of the zspage's pages
(since a single page migration will reconstruct the entire page list, and
create_page_chain() unconditionally zeroes out each list pointer in the
process).

Fix the races by using migrate_read_lock() in lock_zspage() to synchronize
with page migration.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 4.14 < 4.14.282
Linux ≫ Linux Kernel Version >= 4.15 < 4.19.246
Linux ≫ Linux Kernel Version >= 4.20 < 5.4.197
Linux ≫ Linux Kernel Version >= 5.5 < 5.10.120
Linux ≫ Linux Kernel Version >= 5.11 < 5.15.45
Linux ≫ Linux Kernel Version >= 5.16 < 5.17.13
Linux ≫ Linux Kernel Version >= 5.18 < 5.18.2
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EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.04% 0.123
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 4.7 1 3.6
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.