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CVE-2022-49554

zsmalloc: fix races between asynchronous zspage free and page migration

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 4.14.282, 4.19.246, 5.4.197, 5.10.120, 5.15.45, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From 77ff465799c60294e248000cd22ae8171da3304c · fixed in 3674d8a8dadd03a447dd21069d4dacfc3399b63b; From 77ff465799c60294e248000cd22ae8171da3304c · fixed in 645996efc2ae391246d595832aaa6f9d3cc338c7; From 77ff465799c60294e248000cd22ae8171da3304c · fixed in fc658c083904427abbf8f18280d517ee2668677c; From 77ff465799c60294e248000cd22ae8171da3304c · fixed in fae05b2314b147a78fbed1dc4c645d9a66313758; From 77ff465799c60294e248000cd22ae8171da3304c · fixed in 3ec459c8810e658401be428d3168eacfc380bdd0; From 77ff465799c60294e248000cd22ae8171da3304c · fixed in 8ba7b7c1dad1f6503c541778f31b33f7f62eb966; From 77ff465799c60294e248000cd22ae8171da3304c · fixed in c5402fb5f71f1a725f1e55d9c6799c0c7bec308f; From 77ff465799c60294e248000cd22ae8171da3304c · fixed in 2505a981114dcb715f8977b8433f7540854851d8

  • Linux Linux

    4.14

  • KernelLinux

    From 4.14.0 · fixed in 4.14.282; From 4.15.0 · fixed in 4.19.246; From 4.20.0 · fixed in 5.4.197; From 5.5.0 · fixed in 5.10.120; From 5.11.0 · fixed in 5.15.45; From 5.16.0 · fixed in 5.17.13; From 5.18.0 · fixed in 5.18.2

References 8

git.kernel.org