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CVE-2021-47254

gfs2: Fix use-after-free in gfs2_glock_shrink_scan

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 4.4.274, 4.9.274, 4.14.238, 4.19.196, 5.1, and 1 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

In the Linux kernel, the following vulnerability has been resolved: gfs2: Fix use-after-free in gfs2_glock_shrink_scan The GLF_LRU flag is checked under lru_lock in gfs2_glock_remove_from_lru() to remove the glock from the lru list in __gfs2_glock_put(). On the shrink scan path, the same flag is cleared under lru_lock but because of cond_resched_lock(&lru_lock) in gfs2_dispose_glock_lru(), progress on the put side can be made without deleting the glock from the lru list. Keep GLF_LRU across the race window opened by cond_resched_lock(&lru_lock) to ensure correct behavior on both sides - clear GLF_LRU after list_del under lru_lock.

Timeline

  1. CVE published
  2. CISA SSVC assessment

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

  3. Record last updated

Affected versions

  • Linux Linux

    From 4.4.181 · fixed in 4.4.274; From 4.9.180 · fixed in 4.9.274; From 4.14.123 · fixed in 4.14.238; From 4.19.47 · fixed in 4.19.196; From 5.0.20 · fixed in 5.1; From 5.1.6 · fixed in 5.2

  • Linux Linux

    5.2

References 8

git.kernel.org