CVE-2022-49554
What it is
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.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Weakness
- CWE-362 · Race condition
- Record status
- Modified
Affected
- Linux Kernel < 4.14.282
- Linux Kernel < 4.19.246
- Linux Kernel < 5.4.197
- Linux Kernel < 5.10.120
- Linux Kernel < 5.15.45
- Linux Kernel < 5.17.13
- Linux Kernel < 5.18.2
Attack profile CVSS 3.1 · 7.8
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Fix and advisories
- https://git.kernel.org/stable/c/2505a981114dcb715f8977b8433f7540854851d8
- https://git.kernel.org/stable/c/3674d8a8dadd03a447dd21069d4dacfc3399b63b
- https://git.kernel.org/stable/c/3ec459c8810e658401be428d3168eacfc380bdd0
- https://git.kernel.org/stable/c/645996efc2ae391246d595832aaa6f9d3cc338c7
- https://git.kernel.org/stable/c/8ba7b7c1dad1f6503c541778f31b33f7f62eb966
- https://git.kernel.org/stable/c/c5402fb5f71f1a725f1e55d9c6799c0c7bec308f
- https://git.kernel.org/stable/c/fae05b2314b147a78fbed1dc4c645d9a66313758
- https://git.kernel.org/stable/c/fc658c083904427abbf8f18280d517ee2668677c
References
- https://git.kernel.org/stable/c/2505a981114dcb715f8977b8433f7540854851d8
- https://git.kernel.org/stable/c/3674d8a8dadd03a447dd21069d4dacfc3399b63b
- https://git.kernel.org/stable/c/3ec459c8810e658401be428d3168eacfc380bdd0
- https://git.kernel.org/stable/c/645996efc2ae391246d595832aaa6f9d3cc338c7
- https://git.kernel.org/stable/c/8ba7b7c1dad1f6503c541778f31b33f7f62eb966
- https://git.kernel.org/stable/c/c5402fb5f71f1a725f1e55d9c6799c0c7bec308f
- https://git.kernel.org/stable/c/fae05b2314b147a78fbed1dc4c645d9a66313758
- https://git.kernel.org/stable/c/fc658c083904427abbf8f18280d517ee2668677c