zram: fix slot lock bit position on big-endian 64-bit
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 7.2.5
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: zram: fix slot lock bit position on big-endian 64-bit The slot lock is a bit operation on the whole __lock word, which flags and ac_time alias as two u32s. On little-endian the lock bit lands in the position ZRAM_ENTRY_LOCK reserves in flags, so the aliasing works out. On 64-bit big-endian it lands in ac_time instead: with ZRAM_TRACK_ENTRY_ACTIME enabled, storing the access time from mark_slot_accessed() or slot_free() wipes out the held lock bit, letting another CPU take the same slot lock; an access time value with that bit set makes the slot look locked forever. Shift the lock bit into the flags half of the word on big-endian 64-bit.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From 2e8ff2f51dde73a26b94aed2df4827177bd25e6e · fixed in 052b6b2d5fe97547bd2cdb73fa894f6cfea68b11; From 2e8ff2f51dde73a26b94aed2df4827177bd25e6e · fixed in a8b5875741d416703e19ad8eeac6fce8a12bd6e4
- Linux Linux
7.0
- KernelLinux
From 7.0.0 · fixed in 7.2.5