bpf: Invalidate RCU pointers after final spin unlock
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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 6.18.57, 7.2.6
- 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: bpf: Invalidate RCU pointers after final spin unlock In a sleepable BPF program, a spin lock can provide the only RCU protection for a kptr. The final bpf_spin_unlock() ends that protection, but the verifier leaves the pointer valid. Another CPU can then free the object before the pointer is used. A capability-limited runtime PoC triggered a task_struct use-after-free in __bpf_get_task_stack(). Record whether the program is in an RCU-protected context before releasing the lock. Invalidate RCU-protected pointers only when the unlock leaves the final such context. This preserves valid pointers in non-sleepable programs and inside an explicit RCU read-side section.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From 5861d1e8dbc4e1a03ebffb96ac041026cdd34c07 · fixed in f81972b235f3ebfa40bdce8bcfee3f242fb24065; From 5861d1e8dbc4e1a03ebffb96ac041026cdd34c07 · fixed in 7ae71629357d0a6d0bdadb929c7b296d5b7e61c2; From 5861d1e8dbc4e1a03ebffb96ac041026cdd34c07 · fixed in 180c7000712db77063b3a26f4c97e7dd9038f449
- Linux Linux
6.6
- KernelLinux
From 6.6.0 · fixed in 6.18.57; From 6.19.0 · fixed in 7.2.6