bpf: Reject non-negative offsets in stack_slot_obj_get_spi()
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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 7.2.9
- 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: Reject non-negative offsets in stack_slot_obj_get_spi() bpf_get_spi() computes (-off - 1) / BPF_REG_SIZE using C division, which truncates toward zero. For off == 0, this produces spi 0, the same index used by the valid stack slot at fp-8. stack_slot_obj_get_spi() currently checks alignment and the resulting spi bounds, but does not reject the non-negative offset itself. It can therefore validate a PTR_TO_STACK register holding fp+0 against an iterator stored at fp-8 even though the runtime receives the actual fp+0 pointer. An effectful iterator kfunc can then interpret memory outside the BPF stack as iterator state. Reject non-negative offsets before converting the offset to an spi. All valid stack objects begin at a negative offset from the frame pointer.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From 06accc8779c1d558a5b5a21f2ac82b0c95827ddd · fixed in 89a7241fc7ecc1b5e47c3f071081e314523b8d9d; From 06accc8779c1d558a5b5a21f2ac82b0c95827ddd · fixed in 79a9172f3ab4ad8392c5e5c8944b9b7710ade620
- Linux Linux
6.4
- KernelLinux
From 6.4.0 · fixed in 7.2.9