mm/slab: do not limit zeroing to orig_size when only red zoning is enabled
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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 6.6.145, 6.12.96, 6.18.39, 7.1.4
- 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
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/slab: do not limit zeroing to orig_size when only red zoning is enabled When init (zeroing) on allocation is requested, for kmalloc() we generally have to zero the full object size even if a smaller size is requested, in order to provide krealloc()'s __GFP_ZERO guarantees. But if we track the requested size, krealloc() uses that information to do the right thing, so we can zero only the requested size. With red zoning also enabled, any extra size became part of the red zone, so it must not be zeroed and thus we must zero only the requested size. However the current check is imprecise, and will trigger also when only SLAB_RED_ZONE is enabled without SLAB_STORE_USER (which enables tracking the requested size). This means enabling red zoning alone can compromise krealloc()'s __GFP_ZERO contract. Fix this by using slub_debug_orig_size() instead, which is the exact check for whether the requested size is tracked. We don't need to care if red zoning is also enabled or not. Also update and expand the comment accordingly.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Linux Linux
From 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 · fixed in 6256899c3a34674bba6076884aedbba49fc695e4; From 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 · fixed in 7e706d50fa119eead6376bf0ef973e8d73a96030; From 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 · fixed in 2382971aaaef5bf85a651234c64906f59580b8be; From 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 · fixed in 0d18ccef142f04433dfb2a0c120cf223d2b8a42c; From 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 · fixed in 648927ceb84021a25a0fbd5673740956f318d534
- Linux Linux
6.2
- KernelLinux
From 6.2.0 · fixed in 6.6.145; From 6.7.0 · fixed in 6.12.96; From 6.13.0 · fixed in 6.18.39; From 6.19.0 · fixed in 7.1.4