IT

Tracker / CVE-2022-49077

CVE-2022-49077

Medium 5.5

In the Linux kernel, the following vulnerability has been resolved: mmmremap.c: avoid pointless invalidate_range_start/end on mremap(old_size=0) If an mremap() syscall with old_size=0 ends up in move_page_tables(), it will call invalidate_range_start()/invalidate_range_end() unnecessarily, i.e. with an empty range. This causes a WARN in KVM's mmu_notifier. In the past, empty ranges have been diagnosed to be off-by-one bugs, hence the WARNing. Given the low (so far) number of unique reports, the benefits of detecting more buggy callers seem to outweigh the cost of having to fix cases such as this one, where userspace is doing something silly. In this particular case, an early return from move_page_tables() is enough to fix the issue.

Affected products and versions

linux linux_kernel
linux linux_kernel · … → 4.9.311
linux linux_kernel · 4.10 → 4.14.276
linux linux_kernel · 4.15 → 4.19.238
linux linux_kernel · 4.20 → 5.4.189
linux linux_kernel · 5.11 → 5.15.34
linux linux_kernel · 5.16 → 5.16.20
linux linux_kernel · 5.17 → 5.17.3
linux linux_kernel · 5.5 → 5.10.111

Analysis

This page is not indexable yet.Until it carries original analysis — what it actually exposes, how to check in two minutes whether a system was touched, what to do if it was — the page stays noindex. The database decides that, not the template.

References