CVE-2024-26712 powerpc/kasan: Fix addr error caused by page alignment
A memory corruption vulnerability in the Linux kernel's KASAN initialization allows attackers to overwrite memory, potentially leading to code execution or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-26712?
CVE-2024-26712 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 3 Apr 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
powerpc/kasan: Fix addr error caused by page alignment
In kasan_init_region, when k_start is not page aligned, at the begin of for loop, k_cur = k_start & PAGE_MASK is less than k_start, and then `va = block + k_cur - k_start` is less than block, the addr va is invalid, because the memory address space from va to block is not alloced by memblock_alloc, which will not be reserved by memblock_reserve later, it will be used by other places.
As a result, memory overwriting occurs.
for example: int __init __weak kasan_init_region(void *start, size_t size) { [...] /* if say block(dcd97000) k_start(feef7400) k_end(feeff3fe) */ block = memblock_alloc(k_end - k_start, PAGE_SIZE); [...] for (k_cur = k_start & PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) { /* at the begin of for loop * block(dcd97000) va(dcd96c00) k_cur(feef7000) k_start(feef7400) * va(dcd96c00) is less than block(dcd97000), va is invalid */ void *va = block + k_cur - k_start; [...] } [...] }
Therefore, page alignment is performed on k_start before memblock_alloc() to ensure the validity of the VA address.
Which versions are affected by CVE-2024-26712?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2024-26712?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2024-26712 being exploited?
There is no known exploitation of CVE-2024-26712 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2024-26712, DEBIAN-CVE-2024-26712, GHSA-8vch-c6pw-5chh, UBUNTU-CVE-2024-26712.