CVE-2024-26947 ARM: 9359/1: flush: check if the folio is reserved for no-mapping addresses
A missing check for reserved folios in the ARM cache flush routine causes a kernel crash when mapping specific UIO memory regions.
- 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-2024-26947?
CVE-2024-26947 is a medium-severity vulnerability in Linux kernel, published on 1 May 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:
ARM: 9359/1: flush: check if the folio is reserved for no-mapping addresses
Since commit a4d5613c4dc6 ("arm: extend pfn_valid to take into account freed memory map alignment") changes the semantics of pfn_valid() to check presence of the memory map for a PFN. A valid page for an address which is reserved but not mapped by the kernel[1], the system crashed during some uio test with the following memory layout:
node 0: [mem 0x00000000c0a00000-0x00000000cc8fffff] node 0: [mem 0x00000000d0000000-0x00000000da1fffff] the uio layout is：0xc0900000, 0x100000
the crash backtrace like:
Unable to handle kernel paging request at virtual address bff00000 [...] CPU: 1 PID: 465 Comm: startapp.bin Tainted: G O 5.10.0 #1 Hardware name: Generic DT based system PC is at b15_flush_kern_dcache_area+0x24/0x3c LR is at __sync_icache_dcache+0x6c/0x98 [...] (b15_flush_kern_dcache_area) from (__sync_icache_dcache+0x6c/0x98) (__sync_icache_dcache) from (set_pte_at+0x28/0x54) (set_pte_at) from (remap_pfn_range+0x1a0/0x274) (remap_pfn_range) from (uio_mmap+0x184/0x1b8 [uio]) (uio_mmap [uio]) from (__mmap_region+0x264/0x5f4) (__mmap_region) from (__do_mmap_mm+0x3ec/0x440) (__do_mmap_mm) from (do_mmap+0x50/0x58) (do_mmap) from (vm_mmap_pgoff+0xfc/0x188) (vm_mmap_pgoff) from (ksys_mmap_pgoff+0xac/0xc4) (ksys_mmap_pgoff) from (ret_fast_syscall+0x0/0x5c) Code: e0801001 e2423001 e1c00003 f57ff04f (ee070f3e) ---[ end trace 09cf0734c3805d52 ]--- Kernel panic - not syncing: Fatal exception
So check if PG_reserved was set to solve this issue.
[1]: https://lore.kernel.org/lkml/[email protected]/
Which versions are affected by CVE-2024-26947?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-26947?
Apply the vendor's patch.
Is CVE-2024-26947 being exploited?
There is no known exploitation of CVE-2024-26947 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-67481, BELL-CVE-2024-26947, DEBIAN-CVE-2024-26947, GHSA-xqwg-gh2q-g24c, ROOT-OS-DEBIAN-11-CVE-2024-26947, ROOT-OS-DEBIAN-12-CVE-2024-26947 and 1 more.