- Vulnerability/
- CVE-2024-42293
CVE-2024-42293: arm64: mm: Fix lockless walks with static and dynamic page-table folding
First published: Sat Aug 17 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: arm64: mm: Fix lockless walks with static and dynamic page-table folding Lina reports random oopsen originating from the fast GUP code when 16K pages are used with 4-level page-tables, the fourth level being folded at runtime due to lack of LPA2. In this configuration, the generic implementation of p4d_offset_lockless() will return a 'p4d_t *' corresponding to the 'pgd_t' allocated on the stack of the caller, gup_fast_pgd_range(). This is normally fine, but when the fourth level of page-table is folded at runtime, pud_offset_lockless() will offset from the address of the 'p4d_t' to calculate the address of the PUD in the same page-table page. This results in a stray stack read when the 'p4d_t' has been allocated on the stack and can send the walker into the weeds. Fix the problem by providing our own definition of p4d_offset_lockless() when CONFIG_PGTABLE_LEVELS <= 4 which returns the real page-table pointer rather than the address of the local stack variable.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel |
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Reference Links
Frequently Asked Questions
What is the severity of CVE-2024-42293?
CVE-2024-42293 has been assigned a moderate severity rating due to its potential impact on system stability.
How do I fix CVE-2024-42293?
To fix CVE-2024-42293, ensure your Linux kernel is updated to the latest version containing the security patch.
What are the consequences of not addressing CVE-2024-42293?
Failing to address CVE-2024-42293 may lead to random system crashes and instability when using certain memory configurations.
Which versions of the Linux kernel are affected by CVE-2024-42293?
CVE-2024-42293 affects versions of the Linux kernel using arm64 architecture with 16K pages configured.
Is there a workaround for CVE-2024-42293?
A temporary workaround for CVE-2024-42293 may involve avoiding the use of 16K pages with folding in affected systems until a patch is applied.
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