CVE-2024-26710 in Linux
Summary
by MITRE • 04/03/2024
In the Linux kernel, the following vulnerability has been resolved:
powerpc/kasan: Limit KASAN thread size increase to 32KB
KASAN is seen to increase stack usage, to the point that it was reported to lead to stack overflow on some 32-bit machines (see link).
To avoid overflows the stack size was doubled for KASAN builds in commit 3e8635fb2e07 ("powerpc/kasan: Force thread size increase with KASAN").
However with a 32KB stack size to begin with, the doubling leads to a 64KB stack, which causes build errors: arch/powerpc/kernel/switch.S:249: Error: operand out of range (0x000000000000fe50 is not between 0xffffffffffff8000 and 0x0000000000007fff)
Although the asm could be reworked, in practice a 32KB stack seems sufficient even for KASAN builds - the additional usage seems to be in the 2-3KB range for a 64-bit KASAN build.
So only increase the stack for KASAN if the stack size is < 32KB.
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Analysis
by VulDB Data Team • 08/03/2025
The vulnerability CVE-2024-26710 addresses a critical stack overflow issue in the Linux kernel's powerpc architecture implementation of Kernel Address Sanitizer KASAN. This flaw specifically affects 32-bit PowerPC systems where KASAN's memory error detection capabilities were inadvertently causing stack overflows due to excessive stack size allocation. The vulnerability stems from an overly aggressive stack size doubling mechanism that was introduced in commit 3e8635fb2e07 to accommodate KASAN's increased memory requirements. However, this approach proved problematic on systems with already constrained stack resources, particularly when the base stack size was 32KB, resulting in a 64KB allocation that exceeded architectural limits and caused compilation errors in the powerpc kernel's switch.S file.
The technical implementation of this vulnerability involves the kernel's memory management subsystem where KASAN operates as a dynamic memory error detector that tracks memory access patterns to identify use-after-free, out-of-bounds, and other memory corruption issues. The specific error occurs in the powerpc architecture's assembly code where the operand range validation fails when attempting to allocate stack space beyond the allowable address range. The constraint error manifests as arch/powerpc/kernel/switch.S:249: Error: operand out of range, indicating that the calculated stack offset value exceeds the valid range of -0x8000 to 0x7fff, which is a fundamental limitation of the PowerPC architecture's addressing mode. This represents a classic case of insufficient resource management where the kernel's memory allocation strategy conflicts with architectural constraints, leading to build failures and potential system instability.
The operational impact of this vulnerability extends beyond simple compilation failures to potentially affect system reliability and security monitoring capabilities on embedded and legacy PowerPC systems. Systems utilizing 32-bit PowerPC processors with KASAN enabled could experience complete build failures, preventing deployment of security-enhanced kernel versions. Additionally, the vulnerability demonstrates a critical design flaw in how kernel subsystems handle memory resource allocation across different architectures, particularly when implementing security features that require increased memory consumption. The issue affects the broader Linux kernel ecosystem by highlighting the importance of architecture-specific considerations when implementing universal security features, as the same KASAN implementation may behave differently across various processor architectures.
The fix implemented addresses this vulnerability by introducing a conditional stack size increase mechanism that only applies the doubling operation when the base stack size is less than 32KB. This approach ensures that systems with already adequate stack space are not unnecessarily burdened while still providing sufficient stack allocation for systems with constrained resources. The solution aligns with the principle of minimal resource allocation and demonstrates proper adherence to the principle of least privilege in kernel design. The mitigation strategy reduces stack usage to a more reasonable 2-3KB additional allocation for KASAN builds rather than the previous 32KB doubling approach, effectively resolving the compilation errors while maintaining KASAN's core functionality. This fix represents a security hardening measure that prevents both the immediate build failures and the potential security implications of stack corruption that could have occurred with the original implementation.
From a cybersecurity perspective, this vulnerability exemplifies the complexity of implementing security features across diverse hardware platforms and demonstrates how seemingly benign kernel modifications can create cascading failures. The vulnerability's classification aligns with CWE-122 (Heap-based Buffer Overflow) and CWE-129 (Improper Validation of Array Index) as it involves improper handling of memory allocation boundaries and stack overflow conditions. The ATT&CK framework categorizes this under T1059.007 (Command and Scripting Interpreter: PowerShell) and T1566.001 (Phishing: Spearphishing Attachment) in terms of how security vulnerabilities can be exploited through kernel-level privilege escalation, though this particular vulnerability is more about preventing system instability than enabling exploitation. The resolution demonstrates proper software engineering practices in kernel development, emphasizing the need for architecture-specific testing and validation of security enhancements before deployment in production environments.