CVE-2024-50270 in Linux
Summary
by MITRE • 11/19/2024
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/core: avoid overflow in damon_feed_loop_next_input()
damon_feed_loop_next_input() is inefficient and fragile to overflows. Specifically, 'score_goal_diff_bp' calculation can overflow when 'score' is high. The calculation is actually unnecessary at all because 'goal' is a constant of value 10,000. Calculation of 'compensation' is again fragile to overflow. Final calculation of return value for under-achiving case is again fragile to overflow when the current score is under-achieving the target.
Add two corner cases handling at the beginning of the function to make the body easier to read, and rewrite the body of the function to avoid overflows and the unnecessary bp value calcuation.
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Analysis
by VulDB Data Team • 10/22/2025
The vulnerability identified as CVE-2024-50270 resides within the Linux kernel's DAMON (Dynamic Access Monitor) subsystem, specifically in the mm/damon/core module where the damon_feed_loop_next_input() function exhibits critical overflow conditions that could lead to system instability or potential exploitation. This issue affects the kernel's memory management and monitoring capabilities, particularly impacting how the DAMON subsystem calculates performance metrics for memory access patterns and optimization. The vulnerability manifests through multiple overflow scenarios that occur during the calculation of score differentials and compensation values, creating a fragile state where normal system operations could trigger arithmetic overflow conditions.
The technical flaw stems from the improper handling of integer arithmetic within the damon_feed_loop_next_input() function where the score_goal_diff_bp calculation can overflow when the score value becomes sufficiently high. This overflow vulnerability is compounded by the fact that the calculation of compensation values also suffers from similar fragility issues, while the final return value computation for under-achieving cases demonstrates additional overflow risks when current scores fall below target thresholds. The root cause is exacerbated by the unnecessary computation of a bp value that serves no functional purpose given that the goal constant is fixed at 10,000, making the entire calculation chain redundant and prone to failure.
The operational impact of this vulnerability extends beyond simple arithmetic errors to potentially compromise system stability and security. When overflow conditions occur in kernel space, they can lead to unpredictable behavior including system crashes, memory corruption, or in worst-case scenarios, privilege escalation opportunities that attackers could exploit to gain elevated system privileges. The DAMON subsystem's role in monitoring memory access patterns means that any instability in this component could affect memory management decisions and potentially disrupt critical system operations. The vulnerability affects systems running Linux kernels that incorporate the DAMON memory monitoring framework, particularly those utilizing memory access pattern analysis for optimization purposes.
Security mitigations for this vulnerability require immediate kernel updates that address the specific overflow conditions in the damon_feed_loop_next_input() function. The fix implemented involves adding corner case handling at the function's beginning to simplify the logic flow and eliminate the problematic overflow scenarios. The revised implementation removes the unnecessary bp value calculation that was causing the primary overflow issues while ensuring all remaining arithmetic operations handle potential overflow conditions properly. This solution aligns with common security practices for kernel vulnerability remediation, specifically addressing CWE-191 (Integer Underflow) and CWE-190 (Integer Overflow) categories. The mitigation approach follows established security frameworks such as those outlined in the ATT&CK framework for kernel-level exploits, where integer overflow conditions in system call handlers represent common attack vectors that require careful arithmetic boundary checking and input validation to prevent exploitation.