CVE-2024-50233 in Linux
Summary
by MITRE • 11/09/2024
In the Linux kernel, the following vulnerability has been resolved:
staging: iio: frequency: ad9832: fix division by zero in ad9832_calc_freqreg()
In the ad9832_write_frequency() function, clk_get_rate() might return 0. This can lead to a division by zero when calling ad9832_calc_freqreg(). The check if (fout > (clk_get_rate(st->mclk) / 2)) does not protect against the case when fout is 0. The ad9832_write_frequency() function is called from ad9832_write(), and fout is derived from a text buffer, which can contain any value.
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Analysis
by VulDB Data Team • 10/02/2025
The vulnerability CVE-2024-50233 represents a critical division by zero condition within the Linux kernel's industrial I/O subsystem, specifically affecting the AD9832 frequency synthesizer driver. This flaw exists in the staging directory of the kernel codebase and impacts devices that utilize the Analog Devices AD9832 programmable frequency synthesizer chip. The issue stems from inadequate input validation and error handling within the frequency calculation logic, creating a potential denial of service scenario that could compromise system stability. The vulnerability is classified under CWE-369 as a division by zero error, which represents a fundamental programming flaw that can lead to system crashes and service disruption.
The technical implementation of this vulnerability occurs within the ad9832_write_frequency() function where the clk_get_rate() API call can return zero, typically when the master clock reference is not properly initialized or configured. When this zero value is passed through to the ad9832_calc_freqreg() calculation function, it results in a division by zero error. The existing validation check of fout > (clk_get_rate(st->mclk) / 2) fails to account for the scenario where fout itself equals zero, creating a condition where the division operation executes with a zero denominator. This function is invoked from the ad9832_write() handler which processes user-space input from text buffers, making the vulnerability exploitable through malformed input data that can originate from various system interfaces including device files or sysfs entries.
The operational impact of this vulnerability extends beyond simple system crashes, as it can potentially enable privilege escalation or denial of service conditions within embedded systems that rely on precise frequency control. Attackers could exploit this condition by providing specially crafted frequency values through the I/O interfaces, causing the kernel to crash and potentially leading to system instability. The vulnerability affects systems using the AD9832 chip in industrial I/O applications where precise frequency generation is critical, including telecommunications equipment, scientific instruments, and embedded control systems. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 (Resource Hijacking) and T1566.001 (Phishing with Social Engineering) as it can be leveraged to disrupt system operations and potentially gain unauthorized access to embedded systems through service disruption.
Mitigation strategies for this vulnerability require immediate kernel updates addressing the specific division by zero condition in the ad9832 driver implementation. System administrators should ensure all affected Linux kernel versions are patched, particularly those running embedded systems or industrial I/O applications. The fix should implement proper error handling for clk_get_rate() return values, including checking for zero returns before performing division operations. Additionally, input validation should be strengthened to prevent malformed frequency values from reaching the calculation functions. Organizations should also consider implementing runtime monitoring for kernel panic conditions and system stability indicators. The vulnerability highlights the importance of proper error handling in kernel space drivers and the need for comprehensive testing of edge cases in clock and frequency calculation routines. Regular security audits of kernel subsystems, particularly those handling hardware interfaces, should be conducted to identify similar patterns of inadequate input validation that could lead to similar vulnerabilities.