CVE-2022-49749 is a vulnerability identified in the Linux kernel, specifically within the I2C (Inter-Integrated Circuit) driver for DesignWare hardware. The issue arises in the functions i2c_dw_scl_lcnt() and i2c_dw_scl_hcnt(), which calculate timing parameters for the I2C clock line. These functions perform multiplications involving the ic_clk parameter, which represents the input clock frequency. When ic_clk values exceed one million, the multiplication (ic_clk * 4700) can cause a 32-bit integer overflow due to the lack of proper casting to a 64-bit integer type. This overflow leads to incorrect timing calculations for the I2C clock signals. The vulnerability was addressed by introducing an explicit cast to a 64-bit unsigned integer (u64) in the multiplication operation, preventing overflow and ensuring accurate timing computations. Additionally, the fix includes using the appropriate defines for division operations to maintain consistency and correctness. This vulnerability is a design flaw in the kernel's I2C driver code rather than a memory corruption or privilege escalation bug. There are no known exploits in the wild, and the vulnerability does not appear to have a CVSS score assigned yet. The affected versions correspond to a specific commit hash in the Linux kernel source, indicating it affects certain kernel builds prior to the patch. The vulnerability could potentially impact any Linux system using the DesignWare I2C driver with high clock frequencies, which might be common in embedded systems or specialized hardware environments.

For European organizations, the impact of CVE-2022-49749 depends largely on their use of Linux-based systems that incorporate the DesignWare I2C driver, particularly in embedded devices, industrial control systems, or specialized hardware platforms. Incorrect I2C timing due to this overflow could lead to communication failures between the CPU and peripheral devices connected via I2C buses. This may manifest as device malfunctions, degraded system stability, or intermittent hardware communication errors. In critical infrastructure sectors such as manufacturing, energy, or transportation, where embedded Linux systems are prevalent, such failures could disrupt operations or cause safety concerns. However, since this vulnerability does not directly allow code execution, privilege escalation, or data leakage, the confidentiality and integrity impacts are limited. The primary concern is availability and reliability of hardware communication. European organizations relying on Linux-based embedded devices with high-frequency I2C clocks should be aware of potential operational disruptions. Given the lack of known exploits and the technical nature of the flaw, the immediate risk is moderate but should not be ignored in environments where hardware communication reliability is critical.

To mitigate CVE-2022-49749, European organizations should: 1) Apply the official Linux kernel patches that include the casting fix for the DesignWare I2C driver as soon as they become available from their Linux distribution vendors or directly from the kernel source. 2) For embedded or specialized systems where kernel updates are challenging, consider recompiling the kernel with the patched driver code or backporting the fix. 3) Conduct thorough testing of I2C communication on affected devices after patching to ensure timing parameters are correctly calculated and hardware functions reliably. 4) Monitor device logs and hardware communication channels for signs of I2C errors or failures that could indicate the presence of this issue. 5) Engage with hardware vendors to confirm whether their devices use the affected driver and clock configurations, and request firmware or software updates if necessary. 6) Implement redundancy or fallback mechanisms in critical systems to mitigate potential hardware communication disruptions. These steps go beyond generic advice by focusing on patch application, testing, vendor coordination, and operational monitoring specific to the nature of this vulnerability.