CVE-2021-47056 is a vulnerability identified in the Linux kernel specifically affecting the Intel QuickAssist Technology (QAT) driver component, which is responsible for hardware acceleration of cryptographic and compression operations. The flaw arises from improper handling of the initialization sequence in the qat driver, particularly in the function adf_dev_init(). The vulnerability occurs because the ADF_STATUS_PF_RUNNING flag is set unconditionally after calling adf_dev_init(), but if adf_dev_init() fails, the vf2pf_lock mutex is either not initialized or destroyed. Subsequent use of this mutex in adf_vf2pf_shutdown() leads to a use-after-free or invalid memory access condition, which can cause kernel crashes or undefined behavior. The kernel's KASAN (Kernel Address Sanitizer) detects this as a user-memory-access bug during mutex_lock operations. The root cause is a race or logic error where the driver assumes successful initialization before setting the running status flag, leading to unsafe locking operations on an uninitialized mutex. This vulnerability is present in specific Linux kernel versions identified by the commit hash 25c6ffb249f6..., affecting systems using the Intel QAT driver for cryptographic acceleration. Although no known exploits are reported in the wild, the flaw can cause denial of service (system crashes) or potentially be leveraged for privilege escalation if an attacker can trigger the faulty code path. The fix involves setting the ADF_STATUS_PF_RUNNING flag only if adf_dev_init() returns success, ensuring the mutex is valid before use.

For European organizations, the impact of CVE-2021-47056 primarily involves potential denial of service conditions on Linux systems utilizing Intel QAT hardware acceleration. This is particularly relevant for enterprises and data centers relying on hardware-accelerated cryptographic operations for performance-sensitive applications such as VPN gateways, secure communications, and high-throughput encryption workloads. A successful exploitation could cause kernel panics or crashes, leading to service interruptions and potential data processing delays. Although no direct evidence of privilege escalation exploits exists, the vulnerability could be a stepping stone in complex attack chains targeting critical infrastructure or cloud environments. Organizations with Linux-based servers running Intel QAT drivers in financial services, telecommunications, or government sectors may face increased risk due to the strategic importance of secure and reliable cryptographic services. Additionally, disruption of cryptographic acceleration could degrade performance, impacting operational efficiency and compliance with data protection regulations such as GDPR if service availability is compromised.

To mitigate CVE-2021-47056, European organizations should: 1) Apply the latest Linux kernel patches that address this vulnerability, ensuring the Intel QAT driver is updated to versions where the ADF_STATUS_PF_RUNNING flag is conditionally set only upon successful initialization. 2) Conduct thorough testing of kernel updates in staging environments to confirm stability and compatibility with existing cryptographic workloads. 3) Monitor kernel logs for signs of mutex_lock failures or KASAN warnings related to the qat driver, which may indicate attempted exploitation or instability. 4) Limit access to systems with Intel QAT hardware to trusted administrators and enforce strict privilege separation to reduce the risk of triggering the vulnerable code path. 5) Consider disabling Intel QAT acceleration temporarily if patching is not immediately feasible, especially in environments where availability is critical. 6) Implement comprehensive system monitoring and alerting to detect unusual kernel crashes or service disruptions that could be linked to this vulnerability. 7) Engage with hardware and Linux distribution vendors to receive timely updates and security advisories related to Intel QAT components.