CVE-2022-49564 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
crypto: qat - add param check for DH
Reject requests with a source buffer that is bigger than the size of the key. This is to prevent a possible integer underflow that might happen when copying the source scatterlist into a linear buffer.
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Analysis
by VulDB Data Team • 04/16/2025
The vulnerability identified as CVE-2022-49564 resides within the Linux kernel's Quick Assist Technology QAT crypto driver implementation. This flaw specifically affects the Diffie-Hellman key exchange functionality where the driver fails to properly validate input parameters before processing cryptographic operations. The issue manifests in the cryptographic subsystem that handles hardware acceleration for QAT devices, which are commonly used in enterprise and data center environments for offloading cryptographic workloads. The vulnerability impacts systems utilizing QAT hardware acceleration for cryptographic operations, particularly those implementing Diffie-Hellman key exchange protocols.
The technical root cause of this vulnerability stems from inadequate parameter validation within the QAT crypto driver's Diffie-Hellman implementation. When processing Diffie-Hellman key exchange requests, the driver does not properly verify that the source buffer size does not exceed the legitimate key size limits. This absence of validation creates a potential integer underflow condition during the buffer copying process from a scatterlist structure to a linear buffer. The underlying mechanism involves the driver attempting to allocate and copy data from a source scatterlist into a destination buffer, where the size calculation fails when the source buffer exceeds expected key dimensions. This represents a classic buffer overflow scenario that can be exploited through malformed input parameters, as the integer underflow can lead to memory corruption and potentially arbitrary code execution within the kernel context.
The operational impact of this vulnerability extends beyond simple memory corruption, as it can be leveraged by malicious actors to compromise the integrity of cryptographic operations within the Linux kernel. Systems utilizing QAT hardware acceleration for cryptographic functions become vulnerable to potential privilege escalation attacks, as the kernel's cryptographic subsystem becomes susceptible to malformed input that could trigger the integer underflow condition. The vulnerability affects the confidentiality and integrity of cryptographic communications, particularly in environments where Diffie-Hellman key exchanges are frequently performed. Attackers could exploit this weakness to disrupt cryptographic operations or potentially gain elevated privileges within the kernel space, making it particularly dangerous for enterprise environments that rely on hardware-accelerated cryptographic processing. The vulnerability aligns with CWE-129, which addresses improper validation of array index values, and represents a variant of buffer overflow conditions that can be exploited through integer underflow scenarios.
Mitigation strategies for CVE-2022-49564 focus primarily on applying the official kernel patches released by the Linux kernel development team. System administrators should immediately update their Linux kernel versions to include the fix that implements proper parameter validation for Diffie-Hellman key sizes. The patch introduces a validation check that explicitly compares the source buffer size against the expected key size limits, preventing the problematic integer underflow condition. Organizations should also implement monitoring solutions to detect unusual cryptographic operations or parameter combinations that might indicate exploitation attempts. Additionally, the vulnerability highlights the importance of comprehensive input validation in cryptographic implementations, aligning with ATT&CK technique T1059.001 for command and scripting interpreter execution, where malformed inputs could be used to trigger kernel vulnerabilities. Security teams should consider implementing network segmentation to limit exposure of systems running QAT hardware acceleration and ensure that only authorized processes can access cryptographic operations through the affected driver. The fix addresses the core issue by ensuring that the QAT driver properly validates all input parameters before processing cryptographic operations, thereby preventing the integer underflow condition that could lead to memory corruption and potential privilege escalation within the kernel space.