CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's handling of EP11 CPRB payloads within the zcrypt subsystem, specifically through the use of fragile struct overlays that compromise both maintainability and security. The flawed ASN.1 parsing and lack of proper validation can lead to potential exploitation, making it critical for organizations utilizing Linux systems, particularly those relying on zcrypt for cryptographic operations, to prioritize applying the fix. Immediate attention is recommended to mitigate risks associated with improper payload handling and potential security breaches.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: s390/zcrypt: Improve EP11 CPRB domain handling with ASN.1 parsing The zcrypt_msgtype6_send_ep11_cprb() function uses fragile struct overlays to access and modify the domain field in the EP11 CPRB payload, creating maintainability and security concerns: 1. Struct overlay approach (pld_hdr) assumes fixed payload structure and doesn't validate the actual ASN.1 encoding. 2. Complex length format detection logic is error-prone and doesn't properly validate bounds at each parsing step. 3. Direct struct member access bypasses proper ASN.1 validation. Fix by replacing struct overlays with explicit ASN.1 parsing that validates each field (payload tag/length, function tag/length/value, optional domain tag/length/value) with proper bounds checking at every step. Add asn1_int_encode() helper function to safely write integer values with correct endianness conversion. This makes the code consistent with the validation pattern introduced with the rework of the xcrb_msg_to_type6_ep11cprb_msgx() function.