Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: reject zero shift in nft_bitwise Reject zero shift operands for nft_bitwise left and right shift expressions during initialization. The carry propagation logic computes the carry from the adjacent 32-bit word using BITS_PER_TYPE(u32) - shift. A zero shift operand turns this into a 32-bit shift, which is undefined behaviour. Reject zero shift operands in the control plane, alongside the existing check for values greater than or equal to 32, so malformed rules never reach the packet path.

References 8

• git.kernel.org https://git.kernel.org/stable/c/4fccea585631621c975883911a08d15b6671f7dc
• git.kernel.org https://git.kernel.org/stable/c/6f820139d16a4c9865a145d4a9cf9c92cc632c14
• git.kernel.org https://git.kernel.org/stable/c/9ad26c272405f53834871cc2e46b9b5393a666c3
• git.kernel.org https://git.kernel.org/stable/c/9baa08d6b6b096fad70049533f0d705d85fdc979
• git.kernel.org https://git.kernel.org/stable/c/bffef0acec9c3b837a785248a893137fb7f26c95
• git.kernel.org https://git.kernel.org/stable/c/ca24f1243ad1a4d12d6a23876bbbe3ed02099853
• git.kernel.org https://git.kernel.org/stable/c/f370205974f171a5868c13ff30d7642fed46e47b
• git.kernel.org https://git.kernel.org/stable/c/fe11e5c40817b84abaa5d83bfb6586d8412bfd07

Remediation