Linux Kernel Netfilter nf_tables Register Overlap Vulnerability

A vulnerability in the Linux kernel's netfilter component, specifically within the nf_tables subsystem, has been addressed. The issue involved incorrect handling of register overlaps during left and right shift operations, which could lead to data corruption. When the source and destination registers pointed to the same memory location, the carry for the shift operation was improperly calculated, using the modified destination value instead of the original source value. This vulnerability affected the Linux kernel stable tree.

Impact

The vulnerability could cause data corruption by incorrectly calculating the carry during shift operations, leading to potential logical errors in packet processing.

Reproduction

The vulnerability could be reproduced by creating a test table in the nf_tables subsystem and using bytecode that shifts a value in a register while overlapping the source and destination registers. This would demonstrate the incorrect carry calculation and the resulting data corruption.

Remediation

Users can upgrade to the latest version of the Linux kernel stable tree, where this vulnerability has been fixed.