Linux Kernel RDMA/nldev Counter Underflow Vulnerability

A vulnerability in the Linux kernel's RDMA/nldev component allows for an underflow condition in the function nldev_stat_set_counter_dynamic_doit(). The issue arises because the code checks the 'index' variable for an upper bound but fails to validate negative values. This oversight can lead to unintended behavior, as negative indices are not properly handled. The vulnerability has been addressed by changing the index variable's type to unsigned, eliminating the risk of underflow.

Impact

Exploitation of this vulnerability could lead to an underflow condition, potentially causing unexpected behavior in the affected component.