CVE-2021-47633: 
Linux Kernel vulnerability analysis and mitigation

A vulnerability was discovered in the Linux kernel's ath5k driver, specifically in the ath5k_eeprom_read_pcal_info_5111 function (CVE-2021-47633). The issue was identified through fuzzing and involves an out-of-bounds (OOB) write condition in the ath5k_eeprom_convert_pcal_info_5111 function. When no curve is selected in a loop, the index variable can reach AR5K_EEPROM_N_PD_CURVES, leading to an out-of-bounds memory access (Kernel Git).

The vulnerability occurs when the idx variable reaches AR5K_EEPROM_N_PD_CURVES in the code, causing an out-of-bounds condition with the statement 'pd = &chinfo[pier].pd_curves[idx]'. This results in multiple out-of-bounds writes later in the code execution. The issue was discovered using the Kernel Address Sanitizer (KASAN), which detected a slab-out-of-bounds write of size 1 at address ffff8880174a4d60 during module loading (Kernel Git).

The vulnerability could lead to out-of-bounds memory writes in the Linux kernel's ath5k wireless driver, potentially causing system crashes or memory corruption. This affects systems using the ath5k driver for wireless networking (NVD).

The vulnerability was discovered during fuzzing operations and requires local access to a system with the ath5k driver loaded. A proof-of-concept exists in the form of a fuzzing report that demonstrates the trigger conditions for the vulnerability (Kernel Git).

A patch has been developed that adds a sanity check for the idx variable before it's used to access the pd_curves array. The fix involves adding a condition to check if idx equals AR5K_EEPROM_N_PD_CURVES and redirecting to an error handler if true (Kernel Git).