check_cve.sh

#!/bin/bash
# CVE-2026-31431 (Copy-Fail) Vulnerability Checker
echo "=========================================="
echo "CVE-2026-31431 (Copy-Fail) Checker"
echo "=========================================="
V=0
echo -e "\n[1] algif_aead module"
lsmod | grep -q "^algif_aead" && echo "[VULN] LOADED" && V=1 || echo "[INFO] not loaded"

echo -e "\n[2] CRYPTO_USER_API config"
if zcat /proc/config.gz 2>/dev/null | grep -q "^CONFIG_CRYPTO_USER_API=y"; then
    echo "[VULN] BUILT-IN"; V=1
elif zcat /proc/config.gz 2>/dev/null | grep -q "^CONFIG_CRYPTO_USER_API=m"; then
    echo "[INFO] MODULE (trying to load...)"
    modprobe algif_aead 2>/dev/null
    lsmod | grep -q "^algif_aead" && echo "[VULN] loaded OK" && V=1
else
    echo "[SAFE] not enabled"
fi

echo -e "\n[3] authencesn algorithm"
grep -q "authencesn" /proc/crypto 2>/dev/null && echo "[VULN] available" && V=1 || echo "[SAFE] not found"

echo -e "\n[4] AF_ALG socket test"
python3 -c "
import socket
try:
    s=socket.socket(38,5,0)
    s.bind(('aead','authencesn(hmac(sha256),cbc(aes))'))
    print('[VULN] socket created OK')
    exit(0)
except Exception as e:
    print('[SAFE] failed:',e)
    exit(1)
" 2>/dev/null && V=1

echo -e "\n=========================================="
echo "RESULT: $([ $V -eq 1 ] && echo '[!!!] VULNERABLE' || echo '[OK] NOT vulnerable')"
echo "=========================================="
echo "Fix: rmmod algif_aead || update kernel"