Sign hook for secure boot

zz_sign.sh

#!/usr/bin/bash

LOGPATH="/var/log/zz_sign"
LOGFILE="$LOGPATH/log-$(date).txt"

PUBLICKEYFILE="/home/user/Documents/UEFI/public_key.der"
PRIVATEKEYFILE="/home/user/Documents/UEFI/private_key.priv"

sign() {
    if [ -f "$PUBLICKEYFILE" ]; then
        if [ -f "$PRIVATEKEYFILE" ]; then
            find "/usr/lib/modules/${1}/extra" -name "*.ko" -type f -exec /usr/src/kernels/${1}/scripts/sign-file sha256 "$PRIVATEKEYFILE" "$PUBLICKEYFILE" "{}" \;
        else
            echo "Private key file doesn't exists!"
            exit 1
        fi
    else
        echo "Public key file doesn't exists!"
        exit 1
    fi
}

if [ -d "$LOGPATH" ]; then
    mkdir -p "$LOGPATH"
fi

sign $1 2>&1 | tee "$LOGFILE"