Switch blocksize and count when reading from urandom with dd, to prevent getting fewer bytes for the secret key.

setup/webmail.sh

@@ -36,7 +36,7 @@ if [ ! -d /usr/local/lib/roundcubemail ]; then
 fi
 
 # Generate a safe 24-character secret key of safe characters.
-SECRET_KEY=$(dd if=/dev/random bs=20 count=1 2>/dev/null | base64 | fold -w 24 | head -n 1)
+SECRET_KEY=$(dd if=/dev/random bs=1 count=18 2>/dev/null | base64 | fold -w 24 | head -n 1)
 
 # Create a configuration file.
 #