Editing Buffer overflow protection (section)

===Terminator canaries===
''Terminator canaries'' use the observation that most buffer overflow attacks are based on certain string operations which end at string terminators. The reaction to this observation is that the canaries are built of [[null character|null]] terminators, [[Carriage return|CR]], LF, and [[Page_break#Form_feed|FF]]. As a result, the attacker must write a null character before writing the return address to avoid altering the canary. This prevents attacks using <code>strcpy()</code> and other methods that return upon copying a null character, while the undesirable result is that the canary is known. Even with the protection, an attacker could potentially overwrite the canary with its known value and control information with mismatched values, thus passing the canary check code, which is executed soon before the specific processor's return-from-call instruction.