Raw AES key left unzeroed on kernel stack in rijndael_makeKey

Summary

rijndael_makeKey copies callers raw key material into 32-byte stack buffer u_int8_t cipherKey[RIJNDAEL_MAXKB] and derives AES round schedules but never clears cipherKey before returning. Raw key bytes persist in rijndael_makeKey stack frame until later call reuses those locations. Any separate kernel stack info-disclosure primitive could recover them. No memset/explicit_bzero anywhere in function body. explicit_bzero available in sys/sys/systm.h. Requires separate stack info-leak primitive for exploitation.