[*] zero-length key buffer modeled by a pointer whose first byte
    (key[0]) lies in a PROT_NONE guard page
[*] calling buggy rc4_init(state, key, keylen=0)...
Segmentation fault (core dumped)
RC=139
-- kernel corroboration (guest serial console, same binary):
Oct 25 22:24:25 dfbsd kernel: pid 1063 (p366s), uid 1001: exited on signal 11 (core dumped)