Multiple integer overflows in Sbus PROM driver (drivers/sbus/char/openprom.c) for the Linux kernel 2.4.x up to 2.4.27, 2.6.x up to 2.6.7, and possibly later versions, allow local users to execute arbitrary code by specifying (1) a small buffer size to the copyin_string function or (2) a negative buffer size to the copyin function.