kernel: agp: insufficient pg_start parameter checking in AGPIOC_BIND and AGPIOC_UNBIND ioctls

Integer overflow in the agpgenericinsertmemory function in drivers/char/agp/generic.c in the Linux kernel before 2.6.38.5 allows local users to gain privileges or cause a denial of service system crash via a crafted AGPIOCBIND agpioctl ioctl call...