6296988 format: segfault due to buffer overflow in shell escape code

[nore...@opensolaris.org]

Author: pr131582
Repository: /hg/onnv/onnv-gate
Revision: 26959c951b074bc1c07547c1312dde8eda2bcc74
Log message:
6296988 format: segfault due to buffer overflow in shell escape code

Files:
        update: usr/src/cmd/format/io.c
        update: usr/src/cmd/format/io.h
        update: usr/src/cmd/format/menu_scsi.c