kern/47435: wd_trim doesn't check bounds

[dholland%eecs.harvard.edu@localhost]

>Number:         47435
>Category:       kern
>Synopsis:       wd_trim doesn't check bounds
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jan 12 00:15:00 +0000 2013
>Originator:     David A. Holland
>Release:        NetBSD 6.99.16 (20130108)
>Organization:
>Environment:
System: NetBSD amberdon 6.99.16 NetBSD 6.99.16 (AMBERDON) #7: Tue Jan  8 
17:14:49 EST 2013  root@amberdon:/usr/src/sys/arch/amd64/compile/AMBERDON amd64
Architecture: x86_64
Machine: amd64
>Description:

wd_trim() adds in the partition offset, if you do it on other than
RAW_PART, but it does not check that you aren't running off the end of
the partition into another.

>How-To-Repeat:

code reading.

>Fix:

Straightforward.

(Also, I have my doubts as to whether DIOCGDISCARDPARAMS and
DIOCDISCARD is the API we want to provide in the long term. This is
not the right place to discuss that though.)