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Date:      Tue, 11 Nov 1997 07:13:54 -0800 (PST)
From:      jt@nanoteq.com
To:        freebsd-gnats-submit@FreeBSD.ORG
Subject:   kern/5011: rndcontrol -s 8 causes kernel panic
Message-ID:  <199711111513.HAA28208@hub.freebsd.org>
Resent-Message-ID: <199711111520.HAA28705@hub.freebsd.org>

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>Number:         5011
>Category:       kern
>Synopsis:       rndcontrol -s 8 causes kernel panic
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Nov 11 07:20:00 PST 1997
>Last-Modified:
>Originator:     Johann Tonsing
>Organization:
Nanoteq
>Release:        2.2.5-STABLE
>Environment:
FreeBSD Amnesiac.Domain 2.2.5-STABLE FreeBSD 2.2.5-STABLE #0: Mon Nov 10 05:21:1
4 SAT 1997     root@zibbi.mikom.csir.co.za:/ns/dist/src/kernel/sys/compile/NSR
i386
>Description:
If interrupt 8 is enabled for random information collection,
the kernel panics.

Admittedly this is a silly thing to do (IRQ8=RTC, which
is supposed to NOT be very random ;-)) but rndcontrol 
and/or the kernel /dev/random code should disallow this -
kernel panic is too drastic a punishment.


>How-To-Repeat:
Add interrupt 8 to the random bit collection interrupts.
Example:
# rndcontrol -s 8
rndcontrol: setting irq 8
rndcontrol: Interrupts in use: 8
#
Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0x28
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xf0105ec5
stack pointer           = 0x10:0xf01b9f6c
frame pointer           = 0x10:0xf01b9f74
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = Idle
interrupt mask          =
panic: page fault


>Fix:
Add (more) validation code to rndcontrol and/or /dev/random
to disallow IRQ 8 -or- allow addition but fix whatever causes
panic.




>Audit-Trail:
>Unformatted:



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