Changing time causes ipv6 panics

[Kris Kennaway]

On Tue, Feb 07, 2006 at 07:16:09PM +0900, JINMEI Tatuya / ?$B?@L at C#:H wrote:
> >>>>> On Tue, 7 Feb 2006 00:45:02 -0500, 
> >>>>> Kris Kennaway <kris at obsecurity.org> said:
> 
> >> I ran ntpdate on an amd64 system with ipv6 enabled and a skewed clock
> >> (ntpdate stepped it back by about an hour), and immediately got a
> >> use-after-free panic in ifaddr.  When I rebooted with memguard enabled
> >> on this malloc type and retried, I got this panic upon changing the
> >> date forward, then back, then forward again (also note the garbage
> >> return data from ntpdate):
> 
> > Has anyone looked at this?  This is on the TODO list for 6.1, so the
> > sooner it can be resolved the better.
> 
> Sorry, not really (we've not got a test environment to reproduce it).
> But from a quick review of nd6.c, there seems to be one thing that is
> obviously wrong.  The possible bug has been there since rev. 1.19
> committed in April 2002.  We've been probably just lucky so far...
> 
> Could you try the patch attached below?  We'll probably also need to
> apply this fix to 4.X and 5.X.

The patch did not fix the panic.

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address   = 0xffffffff919d5198
fault code              = supervisor write, protection violation
instruction pointer     = 0x8:0xffffffff8031fa76
stack pointer           = 0x10:0xffffffffbcda4b60
frame pointer           = 0x10:0xffffffffbcda4b90
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 14 (swi4: clock sio)
[thread pid 14 tid 100010 ]
Stopped at      nd6_timer+0x106:        movl    %eax,0x198(%rbx)
db> wh
Tracing pid 14 tid 100010 td 0xffffff03e15d6c30
nd6_timer() at nd6_timer+0x106
softclock() at softclock+0x279
ithread_execute_handlers() at ithread_execute_handlers+0x12f
ithread_loop() at ithread_loop+0x99
fork_exit() at fork_exit+0xdf
fork_trampoline() at fork_trampoline+0xe
--- trap 0, rip = 0, rsp = 0xffffffffbcda4d40, rbp = 0 ---
db>

> (a note about the patch: the first chunk is actually not related to
> the bug, but I could not miss the trivial typo)

You missed the other one though :-)

> -	 * However, from a stricter speci-confrmance standpoint, we should
> +	 * However, from a stricter spec-confrmance standpoint, we should
                                             ^o

Kris
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