[time-nuts] Re: GPS D (i.e. gpsd) roll over bug..Oct 24th

[Bob kb8tq]

Hi

As various GPS module designs done over the last decade or so have shown, you *can*
fix this at the module level. Yes, each of those fixes has its drawbacks. However, the modern
designs are a lot less likely to “die” 10 or 20 years from now.

….. and to address the inevitable follow up question: 

The receiver can “save” the last date it saw. That becomes the “never before” date. If this is
enabled and the receiver gets a spoofed date, that’s a problem. 

You can manually enter a “never before” date. That works fine, except for the “manual” part….
Anything that can be done manually could also be done under the control of the driver. That 
opens a hacking path. There are a *lot* of things that could brick a receiver if the driver is hacked
so this is hardly unique in that regard. 

Bob

> On Oct 22, 2021, at 1:22 PM, Magnus Danielson via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> Hi,
> 
> On 2021-10-22 17:58, Kevin Rowett wrote:
>> For those using GPSD (https://gpsd.gitlab.io/gpsd/index.html <https://gpsd.gitlab.io/gpsd/index.html>) to read GPS receivers, and get the GPS time, there is a bug that could cause problems on Oct 24th.
>> 
>> 
>> https://us-cert.cisa.gov/ncas/current-activity/2021/10/21/gps-daemon-gpsd-rollover-bug <https://us-cert.cisa.gov/ncas/current-activity/2021/10/21/gps-daemon-gpsd-rollover-bug>
> 
> I find it amusing, as this was discussed on ntp-questions email-list in mid August 2013, and clearly explained with due references. It seems that people did not act. There was a misconception that this was a "receiver error" for which they should not do any fixes. It's actually a systemflaw that never was fixed in L1 C/A code. It would have been good if they added additional GPS-weeks bits in that signal, but it never materialized. It did for other newer signals.
> 
> It seems nothing happen in those 8 years until the patching this year.
> 
> Cheers,
> Magnus
> 
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