[ntp:questions] ntpdate.c unsafe buffer write

David L. Mills mills at udel.edu
Tue Feb 12 15:04:45 UTC 2008


Serge,

That was removed as a significant security hazard. If you want to 
rxplicitly set the frequency, use ntptime -f. Ths scheme is designed so 
you can run ntpd until the kernel frequency has stabilized, then kill 
ntpd and run SNTP client at regular intervals. I surely wouldn't 
recommend that, but folks have their biases.

Dave

Serge Bets wrote:

> Hello David,
> 
>  On Tuesday, February 12, 2008 at 2:43:06 +0000, David L. Mills wrote:
> 
> 
>>Just for clarity, neither the daemon nor kernel frequency is adjusted
>>in any way with ntpd -q.
> 
> 
> ntpd -q can make use of the driftfile to set the kernel frequency:
> 
> | # ntpd -q -d | grep frequency
> | addto_syslog: frequency initialized -1.752 PPM from /var/lib/ntp/ntp.drift
> 
> Note that this is plain necessary for the correct operations of ntpd -q.
> If the kernel frequency was not initialised, then a slew would not end
> right on the zero offset.
> 
> 
> Serge.




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