bugGPSD - Bugs: bug #40335, Accept overlong AIS messages?

 
 

bug #40335: Accept overlong AIS messages?

Submitted by:  Marius Kintel <kintel>
Submitted on:  Mon 21 Oct 2013 07:20:58 PM UTC  
 
Category: NoneSeverity: 3 - Normal
Item Group: NoneStatus: Fixed
Privacy: PublicAssigned to: None
Open/Closed: Closed

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Mon 21 Oct 2013 09:40:12 PM UTC, comment #1:

>I would suggest to issue a LOG_WARN (or even LOG_INF) for overlong messages, but to disallow too short messages.


Good plan.

>I'd be happy to write and test code if that helps - just point me to your preferred way of submitting patches.


Clone my repo, make a branch, hack on it, mail me patches made with git-format-patch.

Eric S. Raymond <esr>
Project Administrator
Mon 21 Oct 2013 07:20:58 PM UTC, original submission:

It appears to be very common for AIS messages to contain excess bits.
After listening for messages for a few minutes, I found > 2500 AIS messages with a bit length longer than the specification allows.
Other AIS decoders tend to ignore excess bits, and I think this would make sense for gpsd as well (to avoid losing important data).

Thus far, I've seen excess data for message of type 1, 2, 3, 4, 10, 11, 18 and 24.
The most common occurrence, by far, is for type 1 messages to have 204 bits instead of 168.

I would suggest to issue a LOG_WARN (or even LOG_INF) for overlong messages, but to disallow too short messages.

I'd be happy to write and test code if that helps - just point me to your preferred way of submitting patches.

-Marius

Marius Kintel <kintel>

 

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    Follow 2 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Fri 22 Nov 2013 01:44:00 PM UTCesrOpen/ClosedOpen=>Closed
    Wed 13 Nov 2013 09:37:45 AM UTCesrStatusNone=>Fixed

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