BIND 10 #3279: DHCPv4 server should discard packets with non-matching server id

[BIND 10 Development]

#3279: DHCPv4 server should discard packets with non-matching server id
-------------------------------------+-------------------------------------
            Reporter:  marcin        |                        Owner:  tmark
                Type:  defect        |                       Status:
            Priority:  medium        |  reviewing
           Component:  dhcp4         |                    Milestone:  DHCP-
            Keywords:                |  Kea1.0-alpha
           Sensitive:  0             |                   Resolution:
         Sub-Project:  DHCP          |                 CVSS Scoring:
Estimated Difficulty:  16            |              Defect Severity:
         Total Hours:  10            |  Medium
                                     |  Feature Depending on Ticket:
                                     |          Add Hours to Ticket:  2
                                     |                    Internal?:  0
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Changes (by marcin):

 * owner:  marcin => tmark


Comment:

 Replying to [comment:7 tmark]:
 > The changes are quite straight forward, I only have a few
 questions/comments:
 >
 > General question:
 >
 > * In looking at IfaceMgr::hasOpenSocket(), have you done any impact
 assessment on performance?  Granted we are not likely to have more than a
 few interfaces, with maybe one address per interface.

 I added a comment to say that I am aware of performance penalty. But I
 really don't think it is going to be significant if we just open sockets
 on a couple of interfaces. If the performance penalty is significant, we
 can think about caching the server identifiers, but I don't want to
 complicate this code more than it is complicated now.

 >
 > * Should we consider making this check configurable?

 Unless I misunderstand this question, my answer is no. Accepting or
 rejecting server identifier is a core functionality of DHCPv4 described in
 RFC2131 (section 4.1). How could I make this configurable?


 >
 >
 ----------------------------------------------------------------------------------------
 > Dhcpv4Srv::acceptServerId(const Pkt4Ptr& pkt)
 >
 > You test the address list for size = 1 and return false if it is not.
 I'm
 > assuming there is no valid case for it have more than 1 entry.  You may
 want
 > to add a quick comment on this above the size test.

 Added a comment. There should be no case that the size of the list is
 unequal 1, unless the client has sent a malformed option which we would
 (and want to) catch here.

 >
 >
 -----------------------------------------------------------------------------------------
 >
 > Unit tests run with valgrind on Fedora 19.  cppcheck passes on OS-X.
 >
 >
 >

 Thank you QA team!

-- 
Ticket URL: <https://bind10.isc.org/ticket/3279#comment:8>
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