Wireshark · Wireshark-commits: [Wireshark-commits] master d81fe39: Correct 6LoWPAN NHC datagram size calculations

[Wireshark code review <code-review-do-not-reply@xxxxxxxxxxxxx>]

URL: https://code.wireshark.org/review/gitweb?p=wireshark.git;a=commit;h=d81fe3907b00e00fb05a88eb0812ac874922e835
Submitter: Michael Mann (mmann78@xxxxxxxxxxxx)
Changed: branch: master
Repository: wireshark

Commits:

d81fe39 by Kevin Bracey (kevin.bracey@xxxxxxx):

    Correct 6LoWPAN NHC datagram size calculations
    
    Length calculations updating "remaining datagram size" for fragmented
    6LoWPAN packets with NHC headers were incorrect if there was any elided
    option padding.
    
    The current header's unpadded length was subtracted from dgram_size,
    when it should have been the padded length - the datagram size is
    uncompressed IPv6.
    
    This meant the final nhdr_list entry created to represent the remaining
    payload would have its "reported" field too large. Most visible result
    of this was that the IPv6 payload length written into the packet by
    lowpan_reassemble_ipv6() was too large.
    
    Error probably went unnoticed because the most typical 6LoWPAN options
    don't need padding - the RPL option is 6 bytes, and the MPL option is 6
    bytes if using 16-bit seeds, making the HbH extension header an aligned
    8 bytes.
    
    Bug: 12310
    Change-Id: If94e9ca57f88c4ac41f002a689ce1da7097b5bd0
    Reviewed-on: https://code.wireshark.org/review/14701
    Reviewed-by: Michael Mann <mmann78@xxxxxxxxxxxx>
    

Actions performed:

    from  3467a1f   Squelch a "not allowed in C++" warning.
    adds  d81fe39   Correct 6LoWPAN NHC datagram size calculations


Summary of changes:
 epan/dissectors/packet-6lowpan.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)