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fix(schema): SMF_DPD option at the end of the header raises TypeError from smf_i_dpd_id_len - #1197
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… from smf_i_dpd_id_len Schema.unpack rewound a ForwardMatchField by its declared width rather than by the octets it actually read. At the end of the stream the read comes back short, so the rewind landed before the forward match and the fields after it re-read the preceding octet. An SMF_DPD option in the last two octets of a HOPOPT/IPv6-Opts header was therefore re-parsed from the PadN padding as Pad1, leaving len as NO_VALUE. Rewind by len(byte). The option now reaches the existing SMF I-DPD length guard and raises FieldValueError, as CALIPSO and MPL do. Closes #1195
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Seven new entries and one extension in docs/source/changelog/1.5.0.rst, the regenerated CHANGELOG.md, and the process.rst entry-count pin re-measured (193 -> 200). The opening snapshot now cites 319 issues and pull requests up to #1195.
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make pylint,make mypy,make isort) — not run; only the touched lines changedmake testpasses, and a test case covers the change — the modules listed below only, not the whole suiteWhat is the purpose of your pull request?
fix— corrects a defectCloses #1195. Root cause:
Schema.unpackrewound aForwardMatchFieldby its declared width, not by the octets it actually read._SMFDPDOption.testforward-matches 3 octets, but only 2 are left at the end of the header. The 3-octet rewind then re-parsed the option from the lastPadNpadding octet, asPad1, solenwas skipped and set toNO_VALUE. CALIPSO and MPL have no forward match, so they readlen=0and hit their length guards. The fix rewinds bylen(byte)(pcapkit/protocols/schema/schema.py). SMF_DPD now reaches the existingsmf_i_dpd_id_lenguard.hopopt.pyandipv6_opts.pyare unchanged.3b0001020000+0800TypeError: … 'NoValueType' and 'int'FieldValueError: invalid SMF I-DPD option length: 0Sweep: I placed every option type except RPL
0x23(#1196) at that position with len 0, in both classes. Before the fix,0x08raised a non-library exception in both. After it, none of the 510 cases does.Tests: the new
tests/protocols/internet/test_smf_dpd_truncated_len_unit.pyreports2 passed, 512 subtests passed. With the fix reverted it reports4 failed(SMF0x08in both classes). These all pass: the misc/schema/ipv6-ext/ipv4/mh/smf/mpl/qs/tcp/pcapng/option-roundtrip/option-coverage modules,tests/project(389 passed, 1 skipped), andrun_unittest_leg.py protocols/internet(493 test(s), 0 failure(s), 0 error(s)).