[jira] [Created] (COMPRESS-482) ZipArchiveInputStream's "data descriptor for stored entries" feature doesn't work if the data descriptor doesn't contain a signature

["Stefan Bodewig (JIRA)" <ji...@apache.org>]

Stefan Bodewig created COMPRESS-482:
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             Summary: ZipArchiveInputStream's "data descriptor for stored entries" feature doesn't work if the data descriptor doesn't contain a signature
                 Key: COMPRESS-482
                 URL: https://issues.apache.org/jira/browse/COMPRESS-482
             Project: Commons Compress
          Issue Type: Bug
          Components: Archivers
    Affects Versions: 1.18
            Reporter: Stefan Bodewig
            Assignee: Stefan Bodewig
             Fix For: 1.19


In the first branch of the next block from {{bufferContainSignature}} 

{code:java}
                if ((buf.array()[i + 2] == LFH[2] && buf.array()[i + 3] == LFH[3])
                    || (buf.array()[i] == CFH[2] && buf.array()[i + 3] == CFH[3])) {
                    // found a LFH or CFH:
                    readTooMuch = offset + lastRead - i - expectedDDLen;
                    done = true;
                }
                else if (buf.array()[i + 2] == DD[2] && buf.array()[i + 3] == DD[3]) {
                    // found DD:
                    readTooMuch = offset + lastRead - i;
                    done = true;
                }
{code}

{{readTooMuch}} should probably add {{expectedDDLen}} rather than subtract it. It leaves the DD inside of the read stream for the last stored entry rather than positioning the stream in front of it. Unfortunately we don't seem to have a single unit test that would execute the branch.

Also the current implementation of {{bufferContainSignature}} will stop when a local file header is found even before enough data for a data descriptor has been read at all. In COMPRESS-480 it will detect the very first local file header in the embedded XPI file at offset 0 even though there must be twelve bytes of data descriptor before the first candidate. 



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