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GIF hul Messages

Martin Hoppenheit edited this page Aug 8, 2022 · 1 revision

GIF-HUL-1

Message

Wrong application extension block size

Details

Needs review

Impact

Needs review

Remediation

Needs review

GIF-HUL-2

Message

Unknown data block type

Details

Needs review

Impact

Needs review

Remediation

Needs review

GIF-HUL-3

Message

Unknown extension block type

Details

Needs review

Impact

Needs review

Remediation

Needs review

GIF-HUL-4

Message

Invalid GIF header

Details

Needs review

Impact

Needs review

Remediation

Needs review

GIF-HUL-5

Message

Multiple graphics control blocks for one image

Details

Needs review

Impact

Needs review

Remediation

Needs review

GIF-HUL-6

Message

Wrong graphics control block size

Details

Needs review

Impact

Needs review

Remediation

Needs review

GIF-HUL-7

Message

Wrong plain text extension block size

Details

Needs review

Impact

Needs review

Remediation

Needs review

GIF-HUL-8

Message

Plain text extension requires global color table

Details

Needs review

Impact

Needs review

Remediation

Needs review

GIF-HUL-9

Message

End of file reached without encountering Trailer block

Details

Needs review

Impact

It depends, from minor to severe.

A GIF file must end with the so-called Trailer, a single byte 0x3b (see the GIF specification). This error message indicates that the trailer byte is missing.

If only the trailer byte is missing (e.g., because the GIF file was created by buggy software that did not add it) most viewers will still display the file without complaints. Further more, the trailer byte can then easily be added, fixing the error (see below).

If more than the trailer byte is missing (e.g., because the file was damaged during a transfer) it may be hard or even impossible to repair it, depending on how much is missing.

NB, since the PRONOM signatures for GIF (fmt/3 and fmt/4) rely on the trailer byte as well PRONOM based file format identification will return Unknown for files with this error.

Remediation

If only the trailer byte is missing it can be added like this:

$ echo -ne '\x3b' >> a.gif

GIF-HUL-10

Message

Unexpected end of file

Details

Needs review

Impact

Needs review

Remediation

Needs review