fix: correct ZIP64 data descriptor format detection#10
Merged
Conversation
The uses_zip64_descriptor field was incorrectly set to true whenever a ZIP64 extra field was present. However, a ZIP64 extra field may exist only for the local_header_offset (when offset > 4GB), while file sizes still fit in 32 bits. The data descriptor format depends on whether SIZES overflow 32-bit, not whether the offset does. When uses_zip64_descriptor was incorrectly true, the stream processor consumed 24 bytes for the data descriptor instead of 16, causing it to misalign and fail to parse subsequent frames with errors like: "Stream processor error: Failed to parse frame at offset 97132" The fix checks if compressed_size or uncompressed_size equals 0xFFFFFFFF in the central directory header (indicating the actual values are in the ZIP64 extra field) rather than just checking for ZIP64 extra field presence. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
The uses_zip64_descriptor field was incorrectly set to true whenever a ZIP64 extra field was present. However, a ZIP64 extra field may exist only for the local_header_offset (when offset > 4GB), while file sizes still fit in 32 bits. The data descriptor format depends on whether SIZES overflow 32-bit, not whether the offset does.
When uses_zip64_descriptor was incorrectly true, the stream processor consumed 24 bytes for the data descriptor instead of 16, causing it to misalign and fail to parse subsequent frames with errors like: "Stream processor error: Failed to parse frame at offset 97132"
The fix checks if compressed_size or uncompressed_size equals 0xFFFFFFFF in the central directory header (indicating the actual values are in the ZIP64 extra field) rather than just checking for ZIP64 extra field presence.
Fixes #9