Strict Ustar Archive Workbench

How to use Strict Ustar Archive Workbench

List an uncompressed ustar archive, extract one regular member or create a separate bounded ustar file. Verify header checksums, octal sizes, block boundaries and end markers before selecting any bytes. Extraction downloads one sanitized basename and never recreates archive paths on disk.

1. Provide archive to inspect or extract, zero-based member index, files for archive creation.
2. Choose the supported mode and run the tool. Review its assumptions and any reported errors.
3. Copy the result or download a separate output; reset to clear the current form.

Good to know

• Uncompressed POSIX ustar only, up to 8 MiB including all headers/padding and 200 entries. Exactly two zero end blocks plus optional zero blocks are required. Gzip, pax, old GNU, base-256 numeric fields, sparse entries, links and devices are refused.
• This strict profile requires printable ASCII header strings, unsigned octal metadata, zero reserved/padding bytes, correct checksums and complete 512-byte blocks. Some archives accepted by general-purpose tar utilities intentionally fall outside this subset.
• Listing retains duplicate stored names and flags suspicious paths. Extraction uses the explicit zero-based index and downloads a single sanitized basename; it never follows links or writes stored directories. An empty regular member can be downloaded.
• Creation accepts safe relative ASCII names of at most 100 bytes, refuses duplicate/dot/parent names and writes deterministic regular-file entries: mode 0644, uid/gid 0, mtime 0, no owner names. File bytes are stored without compression.
• Inputs are processed on this device and are not automatically saved or uploaded.