naruto-lgtm opened a new pull request, #1520: URL: https://github.com/apache/poi/pull/1520
Repro: write a POIFS with a 10,000-byte stream, reopen it, delete the stream (or replace it with 10 bytes through `createOrUpdateDocument`) and call `writeFilesystem(OutputStream)`: every byte of the old stream is still in the output. The in-place path behaves the same, e.g. opening an .xls read-write, `removeSheetAt` and `HSSFWorkbook.write()` leaves all cell records of the removed sheet in the file. Cause: `POIFSStream.free` only sets the FAT/SBAT entries to unused and leaves the block contents, while `writeFilesystem()` and `writeFilesystem(OutputStream)` write the whole data source, free blocks included (CWE-226). Every path that gives up stream space goes through it: `DirectoryEntry.delete`, `POIFSDocument.replaceContents` (behind `createOrUpdateDocument`, the HPSF property writers and the in-place `write()` of HSSF, HSLF and HWPF) and `DocumentOutputStream`. Fix: zero each big or mini block in `free()` before marking it unused, the same state POIFS gives newly allocated blocks. `HSSFWorkbook.write(OutputStream)` and `write(File)` build a new file system and were never affected; in-place saves and direct POIFS edits are. The cost is one extra write per released block, the same order as writing the replacement data. File systems that aren't modified are still written byte for byte as before, verified against a few Office-written samples. Blocks that aren't backed by data (a truncated file) are skipped, so deleting entries of such files keeps working. One related leftover is out of scope here: when the directory shrinks, the 128-byte entry of a deleted stream (its name, not its data) can stay in the unused tail of the last directory sector. Clearing that tail also rewrote the free directory entries of unmodified Office files, so I left it for a separate change if you want it. `TestPOIFSStream.deletedDataIsNotWrittenOut` deletes a big-block and a mini-stream entry and shrinks a third, through `writeFilesystem(OutputStream)` and in place, and fails before the change. `:poi`, `:poi-scratchpad`, `:poi-ooxml` and `:poi-integration` pass locally apart from `TestDateSerialRange.testEdgesOfTheRange` and three SXSSF/XSSF auto-size width tests, which fail the same way on trunk here. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
