[Bug 1970762] Re: liblzma failed to decompress a valid lzma file

Qianqian Fang 1970762 at bugs.launchpad.net
Sat Apr 30 01:08:29 UTC 2022


** Information type changed from Public Security to Public

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Title:
  liblzma failed to decompress a valid lzma file

Status in xz-utils package in Ubuntu:
  New

Bug description:
  The lzma file can be accessed here:
  https://kwafoo.coe.neu.edu/~fangq/share/temp/mat.lzma

  This file was created using the public domain lzma C library written
  by Igor Pavlov. It can be decompressed on Ubuntu 20.04 using `lzma
  -d`, based on LZMA SDK 9.22, but on either Ubuntu 18.04 and 22.04,
  where lzma is built based on liblzma, it gives a "Compressed data is
  corrupted" error.

  
  here is the log on Ubuntu 20.04 - where LZMA SDK based lzma works

  ```
  fangq at ubuntu20_04:~$ lzma --version
  LZMA command line tool 9.22
  LZMA SDK 9.22

  fangq at ubuntu20_04:~$ lzma -v -d mat.lzma
  mat.lzma:	 21.83% -- replaced with mat
  ```

  however, on Ubuntu 22.04, lzma -d does not work (same for 18.04)
  ```
  fangq at ubuntu18_04:~$ lzma --version
  xz (XZ Utils) 5.2.5
  liblzma 5.2.5

  fangq at ubuntu22_04$ lzma -v -d mat.lzma
  mat.lzma (1/1)
   99.9 %   1,500.9 KiB / 1,920.0 KiB = 0.782                                    
  lzma: mat.lzma: Compressed data is corrupt
   99.9 %   1,500.9 KiB / 1,920.0 KiB = 0.782   
  ```

  Because of this, I also noticed that the official lzma module of
  Python fails to decompress this file. I want to add that using `lzma`
  or `lzma-purejs` npm module, node.js script can correctly decompress
  this file.

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