[COMPRESS-591] Fix decoding of 7z files containing LZMA streams with end marker

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.21
• Fix Version/s: 1.22
• Component/s: Archivers
• Flags: Patch
• Assignee: Unassigned
• Reporter: Lasse Collin
• Created: 09/Sep/21 20:21
• Updated: 30/Oct/21 01:04
• Resolved: 30/Oct/21 01:04

Description

Some uncommon but valid .7z files contain LZMA streams that use the end of stream marker. Currently Commons Compress together with XZ for Java considers such files to be corrupt.

XZ for Java 1.9 added a new method LZMAInputStream.enableRelaxedEndCondition() specifically for this issue. To use this feature in Commons Compress, a change is needed to the "decode" function in src/main/java/org/apache/commons/compress/archivers/sevenz/LZMADecoder.java:

- return new LZMAInputStream(in, uncompressedLength, propsByte, dictSize);
+ final LZMAInputStream lzmaIn = new LZMAInputStream(in, uncompressedLength, propsByte, dictSize);
+ lzmaIn.enableRelaxedEndCondition();
+ return lzmaIn;

A tiny test file is attached (thanks to Simon for providing it). Another test file "sheet.7z" can be found from <https://sourceforge.net/p/lzmautils/discussion/708858/thread/822d80d5ea/>.

XZ for Java 1.9 is already a few months old, so I apologize for not reporting this earlier.

Issue Links

• links to: #223