[COMPRESS-584] IOUtils.readRange() can read more from a channel than asked for

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.21
• Component/s: Archivers
• Assignee: Peter Lee
• Reporter: Matthijs Laan
• Created: 03/Aug/21 08:45
• Updated: 06/Nov/21 08:02
• Resolved: 13/Sep/21 11:46

Description

When IOUtils.readRange(ReadableByteChannel,int) gets less than the number of bytes asked for in the first read call it does not reduce the buffer size for the next read call and may read more than asked for.

This situation is rare when using a FileChannel but I wrote a SeekableByteChannel backed by a URI using HTTP range requests and reading from a socket can often return less bytes than asked for. When I used this channel to read a ZipFile it only read the ZIP central directory partially sometimes because IOUtils.readRange() called from ZipFile.readCentralDirectoryEntry() read more bytes than asked for and it stopped parsing directory entries.

Fix: https://github.com/apache/commons-compress/pull/214

Issue Links

• fixes: COMPRESS-595 IOUtils.readRange(ReadableByteChannel input, int len) reads more than len when input.read() returns < len (ie. there is a partial read)
• links to: #214