RFR  8139706: JarFile.getBytes could use InputStream.readNBytes
claes.redestad at oracle.com
Thu Oct 15 22:08:13 UTC 2015
On 2015-10-15 23:21, Chris Hegarty wrote:
>> On 15 Oct 2015, at 21:59, ecki at zusammenkunft.net wrote:
>> This does change a bit the semantic of the length check. If the stream would return more bytes than the zipentry says the new version would ignore them, the old version was consuming then and then fail the check. However I am not sure if this is relevant.
> Right, there are certainly some subtle differences resulting from
> the proposed change. When working on JDK-8138978 I thought
> about using readNBytes, but played it safe as IOUtils was growing
> the bye lazily too, so no real perf difference. In fact, I think I seen
> a test failure with using readNBytes here. I’ll have to check.
Seeing no jtreg test failures in java/util/zip nor java/util/jar (apart
from 2 ignored tests), but I can see a reason for the current
implementation being conservative: Corrupt/malicious jar files might lie
about the entry length and report very large values, which could bring a
down with OOME.
I believe we could be both safe and faster than baseline by adding a
reasonable limit for when to use readNBytes, e.g., 32k would deal with
the majority of .class files.
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