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Posted to dev@lucene.apache.org by "Russell A Brown (JIRA)" <ji...@apache.org> on 2019/03/11 18:00:00 UTC
[jira] [Updated] (LUCENE-8720) Integer overflow bug in
NameIntCacheLRU.makeRoomLRU()
[ https://issues.apache.org/jira/browse/LUCENE-8720?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Russell A Brown updated LUCENE-8720:
------------------------------------
Description:
The NameIntCacheLRU.makeRoomLRU() method has an integer overflow bug because if maxCacheSize >= Integer.MAX_VALUE/2, 2*maxCacheSize will overflow to -65536 and the value of n will be negative, which will prevent any clearing of the cache whatsoever.
Moreover, comments in NameIntCacheLRU.java and LruTaxonomyWriterCache.java indicate that 2/3 of the cache will be cleared, whereas in fact only 1/3 of the cache is cleared. So as not to change the behavior of the NameIntCacheLRU.makeRoomLRU() method, I have not changed the code to clear 2/3 of the cache but instead I have changed the comments to indicate that 1/3 of the cache is cleared.
was:
The NameIntCacheLRU.makeRoomLRU() method has an integer overflow bug because if maxCacheSize >= Integer.MAX_VALUE, 2*maxCacheSize will overflow to -65536 and the value of n will be negative, which will prevent any clearing of the cache whatsoever.
Moreover, comments in NameIntCacheLRU.java and LruTaxonomyWriterCache.java indicate that 2/3 of the cache will be cleared, whereas in fact only 1/3 of the cache is cleared. So as not to change the behavior of the NameIntCacheLRU.makeRoomLRU() method, I have not changed the code to clear 2/3 of the cache but instead I have changed the comments to indicate that 1/3 of the cache is cleared.
> Integer overflow bug in NameIntCacheLRU.makeRoomLRU()
> -----------------------------------------------------
>
> Key: LUCENE-8720
> URL: https://issues.apache.org/jira/browse/LUCENE-8720
> Project: Lucene - Core
> Issue Type: Bug
> Components: core/search
> Affects Versions: 7.7.1
> Environment: Mac OS X 10.11.6 but this bug is not affected by the environment because it is a straightforward integer overflow bug.
> Reporter: Russell A Brown
> Priority: Major
> Labels: easyfix, patch
> Fix For: 7.1.1
>
> Attachments: LUCENE-NNNN.patch
>
>
> The NameIntCacheLRU.makeRoomLRU() method has an integer overflow bug because if maxCacheSize >= Integer.MAX_VALUE/2, 2*maxCacheSize will overflow to -65536 and the value of n will be negative, which will prevent any clearing of the cache whatsoever.
> Moreover, comments in NameIntCacheLRU.java and LruTaxonomyWriterCache.java indicate that 2/3 of the cache will be cleared, whereas in fact only 1/3 of the cache is cleared. So as not to change the behavior of the NameIntCacheLRU.makeRoomLRU() method, I have not changed the code to clear 2/3 of the cache but instead I have changed the comments to indicate that 1/3 of the cache is cleared.
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