RFR [7129312] BufferedInputStream calculates negative array size with large streams and mark

Ivan Gerasimov ivan.gerasimov at oracle.com
Fri Aug 16 13:12:33 UTC 2013


Hello everybody!

It was reported that BufferedInputStream#read() method may throw 
NegativeArraySizeException.
This is due to doubling the buffer size in the fill() method without 
checking for a possible overflow.

BUG: http://bugs.sun.com/view_bug.do?bug_id=7129312

Affected versions of jdk are 6, 7 and 8

Would you please help review a fix?
http://cr.openjdk.java.net/~igerasim/7129312/0/webrev/

It uses approach similar to what was suggested for 8020669: The 
maximumBufferSize = (Integer.MAX_INTEGER - 8) constant is introduced and 
we don't make attempts to allocate a bigger array.

Please note, that the sample code as it was originally reported still 
doesn't work. That's because that setting 
buffStream.mark(Integer.MAX_VALUE) actually means that buffStream will 
have to try to allocate an array of that size given a large enough input.

Sincerely yours,
Ivan





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