brk's zero-fill behavior on VAXen

Don Coleman coleman at sdcsvax.UCSD.EDU
Thu Nov 13 12:40:52 AEST 1986


The reason VAXen zero-fill brk'ed data is for security(it wouldn't be good
for a snoopy user to watch until somebody exits vi after editing a 
very private file, and then do lots of brks, and get access to the 'dirty'
pages that the vi was using...).

There are also a lot of other benefits in terms of the predictability of 
programs when they fail, and it makes core images quite a bit cleaner.

But this is *not* something to depend on.  I doubt you'll find it in
the SVID(This of course assumes that you care what's in the SVID).

don
coleman at sdcsvax.ucsd.edu
Newsgroups: net.unix-wizards



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