[poppler] [PATCH] provide type-checking for union pointer accesses
Albert Astals Cid
aacid at kde.org
Sun Apr 20 08:25:21 PDT 2008
A Dissabte 19 Abril 2008, Kees Cook va escriure:
> Hello! This patch is based on some work I did to make the poppler
> Object union member accesses safer in the future (to avoid things
> like CVE-2008-1693). After some discussion on IRC, an improved way of
> handling things was resolved, which should not degrade performance in any
> noticeable way as the checks are memory-local to the union member being
> accessed, and can be hinted to be "unlikely" situations by the compiler.
> Please keep me in CC, as I'm on the list.
After applying your patch i did a bit of testing.
Using the time command to measure speeds i was not able to detect any speed
change outside the typical variations between run and run.
Using cachegrind i saw your patch gives 0.69% more Instruction refs, 0.23%
more Data refs but 3.78% less L2 refs. So it would seem it gives us a small
speed boost as we are accessing L2 cache less than before :D
If noone complains i'll commit it by wednesday.
Thanks for the patch,
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