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if you guys are really worried about a Ken Thompson-style hack in gcc



In a recent thread entitled "Re: Unofficial buildd network has been shut
down", several people started tossing around FUD about the possibility of
a Ken Thompson-style hack in gcc.

If any of you are seriously worried about this, please do the following:

1) prove that there is no KT-style hack on the Solaris version of gcc:
   a) bootstrap gcc from source, starting from Sun's C compiler.
   b) bootstrap gcc from source, starting from any version of gcc

Compare compilers a and b.  Other than timestamps in .o files, the
produced .o files will be byte-for-byte identical (for ELF, you need
to avoid comparing the first 16 bytes of each file; see the code in
"make compare" in GCC's makefile).

To be pedantic, it could be possible that an evil genius has somehow
inserted the same KT-style hack into Sun's compiler, and maintained those
hacks in perfect synchrony over the 15+ years of GCC's existence so that
Sun and GNU would miscompile each others' compilers.  Believe that one and
you're a loon, sorry.

2) now generate a guaranteed-clean GNU/Linux compiler by building a cross
compiler.  This is kind of tricky; Google for "crossgcc howto".

Finally, use this compiler to build the Debian-patched gcc.  You've
eliminated any possible evil that the Debian gcc team might have
installed.  Congratulations.





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