Rather weird corner case admittedly, but workdir perms are fairly locked down- problem is, crappy tarballs can actually modify that. Example is gnuconfig-20070118; the tar has an entry for '.', thus tar tries to enforce the perms/times on cwd, ie, WORKDIR (if that's cwd). suggest adding --exclude . so that weird tarballs don't inadvertantly loosen the perms. As is, gnuconfig reduces workdir from 0700 to 0770. Worst case, the tarball could be particularly retarded and loosen the perms to 0777.
worth noting, --exclude . doesn't cut it, although don't have an appropriate pattern for it atm.
Well, I don't observer the behavior you describe unless I enable tar's -p option, which portage doesn't use in it's unpack function.
as stated in #2, won't touch perms, although it does force a utime through...
