Date: Sun, 13 Jan 2013 19:13:04 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Nathan Whitehorn <nwhitehorn@freebsd.org> Cc: Ed Schouten <ed@80386.nl>, freebsd-toolchain@freebsd.org, freebsd-arch@freebsd.org Subject: Re: LLVM Image Activator Message-ID: <20130113171304.GZ2561@kib.kiev.ua> In-Reply-To: <50F2DF11.50202@freebsd.org> References: <50E9BC2D.7000302@freebsd.org> <201301070936.39052.jhb@freebsd.org> <20130107172433.GX82219@kib.kiev.ua> <CAJOYFBAZ-XQ1vash3H%2B0wA8GCoMS59eARMnA3y%2BsaPwMJqL0aQ@mail.gmail.com> <20130113132057.GQ2561@kib.kiev.ua> <50F2DF11.50202@freebsd.org>
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--GEbvMeJjk36GUqgv Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Jan 13, 2013 at 08:21:37AM -0800, Nathan Whitehorn wrote: > On 01/13/13 05:20, Konstantin Belousov wrote: > > On Sun, Jan 13, 2013 at 12:41:09PM +0100, Ed Schouten wrote: > >> Hi Kostik, > >> > >> 2013/1/7 Konstantin Belousov <kostikbel@gmail.com>: > >>> I still do remember the buzz about the binary format 0xCAFEBABE, which > >>> AFAIR gained image activator support on several OSes, to be garbage > >>> collected. > >> > >> Maybe it would then be a good idea then to add some kind of general > >> purpose remapping imgact? Example: > >> > >> /etc/imgacttab: > >> > >> cafebabe /usr/local/bin/java > >> cffaedfe /usr/local/bin/osx_emulator > >> 4243c0de /usr/bin/lli > >> > >> That way we still give people the freedom to play around with mapping > >> their own executable formats, but don't need to maintain a bunch of > >> imgacts. > >=20 > > A generic module that could be somewhat customized at runtime to map > > offset+signature into the shebang path could be a possibility indeed. > > I strongly prefer to have it as module and not enabled by default. > >=20 > > Asking Nathan for writing the thing is too much, IMHO, esp. in > > the response to the 50-lines hack. > >=20 >=20 > I think this is a good idea, since it both prevents a profusion of > similar activators and works nicely in jails and similar environments. I > probably won't write it quickly, but it should not take more than about > 50 lines, so I can't imagine it will be that bad. There are some > complications with this kind of design from the things in the XXX > comment in imgact_llvm.c about handling argv[0] that I need to think > some more about. Great. I do not believe in the 50 lines, but I am happy that you want to work this out. >=20 > Why are you opposed to having it there by default? I think it's actually > quite important that it be there by default. Having it not "standard" > would be fine, but it should at least be in GENERIC. There are minimal > security risks since it just munges begin_argv and doesn't even load the > executable and it's little enough code that there should not be any > kernel bloat to speak of. If things like this aren't enabled by default, > no one can depend on them being there, no one will use it, and the point > is entirely lost. All image activators demonstrated a constant stream of security holes. Even our ELF activator, and I was guilty there too. I definitely do not fight over the inclusion of the proposed activator into GENERIC, but do insist on the config option + module. --GEbvMeJjk36GUqgv Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iQIcBAEBAgAGBQJQ8usfAAoJEJDCuSvBvK1B7ZEP/3kcYy5fF7Ld9YBfRAwqMaBu IpEiPPpKtK2KarELSvRXTIYIoy92kJE5ax7Ad+cummm3sNN2yolBQAKJ+fAkHnBv +hWLpKxOmzdnjw4fO0GLU71vNEImTtj8YSymErZxNl10HTrwl8usBkl0SlequI11 m5fbbNNmsBK+6TS9OP/6CN9Pq1exqUPsu4HUDUunFJ+ucOAcCh4tNddcTRZwItc9 wMYErq+XWhd7t29g0PyAH3Tw9h9MgvKPGNrRUzji/Ytno5sv9Xg0ZBQ/MP3PLt4i kulsU3Nvko32YGl/Kme7Kl3jU2sGEq0p9S1IIPqbmyVxd49/3w7pW9SSFffoijPX S+R5MCEKQo3cGvyAEawa0hxaCY84KZd5njGfNN6FQtThwjZMY8bfFNWqAKpbNRmI bXt+sNipZu8vJnEa2NNjr8CtpShvoczkxNMGHVU+ZWiG81QekqdaH8yRSAsgRGB9 T4s0cQTXoI4GmX8Zl6u9p1yFVQ5bS3zs4oCbRUme5zsqHX1L7ufNUl6F8TayELvX 46YOhiuWZIShvI/oRU1MZcgVq6VZy/eElf8WbiiNDKZVyI9VsfJRm6x+b2KM9OlC KdGV4aUDaesjAkk5KQCS118vxZDvtSY7lyksSlN1UqFqq4G+tQi2Ch4I+FvqLV5d kEsyiEh666KnTaWUAZI4 =Xf2/ -----END PGP SIGNATURE----- --GEbvMeJjk36GUqgv--
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