-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On Tue, Feb 20, 2018 at 04:27:16PM +0100, 'Tom Zander' via qubes-devel wrote: > On Tuesday, 20 February 2018 14:04:03 CET Wojtek Porczyk wrote: > > On Tue, Feb 20, 2018 at 01:21:30PM +0100, 'Tom Zander' via qubes-devel > wrote: > > > On Tuesday, 20 February 2018 01:49:37 CET Marek Marczykowski-Górecki > wrote: > > > > We've decided to deprecate the '$' character from qrexec-related > > > > usage. > > > > Instead, to denote special tokens, we will use the '@' character, > > > > which we believe is less likely to be interpreted in a special way > > > > by the relevant software. > > > > > > I would argue against the @ sign on account that it is a special > > > character in bash as well. > > > > > > I don't immediately see a way to exploit it, but why risk it? > > > > We absolutely need a special character that is not allowed in qube name to > > make the special tokens immediately obvious in policy. The process I used > > was to list available characters (POSIX Portable Character Set [1]) > [] > > If I missed something, could you please point out? I know shell just good > > enough to know that it's not possible to know every shell quirk. :) > > The thing you have to rememeber is that the escape character never needs to > be typed by the user. > In QRexec you are defining an API, applications like qvm-run are using that > API. What the user passes into qvm-run and what is actually sent to dom0 > does not have to be identical.
In theory yes, but this would introduce more complexity to this code (taking care where which encoding is used etc). > I guess you do the translation currently as well; '$' turns into '@' in your > new code. > > The consequence of this is that you don't have to limit yourself to the > posix list. > Using the portable characters set for a non-character simply isn't needed. > > So, knowing that your API is actually based on 8-bit characters and not 7 > bits which you are limiting yourself to, my suggestion is to take something > above 127 and below 256 as a special char. > Most fun one would be “ÿ” which is a normal character you can pass on a > shell script if you must, its actual byte-value is 0xFF Until some helpful application (shell or else) will try to interpret it as UTF-8. - -- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhrpukzGPukRmQqkK24/THMrX1ywFAlqMRLUACgkQ24/THMrX 1yxCegf+Iii677oWd0CmJgoygfVfiQnmDl+a7XBX/i+tb8BMqO67AgwzoM6cWXq6 ZaA76a50qKSmcSjj6xSPtg4sPV0hqpgORsnxikAn5zg9vi7QJMJ0q+hKuKVxHAY1 TZSVFynTs6ci0JjgVRiB8QZCrl2eC9hQraGs46u6Zevvj80ZapaEqu0Sh0rowpDe SZ+QbiKi/QD1IeSF03OjnlqtoEyAZtPJ4dMY9F8IpR0P/vzsPxnkx/493HVjSA1i 7Z7kutdCcrGAqCtROhQ9DnS7+GTfdNcDJ5zwZ5yz5fJWlrzFgDSjENuwrSUqU/13 W6HNQVwx/fW+RBseUkJ/o98GHVW8sg== =af4O -----END PGP SIGNATURE----- -- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to qubes-users+unsubscr...@googlegroups.com. To post to this group, send email to qubes-users@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/20180220155436.GC2084%40mail-itl. For more options, visit https://groups.google.com/d/optout.
