On Fri, Feb 28, 2014 at 23:06:30 CET, Sven Eschenberg wrote: > On Fri, February 28, 2014 22:46, Arno Wagner wrote: > > On Fri, Feb 28, 2014 at 22:26:03 CET, Sven Eschenberg wrote: > >> Just out of curiosity, > >> > >> Isn't it possible (yet) to override header fields during luksopen? If > >> not, > >> wouldn't it make sense to add something like that in future versions? I > >> think it could be of great help when the header is partly damaged, to be > >> able to override things without using a hex editor. > > > > I doubt this makes much sense. From what I have seen, > > usually the magic string at the start is gone as well, > > and then there is a real risk that people try this with > > the wrong data. Using a hex-editor is not that hard and > > using a hex-dumper is basically required to get any > > reasonable form of diagnostics. Even the keyslot- > > checker is basically a specialized hexdump tool. > > Okay, that's true. I personally do use a hexeditor too, I have to admit, > just thought it could help less experienced people. Then again, if people > fail to use a hex editor chances are big they make things worse. I guess I > didn't think this through long enough. I have a _lot_ of experience with students, some not so bright or experienced ;-) > >> I am aware that one could use the non-LUKS mode to open a LUKS device by > >> passing all required parameters, admitted. But a mode where one can use > >> what's in the header and override single fields could be interesting. > >> Once > >> the correct params are determinde this way, one could maybe add an > >> option > >> to repair the header with the given replacements (Maybe by adding the > >> option to reencryt?). > >> > >> Just some thoughts that crossed my mind. > > > > I doubt this really helps. Also remember that finding out what > > actually broke the header is important, so fiddeling around > > with an opaque header and commandline arguments to cryptsetup > > after you have analyzed a hexdump strikes me as not that effective. > > That's absolutely true, indeed. > > > > > I do understand that hex-editing is akward for many people, > > but I do not think this makes it any better or clearer. > > One thing that would help a bit is a header layout with > > hex offsets. I think I am going to add that to the FAQ. > > Good point, I'd propose adding this to the luks on disk format document as > well. If you cannot convert HEX<->DEC inside your head having the hex > offsets at disposal helps alot. I admit, I used a converter when I edited > my headers lately. Me too. For the time being, there now is a nice hex + dec table in FAQ Item 6.12 Arno -- Arno Wagner, Dr. sc. techn., Dipl. Inform., Email: arno@xxxxxxxxxxx GnuPG: ID: CB5D9718 FP: 12D6 C03B 1B30 33BB 13CF B774 E35C 5FA1 CB5D 9718 ---- A good decision is based on knowledge and not on numbers. - Plato _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
