Re: RFC: should the 'trust' and 'verify_detached' commands respect 'check_signatures=enforce'?

["Vladimir 'φ-coder/phcoder' Serbinenko" <phcoder@gmail.com>]

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On 21.10.2013 19:44, Jonathan McCune wrote:
> On Mon, Oct 21, 2013 at 10:33 AM, Vladimir 'φ-coder/phcoder' Serbinenko
> <phcoder@gmail.com <mailto:phcoder@gmail.com>> wrote:
> 
>     On 18.10.2013 04:44, Andrey Borzenkov wrote:
>     > В Thu, 17 Oct 2013 23:44:05 +0200
>     > Vladimir 'φ-coder/phcoder' Serbinenko <phcoder@gmail.com
>     <mailto:phcoder@gmail.com>> пишет:
>     >
>     >> On 17.10.2013 20:28, Jonathan McCune wrote:
>     >>> Presently the 'trust' and 'verify_detached' commands disable all
>     filters
>     >>> (e.g., verify.c:grub_cmd_trust() calls
>     grub_file_filter_disable_all())
>     >>> when opening a file containing a public key (note the
>     distinction from
>     >>> verify_detached implicitly using an already-loaded key).
>     >>
>     >> This is the intended behaviour. Usecase to manually add keys when
>     >> needed. Your proposal is for other usecases which would probably
>     require
>     >> special arguments or separate functions.
>     >>
>     >
>     > This has the same MITM problem we already discussed and that was fixed
>     > if pubkey filter is used - you cannot actually know that key you trust
>     > is the same as key you verified. So I think that at least by default
>     > "trust" should not disable pubkey filter.
>     >
>     > verify_detached probably should, but may be only for file that is
>     > verified itself, bit for pubkey.
>     >
>     I didn't oppose to a command or options having the described
>     functionality. Thinking about it, I have to agree that default behaviour
>     should be paranoid with options to relax it. Would you or Jonathan
>     prepare a patch to change the behaviour with an option to restore
>     current behaviour?
> 
> 
> How about addressing this by adding a --skip-sig option to both trust
> and verify_detached, that disables signature checking for the loaded
> public key?  This would be similar in structure to the --skip-sig option
> to load_env, and the consistent use of --skip-sig would hopefully make
> things easier on the author of a .cfg file.  It's mildly confusing to
> say verify_detached --skip-sig since the whole point of that command is
> to check a signature, but the documentation can make it clear.
> 
> I can prepare a patch but it could be a week or more before I have time
> to do so.
> 
Patch attached. Completely untested. Anyone to test it?
> Thanks,
> -Jon
> 
> 
> 
>  
> 
> 
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