Re: Hardened toolchain

[kiasoc5]

Hi Simon,

Mar 25, 2022, 22:54 by zimon.toutoune@gmail.com:

> Hi,
>
> On Fri, 25 Mar 2022 at 20:39, kiasoc5@tutanota.com wrote:
>
>> ====the middle of guix build -f hardened.scm====
>> building /gnu/store/1nlrgg5ryl486haw0kdqnbp4wa17lhwh-gcc-10.3.0.drv...
>> Backtrace:
>> In ice-9/eval.scm:
>>    217:50 19 (lp (#<procedure 7ffff3fff5e0 at ice-9/eval.scm:282:?> ?))
>>    217:50 18 (lp (#<procedure 7ffff3fff580 at ice-9/eval.scm:282:?> ?))
>>    217:50 17 (lp (#<procedure 7ffff3fff4c0 at ice-9/eval.scm:649:?> ?))
>>    217:50 16 (lp (#<procedure 7ffff3fff300 at ice-9/eval.scm:282:?> ?))
>>    217:50 15 (lp (#<procedure 7ffff3fff2a0 at ice-9/eval.scm:649:?> ?))
>>    217:50 14 (lp (#<procedure 7ffff3fff140 at ice-9/eval.scm:282:?> ?))
>>    217:50 13 (lp (#<procedure 7ffff3fff120 at ice-9/eval.scm:282:?> ?))
>>    217:50 12 (lp (#<procedure 7ffff3fff100 at ice-9/eval.scm:282:?> ?))
>>    217:50 11 (lp (#<procedure 7ffff2c01f40 at ice-9/eval.scm:649:?> ?))
>>    217:50 10 (lp (#<procedure 7ffff2c01f20 at ice-9/eval.scm:282:?> ?))
>>    217:50  9 (lp (#<procedure 7ffff2c01f00 at ice-9/eval.scm:282:?> ?))
>>    217:50  8 (lp (#<procedure 7ffff2c01ee0 at ice-9/eval.scm:282:?> ?))
>>    217:50  7 (lp (#<procedure 7ffff2c01e80 at ice-9/eval.scm:649:?> ?))
>>    217:50  6 (lp (#<procedure 7ffff2c01e60 at ice-9/eval.scm:282:?> ?))
>>    217:50  5 (lp (#<procedure 7ffff2c20ed0 at ice-9/eval.scm:196:?> ?))
>>    217:50  4 (lp (#<procedure 7ffff2c01d20 at ice-9/eval.scm:282:?> ?))
>>    217:33  3 (lp (#<procedure 7ffff2c01b20 at ice-9/eval.scm:649:?> ?))
>>     159:9  2 (_ #(#(#<directory (guile-user) 7ffff3fd7c80> #f) #f))
>>     159:9  1 (_ #(#(#<directory (guile-user) 7ffff3fd7c80> #f) #f))
>> In unknown file:
>>            0 (string-append "LDFLAGS=" "-Wl,-rpath=" #f "/lib " "-W?" ?)
>>
>> ERROR: In procedure string-append:
>> In procedure string-append: Wrong type (expecting string): #f
>> builder for `/gnu/store/1nlrgg5ryl486haw0kdqnbp4wa17lhwh-gcc-10.3.0.drv' 
>> failed with exit code 1
>> build of /gnu/store/1nlrgg5ryl486haw0kdqnbp4wa17lhwh-gcc-10.3.0.drv failed
>> View build log at 
>> '/var/log/guix/drvs/1n/lrgg5ryl486haw0kdqnbp4wa17lhwh-gcc-10.3.0.drv.gz'.
>> guix build: error: build of 
>> `/gnu/store/1nlrgg5ryl486haw0kdqnbp4wa17lhwh-gcc-10.3.0.drv' failed
>> ====the middle of guix build -f hardened.scm====
>>
>
> You are creating a cycle, no?  It is not a DAG and so the transformation
> fails, no?
>
Oh I didn't notice that. The example makes sense too.

> For instance, this:
>
> --8<---------------cut here---------------start------------->8---
> (use-modules (guix packages)
>  (gnu packages gcc)
>  (gnu packages base))
>
> (define make-gcc-toolchain
>  (@@ (gnu packages commencement) make-gcc-toolchain))
>
> (define gcc-bis
>  (package
>  (inherit gcc)
>  (version (string-append (package-version gcc) "-bis"))))
>
> (define gcc-toolchain-bis
>  (make-gcc-toolchain gcc-bis glibc))
>
> (define (package-with-c-toolchain-bis package)
>  (package-with-c-toolchain
>  package `(("toolchain" ,gcc-toolchain-bis))))
>
>
> (package-with-c-toolchain-bis gcc-bis)
> --8<---------------cut here---------------end--------------->8---
>
> fails with the same message.  There is bootstrapping issue: the binary
> of gcc-bis is required to compile the source of gcc-bis; where does come
> from such binary of gcc-bis?
>
>
> Considering your use case, you need:
>
>  - gcc considered as binary seed
>  
>  - use this binary gcc with the hardened options to compile the source
>  of GCC; resulting to the binary gcc-hardened-1
>
>  - use this binary gcc-hardened-2 with the hardened options to recompile
>  the source of GCC; resulting to the binary gcc-hardened-2
>
>  - if checksum(gcc-hardened-1) == checksum(gcc-hardened-2)
>  then use this binary to define a new toolchain
>  else reach the fixed point
>
> fixed point: use this binary gcc-hardened-{n-1} to compile the source of
>  GCC and output the binary gcc-hardened-{n}; compare the checksum of
>  the binary {n-1} and {n} and repeat until equality is reached.
>
Just so I understand, in other (imperative) words:

gcc-hardened-1 = gcc-hardened built with regular gcc
gcc-hardened-2 = gcc-hardened built with gcc-hardened-1
n = 1
while checksum(gcc-hardened-{n}) != checksum(gcc-hardened-{n+1}):
   gcc-hardened-{n+1} = gcc-hardened built with gcc-hardened-{n}
   n++
define the new toolchain with gcc-hardened-{n+1}


> Guix is not auto-magically resolving the fixed-point, i.e., it does not
> unroll the cycle by magic. :-) You have to do it manually or write code
> for automatise the process; described above.
>
Thanks, are there any examples in the code base that would be a good reference?

>
> Hope that helps.
>
> Cheers,
> simon
>