Re: modinfo shows md4 signature instead of sha256

[Lucas De Marchi <lucas.de.marchi@gmail.com>]

Now really CC Yauheni.

On Wed, Jan 31, 2018 at 9:39 AM, Lucas De Marchi
<lucas.de.marchi@gmail.com> wrote:
> Hi Ferry,
>
> CC'ing mailing list and Yauheni who worked on fixing modinfo output in
> the last release.
>
>
> On Wed, Jan 31, 2018 at 1:23 AM, Ferry van Steen
> <Ferry.van.Steen@citrus.nl> wrote:
>> Hi,
>>
>>
>> sorry, not sure where to file this. There seems to be a bug in either th=
e
>> kernel signing modules with a wrong signature algorithm, or modinfo is
>> reporting it incorrectly. I presume it's the latter.
>>
>>
>> More details are here: https://bugzilla.redhat.com/show_bug.cgi?id=3D149=
0975
>
> Not showing the output on older versions is a known issue: support for
> PKCS#7 sig type was
> only added to kmod in v23.
>
> Now for the incorrect info, the problem appears to be in the kernel
> implementation:
> it appends a PKCS#7, but doens't fill out the struct module_signature
> correctly. So in F27 I get this from, e.g.
> soundcore.ko:
>
> $ xxd -c 8 -g 1 mod.ko | tail -n6
> 00004d80: b9 d5 04 00 00 02 00 00  ........   <<<<<<
> 00004d88: 00 00 00 00 00 02 d3 7e  .......~
> 00004d90: 4d 6f 64 75 6c 65 20 73  Module s
> 00004d98: 69 67 6e 61 74 75 72 65  ignature
> 00004da0: 20 61 70 70 65 6e 64 65   appende
> 00004da8: 64 7e 0a                 d~.
>
> See line marked above. It should match a struct module_signature. So:
> id_type =3D=3D 0x2 // PKCS7
> hash =3D=3D 0 // md4
> algo =3D=3D 0 // dsa
>
> Looking at scripts/sign-file.c, indeed id_type is the only field that
> is filled out.
> CC'ing  David Howells as well. Any input here?
>
> Lucas De Marchi
>
>>
>>
>> Thanks in advance and kind regards,
>>
>>
>> Ferry van Steen
>> Linux Developer
>> Ferry.van.Steen@Citrus.nl
>>
>> Citrus Software
>> =E2=97=8F  Almystraat 10A
>> =E2=97=8F  5061 PA Oisterwijk
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>
>
>
> --
> Lucas De Marchi



--=20
Lucas De Marchi