Hi Andreas,
On Fri, 2023 Mar 31 09:22-04:00, Andreas Beckmann wrote:
>
> Do you have an example how the kernel modules differ? diffoscope might
> help ...
> Does this happen with all or only with certain dkms modules?
The only DKMS modules I am using currently are the ones associated with
virtualbox, so I can't offer a comparison. Here is the output from
diffoscope, however, for one of the modules:
$ diffoscope
test-debian-sid-amd64-[12]/usr/lib/modules/6.1.0-7-amd64/updates/dkms
--- test-debian-sid-amd64-1/usr/lib/modules/6.1.0-7-amd64/updates/dkms
+++ test-debian-sid-amd64-2/usr/lib/modules/6.1.0-7-amd64/updates/dkms
│ ---
test-debian-sid-amd64-1/usr/lib/modules/6.1.0-7-amd64/updates/dkms/vboxdrv.ko
├── +++
test-debian-sid-amd64-2/usr/lib/modules/6.1.0-7-amd64/updates/dkms/vboxdrv.ko
│┄ Format-specific differences are supported for ELF binaries but no
file-specific differences were detected; falling back to a binary diff. file(1)
reports: ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV),
BuildID[sha1]=5ed23a6ee7417643717766d7b5307da88409fe5a, not stripped
│┄ File has been modified after NT_GNU_BUILD_ID has been applied.
│ @@ -55695,29 +55695,29 @@
│ 000d98e0: 0000 0000 0000 0000 3082 0199 0609 2a86 ........0.....*.
│ 000d98f0: 4886 f70d 0107 02a0 8201 8a30 8201 8602 H..........0....
│ 000d9900: 0101 310d 300b 0609 6086 4801 6503 0402 ..1.0...`.H.e...
│ 000d9910: 0130 0b06 092a 8648 86f7 0d01 0701 3182 .0...*.H......1.
│ 000d9920: 0163 3082 015f 0201 0130 3a30 2231 2030 .c0.._...0:0"1 0
│ 000d9930: 1e06 0355 0403 0c17 444b 4d53 206d 6f64 ...U....DKMS mod
│ 000d9940: 756c 6520 7369 676e 696e 6720 6b65 7902 ule signing key.
│ -000d9950: 1420 b794 fc24 18fe 9e24 595e b7f3 026d . ...$...$Y^...m
│ -000d9960: 4469 13b4 5230 0b06 0960 8648 0165 0304 Di..R0...`.H.e..
│ +000d9950: 1412 4e86 5c0c d923 77b1 7c57 6b90 8c67 ..N.\..#w.|Wk..g
│ +000d9960: 9f64 a4e0 9930 0b06 0960 8648 0165 0304 .d...0...`.H.e..
│ 000d9970: 0201 300d 0609 2a86 4886 f70d 0101 0105 ..0...*.H.......
│ -000d9980: 0004 8201 0057 6678 aee0 2003 cfc3 6f00 .....Wfx.. ...o.
│ -000d9990: 29d9 f1ee 301a 35a9 2fb4 d127 ef5f db28 )...0.5./..'._.(
│ -000d99a0: 6902 15cf 725d 04c4 69c6 58e2 e1e8 2643 i...r]..i.X...&C
│ -000d99b0: 592b 91bd 9fcd 2966 8460 4797 9069 a5cd Y+....)f.`G..i..
│ -000d99c0: bba6 3cf4 9e0b 1c7f 9277 121e ed08 156d ..<......w.....m
│ -000d99d0: c180 4ca4 d84f 6884 ecdd 5fe9 0939 b681 ..L..Oh..._..9..
│ -000d99e0: 2b6f 3e32 d63e 4231 2b2e 1a96 5732 0ad7 +o>2.>B1+...W2..
│ -000d99f0: cb62 7a5b 4bf6 491a c197 0833 d61a 7bd4 .bz[K.I....3..{.
│ -000d9a00: 59f3 7c2b c834 ad42 fc19 f4c3 6de9 c20b Y.|+.4.B....m...
│ -000d9a10: 54d1 78de 9034 ba24 da45 9346 74ba efb7 T.x..4.$.E.Ft...
│ -000d9a20: 4e67 4743 ee19 dd06 8722 d8cd 3c99 ad27 NgGC....."..<..'
│ -000d9a30: ca63 067b 1310 5c52 3f76 f860 b625 6a54 .c.{..\R?v.`.%jT
│ -000d9a40: a40a 3142 c889 b921 e19b 4b92 9725 248e ..1B...!..K..%$.
│ -000d9a50: ec81 7aad 86d4 28d6 e832 3f0d d09d 3ee0 ..z...(..2?...>.
│ -000d9a60: c88d dbce 32ac 7d6d 8047 5c39 ab3f 9289 ....2.}m.G\9.?..
│ -000d9a70: 424c bb85 293c 4cbf 2ca6 7006 a0d5 2b7f BL..)<L.,.p...+.
│ -000d9a80: ae05 4760 fb00 0002 0000 0000 0000 0001 ..G`............
│ +000d9980: 0004 8201 0063 6217 3b4b 51c1 25c4 49e5 .....cb.;KQ.%.I.
│ +000d9990: c3d8 0800 2a72 f0b1 c213 b8c1 1a22 c6d4 ....*r......."..
│ +000d99a0: 7ce3 9cf9 8db6 543a 7251 1f52 ae92 bf3c |.....T:rQ.R...<
│ +000d99b0: 303c bf29 e79a b704 0892 c410 cca3 ee42 0<.)...........B
│ +000d99c0: cd3c dee6 2776 1915 b829 c0c6 5e62 40ea .<..'v...)..^b@.
│ +000d99d0: 3481 78bb b076 c757 58b7 03a4 6abf cef3 4.x..v.WX...j...
│ +000d99e0: 4d9b 5cdf 5b5b e1e5 8629 6600 b914 3701 M.\.[[...)f...7.
│ +000d99f0: a451 7b57 8dc7 136c ddb7 b5b9 6f23 27db .Q{W...l....o#'.
│ +000d9a00: de4f 46a3 11b3 d80b 11f3 d3cc 3420 e1c6 .OF.........4 ..
│ +000d9a10: 2d00 1109 b58b 0ff0 10c7 c7ae 12a9 32be -.............2.
│ +000d9a20: c5c0 7768 8c47 ad30 e1f4 07f9 0189 574e ..wh.G.0......WN
│ +000d9a30: 27f1 e3ef b4f5 8ae4 3d16 787d 7ed9 08e4 '.......=.x}~...
│ +000d9a40: 9339 993e af12 f90e 28c0 b42b b043 6b8c .9.>....(..+.Ck.
│ +000d9a50: 9e80 c7ac 8e83 7b8b de36 6624 67fe 7a40 ......{..6f$g.z@
│ +000d9a60: 77cf bf6d 6220 2cb6 e42a 7dff eceb 3102 w..mb ,..*}...1.
│ +000d9a70: 7265 3b0b 28d3 f8c6 53af 6b09 57e5 e42e re;.(...S.k.W...
│ +000d9a80: 7beb 1fec 4600 0002 0000 0000 0000 0001 {...F...........
│ 000d9a90: 9d7e 4d6f 6475 6c65 2073 6967 6e61 7475 .~Module signatu
│ 000d9aa0: 7265 2061 7070 656e 6465 647e 0a re appended~.
Is a unique signature being added to the modules? I noticed that
/var/lib/dkms/mok.{key,pub} differ between the two systems.
(No secure-boot configuration has been performed on these systems;
everything was debootstrap'ed and installed from scratch in chroots)
> Is the build reproducible on the same host, e.g. does the sequence
> dkms build
> dkms unbuild
> dkms build
> produce binary identical modules?
I had to do "dkms install ..." / "dkms unbuild ...", but yes, the
resulting modules are identical.
--Daniel
--
Daniel Richard G. || sk...@iskunk.org
My ASCII-art .sig got a bad case of Times New Roman.
