Gentoo Archives: gentoo-user

From: Dave Trombley <dave.trombley@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Kernel module signature now shown on modinfo
Date: Thu, 12 Apr 2018 21:47:42
Message-Id: CACggcZQOqVVGTTtFN7uudfVdbXHr9zEvZ05oXx7jUzys1UNiFw@mail.gmail.com
In Reply to: [gentoo-user] Kernel module signature now shown on modinfo by Ben Mezger
1 This has been broken for almost two years; the signature format switched to
2 PKCS#7 and modinfo doesn't support it. It's not as simple as just
3 patching kmod because evidently the kernel change regressed or disrespected
4 the relevent structure in the modules in a way that makes it impossible for
5 kmod to even make sense of. Details here:
6 https://github.com/coreos/bugs/issues/1054
7
8 -David
9
10 On Wed, Apr 11, 2018 at 4:39 PM, Ben Mezger <su@××××.nl> wrote:
11
12 > Greetings,
13 >
14 > I have enabled module signature verification on my kernel, and it does
15 > seem to be enabled upon boot:
16 >
17 > $ dmesg | grep -i 'x.*509'
18 > [ 1.259988] Asymmetric key parser 'x509' registered
19 > [ 1.811026] Loading compiled-in X.509 certificates
20 > [ 1.813833] Loaded X.509 cert 'Build time autogenerated kernel key:
21 > 77e716fc52a6293567d953cd24a5977e55b41a5e'
22 >
23 > and doing a cat /proc/keys seems to show the key enabled:
24 >
25 > $ cat /proc/keys
26 > ...
27 > 37c67374 I------ 1 perm 1f030000 0 0 asymmetri Build time
28 > autogenerated kernel key: 77e716fc52a6293567d953cd24a5977e55b41a5e:
29 > X509.rsa 55b41a5e []
30 > ...
31 >
32 > However, if I do a modinfo to see the key on a module, it seems empty:
33 >
34 > $modinfo ntfs
35 > filename: /lib/modules/4.9.76-gentoo-r1/kernel/fs/ntfs/ntfs.ko
36 > license: GPL
37 > version: 2.1.32
38 > description: NTFS 1.2/3.x driver - Copyright (c) 2001-2014 Anton
39 > Altaparmakov and Tuxera Inc.
40 > author: Anton Altaparmakov <anton@××××××.com>
41 > alias: fs-ntfs
42 > srcversion: 0D7ACE93F603E9350827FB8
43 > depends:
44 > intree: Y
45 > vermagic: 4.9.76-gentoo-r1 SMP mod_unload
46 > signat: PKCS#7
47 > signer:
48 > sig_key:
49 > sig_hashalgo: md4
50 >
51 > And hex dump does show me the digital signature appended at the end:
52 >
53 > $ hexdump -C /lib64/modules/4.9.76-gentoo-r1/kernel/fs/ntfs/ntfs.ko| tail
54 > 0004e8c0 e3 dd 54 9d 5e f1 1a 12 56 47 4e 54 91 b9 fa ce
55 > |..T.^...VGNT....|
56 > 0004e8d0 e6 01 db 37 eb 83 f3 77 10 f0 b5 f8 11 fd 4e 86
57 > |...7...w......N.|
58 > 0004e8e0 6c 81 8a 61 c2 15 6d 5a 35 93 8b 33 c0 32 2f e4
59 > |l..a..mZ5..3.2/.|
60 > 0004e8f0 8c 15 71 de c8 c5 39 58 cc e8 65 e1 be 36 e6 02
61 > |..q...9X..e..6..|
62 > 0004e900 b0 75 b5 a2 73 d8 4d 22 e7 2f 53 1f 42 fb ee 58
63 > |.u..s.M"./S.B..X|
64 > 0004e910 f2 65 44 13 26 30 7b 31 1c 58 12 5a f2 5d b1 45
65 > |.eD.&0{1.X.Z.].E|
66 > 0004e920 3a f0 a5 79 74 f4 00 00 02 00 00 00 00 00 00 00
67 > |:..yt...........|
68 > 0004e930 02 9e 7e 4d 6f 64 75 6c 65 20 73 69 67 6e 61 74 |..~Module
69 > signat|
70 > 0004e940 75 72 65 20 61 70 70 65 6e 64 65 64 7e 0a |ure
71 > appended~.|
72 > 0004e94e
73 >
74 > My question is: why doesn't modinfo show me the key fingerprint?
75 >
76 > --
77 > Kind regards,
78 > Met een vriendelijke groet,
79 >
80 > Ben Mezger
81 > https://seds.nl
82 > PGP: C473 DDC9 D1B1 40AF 2051 1CF6 18C4 6052 1688 92F7
83 >
84 >

Replies

Subject Author
Re: [gentoo-user] Kernel module signature now shown on modinfo Mick <michaelkintzios@×××××.com>