On Tue, Jun 15, 2021 at 12:26:19PM -0600, jim.cromie@gmail.com wrote:
On Tue, Jun 15, 2021 at 10:24 AM Greg KH <greg@kroah.com> wrote:
On Tue, Jun 15, 2021 at 10:06:08AM -0600, jim.cromie@gmail.com wrote:
On Mon, Jun 14, 2021 at 1:20 AM Greg KH <greg@kroah.com> wrote:
On Mon, Jun 14, 2021 at 01:09:25AM -0600, jim.cromie@gmail.com wrote:
serio_raw is apparently tainting the kernel when its modprobed. why ? other modules load properly, no code changes to this module
bash-5.1# dmesg | grep -i taint [ 6.517150] serio_raw: module verification failed: signature and/or required key missing - tainting kernel
You did not build this with the correct module signing key that your kernel was built with. That is what this warning is showing you, try building all modules with the same key as your kernel had and you should be fine.
OK, I understand better now -
its nothing wrong with serio_raw, its just the 1st module to load, and warning comes just once. kernel/module.c 3962: pr_notice_once("%s: module verification failed: signature "
Whats odd is that the same module has a signature when modinfo'd in the kernel running the laptop, but not from the same kernel running inside a VM. Does this constitute a bug of some sort ?
I do not understand, what is different here and what is not working properly?
I have built and installed 5.13-rc6 onto my laptop, Im running it now. When I modinfo something, it shows a signature
[jimc@frodo ~]$ modinfo pcspkr filename: /lib/modules/5.13.0-rc6-lm1-00004-g28dc6f490a7f/kernel/drivers/input/misc/pcspkr.ko alias: platform:pcspkr license: GPL description: PC Speaker beeper driver author: Vojtech Pavlik <vojtech@ucw.cz> depends: retpoline: Y intree: Y name: pcspkr vermagic: 5.13.0-rc6-lm1-00004-g28dc6f490a7f SMP mod_unload sig_id: PKCS#7 signer: Build time autogenerated kernel key sig_key: 73:9F:4D:24:D7:05:0A:55:AE:5C:B1:F6:52:B1:BA:E0:5C:68:32:36 sig_hashalgo: sha512 signature: 47:10:D7:A0:79:BE:B5:24:B1:BE:7F:53:8D:EF:4E:73:BD:39:5C:B4: CB:7A:CD:3F:C8:96:E4:7A:72:17:A0:2B:42:63:5A:0F:F6:8B:70:7E: ...
when I run precisely the same kernel inside a virtme/kvm/qemu VM, the same modinfo lacks that sig stuff Note that vermagic matches exactly
bash-5.1# modinfo pcspkr filename: /lib/modules/5.13.0-rc6-lm1-00004-g28dc6f490a7f/kernel/drivers/input/misc/pcspkr.ko alias: platform:pcspkr license: GPL description: PC Speaker beeper driver author: Vojtech Pavlik <vojtech@ucw.cz> depends: retpoline: Y intree: Y name: pcspkr vermagic: 5.13.0-rc6-lm1-00004-g28dc6f490a7f SMP mod_unload bash-5.1#
Are you sure the modinfo you are running inside the vm knows to read the signature information? Odds are a busybox/toybox modinfo does not know this type of thing. Let me check: $ ./busybox modinfo visor | grep signature $ modinfo visor | grep signature signature: 51:F5:13:E1:F9:49:FA:20:68:45:F8:32:67:E2:4D:9C:DD:B6:55:EA: Yup, busybox does not know about these things. Is the md5sum the same for these modules?
If you rebuild modules for a kernel without having the key, yes, you will get this warning. You have to have the same key here.
heres how Ive configured: - copy distro .config from /boot (Fedora) - make localmodconfig (to drop building parts I wont need) - virtme-configkernel --update (to get support for 9P, virtio etc to mount host disks)
all the SECURITY stuff came from the distro config, I havent yet tried to unconfigure it.
I havent done anything specific with keys, I dont know why whatever key is involved is not available for both scenarios. here's the relevant (I hope) config items:
Look at the CONFIG_MODULE_SIG* items, that's the relevant ones. Here's what I use in my custom kernels for my systems: $ zcat /proc/config.gz | grep MODULE_SIG CONFIG_MODULE_SIG_FORMAT=y CONFIG_MODULE_SIG=y CONFIG_MODULE_SIG_FORCE=y CONFIG_MODULE_SIG_ALL=y # CONFIG_MODULE_SIG_SHA1 is not set # CONFIG_MODULE_SIG_SHA224 is not set # CONFIG_MODULE_SIG_SHA256 is not set # CONFIG_MODULE_SIG_SHA384 is not set CONFIG_MODULE_SIG_SHA512=y CONFIG_MODULE_SIG_HASH="sha512" CONFIG_MODULE_SIG_KEY="certs/signing_key.pem" Watch out when using MODULE_SIG_FORCE, that requires you to sign all modules. If you want to keep a keyset around when building custom kernels, that's fine, but I delete mine instantly after signing the kernel so that it's impossible (well harder) to load modules that were not signed as part of my local build process. I do that by doing: rm certs/signing_key.* after installing the kernel. Hope this helps, greg k-h