Messages in this thread | | | Date | Thu, 12 Jun 2014 22:04:02 +0300 | Subject | Re: [PATCH 3/4] KEYS: validate key trust only with selected owner key | From | Dmitry Kasatkin <> |
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On 12 June 2014 22:01, Vivek Goyal <vgoyal@redhat.com> wrote: > On Thu, Jun 12, 2014 at 09:36:46PM +0300, Dmitry Kasatkin wrote: >> On 12 June 2014 20:32, Vivek Goyal <vgoyal@redhat.com> wrote: >> > On Thu, Jun 12, 2014 at 08:23:57PM +0300, Dmitry Kasatkin wrote: >> >> On 12/06/14 19:03, Vivek Goyal wrote: >> >> > On Tue, Jun 10, 2014 at 11:48:17AM +0300, Dmitry Kasatkin wrote: >> >> >> This patch provides kernel parameter to specify owner's key id which >> >> >> must be used for trust validate of keys. Keys signed with other keys >> >> >> are not trusted. >> >> >> >> >> >> Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com> >> >> > Hi, >> >> > >> >> > I am continuing to work on verifying kernel signature for kexec/kdump. I >> >> > am planning to take david howell's patches for pkcs7 signature >> >> > verification and verify bzImage signature. >> >> > >> >> > Part of that process will boil down to verifying a certificate in >> >> > pkcs7 x509 cert chain using a key in system_trusted_keyring. >> >> > >> >> > I think the OS vendor key which signs the kernel signing key propagates to >> >> > system_trusted_keyring. (shim has that and I am not sure how shim makes >> >> > it propogate all they way to system_trusted_keyring). >> >> > >> >> > So I was planning to use same functionality where I look for any key >> >> > which can verify the signing cert of kernel. As OS vendor key will be >> >> > in system_trusted_keyring, it should work. >> >> > >> >> > Now with this change where you will trust only one selected owner key. >> >> > That means you will not even trust the OS vendor key which signs kernel >> >> > signing key. I think this will stop working with keys_ownerid=<....> >> >> > >> >> > As I am doing that work in parallel and I saw these patches, I thought >> >> > I will bring it up. >> >> >> >> Hi Vivek, >> >> >> >> All keys stays in the keyring. Usage of owner_keyid is limited to >> >> validate the trust of the loaded keys. >> > >> > Hi Dmitry, >> > >> > If owner_keyid scope is just limited to loading extra keys, then it >> > should be fine as I don't want to load extra keys. I just want to >> > verify already signed image whose key is supposed to be in >> > system_trusted_keyring. >> > >> >> >> >> >> >> Do you really see OS verndor key (Fedora) on the system keyring? >> >> shim is UEFI binary and can add it to the MOK database.. >> > >> > I have been told that mechanism to propagate they key in shim which is >> > used to verify kernel signature is in place and that key should show >> > up in system_trusted_keyring. I have never verified it though. I will >> > check it out. >> > >> > Thanks >> > Vivek >> >> >> Hi Vivek, >> >> The easiest way to get OS Vendor ker/certificate is just embed it into >> the kernel along with >> ephemeral (or not) module signing key... They all appears on .system keyring... > > I think it will be tricky as in current setup, signing happens on a different > server and build server does not have access to keys. > > Thanks > Vivek
It should not be tricky... Signing is done with private key... Security measure has to be considered.
Certificate is public and is not a secret.. It can be on any build machine in the world...
-- Thanks, Dmitry
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