Messages in this thread | | | Date | Mon, 9 Jun 2014 16:58:46 +0300 | Subject | Re: [RFC PATCH v5 4/4] KEYS: define an owner trusted keyring | From | Dmitry Kasatkin <> |
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On 9 June 2014 16:48, Mimi Zohar <zohar@linux.vnet.ibm.com> wrote: > On Mon, 2014-06-09 at 16:05 +0300, Dmitry Kasatkin wrote: >> On 09/06/14 15:51, Mimi Zohar wrote: >> > On Mon, 2014-06-09 at 15:13 +0300, Dmitry Kasatkin wrote: >> >> On 03/06/14 20:58, Mimi Zohar wrote: >> >>> Instead of allowing public keys, with certificates signed by any >> >>> key on the system trusted keyring, to be added to a trusted >> >>> keyring, this patch further restricts the certificates to those >> >>> signed by a particular key on the system keyring. >> >>> >> >>> When the UEFI secure boot keys are added to the system keyring, the >> >>> platform owner will be able to load their key in one of the UEFI DBs >> >>> (eg. Machine Owner Key(MOK) list) and select their key, without >> >>> having to rebuild the kernel. >> >>> >> >>> This patch defines an owner trusted keyring, a new boot command >> >>> line option 'keys_ownerid=', and defines a new function >> >>> get_system_or_owner_trusted_keyring(). >> >> Hello, >> >> >> >> The functionality of this entire patch can be replaced by only ~2 lines >> >> of code in x509_request_asymmetric_key() >> >> >> >> if (keys_ownerid || strcmp(keys_ownerid, id)) >> >> return -EPERM; >> >> >> >> Right? >> > Are you suggesting only add the one matching key to the system keyring? >> >> No. I am not suggesting this. >> >> All built in keys are allocated with KEY_ALLOC_TRUSTED flag and >> prep.trusted is set to "true". >> >> So the following statement has no effect. > > Ok, so it has no affect on adding builtin keys to the system keyring. > >> >> #ifdef CONFIG_SYSTEM_TRUSTED_KEYRING >> ret = x509_validate_trust(cert, system_trusted_keyring); >> if (!ret) >> prep->trusted = 1; >> #endif > > The last patch set changes the test to: > ret = x509_validate_trust(cert, get_system_or_owner_trusted_keyring()); >
It does not really mater. I just copied original code to my response.
>> Keys which come from user-space will check for >> >> if (keys_ownerid && strcmp(keys_ownerid, id)) >> return -EPERM; >> >> >> So 2 lines patch works fine.. > > It works based on the assumption, that you would ever only want a single > key on the 'owner' keyring, which is probably not the case. >
There is no any assumption here. I am discussing functionality of this patch. That is exactly what this patch does - loads single key on the owners keyring.
There is no need for additional keyring for a single key. That is just enough to limit verification to the owners key id.
- Dmitry
> Mimi > > -- > To unsubscribe from this list: send the line "unsubscribe linux-security-module" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
-- Thanks, Dmitry
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