Commit Graph

5 Commits

Author SHA1 Message Date
Josh Boyer 386b49f51d efi: Allow the "db" UEFI variable to be suppressed
If a user tells shim to not use the certs/hashes in the UEFI db variable
for verification purposes, shim will set a UEFI variable called
MokIgnoreDB. Have the uefi import code look for this and ignore the db
variable if it is found.

[zohar@linux.ibm.com: removed reference to "secondary" keyring comment]
Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Nayna Jain <nayna@linux.ibm.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: James Morris <james.morris@microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2018-12-12 22:09:10 -05:00
Josh Boyer 15ea0e1e3e efi: Import certificates from UEFI Secure Boot
Secure Boot stores a list of allowed certificates in the 'db' variable.
This patch imports those certificates into the platform keyring. The shim
UEFI bootloader has a similar certificate list stored in the 'MokListRT'
variable. We import those as well.

Secure Boot also maintains a list of disallowed certificates in the 'dbx'
variable. We load those certificates into the system blacklist keyring
and forbid any kernel signed with those from loading.

[zohar@linux.ibm.com: dropped Josh's original patch description]
Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2018-12-12 22:04:33 -05:00
Dave Howells 0bc9ae395b efi: Add an EFI signature blob parser
Add a function to parse an EFI signature blob looking for elements of
interest. A list is made up of a series of sublists, where all the
elements in a sublist are of the same type, but sublists can be of
different types.

For each sublist encountered, the function pointed to by the
get_handler_for_guid argument is called with the type specifier GUID and
returns either a pointer to a function to handle elements of that type or
NULL if the type is not of interest.

If the sublist is of interest, each element is passed to the handler
function in turn.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2018-12-12 22:04:29 -05:00
Nayna Jain 60740accf7 integrity: Load certs to the platform keyring
The patch refactors integrity_load_x509(), making it a wrapper for a new
function named integrity_add_key(). This patch also defines a new
function named integrity_load_cert() for loading the platform keys.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: James Morris <james.morris@microsoft.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2018-12-12 22:02:54 -05:00
Nayna Jain 9dc92c4517 integrity: Define a trusted platform keyring
On secure boot enabled systems, a verified kernel may need to kexec
additional kernels. For example, it may be used as a bootloader needing
to kexec a target kernel or it may need to kexec a crashdump kernel. In
such cases, it may want to verify the signature of the next kernel
image.

It is further possible that the kernel image is signed with third party
keys which are stored as platform or firmware keys in the 'db' variable.
The kernel, however, can not directly verify these platform keys, and an
administrator may therefore not want to trust them for arbitrary usage.
In order to differentiate platform keys from other keys and provide the
necessary separation of trust, the kernel needs an additional keyring to
store platform keys.

This patch creates the new keyring called ".platform" to isolate keys
provided by platform from keys by kernel. These keys are used to
facilitate signature verification during kexec. Since the scope of this
keyring is only the platform/firmware keys, it cannot be updated from
userspace.

This keyring can be enabled by setting CONFIG_INTEGRITY_PLATFORM_KEYRING.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: James Morris <james.morris@microsoft.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2018-12-12 22:02:28 -05:00