The Secure Boot Forbidden Signature Database, dbx, contains a list of
now revoked signatures and keys previously approved to boot with UEFI
Secure Boot enabled. Currently EFI_CERT_X509_SHA256_GUID and
EFI_CERT_SHA256_GUID can be preloaded (at build time) into the system
blacklist keyring.
Add the ability to also preload EFI_CERT_X509_GUID dbx entries.
This series can be applied on its own; however to use preloaded
revocation certificates, [1] should be applied first.
[1] https://www.spinics.net/lists/keyrings/msg08422.html
Eric Snowberg (2):
certs: Move load_system_certificate_list to a common function
certs: Add ability to preload revocation certs
certs/Kconfig | 8 +++++
certs/Makefile | 20 ++++++++++--
certs/blacklist.c | 17 ++++++++++
certs/common.c | 56 +++++++++++++++++++++++++++++++++
certs/common.h | 9 ++++++
certs/revocation_certificates.S | 21 +++++++++++++
certs/system_keyring.c | 49 ++---------------------------
scripts/Makefile | 1 +
8 files changed, 132 insertions(+), 49 deletions(-)
create mode 100644 certs/common.c
create mode 100644 certs/common.h
create mode 100644 certs/revocation_certificates.S
base-commit: 02de58b24d2e1b2cf947d57205bd2221d897193c
--
2.18.1
Move functionality within load_system_certificate_list to a common
function, so it can be reused in the future.
Signed-off-by: Eric Snowberg <[email protected]>
---
certs/Makefile | 2 +-
certs/common.c | 56 ++++++++++++++++++++++++++++++++++++++++++
certs/common.h | 9 +++++++
certs/system_keyring.c | 49 +++---------------------------------
4 files changed, 69 insertions(+), 47 deletions(-)
create mode 100644 certs/common.c
create mode 100644 certs/common.h
diff --git a/certs/Makefile b/certs/Makefile
index f4c25b67aad9..f4b90bad8690 100644
--- a/certs/Makefile
+++ b/certs/Makefile
@@ -3,7 +3,7 @@
# Makefile for the linux kernel signature checking certificates.
#
-obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
+obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o common.o
obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o
ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"")
obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o
diff --git a/certs/common.c b/certs/common.c
new file mode 100644
index 000000000000..83800f51a1a1
--- /dev/null
+++ b/certs/common.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/kernel.h>
+#include <linux/key.h>
+
+int load_certificate_list(const u8 cert_list[],
+ const unsigned long list_size,
+ const struct key *keyring)
+{
+ key_ref_t key;
+ const u8 *p, *end;
+ size_t plen;
+
+ p = cert_list;
+ end = p + list_size;
+ while (p < end) {
+ /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
+ * than 256 bytes in size.
+ */
+ if (end - p < 4)
+ goto dodgy_cert;
+ if (p[0] != 0x30 &&
+ p[1] != 0x82)
+ goto dodgy_cert;
+ plen = (p[2] << 8) | p[3];
+ plen += 4;
+ if (plen > end - p)
+ goto dodgy_cert;
+
+ key = key_create_or_update(make_key_ref(keyring, 1),
+ "asymmetric",
+ NULL,
+ p,
+ plen,
+ ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW | KEY_USR_READ),
+ KEY_ALLOC_NOT_IN_QUOTA |
+ KEY_ALLOC_BUILT_IN |
+ KEY_ALLOC_BYPASS_RESTRICTION);
+ if (IS_ERR(key)) {
+ pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
+ PTR_ERR(key));
+ } else {
+ pr_notice("Loaded X.509 cert '%s'\n",
+ key_ref_to_ptr(key)->description);
+ key_ref_put(key);
+ }
+ p += plen;
+ }
+
+ return 0;
+
+dodgy_cert:
+ pr_err("Problem parsing in-kernel X.509 certificate list\n");
+ return 0;
+}
diff --git a/certs/common.h b/certs/common.h
new file mode 100644
index 000000000000..abdb5795936b
--- /dev/null
+++ b/certs/common.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _CERT_COMMON_H
+#define _CERT_COMMON_H
+
+int load_certificate_list(const u8 cert_list[], const unsigned long list_size,
+ const struct key *keyring);
+
+#endif
diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index 798291177186..4510fb5462fb 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -15,6 +15,7 @@
#include <keys/asymmetric-type.h>
#include <keys/system_keyring.h>
#include <crypto/pkcs7.h>
+#include "common.h"
static struct key *builtin_trusted_keys;
#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
@@ -136,54 +137,10 @@ device_initcall(system_trusted_keyring_init);
*/
static __init int load_system_certificate_list(void)
{
- key_ref_t key;
- const u8 *p, *end;
- size_t plen;
-
pr_notice("Loading compiled-in X.509 certificates\n");
- p = system_certificate_list;
- end = p + system_certificate_list_size;
- while (p < end) {
- /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
- * than 256 bytes in size.
- */
- if (end - p < 4)
- goto dodgy_cert;
- if (p[0] != 0x30 &&
- p[1] != 0x82)
- goto dodgy_cert;
- plen = (p[2] << 8) | p[3];
- plen += 4;
- if (plen > end - p)
- goto dodgy_cert;
-
- key = key_create_or_update(make_key_ref(builtin_trusted_keys, 1),
- "asymmetric",
- NULL,
- p,
- plen,
- ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
- KEY_USR_VIEW | KEY_USR_READ),
- KEY_ALLOC_NOT_IN_QUOTA |
- KEY_ALLOC_BUILT_IN |
- KEY_ALLOC_BYPASS_RESTRICTION);
- if (IS_ERR(key)) {
- pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
- PTR_ERR(key));
- } else {
- pr_notice("Loaded X.509 cert '%s'\n",
- key_ref_to_ptr(key)->description);
- key_ref_put(key);
- }
- p += plen;
- }
-
- return 0;
-
-dodgy_cert:
- pr_err("Problem parsing in-kernel X.509 certificate list\n");
- return 0;
+ return load_certificate_list(system_certificate_list, system_certificate_list_size,
+ builtin_trusted_keys);
}
late_initcall(load_system_certificate_list);
--
2.18.1
On Wed, Sep 30, 2020 at 04:15:07PM -0400, Eric Snowberg wrote:
> Move functionality within load_system_certificate_list to a common
> function, so it can be reused in the future.
>
> Signed-off-by: Eric Snowberg <[email protected]>
I rather think now rather than the future. I think this should be part
of a patch set where the re-use actually happens.
Without that context, I rather not say anything about this patch.
Neither an issue for me if it gets applied. This is just a guideline
that I follow (in order to manage this chaos).
Looking at the code change, I do not see anything strikingly wrong in
it.
/Jarkko
> On Sep 30, 2020, at 3:02 PM, Jarkko Sakkinen <[email protected]> wrote:
>
> On Wed, Sep 30, 2020 at 04:15:07PM -0400, Eric Snowberg wrote:
>> Move functionality within load_system_certificate_list to a common
>> function, so it can be reused in the future.
>>
>> Signed-off-by: Eric Snowberg <[email protected]>
>
> I rather think now rather than the future. I think this should be part
> of a patch set where the re-use actually happens.
load_certificate_list is being used in the second patch in the series [1].
It uses the now common code, to load the revocation certificates, just like
the system certificates are being loaded in this patch.
> Without that context, I rather not say anything about this patch.
> Neither an issue for me if it gets applied. This is just a guideline
> that I follow (in order to manage this chaos).
>
> Looking at the code change, I do not see anything strikingly wrong in
> it.
Thanks
[1] https://lore.kernel.org/patchwork/patch/1315486/
On Wed, Sep 30, 2020 at 03:15:10PM -0600, Eric Snowberg wrote:
>
> > On Sep 30, 2020, at 3:02 PM, Jarkko Sakkinen <[email protected]> wrote:
> >
> > On Wed, Sep 30, 2020 at 04:15:07PM -0400, Eric Snowberg wrote:
> >> Move functionality within load_system_certificate_list to a common
> >> function, so it can be reused in the future.
> >>
> >> Signed-off-by: Eric Snowberg <[email protected]>
> >
> > I rather think now rather than the future. I think this should be part
> > of a patch set where the re-use actually happens.
>
> load_certificate_list is being used in the second patch in the series [1].
> It uses the now common code, to load the revocation certificates, just like
> the system certificates are being loaded in this patch.
Ugh, better to get some sleep. Double checked 2/2 and ack still holds.
Sorry about this.
Acked-by: Jarkko Sakkinen <[email protected]>
/Jarkko