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 <eric.snowberg@oracle.com> --- 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
Add a new Kconfig option called SYSTEM_REVOCATION_KEYS. If set, this option should be the filename of a PEM-formated file containing X.509 certificates to be included in the default blacklist keyring. Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> --- certs/Kconfig | 8 ++++++++ certs/Makefile | 18 ++++++++++++++++-- certs/blacklist.c | 17 +++++++++++++++++ certs/revocation_certificates.S | 21 +++++++++++++++++++++ scripts/Makefile | 1 + 5 files changed, 63 insertions(+), 2 deletions(-) create mode 100644 certs/revocation_certificates.S diff --git a/certs/Kconfig b/certs/Kconfig index c94e93d8bccf..379a6e198459 100644 --- a/certs/Kconfig +++ b/certs/Kconfig @@ -83,4 +83,12 @@ config SYSTEM_BLACKLIST_HASH_LIST wrapper to incorporate the list into the kernel. Each <hash> should be a string of hex digits. +config SYSTEM_REVOCATION_KEYS + string "X.509 certificates to be preloaded into the system blacklist keyring" + depends on SYSTEM_BLACKLIST_KEYRING + help + If set, this option should be the filename of a PEM-formatted file + containing X.509 certificates to be included in the default blacklist + keyring. + endmenu diff --git a/certs/Makefile b/certs/Makefile index f4b90bad8690..e3f4926fd21e 100644 --- a/certs/Makefile +++ b/certs/Makefile @@ -4,7 +4,7 @@ # obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o common.o -obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o +obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o revocation_certificates.o common.o ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"") obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o else @@ -29,7 +29,7 @@ $(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREF $(call if_changed,extract_certs,$(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_TRUSTED_KEYS)) endif # CONFIG_SYSTEM_TRUSTED_KEYRING -clean-files := x509_certificate_list .x509.list +clean-files := x509_certificate_list .x509.list x509_revocation_list ifeq ($(CONFIG_MODULE_SIG),y) ############################################################################### @@ -104,3 +104,17 @@ targets += signing_key.x509 $(obj)/signing_key.x509: scripts/extract-cert $(X509_DEP) FORCE $(call if_changed,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY)) endif # CONFIG_MODULE_SIG + +ifeq ($(CONFIG_SYSTEM_BLACKLIST_KEYRING),y) + +$(eval $(call config_filename,SYSTEM_REVOCATION_KEYS)) + +$(obj)/revocation_certificates.o: $(obj)/x509_revocation_list + +quiet_cmd_extract_certs = EXTRACT_CERTS $(patsubst "%",%,$(2)) + cmd_extract_certs = scripts/extract-cert $(2) $@ + +targets += x509_revocation_list +$(obj)/x509_revocation_list: scripts/extract-cert $(SYSTEM_REVOCATION_KEYS_SRCPREFIX)$(SYSTEM_REVOCATION_KEYS_FILENAME) FORCE + $(call if_changed,extract_certs,$(SYSTEM_REVOCATION_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_REVOCATION_KEYS)) +endif diff --git a/certs/blacklist.c b/certs/blacklist.c index 6514f9ebc943..a0e7770895ce 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -16,9 +16,13 @@ #include <linux/seq_file.h> #include <keys/system_keyring.h> #include "blacklist.h" +#include "common.h" static struct key *blacklist_keyring; +extern __initconst const u8 revocation_certificate_list[]; +extern __initconst const unsigned long revocation_certificate_list_size; + /* * The description must be a type prefix, a colon and then an even number of * hex digits. The hash is kept in the description. @@ -177,3 +181,16 @@ static int __init blacklist_init(void) * Must be initialised before we try and load the keys into the keyring. */ device_initcall(blacklist_init); + +/* + * Load the compiled-in list of revocation X.509 certificates. + */ +static __init int load_revocation_certificate_list(void) +{ + if (revocation_certificate_list_size) + pr_notice("Loading compiled-in revocation X.509 certificates\n"); + + return load_certificate_list(revocation_certificate_list, revocation_certificate_list_size, + blacklist_keyring); +} +late_initcall(load_revocation_certificate_list); diff --git a/certs/revocation_certificates.S b/certs/revocation_certificates.S new file mode 100644 index 000000000000..f21aae8a8f0e --- /dev/null +++ b/certs/revocation_certificates.S @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include <linux/export.h> +#include <linux/init.h> + + __INITRODATA + + .align 8 + .globl revocation_certificate_list +revocation_certificate_list: +__revocation_list_start: + .incbin "certs/x509_revocation_list" +__revocation_list_end: + + .align 8 + .globl revocation_certificate_list_size +revocation_certificate_list_size: +#ifdef CONFIG_64BIT + .quad __revocation_list_end - __revocation_list_start +#else + .long __revocation_list_end - __revocation_list_start +#endif diff --git a/scripts/Makefile b/scripts/Makefile index bc018e4b733e..fb105b2bc006 100644 --- a/scripts/Makefile +++ b/scripts/Makefile @@ -11,6 +11,7 @@ hostprogs-always-$(CONFIG_ASN1) += asn1_compiler hostprogs-always-$(CONFIG_MODULE_SIG_FORMAT) += sign-file hostprogs-always-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += extract-cert hostprogs-always-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE) += insert-sys-cert + hostprogs-always-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += extract-cert HOSTCFLAGS_sorttable.o = -I$(srctree)/tools/include HOSTCFLAGS_asn1_compiler.o = -I$(srctree)/include -- 2.18.1
On Wed, Sep 30, 2020 at 04:15:08PM -0400, Eric Snowberg wrote:
> Add a new Kconfig option called SYSTEM_REVOCATION_KEYS. If set,
> this option should be the filename of a PEM-formated file containing
> X.509 certificates to be included in the default blacklist keyring.
>
> Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Acked-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
/Jarkko
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 <eric.snowberg@oracle.com>
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 <jarkko.sakkinen@linux.intel.com> 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 <eric.snowberg@oracle.com> > > 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 <jarkko.sakkinen@linux.intel.com> 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 <eric.snowberg@oracle.com>
> >
> > 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 <jarkko.sakkinen@linux.intel.com>
/Jarkko