KEYS: Separate the kernel signature checking keyring from module signing
Separate the kernel signature checking keyring from module signing so that it
can be used by code other than the module-signing code.
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
new file mode 100644
index 0000000..8dabc39
--- /dev/null
+++ b/include/keys/system_keyring.h
@@ -0,0 +1,23 @@
+/* System keyring containing trusted public keys.
+ *
+ * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#ifndef _KEYS_SYSTEM_KEYRING_H
+#define _KEYS_SYSTEM_KEYRING_H
+
+#ifdef CONFIG_SYSTEM_TRUSTED_KEYRING
+
+#include <linux/key.h>
+
+extern struct key *system_trusted_keyring;
+
+#endif
+
+#endif /* _KEYS_SYSTEM_KEYRING_H */
diff --git a/init/Kconfig b/init/Kconfig
index 3ecd8a1..0ff5407 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1668,6 +1668,18 @@
default 0 if BASE_FULL
default 1 if !BASE_FULL
+config SYSTEM_TRUSTED_KEYRING
+ bool "Provide system-wide ring of trusted keys"
+ depends on KEYS
+ help
+ Provide a system keyring to which trusted keys can be added. Keys in
+ the keyring are considered to be trusted. Keys may be added at will
+ by the kernel from compiled-in data and from hardware key stores, but
+ userspace may only add extra keys if those keys can be verified by
+ keys already in the keyring.
+
+ Keys in this keyring are used by module signature checking.
+
menuconfig MODULES
bool "Enable loadable module support"
option modules
@@ -1741,6 +1753,7 @@
config MODULE_SIG
bool "Module signature verification"
depends on MODULES
+ select SYSTEM_TRUSTED_KEYRING
select KEYS
select CRYPTO
select ASYMMETRIC_KEY_TYPE
diff --git a/kernel/Makefile b/kernel/Makefile
index 2c24195..6313698 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -54,8 +54,9 @@
obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
obj-$(CONFIG_UID16) += uid16.o
+obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
obj-$(CONFIG_MODULES) += module.o
-obj-$(CONFIG_MODULE_SIG) += module_signing.o modsign_pubkey.o modsign_certificate.o
+obj-$(CONFIG_MODULE_SIG) += module_signing.o
obj-$(CONFIG_KALLSYMS) += kallsyms.o
obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_KEXEC) += kexec.o
@@ -141,11 +142,11 @@
$(obj)/timeconst.h: $(obj)/hz.bc $(src)/timeconst.bc FORCE
$(call if_changed,bc)
-ifeq ($(CONFIG_MODULE_SIG),y)
###############################################################################
#
# Roll all the X.509 certificates that we can find together and pull them into
-# the kernel.
+# the kernel so that they get loaded into the system trusted keyring during
+# boot.
#
# We look in the source root and the build root for all files whose name ends
# in ".x509". Unfortunately, this will generate duplicate filenames, so we
@@ -153,6 +154,7 @@
# duplicates.
#
###############################################################################
+ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y)
X509_CERTIFICATES-y := $(wildcard *.x509) $(wildcard $(srctree)/*.x509)
X509_CERTIFICATES-$(CONFIG_MODULE_SIG) += signing_key.x509
X509_CERTIFICATES := $(sort $(foreach CERT,$(X509_CERTIFICATES-y), \
@@ -169,10 +171,11 @@
endif
endif
-kernel/modsign_certificate.o: $(obj)/x509_certificate_list
+kernel/system_certificates.o: $(obj)/x509_certificate_list
quiet_cmd_x509certs = CERTS $@
- cmd_x509certs = cat $(X509_CERTIFICATES) /dev/null >$@
+ cmd_x509certs = cat $(X509_CERTIFICATES) /dev/null >$@ $(foreach X509,$(X509_CERTIFICATES),; echo " - Including cert $(X509)")
+
targets += $(obj)/x509_certificate_list
$(obj)/x509_certificate_list: $(X509_CERTIFICATES) $(obj)/.x509.list
$(call if_changed,x509certs)
@@ -182,7 +185,9 @@
@echo $(X509_CERTIFICATES) >$@
clean-files := x509_certificate_list .x509.list
+endif
+ifeq ($(CONFIG_MODULE_SIG),y)
###############################################################################
#
# If module signing is requested, say by allyesconfig, but a key has not been
diff --git a/kernel/modsign_certificate.S b/kernel/modsign_certificate.S
deleted file mode 100644
index 6fe03c7..0000000
--- a/kernel/modsign_certificate.S
+++ /dev/null
@@ -1,11 +0,0 @@
-#include <linux/export.h>
-
-#define GLOBAL(name) \
- .globl VMLINUX_SYMBOL(name); \
- VMLINUX_SYMBOL(name):
-
- .section ".init.data","aw"
-
-GLOBAL(modsign_certificate_list)
- .incbin "kernel/x509_certificate_list"
-GLOBAL(modsign_certificate_list_end)
diff --git a/kernel/modsign_pubkey.c b/kernel/modsign_pubkey.c
deleted file mode 100644
index 7cbd450..0000000
--- a/kernel/modsign_pubkey.c
+++ /dev/null
@@ -1,104 +0,0 @@
-/* Public keys for module signature verification
- *
- * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
-
-#include <linux/kernel.h>
-#include <linux/sched.h>
-#include <linux/cred.h>
-#include <linux/err.h>
-#include <keys/asymmetric-type.h>
-#include "module-internal.h"
-
-struct key *modsign_keyring;
-
-extern __initconst const u8 modsign_certificate_list[];
-extern __initconst const u8 modsign_certificate_list_end[];
-
-/*
- * We need to make sure ccache doesn't cache the .o file as it doesn't notice
- * if modsign.pub changes.
- */
-static __initconst const char annoy_ccache[] = __TIME__ "foo";
-
-/*
- * Load the compiled-in keys
- */
-static __init int module_verify_init(void)
-{
- pr_notice("Initialise module verification\n");
-
- modsign_keyring = keyring_alloc(".module_sign",
- KUIDT_INIT(0), KGIDT_INIT(0),
- current_cred(),
- ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
- KEY_USR_VIEW | KEY_USR_READ),
- KEY_ALLOC_NOT_IN_QUOTA, NULL);
- if (IS_ERR(modsign_keyring))
- panic("Can't allocate module signing keyring\n");
-
- return 0;
-}
-
-/*
- * Must be initialised before we try and load the keys into the keyring.
- */
-device_initcall(module_verify_init);
-
-/*
- * Load the compiled-in keys
- */
-static __init int load_module_signing_keys(void)
-{
- key_ref_t key;
- const u8 *p, *end;
- size_t plen;
-
- pr_notice("Loading module verification certificates\n");
-
- end = modsign_certificate_list_end;
- p = modsign_certificate_list;
- 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(modsign_keyring, 1),
- "asymmetric",
- NULL,
- p,
- plen,
- (KEY_POS_ALL & ~KEY_POS_SETATTR) |
- KEY_USR_VIEW,
- KEY_ALLOC_NOT_IN_QUOTA);
- if (IS_ERR(key))
- pr_err("MODSIGN: Problem loading in-kernel X.509 certificate (%ld)\n",
- PTR_ERR(key));
- else
- pr_notice("MODSIGN: Loaded cert '%s'\n",
- key_ref_to_ptr(key)->description);
- p += plen;
- }
-
- return 0;
-
-dodgy_cert:
- pr_err("MODSIGN: Problem parsing in-kernel X.509 certificate list\n");
- return 0;
-}
-late_initcall(load_module_signing_keys);
diff --git a/kernel/module-internal.h b/kernel/module-internal.h
index 24f9247..915e123 100644
--- a/kernel/module-internal.h
+++ b/kernel/module-internal.h
@@ -9,6 +9,4 @@
* 2 of the Licence, or (at your option) any later version.
*/
-extern struct key *modsign_keyring;
-
extern int mod_verify_sig(const void *mod, unsigned long *_modlen);
diff --git a/kernel/module_signing.c b/kernel/module_signing.c
index ee47640..0b6b870 100644
--- a/kernel/module_signing.c
+++ b/kernel/module_signing.c
@@ -14,6 +14,7 @@
#include <crypto/public_key.h>
#include <crypto/hash.h>
#include <keys/asymmetric-type.h>
+#include <keys/system_keyring.h>
#include "module-internal.h"
/*
@@ -157,7 +158,7 @@
pr_debug("Look up: \"%s\"\n", id);
- key = keyring_search(make_key_ref(modsign_keyring, 1),
+ key = keyring_search(make_key_ref(system_trusted_keyring, 1),
&key_type_asymmetric, id);
if (IS_ERR(key))
pr_warn("Request for unknown module key '%s' err %ld\n",
diff --git a/kernel/system_certificates.S b/kernel/system_certificates.S
new file mode 100644
index 0000000..552d47b
--- /dev/null
+++ b/kernel/system_certificates.S
@@ -0,0 +1,12 @@
+#include <linux/export.h>
+#include <linux/init.h>
+
+#define GLOBAL(name) \
+ .globl VMLINUX_SYMBOL(name); \
+ VMLINUX_SYMBOL(name):
+
+ __INITRODATA
+
+GLOBAL(system_certificate_list)
+ .incbin "kernel/x509_certificate_list"
+GLOBAL(system_certificate_list_end)
diff --git a/kernel/system_keyring.c b/kernel/system_keyring.c
new file mode 100644
index 0000000..51c3514
--- /dev/null
+++ b/kernel/system_keyring.c
@@ -0,0 +1,103 @@
+/* System trusted keyring for trusted public keys
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <keys/asymmetric-type.h>
+#include <keys/system_keyring.h>
+#include "module-internal.h"
+
+struct key *system_trusted_keyring;
+EXPORT_SYMBOL_GPL(system_trusted_keyring);
+
+extern __initconst const u8 system_certificate_list[];
+extern __initconst const u8 system_certificate_list_end[];
+
+/*
+ * Load the compiled-in keys
+ */
+static __init int system_trusted_keyring_init(void)
+{
+ pr_notice("Initialise system trusted keyring\n");
+
+ system_trusted_keyring =
+ keyring_alloc(".system_keyring",
+ KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
+ ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW | KEY_USR_READ),
+ KEY_ALLOC_NOT_IN_QUOTA, NULL);
+ if (IS_ERR(system_trusted_keyring))
+ panic("Can't allocate system trusted keyring\n");
+
+ return 0;
+}
+
+/*
+ * Must be initialised before we try and load the keys into the keyring.
+ */
+device_initcall(system_trusted_keyring_init);
+
+/*
+ * Load the compiled-in list of X.509 certificates.
+ */
+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");
+
+ end = system_certificate_list_end;
+ p = system_certificate_list;
+ 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(system_trusted_keyring, 1),
+ "asymmetric",
+ NULL,
+ p,
+ plen,
+ (KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW,
+ KEY_ALLOC_NOT_IN_QUOTA);
+ 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;
+}
+late_initcall(load_system_certificate_list);