MODSIGN: Provide module signing public keys to the kernel
Include a PGP keyring containing the public keys required to perform module
verification in the kernel image during build and create a special keyring
during boot which is then populated with keys of crypto type holding the public
keys found in the PGP keyring.
These can be seen by root:
[root@andromeda ~]# cat /proc/keys
07ad4ee0 I----- 1 perm 3f010000 0 0 crypto modsign.0: RSA 87b9b3bd []
15c7f8c3 I----- 1 perm 1f030000 0 0 keyring .module_sign: 1/4
...
It is probably worth permitting root to invalidate these keys, resulting in
their removal and preventing further modules from being loaded with that key.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/kernel/Makefile b/kernel/Makefile
index 58c6f11..111a845 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -55,7 +55,7 @@
obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
obj-$(CONFIG_UID16) += uid16.o
obj-$(CONFIG_MODULES) += module.o
-obj-$(CONFIG_MODULE_SIG) += module_signing.o
+obj-$(CONFIG_MODULE_SIG) += module_signing.o modsign_pubkey.o
obj-$(CONFIG_KALLSYMS) += kallsyms.o
obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_KEXEC) += kexec.o
@@ -134,6 +134,13 @@
$(call if_changed,timeconst)
ifeq ($(CONFIG_MODULE_SIG),y)
+#
+# Pull the signing certificate and any extra certificates into the kernel
+#
+extra_certificates:
+ touch $@
+
+kernel/modsign_pubkey.o: signing_key.x509 extra_certificates
###############################################################################
#
@@ -180,4 +187,4 @@
@echo >>x509.genkey "subjectKeyIdentifier=hash"
@echo >>x509.genkey "authorityKeyIdentifier=keyid"
endif
-CLEAN_FILES += signing_key.priv signing_key.x509 x509.genkey
+CLEAN_FILES += signing_key.priv signing_key.x509 x509.genkey extra_certificates