ima: enable signing of modules with build time generated key

The kernel build process currently only signs kernel modules when
MODULE_SIG is enabled. Also, sign the kernel modules at build time when
IMA_APPRAISE_MODSIG is enabled.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Acked-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

certs/Kconfig

@@ -4,7 +4,7 @@ menu "Certificates for signature checking"
 config MODULE_SIG_KEY
 	string "File name or PKCS#11 URI of module signing key"
 	default "certs/signing_key.pem"
-	depends on MODULE_SIG
+	depends on MODULE_SIG || IMA_APPRAISE_MODSIG
 	help
          Provide the file name of a private key/certificate in PEM format,
          or a PKCS#11 URI according to RFC7512. The file should contain, or

certs/Makefile

@@ -32,6 +32,14 @@ endif # CONFIG_SYSTEM_TRUSTED_KEYRING
 clean-files := x509_certificate_list .x509.list
 
 ifeq ($(CONFIG_MODULE_SIG),y)
+	SIGN_KEY = y
+endif
+
+ifeq ($(CONFIG_IMA_APPRAISE_MODSIG),y)
+	SIGN_KEY = y
+endif
+
+ifdef SIGN_KEY
 ###############################################################################
 #
 # If module signing is requested, say by allyesconfig, but a key has not been

init/Kconfig

@@ -2164,7 +2164,7 @@ config MODULE_SIG_FORCE
 config MODULE_SIG_ALL
 	bool "Automatically sign all modules"
 	default y
-	depends on MODULE_SIG
+	depends on MODULE_SIG || IMA_APPRAISE_MODSIG
 	help
 	  Sign all modules during make modules_install. Without this option,
 	  modules must be signed manually, using the scripts/sign-file tool.
@@ -2174,7 +2174,7 @@ comment "Do not forget to sign required modules with scripts/sign-file"
 
 choice
 	prompt "Which hash algorithm should modules be signed with?"
-	depends on MODULE_SIG
+	depends on MODULE_SIG || IMA_APPRAISE_MODSIG
 	help
 	  This determines which sort of hashing algorithm will be used during
 	  signature generation.  This algorithm _must_ be built into the kernel
@@ -2206,7 +2206,7 @@ endchoice
 
 config MODULE_SIG_HASH
 	string
-	depends on MODULE_SIG
+	depends on MODULE_SIG || IMA_APPRAISE_MODSIG
 	default "sha1" if MODULE_SIG_SHA1
 	default "sha224" if MODULE_SIG_SHA224
 	default "sha256" if MODULE_SIG_SHA256