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 <[e-mail]>
Acked-by: Stefan Berger <[e-mail]>
Signed-off-by: Mimi Zohar <[e-mail]>

certs/Kconfig

···
 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

···
 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

···
 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.
···
 
 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
···
 
 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