Re: [PATCH v3 2/3] ima: enable signing of modules with build time generated key

[Stefan Berger]

On 3/30/21 9:16 AM, Nayna Jain wrote:

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 <na...@linux.ibm.com>

Acked-by: Stefan Berger <stef...@linux.ibm.com>

---
  certs/Kconfig  | 2 +-
  certs/Makefile | 8 ++++++++
  init/Kconfig   | 6 +++---
  3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/certs/Kconfig b/certs/Kconfig
index c94e93d8bccf..48675ad319db 100644
--- a/certs/Kconfig
+++ b/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
diff --git a/certs/Makefile b/certs/Makefile
index f4c25b67aad9..e3185c57fbd8 100644
--- a/certs/Makefile
+++ b/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
diff --git a/init/Kconfig b/init/Kconfig
index 5f5c776ef192..85e48a578f90 100644
--- a/init/Kconfig
+++ b/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