[PATCH v3 4/6] integrity: check whether imputed trust is enabled

[Nayna Jain]

trust_moklist() is specific to UEFI enabled systems. Other platforms
rely only on the Kconfig.

Define a generic wrapper named imputed_trust_enabled().

Signed-off-by: Nayna Jain <na...@linux.ibm.com>
Reviewed-off-by: Mimi Zohar <zo...@linux.ibm.com>
---
 security/integrity/digsig.c                    |  2 +-
 security/integrity/integrity.h                 |  5 +++--
 .../integrity/platform_certs/keyring_handler.c |  3 ++-
 .../integrity/platform_certs/machine_keyring.c | 18 ++++++++++++++++--
 4 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index d0704b1597d4..df387de29bfa 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -113,7 +113,7 @@ static int __init __integrity_init_keyring(const unsigned 
int id,
        } else {
                if (id == INTEGRITY_KEYRING_PLATFORM)
                        set_platform_trusted_keys(keyring[id]);
-               if (id == INTEGRITY_KEYRING_MACHINE && trust_moklist())
+               if (id == INTEGRITY_KEYRING_MACHINE && imputed_trust_enabled())
                        set_machine_trusted_keys(keyring[id]);
                if (id == INTEGRITY_KEYRING_IMA)
                        load_module_cert(keyring[id]);
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 7167a6e99bdc..d7553c93f5c0 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -320,13 +320,14 @@ static inline void __init add_to_platform_keyring(const 
char *source,
 
 #ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
 void __init add_to_machine_keyring(const char *source, const void *data, 
size_t len);
-bool __init trust_moklist(void);
+bool __init imputed_trust_enabled(void);
 #else
 static inline void __init add_to_machine_keyring(const char *source,
                                                  const void *data, size_t len)
 {
 }
-static inline bool __init trust_moklist(void)
+
+static inline bool __init imputed_trust_enabled(void)
 {
        return false;
 }
diff --git a/security/integrity/platform_certs/keyring_handler.c 
b/security/integrity/platform_certs/keyring_handler.c
index 1649d047e3b8..586027b9a3f5 100644
--- a/security/integrity/platform_certs/keyring_handler.c
+++ b/security/integrity/platform_certs/keyring_handler.c
@@ -61,7 +61,8 @@ __init efi_element_handler_t get_handler_for_db(const 
efi_guid_t *sig_type)
 __init efi_element_handler_t get_handler_for_mok(const efi_guid_t *sig_type)
 {
        if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0) {
-               if (IS_ENABLED(CONFIG_INTEGRITY_MACHINE_KEYRING) && 
trust_moklist())
+               if (IS_ENABLED(CONFIG_INTEGRITY_MACHINE_KEYRING) &&
+                   imputed_trust_enabled())
                        return add_to_machine_keyring;
                else
                        return add_to_platform_keyring;
diff --git a/security/integrity/platform_certs/machine_keyring.c 
b/security/integrity/platform_certs/machine_keyring.c
index 9482e16cb2ca..a401640a63cd 100644
--- a/security/integrity/platform_certs/machine_keyring.c
+++ b/security/integrity/platform_certs/machine_keyring.c
@@ -34,7 +34,8 @@ void __init add_to_machine_keyring(const char *source, const 
void *data, size_t
         * If the restriction check does not pass and the platform keyring
         * is configured, try to add it into that keyring instead.
         */
-       if (rc && efi_enabled(EFI_BOOT) && 
IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING))
+       if (rc && efi_enabled(EFI_BOOT) &&
+           IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING))
                rc = integrity_load_cert(INTEGRITY_KEYRING_PLATFORM, source,
                                         data, len, perm);
 
@@ -60,7 +61,7 @@ static __init bool uefi_check_trust_mok_keys(void)
        return false;
 }
 
-bool __init trust_moklist(void)
+static bool __init trust_moklist(void)
 {
        static bool initialized;
        static bool trust_mok;
@@ -75,3 +76,16 @@ bool __init trust_moklist(void)
 
        return trust_mok;
 }
+
+/*
+ * Provides platform specific check for trusting imputed keys before loading
+ * on .machine keyring. UEFI systems enable this trust based on a variable,
+ * and for other platforms, it is always enabled.
+ */
+bool __init imputed_trust_enabled(void)
+{
+       if (efi_enabled(EFI_BOOT))
+               return trust_moklist();
+
+       return true;
+}
-- 
2.31.1