[PATCH] ima: debugging late_initcall_sync measurements

[Mimi Zohar]

With this "[RFC PATCH v3 0/4] Fix IMA + TPM initialisation ordering
issue" patch set, how many records would be missing if IMA
initialization is deferred to late_initcall_sync [1]?

[1]https://lore.kernel.org/linux-integrity/cover.1777036497.git.noodles@meta.com/
---
Jonathan, Yeoreum, others -

By going into TPM-bypass mode, we can see how many measurements are actually
missing when deferring IMA initialization to late_initcall_sync. As this is
system/TPM dependent, I'd appreciate your checking. Please use the boot command
line option "ima_policy=tcb|critical_data".

thanks, Mimi

 security/integrity/ima/ima.h      |  1 +
 security/integrity/ima/ima_init.c |  6 ++++++
 security/integrity/ima/ima_main.c | 19 +++++++++++++++++++
 3 files changed, 26 insertions(+)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 01aae19ed365..9a1117112fb2 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -286,6 +286,7 @@ extern bool ima_canonical_fmt;
 
 /* Internal IMA function definitions */
 int ima_init_core(bool late);
+int ima_init_debug(bool late);
 int ima_fs_init(void);
 int ima_add_template_entry(struct ima_template_entry *entry, int violation,
 			   const char *op, struct inode *inode,
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 5f335834a9bb..edd063b99685 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -122,6 +122,12 @@ void __init ima_load_x509(void)
 }
 #endif
 
+int __init ima_init_debug(bool late)
+{
+	ima_add_boot_aggregate(late); /* just add an additional record */
+	return 0;
+}
+
 int __init ima_init_core(bool late)
 {
 	int rc;
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 42099bfe7e43..23e669be54fc 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -1254,6 +1254,7 @@ static int ima_kernel_module_request(char *kmod_name)
 
 #endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */
 
+#define TESTING 1
 static int __init init_ima(bool late)
 {
 	int error;
@@ -1264,6 +1265,23 @@ static int __init init_ima(bool late)
 		return 0;
 	}
 
+#ifdef TESTING
+	/*
+	 * Initialize early, even if it means going into TPM-bypass mode,
+	 * but add an additional boot_aggregrate message for the
+	 * late_initcall_sync.
+	 *
+	 * If measurement list records exist between the boot_aggregate
+	 * and the boot_aggregate_late records, these records would be
+	 * missing when IMA initializion is deferred to late_initcall_sync.
+	 */
+	if (ima_tpm_chip) {
+		ima_init_debug(late); /* Add an additional record */
+		return 0;
+	}
+
+	ima_tpm_chip = tpm_default_chip();
+#elif
 	/*
 	 * If we found the TPM during our first attempt, or we know there's no
 	 * TPM, nothing further to do
@@ -1276,6 +1294,7 @@ static int __init init_ima(bool late)
 		pr_debug("TPM not available, will try later\n");
 		return -EPROBE_DEFER;
 	}
+#endif
 
 	if (!ima_tpm_chip)
 		pr_info("No TPM chip found, activating TPM-bypass!\n");
-- 
2.53.0