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Message-Id: <20191023233950.22072-3-nramas@linux.microsoft.com>
Date:   Wed, 23 Oct 2019 16:39:48 -0700
From:   Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>
To:     zohar@...ux.ibm.com, dhowells@...hat.com, casey@...aufler-ca.com,
        sashal@...nel.org, jamorris@...ux.microsoft.com,
        linux-security-module@...r.kernel.org,
        linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        keyrings@...r.kernel.org
Cc:     nramas@...ux.microsoft.com
Subject: [PATCH v2 2/4] KEYS: Queue key for measurement if ima is not initialized. Measure queued keys when ima is initialized

Defined functions to queue key for measurement if ima is not yet
initialized. ima hook function ima_post_key_create_or_update will
queue the key if ima is not yet initialized.

Process queued keys and measure them when ima initialization
is completed.

Signed-off-by: Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>
---
 security/integrity/ima/ima.h       | 13 +++++
 security/integrity/ima/ima_init.c  |  9 ++-
 security/integrity/ima/ima_main.c  |  4 +-
 security/integrity/ima/ima_queue.c | 94 ++++++++++++++++++++++++++++++
 4 files changed, 118 insertions(+), 2 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 2d4130ff5655..38279707632a 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -199,6 +199,17 @@ enum ima_hooks {
 	__ima_hooks(__ima_hook_enumify)
 };
 
+/*
+ * To track trusted keys that need to be measured when IMA is initialized.
+ */
+struct ima_trusted_key_entry {
+	struct list_head list;
+	void *public_key;
+	u32  public_key_len;
+	char *key_description;
+	enum ima_hooks func;
+};
+
 /* LIM API function definitions */
 int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
 		   int mask, enum ima_hooks func, int *pcr,
@@ -225,6 +236,8 @@ int ima_store_template(struct ima_template_entry *entry, int violation,
 		       const unsigned char *filename, int pcr);
 void ima_free_template_entry(struct ima_template_entry *entry);
 const char *ima_d_path(const struct path *path, char **pathbuf, char *filename);
+int ima_queue_key_for_measurement(struct key *key, enum ima_hooks func);
+void ima_measure_queued_keys(void);
 
 /* IMA policy related functions */
 int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 52847ce765a4..8734ed5322c7 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -132,5 +132,12 @@ int __init ima_init(void)
 
 	ima_init_policy();
 
-	return ima_fs_init();
+	rc = ima_fs_init();
+	if (rc != 0)
+		return rc;
+
+	ima_initialized = true;
+
+	ima_measure_queued_keys();
+	return 0;
 }
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 8bde12385912..bce430b3386e 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -710,8 +710,10 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key,
 	if (key->type != &key_type_asymmetric)
 		return;
 
-	if (!ima_initialized)
+	if (!ima_initialized) {
+		ima_queue_key_for_measurement(key, NONE);
 		return;
+	}
 
 	pk = key->payload.data[asym_crypto];
 	process_buffer_measurement(pk->key, pk->keylen,
diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
index 1ce8b1701566..d42987022c12 100644
--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c
@@ -46,6 +46,13 @@ struct ima_h_table ima_htable = {
  */
 static DEFINE_MUTEX(ima_extend_list_mutex);
 
+/*
+ * Used to synchronize access to the list of trusted keys (ima_trusted_keys)
+ * that need to be measured when IMA is initialized.
+ */
+static DEFINE_MUTEX(ima_trusted_keys_mutex);
+static LIST_HEAD(ima_trusted_keys);
+
 /* lookup up the digest value in the hash table, and return the entry */
 static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value,
 						       int pcr)
@@ -232,3 +239,90 @@ int __init ima_init_digests(void)
 
 	return 0;
 }
+
+static void ima_free_trusted_key_entry(struct ima_trusted_key_entry *entry)
+{
+	if (entry != NULL) {
+		if (entry->public_key != NULL)
+			kzfree(entry->public_key);
+		if (entry->key_description != NULL)
+			kzfree(entry->key_description);
+		kzfree(entry);
+	}
+}
+
+static struct ima_trusted_key_entry *ima_alloc_trusted_queue_entry(
+	struct key *key,
+	enum ima_hooks func)
+{
+	int rc = 0;
+	const struct public_key *pk;
+	size_t key_description_len;
+	struct ima_trusted_key_entry *entry = NULL;
+
+	pk = key->payload.data[asym_crypto];
+	key_description_len = strlen(key->description) + 1;
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	if (entry != NULL) {
+		entry->public_key = kzalloc(pk->keylen, GFP_KERNEL);
+		entry->key_description =
+			kzalloc(key_description_len, GFP_KERNEL);
+	}
+
+	if ((entry == NULL) || (entry->public_key == NULL) ||
+	    (entry->key_description == NULL)) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	strcpy(entry->key_description, key->description);
+	memcpy(entry->public_key, pk->key, pk->keylen);
+	entry->public_key_len = pk->keylen;
+	entry->func = func;
+	rc = 0;
+
+out:
+	if (rc) {
+		ima_free_trusted_key_entry(entry);
+		entry = NULL;
+	}
+
+	return entry;
+}
+
+int ima_queue_key_for_measurement(struct key *key, enum ima_hooks func)
+{
+	int rc = 0;
+	struct ima_trusted_key_entry *entry = NULL;
+
+	mutex_lock(&ima_trusted_keys_mutex);
+
+	entry = ima_alloc_trusted_queue_entry(key, func);
+	if (entry != NULL) {
+		INIT_LIST_HEAD(&entry->list);
+		list_add_tail(&entry->list, &ima_trusted_keys);
+	} else
+		rc = -ENOMEM;
+
+	mutex_unlock(&ima_trusted_keys_mutex);
+
+	return rc;
+}
+
+void ima_measure_queued_keys(void)
+{
+	struct ima_trusted_key_entry *entry, *tmp;
+
+	mutex_lock(&ima_trusted_keys_mutex);
+
+	list_for_each_entry_safe(entry, tmp, &ima_trusted_keys, list) {
+		process_buffer_measurement(entry->public_key,
+					   entry->public_key_len,
+					   entry->key_description,
+					   NONE, 0);
+		list_del(&entry->list);
+		ima_free_trusted_key_entry(entry);
+	}
+
+	mutex_unlock(&ima_trusted_keys_mutex);
+}
-- 
2.17.1

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