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-rw-r--r--security/integrity/ima/ima_queue.c150
1 files changed, 150 insertions, 0 deletions
diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
new file mode 100644
index 000000000..552705d5a
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+++ b/security/integrity/ima/ima_queue.c
@@ -0,0 +1,150 @@
+/*
+ * Copyright (C) 2005,2006,2007,2008 IBM Corporation
+ *
+ * Authors:
+ * Serge Hallyn <serue@us.ibm.com>
+ * Reiner Sailer <sailer@watson.ibm.com>
+ * Mimi Zohar <zohar@us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ *
+ * File: ima_queue.c
+ * Implements queues that store template measurements and
+ * maintains aggregate over the stored measurements
+ * in the pre-configured TPM PCR (if available).
+ * The measurement list is append-only. No entry is
+ * ever removed or changed during the boot-cycle.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/rculist.h>
+#include <linux/slab.h>
+#include "ima.h"
+
+#define AUDIT_CAUSE_LEN_MAX 32
+
+LIST_HEAD(ima_measurements); /* list of all measurements */
+
+/* key: inode (before secure-hashing a file) */
+struct ima_h_table ima_htable = {
+ .len = ATOMIC_LONG_INIT(0),
+ .violations = ATOMIC_LONG_INIT(0),
+ .queue[0 ... IMA_MEASURE_HTABLE_SIZE - 1] = HLIST_HEAD_INIT
+};
+
+/* mutex protects atomicity of extending measurement list
+ * and extending the TPM PCR aggregate. Since tpm_extend can take
+ * long (and the tpm driver uses a mutex), we can't use the spinlock.
+ */
+static DEFINE_MUTEX(ima_extend_list_mutex);
+
+/* 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)
+{
+ struct ima_queue_entry *qe, *ret = NULL;
+ unsigned int key;
+ int rc;
+
+ key = ima_hash_key(digest_value);
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(qe, &ima_htable.queue[key], hnext) {
+ rc = memcmp(qe->entry->digest, digest_value, TPM_DIGEST_SIZE);
+ if (rc == 0) {
+ ret = qe;
+ break;
+ }
+ }
+ rcu_read_unlock();
+ return ret;
+}
+
+/* ima_add_template_entry helper function:
+ * - Add template entry to measurement list and hash table.
+ *
+ * (Called with ima_extend_list_mutex held.)
+ */
+static int ima_add_digest_entry(struct ima_template_entry *entry)
+{
+ struct ima_queue_entry *qe;
+ unsigned int key;
+
+ qe = kmalloc(sizeof(*qe), GFP_KERNEL);
+ if (qe == NULL) {
+ pr_err("OUT OF MEMORY ERROR creating queue entry\n");
+ return -ENOMEM;
+ }
+ qe->entry = entry;
+
+ INIT_LIST_HEAD(&qe->later);
+ list_add_tail_rcu(&qe->later, &ima_measurements);
+
+ atomic_long_inc(&ima_htable.len);
+ key = ima_hash_key(entry->digest);
+ hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
+ return 0;
+}
+
+static int ima_pcr_extend(const u8 *hash)
+{
+ int result = 0;
+
+ if (!ima_used_chip)
+ return result;
+
+ result = tpm_pcr_extend(TPM_ANY_NUM, CONFIG_IMA_MEASURE_PCR_IDX, hash);
+ if (result != 0)
+ pr_err("Error Communicating to TPM chip, result: %d\n", result);
+ return result;
+}
+
+/* Add template entry to the measurement list and hash table,
+ * and extend the pcr.
+ */
+int ima_add_template_entry(struct ima_template_entry *entry, int violation,
+ const char *op, struct inode *inode,
+ const unsigned char *filename)
+{
+ u8 digest[TPM_DIGEST_SIZE];
+ const char *audit_cause = "hash_added";
+ char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX];
+ int audit_info = 1;
+ int result = 0, tpmresult = 0;
+
+ mutex_lock(&ima_extend_list_mutex);
+ if (!violation) {
+ memcpy(digest, entry->digest, sizeof(digest));
+ if (ima_lookup_digest_entry(digest)) {
+ audit_cause = "hash_exists";
+ result = -EEXIST;
+ goto out;
+ }
+ }
+
+ result = ima_add_digest_entry(entry);
+ if (result < 0) {
+ audit_cause = "ENOMEM";
+ audit_info = 0;
+ goto out;
+ }
+
+ if (violation) /* invalidate pcr */
+ memset(digest, 0xff, sizeof(digest));
+
+ tpmresult = ima_pcr_extend(digest);
+ if (tpmresult != 0) {
+ snprintf(tpm_audit_cause, AUDIT_CAUSE_LEN_MAX, "TPM_error(%d)",
+ tpmresult);
+ audit_cause = tpm_audit_cause;
+ audit_info = 0;
+ }
+out:
+ mutex_unlock(&ima_extend_list_mutex);
+ integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
+ op, audit_cause, result, audit_info);
+ return result;
+}