1 files changed, 241 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..532da87ce
--- /dev/null
+++ b/security/integrity/ima/ima_queue.c
@@ -0,0 +1,241 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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>
+ *
+ * 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.
+ */
+
+#include <linux/rculist.h>
+#include <linux/slab.h>
+#include "ima.h"
+
+#define AUDIT_CAUSE_LEN_MAX 32
+
+/* pre-allocated array of tpm_digest structures to extend a PCR */
+static struct tpm_digest *digests;
+
+LIST_HEAD(ima_measurements);	/* list of all measurements */
+#ifdef CONFIG_IMA_KEXEC
+static unsigned long binary_runtime_size;
+#else
+static unsigned long binary_runtime_size = ULONG_MAX;
+#endif
+
+/* 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,
+						       int pcr)
+{
+	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->digests[ima_hash_algo_idx].digest,
+			    digest_value, hash_digest_size[ima_hash_algo]);
+		if ((rc == 0) && (qe->entry->pcr == pcr)) {
+			ret = qe;
+			break;
+		}
+	}
+	rcu_read_unlock();
+	return ret;
+}
+
+/*
+ * Calculate the memory required for serializing a single
+ * binary_runtime_measurement list entry, which contains a
+ * couple of variable length fields (e.g template name and data).
+ */
+static int get_binary_runtime_size(struct ima_template_entry *entry)
+{
+	int size = 0;
+
+	size += sizeof(u32);	/* pcr */
+	size += TPM_DIGEST_SIZE;
+	size += sizeof(int);	/* template name size field */
+	size += strlen(entry->template_desc->name);
+	size += sizeof(entry->template_data_len);
+	size += entry->template_data_len;
+	return size;
+}
+
+/* ima_add_template_entry helper function:
+ * - Add template entry to the measurement list and hash table, for
+ *   all entries except those carried across kexec.
+ *
+ * (Called with ima_extend_list_mutex held.)
+ */
+static int ima_add_digest_entry(struct ima_template_entry *entry,
+				bool update_htable)
+{
+	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);
+	if (update_htable) {
+		key = ima_hash_key(entry->digests[ima_hash_algo_idx].digest);
+		hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
+	}
+
+	if (binary_runtime_size != ULONG_MAX) {
+		int size;
+
+		size = get_binary_runtime_size(entry);
+		binary_runtime_size = (binary_runtime_size < ULONG_MAX - size) ?
+		     binary_runtime_size + size : ULONG_MAX;
+	}
+	return 0;
+}
+
+/*
+ * Return the amount of memory required for serializing the
+ * entire binary_runtime_measurement list, including the ima_kexec_hdr
+ * structure.
+ */
+unsigned long ima_get_binary_runtime_size(void)
+{
+	if (binary_runtime_size >= (ULONG_MAX - sizeof(struct ima_kexec_hdr)))
+		return ULONG_MAX;
+	else
+		return binary_runtime_size + sizeof(struct ima_kexec_hdr);
+}
+
+static int ima_pcr_extend(struct tpm_digest *digests_arg, int pcr)
+{
+	int result = 0;
+
+	if (!ima_tpm_chip)
+		return result;
+
+	result = tpm_pcr_extend(ima_tpm_chip, pcr, digests_arg);
+	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.
+ *
+ * On systems which support carrying the IMA measurement list across
+ * kexec, maintain the total memory size required for serializing the
+ * binary_runtime_measurements.
+ */
+int ima_add_template_entry(struct ima_template_entry *entry, int violation,
+			   const char *op, struct inode *inode,
+			   const unsigned char *filename)
+{
+	u8 *digest = entry->digests[ima_hash_algo_idx].digest;
+	struct tpm_digest *digests_arg = entry->digests;
+	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 && !IS_ENABLED(CONFIG_IMA_DISABLE_HTABLE)) {
+		if (ima_lookup_digest_entry(digest, entry->pcr)) {
+			audit_cause = "hash_exists";
+			result = -EEXIST;
+			goto out;
+		}
+	}
+
+	result = ima_add_digest_entry(entry,
+				      !IS_ENABLED(CONFIG_IMA_DISABLE_HTABLE));
+	if (result < 0) {
+		audit_cause = "ENOMEM";
+		audit_info = 0;
+		goto out;
+	}
+
+	if (violation)		/* invalidate pcr */
+		digests_arg = digests;
+
+	tpmresult = ima_pcr_extend(digests_arg, entry->pcr);
+	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;
+}
+
+int ima_restore_measurement_entry(struct ima_template_entry *entry)
+{
+	int result = 0;
+
+	mutex_lock(&ima_extend_list_mutex);
+	result = ima_add_digest_entry(entry, 0);
+	mutex_unlock(&ima_extend_list_mutex);
+	return result;
+}
+
+int __init ima_init_digests(void)
+{
+	u16 digest_size;
+	u16 crypto_id;
+	int i;
+
+	if (!ima_tpm_chip)
+		return 0;
+
+	digests = kcalloc(ima_tpm_chip->nr_allocated_banks, sizeof(*digests),
+			  GFP_NOFS);
+	if (!digests)
+		return -ENOMEM;
+
+	for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) {
+		digests[i].alg_id = ima_tpm_chip->allocated_banks[i].alg_id;
+		digest_size = ima_tpm_chip->allocated_banks[i].digest_size;
+		crypto_id = ima_tpm_chip->allocated_banks[i].crypto_id;
+
+		/* for unmapped TPM algorithms digest is still a padded SHA1 */
+		if (crypto_id == HASH_ALGO__LAST)
+			digest_size = SHA1_DIGEST_SIZE;
+
+		memset(digests[i].digest, 0xff, digest_size);
+	}
+
+	return 0;
+}