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-rw-r--r--security/integrity/ima/ima_queue.c241
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
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+// 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;
+}