/* * Copyright (C) 2005,2006,2007,2008 IBM Corporation * * Authors: * Serge Hallyn * Reiner Sailer * Mimi Zohar * * 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. */ #include #include #include "ima.h" 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; struct hlist_node *pos; int rc; key = ima_hash_key(digest_value); rcu_read_lock(); hlist_for_each_entry_rcu(qe, pos, &ima_htable.queue[key], hnext) { rc = memcmp(qe->entry->digest, digest_value, IMA_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\n"); 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) { u8 digest[IMA_DIGEST_SIZE]; const char *audit_cause = "hash_added"; int audit_info = 1; int result = 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); result = ima_pcr_extend(digest); if (result != 0) { audit_cause = "TPM error"; audit_info = 0; } out: mutex_unlock(&ima_extend_list_mutex); integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, entry->template.file_name, op, audit_cause, result, audit_info); return result; }