/* * 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/rculist.h>#include <linux/slab.h>#include "ima.h" #define AUDIT_CAUSE_LEN_MAX 32 LIST_HEAD(ima_measurements);	/* list of all measurements */#ifdef CONFIG_IMA_KEXECstatic unsigned long binary_runtime_size;#elsestatic 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->digest, digest_value, TPM_DIGEST_SIZE);		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 += sizeof(entry->digest);	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->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(const u8 *hash, int pcr){	int result = 0; 	if (!ima_tpm_chip)		return result; 	result = tpm_pcr_extend(ima_tpm_chip, pcr, 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. * * 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[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, entry->pcr)) {			audit_cause = "hash_exists";			result = -EEXIST;			goto out;		}	} 	result = ima_add_digest_entry(entry, 1);	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, 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;}