linux_kernel/security/integrity/ima/ima.h

/*
 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
 *
 * Authors:
 * 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.h
 *	internal Integrity Measurement Architecture (IMA) definitions
 */

#ifndef __LINUX_IMA_H
#define __LINUX_IMA_H

#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/hash.h>
#include <linux/tpm.h>
#include <linux/audit.h>
#include <crypto/hash_info.h>

#include "../integrity.h"

enum ima_show_type { IMA_SHOW_BINARY, IMA_SHOW_BINARY_NO_FIELD_LEN,
		     IMA_SHOW_BINARY_OLD_STRING_FMT, IMA_SHOW_ASCII };
enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 };

/* digest size for IMA, fits SHA1 or MD5 */
#define IMA_DIGEST_SIZE		SHA1_DIGEST_SIZE
#define IMA_EVENT_NAME_LEN_MAX	255

#define IMA_HASH_BITS 9
#define IMA_MEASURE_HTABLE_SIZE (1 << IMA_HASH_BITS)

#define IMA_TEMPLATE_FIELD_ID_MAX_LEN	16
#define IMA_TEMPLATE_NUM_FIELDS_MAX	15

#define IMA_TEMPLATE_IMA_NAME "ima"
#define IMA_TEMPLATE_IMA_FMT "d|n"

/* current content of the policy */
extern int ima_policy_flag;

/* set during initialization */
extern int ima_initialized;
extern int ima_used_chip;
extern int ima_hash_algo;
extern int ima_appraise;

/* IMA event related data */
struct ima_event_data {
	struct integrity_iint_cache *iint;
	struct file *file;
	const unsigned char *filename;
	struct evm_ima_xattr_data *xattr_value;
	int xattr_len;
	const char *violation;
};

/* IMA template field data definition */
struct ima_field_data {
	u8 *data;
	u32 len;
};

/* IMA template field definition */
struct ima_template_field {
	const char field_id[IMA_TEMPLATE_FIELD_ID_MAX_LEN];
	int (*field_init)(struct ima_event_data *event_data,
			  struct ima_field_data *field_data);
	void (*field_show)(struct seq_file *m, enum ima_show_type show,
			   struct ima_field_data *field_data);
};

/* IMA template descriptor definition */
struct ima_template_desc {
	char *name;
	char *fmt;
	int num_fields;
	struct ima_template_field **fields;
};

struct ima_template_entry {
	u8 digest[TPM_DIGEST_SIZE];	/* sha1 or md5 measurement hash */
	struct ima_template_desc *template_desc; /* template descriptor */
	u32 template_data_len;
	struct ima_field_data template_data[0];	/* template related data */
};

struct ima_queue_entry {
	struct hlist_node hnext;	/* place in hash collision list */
	struct list_head later;		/* place in ima_measurements list */
	struct ima_template_entry *entry;
};
extern struct list_head ima_measurements;	/* list of all measurements */

/* Internal IMA function definitions */
int ima_init(void);
int ima_fs_init(void);
int ima_add_template_entry(struct ima_template_entry *entry, int violation,
			   const char *op, struct inode *inode,
			   const unsigned char *filename);
int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash);
int ima_calc_buffer_hash(const void *buf, loff_t len,
			 struct ima_digest_data *hash);
int ima_calc_field_array_hash(struct ima_field_data *field_data,
			      struct ima_template_desc *desc, int num_fields,
			      struct ima_digest_data *hash);
int __init ima_calc_boot_aggregate(struct ima_digest_data *hash);
void ima_add_violation(struct file *file, const unsigned char *filename,
		       struct integrity_iint_cache *iint,
		       const char *op, const char *cause);
int ima_init_crypto(void);
void ima_putc(struct seq_file *m, void *data, int datalen);
void ima_print_digest(struct seq_file *m, u8 *digest, u32 size);
struct ima_template_desc *ima_template_desc_current(void);
int ima_init_template(void);

/*
 * used to protect h_table and sha_table
 */
extern spinlock_t ima_queue_lock;

struct ima_h_table {
	atomic_long_t len;	/* number of stored measurements in the list */
	atomic_long_t violations;
	struct hlist_head queue[IMA_MEASURE_HTABLE_SIZE];
};
extern struct ima_h_table ima_htable;

static inline unsigned long ima_hash_key(u8 *digest)
{
	return hash_long(*digest, IMA_HASH_BITS);
}

enum ima_hooks {
	FILE_CHECK = 1,
	MMAP_CHECK,
	BPRM_CHECK,
	POST_SETATTR,
	MODULE_CHECK,
	FIRMWARE_CHECK,
	KEXEC_KERNEL_CHECK,
	KEXEC_INITRAMFS_CHECK,
	POLICY_CHECK,
	MAX_CHECK
};

/* LIM API function definitions */
int ima_get_action(struct inode *inode, int mask, enum ima_hooks func);
int ima_must_measure(struct inode *inode, int mask, enum ima_hooks func);
int ima_collect_measurement(struct integrity_iint_cache *iint,
			    struct file *file, void *buf, loff_t size,
			    enum hash_algo algo);
void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file,
			   const unsigned char *filename,
			   struct evm_ima_xattr_data *xattr_value,
			   int xattr_len);
void ima_audit_measurement(struct integrity_iint_cache *iint,
			   const unsigned char *filename);
int ima_alloc_init_template(struct ima_event_data *event_data,
			    struct ima_template_entry **entry);
int ima_store_template(struct ima_template_entry *entry, int violation,
		       struct inode *inode, const unsigned char *filename);
void ima_free_template_entry(struct ima_template_entry *entry);
const char *ima_d_path(struct path *path, char **pathbuf);

/* IMA policy related functions */
int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
		     int flags);
void ima_init_policy(void);
void ima_update_policy(void);
void ima_update_policy_flag(void);
ssize_t ima_parse_add_rule(char *);
void ima_delete_rules(void);
int ima_check_policy(void);
void *ima_policy_start(struct seq_file *m, loff_t *pos);
void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos);
void ima_policy_stop(struct seq_file *m, void *v);
int ima_policy_show(struct seq_file *m, void *v);

/* Appraise integrity measurements */
#define IMA_APPRAISE_ENFORCE	0x01
#define IMA_APPRAISE_FIX	0x02
#define IMA_APPRAISE_LOG	0x04
#define IMA_APPRAISE_MODULES	0x08
#define IMA_APPRAISE_FIRMWARE	0x10
#define IMA_APPRAISE_POLICY	0x20

#ifdef CONFIG_IMA_APPRAISE
int ima_appraise_measurement(enum ima_hooks func,
			     struct integrity_iint_cache *iint,
			     struct file *file, const unsigned char *filename,
			     struct evm_ima_xattr_data *xattr_value,
			     int xattr_len, int opened);
int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func);
void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file);
enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
					   enum ima_hooks func);
enum hash_algo ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value,
				 int xattr_len);
int ima_read_xattr(struct dentry *dentry,
		   struct evm_ima_xattr_data **xattr_value);

#else
static inline int ima_appraise_measurement(enum ima_hooks func,
					   struct integrity_iint_cache *iint,
					   struct file *file,
					   const unsigned char *filename,
					   struct evm_ima_xattr_data *xattr_value,
					   int xattr_len, int opened)
{
	return INTEGRITY_UNKNOWN;
}

static inline int ima_must_appraise(struct inode *inode, int mask,
				    enum ima_hooks func)
{
	return 0;
}

static inline void ima_update_xattr(struct integrity_iint_cache *iint,
				    struct file *file)
{
}

static inline enum integrity_status ima_get_cache_status(struct integrity_iint_cache
							 *iint,
							 enum ima_hooks func)
{
	return INTEGRITY_UNKNOWN;
}

static inline enum hash_algo
ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value, int xattr_len)
{
	return ima_hash_algo;
}

static inline int ima_read_xattr(struct dentry *dentry,
				 struct evm_ima_xattr_data **xattr_value)
{
	return 0;
}

#endif

/* LSM based policy rules require audit */
#ifdef CONFIG_IMA_LSM_RULES

#define security_filter_rule_init security_audit_rule_init
#define security_filter_rule_match security_audit_rule_match

#else

static inline int security_filter_rule_init(u32 field, u32 op, char *rulestr,
					    void **lsmrule)
{
	return -EINVAL;
}

static inline int security_filter_rule_match(u32 secid, u32 field, u32 op,
					     void *lsmrule,
					     struct audit_context *actx)
{
	return -EINVAL;
}
#endif /* CONFIG_IMA_TRUSTED_KEYRING */

#ifdef	CONFIG_IMA_READ_POLICY
#define	POLICY_FILE_FLAGS	(S_IWUSR | S_IRUSR)
#else
#define	POLICY_FILE_FLAGS	S_IWUSR
#endif /* CONFIG_IMA_WRITE_POLICY */

#endif /* __LINUX_IMA_H */