ima.h

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
  4 *
  5 * Authors:
  6 * Reiner Sailer <sailer@watson.ibm.com>
  7 * Mimi Zohar <zohar@us.ibm.com>
  8 *
  9 * File: ima.h
 10 *	internal Integrity Measurement Architecture (IMA) definitions
 11 */
 12
 13#ifndef __LINUX_IMA_H
 14#define __LINUX_IMA_H
 15
 16#include <linux/types.h>
 17#include <linux/crypto.h>
 18#include <linux/fs.h>
 19#include <linux/security.h>
 20#include <linux/hash.h>
 21#include <linux/tpm.h>
 22#include <linux/audit.h>
 23#include <crypto/hash_info.h>
 24
 25#include "../integrity.h"
 26
 27enum ima_show_type { IMA_SHOW_BINARY, IMA_SHOW_BINARY_NO_FIELD_LEN,
 28		     IMA_SHOW_BINARY_OLD_STRING_FMT, IMA_SHOW_ASCII };
 29enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8, TPM_PCR10 = 10 };
 30
 31/* digest size for IMA, fits SHA1 or MD5 */
 32#define IMA_DIGEST_SIZE		SHA1_DIGEST_SIZE
 33#define IMA_EVENT_NAME_LEN_MAX	255
 34
 35#define IMA_HASH_BITS 10
 36#define IMA_MEASURE_HTABLE_SIZE (1 << IMA_HASH_BITS)
 37
 38#define IMA_TEMPLATE_FIELD_ID_MAX_LEN	16
 39#define IMA_TEMPLATE_NUM_FIELDS_MAX	15
 40
 41#define IMA_TEMPLATE_IMA_NAME "ima"
 42#define IMA_TEMPLATE_IMA_FMT "d|n"
 43
 44#define NR_BANKS(chip) ((chip != NULL) ? chip->nr_allocated_banks : 0)
 45
 46/* current content of the policy */
 47extern int ima_policy_flag;
 48
 49/* bitset of digests algorithms allowed in the setxattr hook */
 50extern atomic_t ima_setxattr_allowed_hash_algorithms;
 51
 52/* IMA hash algorithm description */
 53struct ima_algo_desc {
 54	struct crypto_shash *tfm;
 55	enum hash_algo algo;
 56};
 57
 58/* set during initialization */
 59extern int ima_hash_algo __ro_after_init;
 60extern int ima_sha1_idx __ro_after_init;
 61extern int ima_hash_algo_idx __ro_after_init;
 62extern int ima_extra_slots __ro_after_init;
 63extern struct ima_algo_desc *ima_algo_array __ro_after_init;
 64
 65extern int ima_appraise;
 66extern struct tpm_chip *ima_tpm_chip;
 67extern const char boot_aggregate_name[];
 68
 69/* IMA event related data */
 70struct ima_event_data {
 71	struct ima_iint_cache *iint;
 72	struct file *file;
 73	const unsigned char *filename;
 74	struct evm_ima_xattr_data *xattr_value;
 75	int xattr_len;
 76	const struct modsig *modsig;
 77	const char *violation;
 78	const void *buf;
 79	int buf_len;
 80};
 81
 82/* IMA template field data definition */
 83struct ima_field_data {
 84	u8 *data;
 85	u32 len;
 86};
 87
 88/* IMA template field definition */
 89struct ima_template_field {
 90	const char field_id[IMA_TEMPLATE_FIELD_ID_MAX_LEN];
 91	int (*field_init)(struct ima_event_data *event_data,
 92			  struct ima_field_data *field_data);
 93	void (*field_show)(struct seq_file *m, enum ima_show_type show,
 94			   struct ima_field_data *field_data);
 95};
 96
 97/* IMA template descriptor definition */
 98struct ima_template_desc {
 99	struct list_head list;
100	char *name;
101	char *fmt;
102	int num_fields;
103	const struct ima_template_field **fields;
104};
105
106struct ima_template_entry {
107	int pcr;
108	struct tpm_digest *digests;
109	struct ima_template_desc *template_desc; /* template descriptor */
110	u32 template_data_len;
111	struct ima_field_data template_data[];	/* template related data */
112};
113
114struct ima_queue_entry {
115	struct hlist_node hnext;	/* place in hash collision list */
116	struct list_head later;		/* place in ima_measurements list */
117	struct ima_template_entry *entry;
118};
119extern struct list_head ima_measurements;	/* list of all measurements */
120
121/* Some details preceding the binary serialized measurement list */
122struct ima_kexec_hdr {
123	u16 version;
124	u16 _reserved0;
125	u32 _reserved1;
126	u64 buffer_size;
127	u64 count;
128};
129
130/* IMA iint action cache flags */
131#define IMA_MEASURE		0x00000001
132#define IMA_MEASURED		0x00000002
133#define IMA_APPRAISE		0x00000004
134#define IMA_APPRAISED		0x00000008
135/*#define IMA_COLLECT		0x00000010  do not use this flag */
136#define IMA_COLLECTED		0x00000020
137#define IMA_AUDIT		0x00000040
138#define IMA_AUDITED		0x00000080
139#define IMA_HASH		0x00000100
140#define IMA_HASHED		0x00000200
141
142/* IMA iint policy rule cache flags */
143#define IMA_NONACTION_FLAGS	0xff000000
144#define IMA_DIGSIG_REQUIRED	0x01000000
145#define IMA_PERMIT_DIRECTIO	0x02000000
146#define IMA_NEW_FILE		0x04000000
147#define IMA_FAIL_UNVERIFIABLE_SIGS	0x10000000
148#define IMA_MODSIG_ALLOWED	0x20000000
149#define IMA_CHECK_BLACKLIST	0x40000000
150#define IMA_VERITY_REQUIRED	0x80000000
151
152/* Exclude non-action flags which are not rule-specific. */
153#define IMA_NONACTION_RULE_FLAGS	(IMA_NONACTION_FLAGS & ~IMA_NEW_FILE)
154
155#define IMA_DO_MASK		(IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT | \
156				 IMA_HASH | IMA_APPRAISE_SUBMASK)
157#define IMA_DONE_MASK		(IMA_MEASURED | IMA_APPRAISED | IMA_AUDITED | \
158				 IMA_HASHED | IMA_COLLECTED | \
159				 IMA_APPRAISED_SUBMASK)
160
161/* IMA iint subaction appraise cache flags */
162#define IMA_FILE_APPRAISE	0x00001000
163#define IMA_FILE_APPRAISED	0x00002000
164#define IMA_MMAP_APPRAISE	0x00004000
165#define IMA_MMAP_APPRAISED	0x00008000
166#define IMA_BPRM_APPRAISE	0x00010000
167#define IMA_BPRM_APPRAISED	0x00020000
168#define IMA_READ_APPRAISE	0x00040000
169#define IMA_READ_APPRAISED	0x00080000
170#define IMA_CREDS_APPRAISE	0x00100000
171#define IMA_CREDS_APPRAISED	0x00200000
172#define IMA_APPRAISE_SUBMASK	(IMA_FILE_APPRAISE | IMA_MMAP_APPRAISE | \
173				 IMA_BPRM_APPRAISE | IMA_READ_APPRAISE | \
174				 IMA_CREDS_APPRAISE)
175#define IMA_APPRAISED_SUBMASK	(IMA_FILE_APPRAISED | IMA_MMAP_APPRAISED | \
176				 IMA_BPRM_APPRAISED | IMA_READ_APPRAISED | \
177				 IMA_CREDS_APPRAISED)
178
179/* IMA iint cache atomic_flags */
180#define IMA_CHANGE_XATTR	0
181#define IMA_UPDATE_XATTR	1
182#define IMA_CHANGE_ATTR		2
183#define IMA_DIGSIG		3
184#define IMA_MAY_EMIT_TOMTOU	4
185#define IMA_EMITTED_OPENWRITERS	5
186
187/* IMA integrity metadata associated with an inode */
188struct ima_iint_cache {
189	struct mutex mutex;	/* protects: version, flags, digest */
190	struct integrity_inode_attributes real_inode;
191	unsigned long flags;
192	unsigned long measured_pcrs;
193	unsigned long atomic_flags;
194	enum integrity_status ima_file_status:4;
195	enum integrity_status ima_mmap_status:4;
196	enum integrity_status ima_bprm_status:4;
197	enum integrity_status ima_read_status:4;
198	enum integrity_status ima_creds_status:4;
199	struct ima_digest_data *ima_hash;
200};
201
202extern struct lsm_blob_sizes ima_blob_sizes;
203
204static inline struct ima_iint_cache *
205ima_inode_get_iint(const struct inode *inode)
206{
207	struct ima_iint_cache **iint_sec;
208
209	if (unlikely(!inode->i_security))
210		return NULL;
211
212	iint_sec = inode->i_security + ima_blob_sizes.lbs_inode;
213	return *iint_sec;
214}
215
216static inline void ima_inode_set_iint(const struct inode *inode,
217				      struct ima_iint_cache *iint)
218{
219	struct ima_iint_cache **iint_sec;
220
221	if (unlikely(!inode->i_security))
222		return;
223
224	iint_sec = inode->i_security + ima_blob_sizes.lbs_inode;
225	*iint_sec = iint;
226}
227
228struct ima_iint_cache *ima_iint_find(struct inode *inode);
229struct ima_iint_cache *ima_inode_get(struct inode *inode);
230void ima_inode_free_rcu(void *inode_security);
231void __init ima_iintcache_init(void);
232
233extern const int read_idmap[];
234
235#ifdef CONFIG_HAVE_IMA_KEXEC
236void ima_load_kexec_buffer(void);
237#else
238static inline void ima_load_kexec_buffer(void) {}
239#endif /* CONFIG_HAVE_IMA_KEXEC */
240
241#ifdef CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS
242void ima_post_key_create_or_update(struct key *keyring, struct key *key,
243				   const void *payload, size_t plen,
244				   unsigned long flags, bool create);
245#endif
246
247#ifdef CONFIG_IMA_KEXEC
248void ima_measure_kexec_event(const char *event_name);
249#else
250static inline void ima_measure_kexec_event(const char *event_name) {}
251#endif
252
253/*
254 * The default binary_runtime_measurements list format is defined as the
255 * platform native format.  The canonical format is defined as little-endian.
256 */
257extern bool ima_canonical_fmt;
258
259/* Internal IMA function definitions */
260int ima_init(void);
261int ima_fs_init(void);
262int ima_add_template_entry(struct ima_template_entry *entry, int violation,
263			   const char *op, struct inode *inode,
264			   const unsigned char *filename);
265int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash);
266int ima_calc_buffer_hash(const void *buf, loff_t len,
267			 struct ima_digest_data *hash);
268int ima_calc_field_array_hash(struct ima_field_data *field_data,
269			      struct ima_template_entry *entry);
270int ima_calc_boot_aggregate(struct ima_digest_data *hash);
271void ima_add_violation(struct file *file, const unsigned char *filename,
272		       struct ima_iint_cache *iint, const char *op,
273		       const char *cause);
274int ima_init_crypto(void);
275void ima_putc(struct seq_file *m, void *data, int datalen);
276void ima_print_digest(struct seq_file *m, u8 *digest, u32 size);
277int template_desc_init_fields(const char *template_fmt,
278			      const struct ima_template_field ***fields,
279			      int *num_fields);
280struct ima_template_desc *ima_template_desc_current(void);
281struct ima_template_desc *ima_template_desc_buf(void);
282struct ima_template_desc *lookup_template_desc(const char *name);
283bool ima_template_has_modsig(const struct ima_template_desc *ima_template);
284int ima_restore_measurement_entry(struct ima_template_entry *entry);
285int ima_restore_measurement_list(loff_t bufsize, void *buf);
286int ima_measurements_show(struct seq_file *m, void *v);
287unsigned long ima_get_binary_runtime_size(void);
288int ima_init_template(void);
289void ima_init_template_list(void);
290int __init ima_init_digests(void);
291void __init ima_init_reboot_notifier(void);
292int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
293			  void *lsm_data);
294
295/*
296 * used to protect h_table and sha_table
297 */
298extern spinlock_t ima_queue_lock;
299
300struct ima_h_table {
301	atomic_long_t len;	/* number of stored measurements in the list */
302	atomic_long_t violations;
303	struct hlist_head queue[IMA_MEASURE_HTABLE_SIZE];
304};
305extern struct ima_h_table ima_htable;
306
307static inline unsigned int ima_hash_key(u8 *digest)
308{
309	/* there is no point in taking a hash of part of a digest */
310	return (digest[0] | digest[1] << 8) % IMA_MEASURE_HTABLE_SIZE;
311}
312
313#define __ima_hooks(hook)				\
314	hook(NONE, none)				\
315	hook(FILE_CHECK, file)				\
316	hook(MMAP_CHECK, mmap)				\
317	hook(MMAP_CHECK_REQPROT, mmap_reqprot)		\
318	hook(BPRM_CHECK, bprm)				\
319	hook(CREDS_CHECK, creds)			\
320	hook(POST_SETATTR, post_setattr)		\
321	hook(MODULE_CHECK, module)			\
322	hook(FIRMWARE_CHECK, firmware)			\
323	hook(KEXEC_KERNEL_CHECK, kexec_kernel)		\
324	hook(KEXEC_INITRAMFS_CHECK, kexec_initramfs)	\
325	hook(POLICY_CHECK, policy)			\
326	hook(KEXEC_CMDLINE, kexec_cmdline)		\
327	hook(KEY_CHECK, key)				\
328	hook(CRITICAL_DATA, critical_data)		\
329	hook(SETXATTR_CHECK, setxattr_check)		\
330	hook(MAX_CHECK, none)
331
332#define __ima_hook_enumify(ENUM, str)	ENUM,
333#define __ima_stringify(arg) (#arg)
334#define __ima_hook_measuring_stringify(ENUM, str) \
335		(__ima_stringify(measuring_ ##str)),
336
337enum ima_hooks {
338	__ima_hooks(__ima_hook_enumify)
339};
340
341static const char * const ima_hooks_measure_str[] = {
342	__ima_hooks(__ima_hook_measuring_stringify)
343};
344
345static inline const char *func_measure_str(enum ima_hooks func)
346{
347	if (func >= MAX_CHECK)
348		return ima_hooks_measure_str[NONE];
349
350	return ima_hooks_measure_str[func];
351}
352
353extern const char *const func_tokens[];
354
355struct modsig;
356
357#ifdef CONFIG_IMA_QUEUE_EARLY_BOOT_KEYS
358/*
359 * To track keys that need to be measured.
360 */
361struct ima_key_entry {
362	struct list_head list;
363	void *payload;
364	size_t payload_len;
365	char *keyring_name;
366};
367void ima_init_key_queue(void);
368bool ima_should_queue_key(void);
369bool ima_queue_key(struct key *keyring, const void *payload,
370		   size_t payload_len);
371void ima_process_queued_keys(void);
372#else
373static inline void ima_init_key_queue(void) {}
374static inline bool ima_should_queue_key(void) { return false; }
375static inline bool ima_queue_key(struct key *keyring,
376				 const void *payload,
377				 size_t payload_len) { return false; }
378static inline void ima_process_queued_keys(void) {}
379#endif /* CONFIG_IMA_QUEUE_EARLY_BOOT_KEYS */
380
381/* LIM API function definitions */
382int ima_get_action(struct mnt_idmap *idmap, struct inode *inode,
383		   const struct cred *cred, struct lsm_prop *prop, int mask,
384		   enum ima_hooks func, int *pcr,
385		   struct ima_template_desc **template_desc,
386		   const char *func_data, unsigned int *allowed_algos);
387int ima_must_measure(struct inode *inode, int mask, enum ima_hooks func);
388int ima_collect_measurement(struct ima_iint_cache *iint, struct file *file,
389			    void *buf, loff_t size, enum hash_algo algo,
390			    struct modsig *modsig);
391void ima_store_measurement(struct ima_iint_cache *iint, struct file *file,
392			   const unsigned char *filename,
393			   struct evm_ima_xattr_data *xattr_value,
394			   int xattr_len, const struct modsig *modsig, int pcr,
395			   struct ima_template_desc *template_desc);
396int process_buffer_measurement(struct mnt_idmap *idmap,
397			       struct inode *inode, const void *buf, int size,
398			       const char *eventname, enum ima_hooks func,
399			       int pcr, const char *func_data,
400			       bool buf_hash, u8 *digest, size_t digest_len);
401void ima_audit_measurement(struct ima_iint_cache *iint,
402			   const unsigned char *filename);
403int ima_alloc_init_template(struct ima_event_data *event_data,
404			    struct ima_template_entry **entry,
405			    struct ima_template_desc *template_desc);
406int ima_store_template(struct ima_template_entry *entry, int violation,
407		       struct inode *inode,
408		       const unsigned char *filename, int pcr);
409void ima_free_template_entry(struct ima_template_entry *entry);
410const char *ima_d_path(const struct path *path, char **pathbuf, char *filename);
411
412/* IMA policy related functions */
413int ima_match_policy(struct mnt_idmap *idmap, struct inode *inode,
414		     const struct cred *cred, struct lsm_prop *prop,
415		     enum ima_hooks func, int mask, int flags, int *pcr,
416		     struct ima_template_desc **template_desc,
417		     const char *func_data, unsigned int *allowed_algos);
418void ima_init_policy(void);
419void ima_update_policy(void);
420void ima_update_policy_flags(void);
421ssize_t ima_parse_add_rule(char *);
422void ima_delete_rules(void);
423int ima_check_policy(void);
424void *ima_policy_start(struct seq_file *m, loff_t *pos);
425void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos);
426void ima_policy_stop(struct seq_file *m, void *v);
427int ima_policy_show(struct seq_file *m, void *v);
428
429/* Appraise integrity measurements */
430#define IMA_APPRAISE_ENFORCE	0x01
431#define IMA_APPRAISE_FIX	0x02
432#define IMA_APPRAISE_LOG	0x04
433#define IMA_APPRAISE_MODULES	0x08
434#define IMA_APPRAISE_FIRMWARE	0x10
435#define IMA_APPRAISE_POLICY	0x20
436#define IMA_APPRAISE_KEXEC	0x40
437
438#ifdef CONFIG_IMA_APPRAISE
439int ima_check_blacklist(struct ima_iint_cache *iint,
440			const struct modsig *modsig, int pcr);
441int ima_appraise_measurement(enum ima_hooks func, struct ima_iint_cache *iint,
442			     struct file *file, const unsigned char *filename,
443			     struct evm_ima_xattr_data *xattr_value,
444			     int xattr_len, const struct modsig *modsig,
445			     bool bprm_is_check);
446int ima_must_appraise(struct mnt_idmap *idmap, struct inode *inode,
447		      int mask, enum ima_hooks func);
448void ima_update_xattr(struct ima_iint_cache *iint, struct file *file);
449enum integrity_status ima_get_cache_status(struct ima_iint_cache *iint,
450					   enum ima_hooks func);
451enum hash_algo ima_get_hash_algo(const struct evm_ima_xattr_data *xattr_value,
452				 int xattr_len);
453int ima_read_xattr(struct dentry *dentry,
454		   struct evm_ima_xattr_data **xattr_value, int xattr_len);
455void __init init_ima_appraise_lsm(const struct lsm_id *lsmid);
456
457#else
458static inline int ima_check_blacklist(struct ima_iint_cache *iint,
459				      const struct modsig *modsig, int pcr)
460{
461	return 0;
462}
463
464static inline int ima_appraise_measurement(enum ima_hooks func,
465					   struct ima_iint_cache *iint,
466					   struct file *file,
467					   const unsigned char *filename,
468					   struct evm_ima_xattr_data *xattr_value,
469					   int xattr_len,
470					   const struct modsig *modsig,
471					   bool bprm_is_check)
472{
473	return INTEGRITY_UNKNOWN;
474}
475
476static inline int ima_must_appraise(struct mnt_idmap *idmap,
477				    struct inode *inode, int mask,
478				    enum ima_hooks func)
479{
480	return 0;
481}
482
483static inline void ima_update_xattr(struct ima_iint_cache *iint,
484				    struct file *file)
485{
486}
487
488static inline enum integrity_status
489ima_get_cache_status(struct ima_iint_cache *iint, enum ima_hooks func)
490{
491	return INTEGRITY_UNKNOWN;
492}
493
494static inline enum hash_algo
495ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value, int xattr_len)
496{
497	return ima_hash_algo;
498}
499
500static inline int ima_read_xattr(struct dentry *dentry,
501				 struct evm_ima_xattr_data **xattr_value,
502				 int xattr_len)
503{
504	return 0;
505}
506
507static inline void __init init_ima_appraise_lsm(const struct lsm_id *lsmid)
508{
509}
510
511#endif /* CONFIG_IMA_APPRAISE */
512
513#ifdef CONFIG_IMA_APPRAISE_MODSIG
514int ima_read_modsig(enum ima_hooks func, const void *buf, loff_t buf_len,
515		    struct modsig **modsig);
516void ima_collect_modsig(struct modsig *modsig, const void *buf, loff_t size);
517int ima_get_modsig_digest(const struct modsig *modsig, enum hash_algo *algo,
518			  const u8 **digest, u32 *digest_size);
519int ima_get_raw_modsig(const struct modsig *modsig, const void **data,
520		       u32 *data_len);
521void ima_free_modsig(struct modsig *modsig);
522#else
523static inline int ima_read_modsig(enum ima_hooks func, const void *buf,
524				  loff_t buf_len, struct modsig **modsig)
525{
526	return -EOPNOTSUPP;
527}
528
529static inline void ima_collect_modsig(struct modsig *modsig, const void *buf,
530				      loff_t size)
531{
532}
533
534static inline int ima_get_modsig_digest(const struct modsig *modsig,
535					enum hash_algo *algo, const u8 **digest,
536					u32 *digest_size)
537{
538	return -EOPNOTSUPP;
539}
540
541static inline int ima_get_raw_modsig(const struct modsig *modsig,
542				     const void **data, u32 *data_len)
543{
544	return -EOPNOTSUPP;
545}
546
547static inline void ima_free_modsig(struct modsig *modsig)
548{
549}
550#endif /* CONFIG_IMA_APPRAISE_MODSIG */
551
552/* LSM based policy rules require audit */
553#ifdef CONFIG_IMA_LSM_RULES
554
555#define ima_filter_rule_init security_audit_rule_init
556#define ima_filter_rule_free security_audit_rule_free
557#define ima_filter_rule_match security_audit_rule_match
558
559#else
560
561static inline int ima_filter_rule_init(u32 field, u32 op, char *rulestr,
562				       void **lsmrule, gfp_t gfp)
563{
564	return -EINVAL;
565}
566
567static inline void ima_filter_rule_free(void *lsmrule)
568{
569}
570
571static inline int ima_filter_rule_match(struct lsm_prop *prop, u32 field, u32 op,
572					void *lsmrule)
573{
574	return -EINVAL;
575}
576#endif /* CONFIG_IMA_LSM_RULES */
577
578#ifdef	CONFIG_IMA_READ_POLICY
579#define	POLICY_FILE_FLAGS	(S_IWUSR | S_IRUSR)
580#else
581#define	POLICY_FILE_FLAGS	S_IWUSR
582#endif /* CONFIG_IMA_READ_POLICY */
583
584#endif /* __LINUX_IMA_H */