2 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
5 * Reiner Sailer <sailer@watson.ibm.com>
6 * Serge Hallyn <serue@us.ibm.com>
7 * Kylene Hall <kylene@us.ibm.com>
8 * Mimi Zohar <zohar@us.ibm.com>
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation, version 2 of the
16 * implements the IMA hooks: ima_bprm_check, ima_file_mmap,
19 #include <linux/module.h>
20 #include <linux/file.h>
21 #include <linux/binfmts.h>
22 #include <linux/mount.h>
23 #include <linux/mman.h>
24 #include <linux/slab.h>
25 #include <linux/xattr.h>
26 #include <linux/ima.h>
27 #include <crypto/hash_info.h>
33 #ifdef CONFIG_IMA_APPRAISE
34 int ima_appraise
= IMA_APPRAISE_ENFORCE
;
39 int ima_hash_algo
= HASH_ALGO_SHA1
;
40 static int hash_setup_done
;
42 static int __init
hash_setup(char *str
)
44 struct ima_template_desc
*template_desc
= ima_template_desc_current();
50 if (strcmp(template_desc
->name
, IMA_TEMPLATE_IMA_NAME
) == 0) {
51 if (strncmp(str
, "sha1", 4) == 0)
52 ima_hash_algo
= HASH_ALGO_SHA1
;
53 else if (strncmp(str
, "md5", 3) == 0)
54 ima_hash_algo
= HASH_ALGO_MD5
;
58 for (i
= 0; i
< HASH_ALGO__LAST
; i
++) {
59 if (strcmp(str
, hash_algo_name
[i
]) == 0) {
68 __setup("ima_hash=", hash_setup
);
71 * ima_rdwr_violation_check
73 * Only invalidate the PCR for measured files:
74 * - Opening a file for write when already open for read,
75 * results in a time of measure, time of use (ToMToU) error.
76 * - Opening a file for read when already open for write,
77 * could result in a file measurement error.
80 static void ima_rdwr_violation_check(struct file
*file
)
82 struct inode
*inode
= file_inode(file
);
83 fmode_t mode
= file
->f_mode
;
84 bool send_tomtou
= false, send_writers
= false;
88 if (!S_ISREG(inode
->i_mode
) || !ima_initialized
)
91 if (mode
& FMODE_WRITE
) {
92 if (atomic_read(&inode
->i_readcount
) && IS_IMA(inode
)) {
93 struct integrity_iint_cache
*iint
;
94 iint
= integrity_iint_find(inode
);
95 /* IMA_MEASURE is set from reader side */
96 if (iint
&& (iint
->flags
& IMA_MEASURE
))
100 if ((atomic_read(&inode
->i_writecount
) > 0) &&
101 ima_must_measure(inode
, MAY_READ
, FILE_CHECK
))
105 if (!send_tomtou
&& !send_writers
)
108 pathname
= ima_d_path(&file
->f_path
, &pathbuf
);
111 ima_add_violation(file
, pathname
, "invalid_pcr", "ToMToU");
113 ima_add_violation(file
, pathname
,
114 "invalid_pcr", "open_writers");
118 static void ima_check_last_writer(struct integrity_iint_cache
*iint
,
119 struct inode
*inode
, struct file
*file
)
121 fmode_t mode
= file
->f_mode
;
123 if (!(mode
& FMODE_WRITE
))
126 mutex_lock(&inode
->i_mutex
);
127 if (atomic_read(&inode
->i_writecount
) == 1 &&
128 iint
->version
!= inode
->i_version
) {
129 iint
->flags
&= ~IMA_DONE_MASK
;
130 if (iint
->flags
& IMA_APPRAISE
)
131 ima_update_xattr(iint
, file
);
133 mutex_unlock(&inode
->i_mutex
);
137 * ima_file_free - called on __fput()
138 * @file: pointer to file structure being freed
140 * Flag files that changed, based on i_version
142 void ima_file_free(struct file
*file
)
144 struct inode
*inode
= file_inode(file
);
145 struct integrity_iint_cache
*iint
;
147 if (!iint_initialized
|| !S_ISREG(inode
->i_mode
))
150 iint
= integrity_iint_find(inode
);
154 ima_check_last_writer(iint
, inode
, file
);
157 static int process_measurement(struct file
*file
, const char *filename
,
158 int mask
, int function
)
160 struct inode
*inode
= file_inode(file
);
161 struct integrity_iint_cache
*iint
;
162 struct ima_template_desc
*template_desc
;
163 char *pathbuf
= NULL
;
164 const char *pathname
= NULL
;
165 int rc
= -ENOMEM
, action
, must_appraise
, _func
;
166 struct evm_ima_xattr_data
*xattr_value
= NULL
, **xattr_ptr
= NULL
;
169 if (!ima_initialized
|| !S_ISREG(inode
->i_mode
))
172 /* Return an IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT action
173 * bitmask based on the appraise/audit/measurement policy.
174 * Included is the appraise submask.
176 action
= ima_get_action(inode
, mask
, function
);
180 must_appraise
= action
& IMA_APPRAISE
;
182 /* Is the appraise rule hook specific? */
183 _func
= (action
& IMA_FILE_APPRAISE
) ? FILE_CHECK
: function
;
185 mutex_lock(&inode
->i_mutex
);
187 iint
= integrity_inode_get(inode
);
191 /* Determine if already appraised/measured based on bitmask
192 * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED,
193 * IMA_AUDIT, IMA_AUDITED)
195 iint
->flags
|= action
;
196 action
&= IMA_DO_MASK
;
197 action
&= ~((iint
->flags
& IMA_DONE_MASK
) >> 1);
199 /* Nothing to do, just return existing appraised status */
202 rc
= ima_get_cache_status(iint
, _func
);
206 template_desc
= ima_template_desc_current();
207 if (strcmp(template_desc
->name
, IMA_TEMPLATE_IMA_NAME
) == 0) {
208 if (action
& IMA_APPRAISE_SUBMASK
)
209 xattr_ptr
= &xattr_value
;
211 xattr_ptr
= &xattr_value
;
213 rc
= ima_collect_measurement(iint
, file
, xattr_ptr
, &xattr_len
);
215 if (file
->f_flags
& O_DIRECT
)
216 rc
= (iint
->flags
& IMA_PERMIT_DIRECTIO
) ? 0 : -EACCES
;
220 pathname
= filename
?: ima_d_path(&file
->f_path
, &pathbuf
);
222 if (action
& IMA_MEASURE
)
223 ima_store_measurement(iint
, file
, pathname
,
224 xattr_value
, xattr_len
);
225 if (action
& IMA_APPRAISE_SUBMASK
)
226 rc
= ima_appraise_measurement(_func
, iint
, file
, pathname
,
227 xattr_value
, xattr_len
);
228 if (action
& IMA_AUDIT
)
229 ima_audit_measurement(iint
, pathname
);
232 if ((mask
& MAY_WRITE
) && (iint
->flags
& IMA_DIGSIG
))
235 mutex_unlock(&inode
->i_mutex
);
237 if ((rc
&& must_appraise
) && (ima_appraise
& IMA_APPRAISE_ENFORCE
))
243 * ima_file_mmap - based on policy, collect/store measurement.
244 * @file: pointer to the file to be measured (May be NULL)
245 * @prot: contains the protection that will be applied by the kernel.
247 * Measure files being mmapped executable based on the ima_must_measure()
250 * On success return 0. On integrity appraisal error, assuming the file
251 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
253 int ima_file_mmap(struct file
*file
, unsigned long prot
)
255 if (file
&& (prot
& PROT_EXEC
))
256 return process_measurement(file
, NULL
, MAY_EXEC
, MMAP_CHECK
);
261 * ima_bprm_check - based on policy, collect/store measurement.
262 * @bprm: contains the linux_binprm structure
264 * The OS protects against an executable file, already open for write,
265 * from being executed in deny_write_access() and an executable file,
266 * already open for execute, from being modified in get_write_access().
267 * So we can be certain that what we verify and measure here is actually
268 * what is being executed.
270 * On success return 0. On integrity appraisal error, assuming the file
271 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
273 int ima_bprm_check(struct linux_binprm
*bprm
)
275 return process_measurement(bprm
->file
,
276 (strcmp(bprm
->filename
, bprm
->interp
) == 0) ?
277 bprm
->filename
: bprm
->interp
,
278 MAY_EXEC
, BPRM_CHECK
);
282 * ima_path_check - based on policy, collect/store measurement.
283 * @file: pointer to the file to be measured
284 * @mask: contains MAY_READ, MAY_WRITE or MAY_EXECUTE
286 * Measure files based on the ima_must_measure() policy decision.
288 * On success return 0. On integrity appraisal error, assuming the file
289 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
291 int ima_file_check(struct file
*file
, int mask
)
293 ima_rdwr_violation_check(file
);
294 return process_measurement(file
, NULL
,
295 mask
& (MAY_READ
| MAY_WRITE
| MAY_EXEC
),
298 EXPORT_SYMBOL_GPL(ima_file_check
);
301 * ima_module_check - based on policy, collect/store/appraise measurement.
302 * @file: pointer to the file to be measured/appraised
304 * Measure/appraise kernel modules based on policy.
306 * On success return 0. On integrity appraisal error, assuming the file
307 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
309 int ima_module_check(struct file
*file
)
312 #ifndef CONFIG_MODULE_SIG_FORCE
313 if ((ima_appraise
& IMA_APPRAISE_MODULES
) &&
314 (ima_appraise
& IMA_APPRAISE_ENFORCE
))
315 return -EACCES
; /* INTEGRITY_UNKNOWN */
317 return 0; /* We rely on module signature checking */
319 return process_measurement(file
, NULL
, MAY_EXEC
, MODULE_CHECK
);
322 int ima_fw_from_file(struct file
*file
, char *buf
, size_t size
)
325 if ((ima_appraise
& IMA_APPRAISE_FIRMWARE
) &&
326 (ima_appraise
& IMA_APPRAISE_ENFORCE
))
327 return -EACCES
; /* INTEGRITY_UNKNOWN */
330 return process_measurement(file
, NULL
, MAY_EXEC
, FIRMWARE_CHECK
);
333 static int __init
init_ima(void)
337 hash_setup(CONFIG_IMA_DEFAULT_HASH
);
342 error
= ima_init_keyring(INTEGRITY_KEYRING_IMA
);
350 late_initcall(init_ima
); /* Start IMA after the TPM is available */
352 MODULE_DESCRIPTION("Integrity Measurement Architecture");
353 MODULE_LICENSE("GPL");