4865f61f9044c68cfaf9da5f6cd7b0901bc72f8d
2 * Copyright (C) 2011 IBM Corporation
5 * Mimi Zohar <zohar@us.ibm.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, version 2 of the License.
11 #include <linux/module.h>
12 #include <linux/file.h>
14 #include <linux/xattr.h>
15 #include <linux/magic.h>
16 #include <linux/ima.h>
17 #include <linux/evm.h>
21 static int __init
default_appraise_setup(char *str
)
23 if (strncmp(str
, "off", 3) == 0)
25 else if (strncmp(str
, "fix", 3) == 0)
26 ima_appraise
= IMA_APPRAISE_FIX
;
30 __setup("ima_appraise=", default_appraise_setup
);
33 * ima_must_appraise - set appraise flag
35 * Return 1 to appraise
37 int ima_must_appraise(struct inode
*inode
, enum ima_hooks func
, int mask
)
42 static void ima_fix_xattr(struct dentry
*dentry
,
43 struct integrity_iint_cache
*iint
)
45 iint
->digest
[0] = IMA_XATTR_DIGEST
;
46 __vfs_setxattr_noperm(dentry
, XATTR_NAME_IMA
,
47 iint
->digest
, IMA_DIGEST_SIZE
+ 1, 0);
51 * ima_appraise_measurement - appraise file measurement
53 * Call evm_verifyxattr() to verify the integrity of 'security.ima'.
54 * Assuming success, compare the xattr hash with the collected measurement.
56 * Return 0 on success, error code otherwise
58 int ima_appraise_measurement(struct integrity_iint_cache
*iint
,
59 struct file
*file
, const unsigned char *filename
)
61 struct dentry
*dentry
= file
->f_dentry
;
62 struct inode
*inode
= dentry
->d_inode
;
63 u8 xattr_value
[IMA_DIGEST_SIZE
];
64 enum integrity_status status
= INTEGRITY_UNKNOWN
;
65 const char *op
= "appraise_data";
66 char *cause
= "unknown";
71 if (!inode
->i_op
->getxattr
)
72 return INTEGRITY_UNKNOWN
;
74 if (iint
->flags
& IMA_APPRAISED
)
75 return iint
->ima_status
;
77 rc
= inode
->i_op
->getxattr(dentry
, XATTR_NAME_IMA
, xattr_value
,
80 if (rc
&& rc
!= -ENODATA
)
83 cause
= "missing-hash";
85 (inode
->i_size
== 0) ? INTEGRITY_PASS
: INTEGRITY_NOLABEL
;
89 status
= evm_verifyxattr(dentry
, XATTR_NAME_IMA
, xattr_value
, rc
, iint
);
90 if ((status
!= INTEGRITY_PASS
) && (status
!= INTEGRITY_UNKNOWN
)) {
91 if ((status
== INTEGRITY_NOLABEL
)
92 || (status
== INTEGRITY_NOXATTRS
))
93 cause
= "missing-HMAC";
94 else if (status
== INTEGRITY_FAIL
)
95 cause
= "invalid-HMAC";
99 rc
= memcmp(xattr_value
, iint
->digest
, IMA_DIGEST_SIZE
);
101 status
= INTEGRITY_FAIL
;
102 cause
= "invalid-hash";
103 print_hex_dump_bytes("security.ima: ", DUMP_PREFIX_NONE
,
104 xattr_value
, IMA_DIGEST_SIZE
);
105 print_hex_dump_bytes("collected: ", DUMP_PREFIX_NONE
,
106 iint
->digest
, IMA_DIGEST_SIZE
);
109 status
= INTEGRITY_PASS
;
110 iint
->flags
|= IMA_APPRAISED
;
112 if (status
!= INTEGRITY_PASS
) {
113 if (ima_appraise
& IMA_APPRAISE_FIX
) {
114 ima_fix_xattr(dentry
, iint
);
115 status
= INTEGRITY_PASS
;
117 integrity_audit_msg(AUDIT_INTEGRITY_DATA
, inode
, filename
,
120 iint
->ima_status
= status
;
125 * ima_update_xattr - update 'security.ima' hash value
127 void ima_update_xattr(struct integrity_iint_cache
*iint
, struct file
*file
)
129 struct dentry
*dentry
= file
->f_dentry
;
132 rc
= ima_collect_measurement(iint
, file
);
135 ima_fix_xattr(dentry
, iint
);
139 * ima_inode_post_setattr - reflect file metadata changes
140 * @dentry: pointer to the affected dentry
142 * Changes to a dentry's metadata might result in needing to appraise.
144 * This function is called from notify_change(), which expects the caller
145 * to lock the inode's i_mutex.
147 void ima_inode_post_setattr(struct dentry
*dentry
)
149 struct inode
*inode
= dentry
->d_inode
;
150 struct integrity_iint_cache
*iint
;
151 int must_appraise
, rc
;
153 if (!ima_initialized
|| !ima_appraise
|| !S_ISREG(inode
->i_mode
)
154 || !inode
->i_op
->removexattr
)
157 must_appraise
= ima_must_appraise(inode
, MAY_ACCESS
, POST_SETATTR
);
158 iint
= integrity_iint_find(inode
);
161 iint
->flags
|= IMA_APPRAISE
;
163 iint
->flags
&= ~(IMA_APPRAISE
| IMA_APPRAISED
);
166 rc
= inode
->i_op
->removexattr(dentry
, XATTR_NAME_IMA
);
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