1 /*
2  * Copyright (C) 2009-2010 IBM Corporation
3  *
4  * Authors:
5  * Mimi Zohar <zohar@us.ibm.com>
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License as
9  * published by the Free Software Foundation, version 2 of the
10  * License.
11  *
12  */
13 
14 #include <linux/types.h>
15 #include <linux/integrity.h>
16 #include <crypto/sha.h>
17 #include <linux/key.h>
18 
19 /* iint action cache flags */
20 #define IMA_MEASURE		0x00000001
21 #define IMA_MEASURED		0x00000002
22 #define IMA_APPRAISE		0x00000004
23 #define IMA_APPRAISED		0x00000008
24 /*#define IMA_COLLECT		0x00000010  do not use this flag */
25 #define IMA_COLLECTED		0x00000020
26 #define IMA_AUDIT		0x00000040
27 #define IMA_AUDITED		0x00000080
28 
29 /* iint cache flags */
30 #define IMA_ACTION_FLAGS	0xff000000
31 #define IMA_DIGSIG		0x01000000
32 #define IMA_DIGSIG_REQUIRED	0x02000000
33 #define IMA_PERMIT_DIRECTIO	0x04000000
34 
35 #define IMA_DO_MASK		(IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT | \
36 				 IMA_APPRAISE_SUBMASK)
37 #define IMA_DONE_MASK		(IMA_MEASURED | IMA_APPRAISED | IMA_AUDITED | \
38 				 IMA_COLLECTED | IMA_APPRAISED_SUBMASK)
39 
40 /* iint subaction appraise cache flags */
41 #define IMA_FILE_APPRAISE	0x00000100
42 #define IMA_FILE_APPRAISED	0x00000200
43 #define IMA_MMAP_APPRAISE	0x00000400
44 #define IMA_MMAP_APPRAISED	0x00000800
45 #define IMA_BPRM_APPRAISE	0x00001000
46 #define IMA_BPRM_APPRAISED	0x00002000
47 #define IMA_MODULE_APPRAISE	0x00004000
48 #define IMA_MODULE_APPRAISED	0x00008000
49 #define IMA_APPRAISE_SUBMASK	(IMA_FILE_APPRAISE | IMA_MMAP_APPRAISE | \
50 				 IMA_BPRM_APPRAISE | IMA_MODULE_APPRAISE)
51 #define IMA_APPRAISED_SUBMASK	(IMA_FILE_APPRAISED | IMA_MMAP_APPRAISED | \
52 				 IMA_BPRM_APPRAISED | IMA_MODULE_APPRAISED)
53 
54 enum evm_ima_xattr_type {
55 	IMA_XATTR_DIGEST = 0x01,
56 	EVM_XATTR_HMAC,
57 	EVM_IMA_XATTR_DIGSIG,
58 	IMA_XATTR_DIGEST_NG,
59 };
60 
61 struct evm_ima_xattr_data {
62 	u8 type;
63 	u8 digest[SHA1_DIGEST_SIZE];
64 } __packed;
65 
66 #define IMA_MAX_DIGEST_SIZE	64
67 
68 struct ima_digest_data {
69 	u8 algo;
70 	u8 length;
71 	union {
72 		struct {
73 			u8 unused;
74 			u8 type;
75 		} sha1;
76 		struct {
77 			u8 type;
78 			u8 algo;
79 		} ng;
80 		u8 data[2];
81 	} xattr;
82 	u8 digest[0];
83 } __packed;
84 
85 /*
86  * signature format v2 - for using with asymmetric keys
87  */
88 struct signature_v2_hdr {
89 	uint8_t type;		/* xattr type */
90 	uint8_t version;	/* signature format version */
91 	uint8_t	hash_algo;	/* Digest algorithm [enum pkey_hash_algo] */
92 	uint32_t keyid;		/* IMA key identifier - not X509/PGP specific */
93 	uint16_t sig_size;	/* signature size */
94 	uint8_t sig[0];		/* signature payload */
95 } __packed;
96 
97 /* integrity data associated with an inode */
98 struct integrity_iint_cache {
99 	struct rb_node rb_node;	/* rooted in integrity_iint_tree */
100 	struct inode *inode;	/* back pointer to inode in question */
101 	u64 version;		/* track inode changes */
102 	unsigned long flags;
103 	enum integrity_status ima_file_status:4;
104 	enum integrity_status ima_mmap_status:4;
105 	enum integrity_status ima_bprm_status:4;
106 	enum integrity_status ima_module_status:4;
107 	enum integrity_status evm_status:4;
108 	struct ima_digest_data *ima_hash;
109 };
110 
111 /* rbtree tree calls to lookup, insert, delete
112  * integrity data associated with an inode.
113  */
114 struct integrity_iint_cache *integrity_iint_insert(struct inode *inode);
115 struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
116 
117 #define INTEGRITY_KEYRING_EVM		0
118 #define INTEGRITY_KEYRING_MODULE	1
119 #define INTEGRITY_KEYRING_IMA		2
120 #define INTEGRITY_KEYRING_MAX		3
121 
122 #ifdef CONFIG_INTEGRITY_SIGNATURE
123 
124 int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
125 			    const char *digest, int digestlen);
126 
127 #else
128 
129 static inline int integrity_digsig_verify(const unsigned int id,
130 					  const char *sig, int siglen,
131 					  const char *digest, int digestlen)
132 {
133 	return -EOPNOTSUPP;
134 }
135 
136 #endif /* CONFIG_INTEGRITY_SIGNATURE */
137 
138 #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
139 int asymmetric_verify(struct key *keyring, const char *sig,
140 		      int siglen, const char *data, int datalen);
141 #else
142 static inline int asymmetric_verify(struct key *keyring, const char *sig,
143 				    int siglen, const char *data, int datalen)
144 {
145 	return -EOPNOTSUPP;
146 }
147 #endif
148 
149 #ifdef CONFIG_INTEGRITY_AUDIT
150 /* declarations */
151 void integrity_audit_msg(int audit_msgno, struct inode *inode,
152 			 const unsigned char *fname, const char *op,
153 			 const char *cause, int result, int info);
154 #else
155 static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
156 				       const unsigned char *fname,
157 				       const char *op, const char *cause,
158 				       int result, int info)
159 {
160 }
161 #endif
162 
163 /* set during initialization */
164 extern int iint_initialized;
165