1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2009-2010 IBM Corporation
4  *
5  * Authors:
6  * Mimi Zohar <zohar@us.ibm.com>
7  */
8 
9 #ifdef pr_fmt
10 #undef pr_fmt
11 #endif
12 
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 
15 #include <linux/types.h>
16 #include <linux/integrity.h>
17 #include <crypto/sha1.h>
18 #include <crypto/hash.h>
19 #include <linux/key.h>
20 #include <linux/audit.h>
21 
22 /* iint action cache flags */
23 #define IMA_MEASURE		0x00000001
24 #define IMA_MEASURED		0x00000002
25 #define IMA_APPRAISE		0x00000004
26 #define IMA_APPRAISED		0x00000008
27 /*#define IMA_COLLECT		0x00000010  do not use this flag */
28 #define IMA_COLLECTED		0x00000020
29 #define IMA_AUDIT		0x00000040
30 #define IMA_AUDITED		0x00000080
31 #define IMA_HASH		0x00000100
32 #define IMA_HASHED		0x00000200
33 
34 /* iint policy rule cache flags */
35 #define IMA_NONACTION_FLAGS	0xff000000
36 #define IMA_DIGSIG_REQUIRED	0x01000000
37 #define IMA_PERMIT_DIRECTIO	0x02000000
38 #define IMA_NEW_FILE		0x04000000
39 #define EVM_IMMUTABLE_DIGSIG	0x08000000
40 #define IMA_FAIL_UNVERIFIABLE_SIGS	0x10000000
41 #define IMA_MODSIG_ALLOWED	0x20000000
42 #define IMA_CHECK_BLACKLIST	0x40000000
43 
44 #define IMA_DO_MASK		(IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT | \
45 				 IMA_HASH | IMA_APPRAISE_SUBMASK)
46 #define IMA_DONE_MASK		(IMA_MEASURED | IMA_APPRAISED | IMA_AUDITED | \
47 				 IMA_HASHED | IMA_COLLECTED | \
48 				 IMA_APPRAISED_SUBMASK)
49 
50 /* iint subaction appraise cache flags */
51 #define IMA_FILE_APPRAISE	0x00001000
52 #define IMA_FILE_APPRAISED	0x00002000
53 #define IMA_MMAP_APPRAISE	0x00004000
54 #define IMA_MMAP_APPRAISED	0x00008000
55 #define IMA_BPRM_APPRAISE	0x00010000
56 #define IMA_BPRM_APPRAISED	0x00020000
57 #define IMA_READ_APPRAISE	0x00040000
58 #define IMA_READ_APPRAISED	0x00080000
59 #define IMA_CREDS_APPRAISE	0x00100000
60 #define IMA_CREDS_APPRAISED	0x00200000
61 #define IMA_APPRAISE_SUBMASK	(IMA_FILE_APPRAISE | IMA_MMAP_APPRAISE | \
62 				 IMA_BPRM_APPRAISE | IMA_READ_APPRAISE | \
63 				 IMA_CREDS_APPRAISE)
64 #define IMA_APPRAISED_SUBMASK	(IMA_FILE_APPRAISED | IMA_MMAP_APPRAISED | \
65 				 IMA_BPRM_APPRAISED | IMA_READ_APPRAISED | \
66 				 IMA_CREDS_APPRAISED)
67 
68 /* iint cache atomic_flags */
69 #define IMA_CHANGE_XATTR	0
70 #define IMA_UPDATE_XATTR	1
71 #define IMA_CHANGE_ATTR		2
72 #define IMA_DIGSIG		3
73 #define IMA_MUST_MEASURE	4
74 
75 enum evm_ima_xattr_type {
76 	IMA_XATTR_DIGEST = 0x01,
77 	EVM_XATTR_HMAC,
78 	EVM_IMA_XATTR_DIGSIG,
79 	IMA_XATTR_DIGEST_NG,
80 	EVM_XATTR_PORTABLE_DIGSIG,
81 	IMA_XATTR_LAST
82 };
83 
84 struct evm_ima_xattr_data {
85 	u8 type;
86 	u8 data[];
87 } __packed;
88 
89 /* Only used in the EVM HMAC code. */
90 struct evm_xattr {
91 	struct evm_ima_xattr_data data;
92 	u8 digest[SHA1_DIGEST_SIZE];
93 } __packed;
94 
95 #define IMA_MAX_DIGEST_SIZE	64
96 
97 struct ima_digest_data {
98 	u8 algo;
99 	u8 length;
100 	union {
101 		struct {
102 			u8 unused;
103 			u8 type;
104 		} sha1;
105 		struct {
106 			u8 type;
107 			u8 algo;
108 		} ng;
109 		u8 data[2];
110 	} xattr;
111 	u8 digest[];
112 } __packed;
113 
114 /*
115  * Instead of wrapping the ima_digest_data struct inside a local structure
116  * with the maximum hash size, define ima_max_digest_data struct.
117  */
118 struct ima_max_digest_data {
119 	struct ima_digest_data hdr;
120 	u8 digest[HASH_MAX_DIGESTSIZE];
121 } __packed;
122 
123 /*
124  * signature format v2 - for using with asymmetric keys
125  */
126 struct signature_v2_hdr {
127 	uint8_t type;		/* xattr type */
128 	uint8_t version;	/* signature format version */
129 	uint8_t	hash_algo;	/* Digest algorithm [enum hash_algo] */
130 	__be32 keyid;		/* IMA key identifier - not X509/PGP specific */
131 	__be16 sig_size;	/* signature size */
132 	uint8_t sig[];		/* signature payload */
133 } __packed;
134 
135 /* integrity data associated with an inode */
136 struct integrity_iint_cache {
137 	struct rb_node rb_node;	/* rooted in integrity_iint_tree */
138 	struct mutex mutex;	/* protects: version, flags, digest */
139 	struct inode *inode;	/* back pointer to inode in question */
140 	u64 version;		/* track inode changes */
141 	unsigned long flags;
142 	unsigned long measured_pcrs;
143 	unsigned long atomic_flags;
144 	enum integrity_status ima_file_status:4;
145 	enum integrity_status ima_mmap_status:4;
146 	enum integrity_status ima_bprm_status:4;
147 	enum integrity_status ima_read_status:4;
148 	enum integrity_status ima_creds_status:4;
149 	enum integrity_status evm_status:4;
150 	struct ima_digest_data *ima_hash;
151 };
152 
153 /* rbtree tree calls to lookup, insert, delete
154  * integrity data associated with an inode.
155  */
156 struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
157 
158 int integrity_kernel_read(struct file *file, loff_t offset,
159 			  void *addr, unsigned long count);
160 
161 #define INTEGRITY_KEYRING_EVM		0
162 #define INTEGRITY_KEYRING_IMA		1
163 #define INTEGRITY_KEYRING_PLATFORM	2
164 #define INTEGRITY_KEYRING_MACHINE	3
165 #define INTEGRITY_KEYRING_MAX		4
166 
167 extern struct dentry *integrity_dir;
168 
169 struct modsig;
170 
171 #ifdef CONFIG_INTEGRITY_SIGNATURE
172 
173 int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
174 			    const char *digest, int digestlen);
175 int integrity_modsig_verify(unsigned int id, const struct modsig *modsig);
176 
177 int __init integrity_init_keyring(const unsigned int id);
178 int __init integrity_load_x509(const unsigned int id, const char *path);
179 int __init integrity_load_cert(const unsigned int id, const char *source,
180 			       const void *data, size_t len, key_perm_t perm);
181 #else
182 
183 static inline int integrity_digsig_verify(const unsigned int id,
184 					  const char *sig, int siglen,
185 					  const char *digest, int digestlen)
186 {
187 	return -EOPNOTSUPP;
188 }
189 
190 static inline int integrity_modsig_verify(unsigned int id,
191 					  const struct modsig *modsig)
192 {
193 	return -EOPNOTSUPP;
194 }
195 
196 static inline int integrity_init_keyring(const unsigned int id)
197 {
198 	return 0;
199 }
200 
201 static inline int __init integrity_load_cert(const unsigned int id,
202 					     const char *source,
203 					     const void *data, size_t len,
204 					     key_perm_t perm)
205 {
206 	return 0;
207 }
208 #endif /* CONFIG_INTEGRITY_SIGNATURE */
209 
210 #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
211 int asymmetric_verify(struct key *keyring, const char *sig,
212 		      int siglen, const char *data, int datalen);
213 #else
214 static inline int asymmetric_verify(struct key *keyring, const char *sig,
215 				    int siglen, const char *data, int datalen)
216 {
217 	return -EOPNOTSUPP;
218 }
219 #endif
220 
221 #ifdef CONFIG_IMA_APPRAISE_MODSIG
222 int ima_modsig_verify(struct key *keyring, const struct modsig *modsig);
223 #else
224 static inline int ima_modsig_verify(struct key *keyring,
225 				    const struct modsig *modsig)
226 {
227 	return -EOPNOTSUPP;
228 }
229 #endif
230 
231 #ifdef CONFIG_IMA_LOAD_X509
232 void __init ima_load_x509(void);
233 #else
234 static inline void ima_load_x509(void)
235 {
236 }
237 #endif
238 
239 #ifdef CONFIG_EVM_LOAD_X509
240 void __init evm_load_x509(void);
241 #else
242 static inline void evm_load_x509(void)
243 {
244 }
245 #endif
246 
247 #ifdef CONFIG_INTEGRITY_AUDIT
248 /* declarations */
249 void integrity_audit_msg(int audit_msgno, struct inode *inode,
250 			 const unsigned char *fname, const char *op,
251 			 const char *cause, int result, int info);
252 
253 void integrity_audit_message(int audit_msgno, struct inode *inode,
254 			     const unsigned char *fname, const char *op,
255 			     const char *cause, int result, int info,
256 			     int errno);
257 
258 static inline struct audit_buffer *
259 integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
260 {
261 	return audit_log_start(ctx, gfp_mask, type);
262 }
263 
264 #else
265 static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
266 				       const unsigned char *fname,
267 				       const char *op, const char *cause,
268 				       int result, int info)
269 {
270 }
271 
272 static inline void integrity_audit_message(int audit_msgno,
273 					   struct inode *inode,
274 					   const unsigned char *fname,
275 					   const char *op, const char *cause,
276 					   int result, int info, int errno)
277 {
278 }
279 
280 static inline struct audit_buffer *
281 integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
282 {
283 	return NULL;
284 }
285 
286 #endif
287 
288 #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
289 void __init add_to_platform_keyring(const char *source, const void *data,
290 				    size_t len);
291 #else
292 static inline void __init add_to_platform_keyring(const char *source,
293 						  const void *data, size_t len)
294 {
295 }
296 #endif
297 
298 #ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
299 void __init add_to_machine_keyring(const char *source, const void *data, size_t len);
300 bool __init trust_moklist(void);
301 #else
302 static inline void __init add_to_machine_keyring(const char *source,
303 						  const void *data, size_t len)
304 {
305 }
306 static inline bool __init trust_moklist(void)
307 {
308 	return false;
309 }
310 #endif
311