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 #define IMA_VERITY_REQUIRED	0x80000000
44 
45 #define IMA_DO_MASK		(IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT | \
46 				 IMA_HASH | IMA_APPRAISE_SUBMASK)
47 #define IMA_DONE_MASK		(IMA_MEASURED | IMA_APPRAISED | IMA_AUDITED | \
48 				 IMA_HASHED | IMA_COLLECTED | \
49 				 IMA_APPRAISED_SUBMASK)
50 
51 /* iint subaction appraise cache flags */
52 #define IMA_FILE_APPRAISE	0x00001000
53 #define IMA_FILE_APPRAISED	0x00002000
54 #define IMA_MMAP_APPRAISE	0x00004000
55 #define IMA_MMAP_APPRAISED	0x00008000
56 #define IMA_BPRM_APPRAISE	0x00010000
57 #define IMA_BPRM_APPRAISED	0x00020000
58 #define IMA_READ_APPRAISE	0x00040000
59 #define IMA_READ_APPRAISED	0x00080000
60 #define IMA_CREDS_APPRAISE	0x00100000
61 #define IMA_CREDS_APPRAISED	0x00200000
62 #define IMA_APPRAISE_SUBMASK	(IMA_FILE_APPRAISE | IMA_MMAP_APPRAISE | \
63 				 IMA_BPRM_APPRAISE | IMA_READ_APPRAISE | \
64 				 IMA_CREDS_APPRAISE)
65 #define IMA_APPRAISED_SUBMASK	(IMA_FILE_APPRAISED | IMA_MMAP_APPRAISED | \
66 				 IMA_BPRM_APPRAISED | IMA_READ_APPRAISED | \
67 				 IMA_CREDS_APPRAISED)
68 
69 /* iint cache atomic_flags */
70 #define IMA_CHANGE_XATTR	0
71 #define IMA_UPDATE_XATTR	1
72 #define IMA_CHANGE_ATTR		2
73 #define IMA_DIGSIG		3
74 #define IMA_MUST_MEASURE	4
75 
76 enum evm_ima_xattr_type {
77 	IMA_XATTR_DIGEST = 0x01,
78 	EVM_XATTR_HMAC,
79 	EVM_IMA_XATTR_DIGSIG,
80 	IMA_XATTR_DIGEST_NG,
81 	EVM_XATTR_PORTABLE_DIGSIG,
82 	IMA_VERITY_DIGSIG,
83 	IMA_XATTR_LAST
84 };
85 
86 struct evm_ima_xattr_data {
87 	u8 type;
88 	u8 data[];
89 } __packed;
90 
91 /* Only used in the EVM HMAC code. */
92 struct evm_xattr {
93 	struct evm_ima_xattr_data data;
94 	u8 digest[SHA1_DIGEST_SIZE];
95 } __packed;
96 
97 #define IMA_MAX_DIGEST_SIZE	HASH_MAX_DIGESTSIZE
98 
99 struct ima_digest_data {
100 	u8 algo;
101 	u8 length;
102 	union {
103 		struct {
104 			u8 unused;
105 			u8 type;
106 		} sha1;
107 		struct {
108 			u8 type;
109 			u8 algo;
110 		} ng;
111 		u8 data[2];
112 	} xattr;
113 	u8 digest[];
114 } __packed;
115 
116 /*
117  * Instead of wrapping the ima_digest_data struct inside a local structure
118  * with the maximum hash size, define ima_max_digest_data struct.
119  */
120 struct ima_max_digest_data {
121 	struct ima_digest_data hdr;
122 	u8 digest[HASH_MAX_DIGESTSIZE];
123 } __packed;
124 
125 /*
126  * signature header format v2 - for using with asymmetric keys
127  *
128  * The signature_v2_hdr struct includes a signature format version
129  * to simplify defining new signature formats.
130  *
131  * signature format:
132  * version 2: regular file data hash based signature
133  * version 3: struct ima_file_id data based signature
134  */
135 struct signature_v2_hdr {
136 	uint8_t type;		/* xattr type */
137 	uint8_t version;	/* signature format version */
138 	uint8_t	hash_algo;	/* Digest algorithm [enum hash_algo] */
139 	__be32 keyid;		/* IMA key identifier - not X509/PGP specific */
140 	__be16 sig_size;	/* signature size */
141 	uint8_t sig[];		/* signature payload */
142 } __packed;
143 
144 /*
145  * IMA signature version 3 disambiguates the data that is signed, by
146  * indirectly signing the hash of the ima_file_id structure data,
147  * containing either the fsverity_descriptor struct digest or, in the
148  * future, the regular IMA file hash.
149  *
150  * (The hash of the ima_file_id structure is only of the portion used.)
151  */
152 struct ima_file_id {
153 	__u8 hash_type;		/* xattr type [enum evm_ima_xattr_type] */
154 	__u8 hash_algorithm;	/* Digest algorithm [enum hash_algo] */
155 	__u8 hash[HASH_MAX_DIGESTSIZE];
156 } __packed;
157 
158 /* integrity data associated with an inode */
159 struct integrity_iint_cache {
160 	struct rb_node rb_node;	/* rooted in integrity_iint_tree */
161 	struct mutex mutex;	/* protects: version, flags, digest */
162 	struct inode *inode;	/* back pointer to inode in question */
163 	u64 version;		/* track inode changes */
164 	unsigned long flags;
165 	unsigned long measured_pcrs;
166 	unsigned long atomic_flags;
167 	enum integrity_status ima_file_status:4;
168 	enum integrity_status ima_mmap_status:4;
169 	enum integrity_status ima_bprm_status:4;
170 	enum integrity_status ima_read_status:4;
171 	enum integrity_status ima_creds_status:4;
172 	enum integrity_status evm_status:4;
173 	struct ima_digest_data *ima_hash;
174 };
175 
176 /* rbtree tree calls to lookup, insert, delete
177  * integrity data associated with an inode.
178  */
179 struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
180 
181 int integrity_kernel_read(struct file *file, loff_t offset,
182 			  void *addr, unsigned long count);
183 
184 #define INTEGRITY_KEYRING_EVM		0
185 #define INTEGRITY_KEYRING_IMA		1
186 #define INTEGRITY_KEYRING_PLATFORM	2
187 #define INTEGRITY_KEYRING_MACHINE	3
188 #define INTEGRITY_KEYRING_MAX		4
189 
190 extern struct dentry *integrity_dir;
191 
192 struct modsig;
193 
194 #ifdef CONFIG_INTEGRITY_SIGNATURE
195 
196 int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
197 			    const char *digest, int digestlen);
198 int integrity_modsig_verify(unsigned int id, const struct modsig *modsig);
199 
200 int __init integrity_init_keyring(const unsigned int id);
201 int __init integrity_load_x509(const unsigned int id, const char *path);
202 int __init integrity_load_cert(const unsigned int id, const char *source,
203 			       const void *data, size_t len, key_perm_t perm);
204 #else
205 
206 static inline int integrity_digsig_verify(const unsigned int id,
207 					  const char *sig, int siglen,
208 					  const char *digest, int digestlen)
209 {
210 	return -EOPNOTSUPP;
211 }
212 
213 static inline int integrity_modsig_verify(unsigned int id,
214 					  const struct modsig *modsig)
215 {
216 	return -EOPNOTSUPP;
217 }
218 
219 static inline int integrity_init_keyring(const unsigned int id)
220 {
221 	return 0;
222 }
223 
224 static inline int __init integrity_load_cert(const unsigned int id,
225 					     const char *source,
226 					     const void *data, size_t len,
227 					     key_perm_t perm)
228 {
229 	return 0;
230 }
231 #endif /* CONFIG_INTEGRITY_SIGNATURE */
232 
233 #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
234 int asymmetric_verify(struct key *keyring, const char *sig,
235 		      int siglen, const char *data, int datalen);
236 #else
237 static inline int asymmetric_verify(struct key *keyring, const char *sig,
238 				    int siglen, const char *data, int datalen)
239 {
240 	return -EOPNOTSUPP;
241 }
242 #endif
243 
244 #ifdef CONFIG_IMA_APPRAISE_MODSIG
245 int ima_modsig_verify(struct key *keyring, const struct modsig *modsig);
246 #else
247 static inline int ima_modsig_verify(struct key *keyring,
248 				    const struct modsig *modsig)
249 {
250 	return -EOPNOTSUPP;
251 }
252 #endif
253 
254 #ifdef CONFIG_IMA_LOAD_X509
255 void __init ima_load_x509(void);
256 #else
257 static inline void ima_load_x509(void)
258 {
259 }
260 #endif
261 
262 #ifdef CONFIG_EVM_LOAD_X509
263 void __init evm_load_x509(void);
264 #else
265 static inline void evm_load_x509(void)
266 {
267 }
268 #endif
269 
270 #ifdef CONFIG_INTEGRITY_AUDIT
271 /* declarations */
272 void integrity_audit_msg(int audit_msgno, struct inode *inode,
273 			 const unsigned char *fname, const char *op,
274 			 const char *cause, int result, int info);
275 
276 void integrity_audit_message(int audit_msgno, struct inode *inode,
277 			     const unsigned char *fname, const char *op,
278 			     const char *cause, int result, int info,
279 			     int errno);
280 
281 static inline struct audit_buffer *
282 integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
283 {
284 	return audit_log_start(ctx, gfp_mask, type);
285 }
286 
287 #else
288 static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
289 				       const unsigned char *fname,
290 				       const char *op, const char *cause,
291 				       int result, int info)
292 {
293 }
294 
295 static inline void integrity_audit_message(int audit_msgno,
296 					   struct inode *inode,
297 					   const unsigned char *fname,
298 					   const char *op, const char *cause,
299 					   int result, int info, int errno)
300 {
301 }
302 
303 static inline struct audit_buffer *
304 integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
305 {
306 	return NULL;
307 }
308 
309 #endif
310 
311 #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
312 void __init add_to_platform_keyring(const char *source, const void *data,
313 				    size_t len);
314 #else
315 static inline void __init add_to_platform_keyring(const char *source,
316 						  const void *data, size_t len)
317 {
318 }
319 #endif
320 
321 #ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
322 void __init add_to_machine_keyring(const char *source, const void *data, size_t len);
323 bool __init imputed_trust_enabled(void);
324 #else
325 static inline void __init add_to_machine_keyring(const char *source,
326 						  const void *data, size_t len)
327 {
328 }
329 
330 static inline bool __init imputed_trust_enabled(void)
331 {
332 	return false;
333 }
334 #endif
335