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 	unsigned long real_ino;
168 	dev_t real_dev;
169 	enum integrity_status ima_file_status:4;
170 	enum integrity_status ima_mmap_status:4;
171 	enum integrity_status ima_bprm_status:4;
172 	enum integrity_status ima_read_status:4;
173 	enum integrity_status ima_creds_status:4;
174 	enum integrity_status evm_status:4;
175 	struct ima_digest_data *ima_hash;
176 };
177 
178 /* rbtree tree calls to lookup, insert, delete
179  * integrity data associated with an inode.
180  */
181 struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
182 
183 int integrity_kernel_read(struct file *file, loff_t offset,
184 			  void *addr, unsigned long count);
185 
186 #define INTEGRITY_KEYRING_EVM		0
187 #define INTEGRITY_KEYRING_IMA		1
188 #define INTEGRITY_KEYRING_PLATFORM	2
189 #define INTEGRITY_KEYRING_MACHINE	3
190 #define INTEGRITY_KEYRING_MAX		4
191 
192 extern struct dentry *integrity_dir;
193 
194 struct modsig;
195 
196 #ifdef CONFIG_INTEGRITY_SIGNATURE
197 
198 int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
199 			    const char *digest, int digestlen);
200 int integrity_modsig_verify(unsigned int id, const struct modsig *modsig);
201 
202 int __init integrity_init_keyring(const unsigned int id);
203 int __init integrity_load_x509(const unsigned int id, const char *path);
204 int __init integrity_load_cert(const unsigned int id, const char *source,
205 			       const void *data, size_t len, key_perm_t perm);
206 #else
207 
integrity_digsig_verify(const unsigned int id,const char * sig,int siglen,const char * digest,int digestlen)208 static inline int integrity_digsig_verify(const unsigned int id,
209 					  const char *sig, int siglen,
210 					  const char *digest, int digestlen)
211 {
212 	return -EOPNOTSUPP;
213 }
214 
integrity_modsig_verify(unsigned int id,const struct modsig * modsig)215 static inline int integrity_modsig_verify(unsigned int id,
216 					  const struct modsig *modsig)
217 {
218 	return -EOPNOTSUPP;
219 }
220 
integrity_init_keyring(const unsigned int id)221 static inline int integrity_init_keyring(const unsigned int id)
222 {
223 	return 0;
224 }
225 
integrity_load_cert(const unsigned int id,const char * source,const void * data,size_t len,key_perm_t perm)226 static inline int __init integrity_load_cert(const unsigned int id,
227 					     const char *source,
228 					     const void *data, size_t len,
229 					     key_perm_t perm)
230 {
231 	return 0;
232 }
233 #endif /* CONFIG_INTEGRITY_SIGNATURE */
234 
235 #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
236 int asymmetric_verify(struct key *keyring, const char *sig,
237 		      int siglen, const char *data, int datalen);
238 #else
asymmetric_verify(struct key * keyring,const char * sig,int siglen,const char * data,int datalen)239 static inline int asymmetric_verify(struct key *keyring, const char *sig,
240 				    int siglen, const char *data, int datalen)
241 {
242 	return -EOPNOTSUPP;
243 }
244 #endif
245 
246 #ifdef CONFIG_IMA_APPRAISE_MODSIG
247 int ima_modsig_verify(struct key *keyring, const struct modsig *modsig);
248 #else
ima_modsig_verify(struct key * keyring,const struct modsig * modsig)249 static inline int ima_modsig_verify(struct key *keyring,
250 				    const struct modsig *modsig)
251 {
252 	return -EOPNOTSUPP;
253 }
254 #endif
255 
256 #ifdef CONFIG_IMA_LOAD_X509
257 void __init ima_load_x509(void);
258 #else
ima_load_x509(void)259 static inline void ima_load_x509(void)
260 {
261 }
262 #endif
263 
264 #ifdef CONFIG_EVM_LOAD_X509
265 void __init evm_load_x509(void);
266 #else
evm_load_x509(void)267 static inline void evm_load_x509(void)
268 {
269 }
270 #endif
271 
272 #ifdef CONFIG_INTEGRITY_AUDIT
273 /* declarations */
274 void integrity_audit_msg(int audit_msgno, struct inode *inode,
275 			 const unsigned char *fname, const char *op,
276 			 const char *cause, int result, int info);
277 
278 void integrity_audit_message(int audit_msgno, struct inode *inode,
279 			     const unsigned char *fname, const char *op,
280 			     const char *cause, int result, int info,
281 			     int errno);
282 
283 static inline struct audit_buffer *
integrity_audit_log_start(struct audit_context * ctx,gfp_t gfp_mask,int type)284 integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
285 {
286 	return audit_log_start(ctx, gfp_mask, type);
287 }
288 
289 #else
integrity_audit_msg(int audit_msgno,struct inode * inode,const unsigned char * fname,const char * op,const char * cause,int result,int info)290 static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
291 				       const unsigned char *fname,
292 				       const char *op, const char *cause,
293 				       int result, int info)
294 {
295 }
296 
integrity_audit_message(int audit_msgno,struct inode * inode,const unsigned char * fname,const char * op,const char * cause,int result,int info,int errno)297 static inline void integrity_audit_message(int audit_msgno,
298 					   struct inode *inode,
299 					   const unsigned char *fname,
300 					   const char *op, const char *cause,
301 					   int result, int info, int errno)
302 {
303 }
304 
305 static inline struct audit_buffer *
integrity_audit_log_start(struct audit_context * ctx,gfp_t gfp_mask,int type)306 integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
307 {
308 	return NULL;
309 }
310 
311 #endif
312 
313 #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
314 void __init add_to_platform_keyring(const char *source, const void *data,
315 				    size_t len);
316 #else
add_to_platform_keyring(const char * source,const void * data,size_t len)317 static inline void __init add_to_platform_keyring(const char *source,
318 						  const void *data, size_t len)
319 {
320 }
321 #endif
322 
323 #ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
324 void __init add_to_machine_keyring(const char *source, const void *data, size_t len);
325 bool __init imputed_trust_enabled(void);
326 #else
add_to_machine_keyring(const char * source,const void * data,size_t len)327 static inline void __init add_to_machine_keyring(const char *source,
328 						  const void *data, size_t len)
329 {
330 }
331 
imputed_trust_enabled(void)332 static inline bool __init imputed_trust_enabled(void)
333 {
334 	return false;
335 }
336 #endif
337