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1 /*
2  * This file describes the internal interface used by the labeler
3  * for calling the user-supplied memory allocation, validation,
4  * and locking routine.
5  *
6  * Author : Eamon Walsh <ewalsh@epoch.ncsc.mil>
7  */
8 #ifndef _SELABEL_INTERNAL_H_
9 #define _SELABEL_INTERNAL_H_
10 
11 #include <stdlib.h>
12 #include <stdarg.h>
13 #include <stdio.h>
14 #include <selinux/selinux.h>
15 #include <selinux/label.h>
16 #include "dso.h"
17 #include "sha1.h"
18 
19 #if defined(ANDROID) || defined(__APPLE__)
20 // Android and Mac do not have fgets_unlocked()
21 #define fgets_unlocked(buf, size, fp) fgets(buf, size, fp)
22 #endif
23 
24 /*
25  * Installed backends
26  */
27 int selabel_file_init(struct selabel_handle *rec,
28 			    const struct selinux_opt *opts,
29 			    unsigned nopts) hidden;
30 int selabel_media_init(struct selabel_handle *rec,
31 			    const struct selinux_opt *opts,
32 			    unsigned nopts) hidden;
33 int selabel_x_init(struct selabel_handle *rec,
34 			    const struct selinux_opt *opts,
35 			    unsigned nopts) hidden;
36 int selabel_db_init(struct selabel_handle *rec,
37 			    const struct selinux_opt *opts,
38 			    unsigned nopts) hidden;
39 int selabel_property_init(struct selabel_handle *rec,
40 			    const struct selinux_opt *opts,
41 			    unsigned nopts) hidden;
42 int selabel_service_init(struct selabel_handle *rec,
43 			    const struct selinux_opt *opts,
44 			    unsigned nopts) hidden;
45 
46 /*
47  * Labeling internal structures
48  */
49 
50 /*
51  * Calculate an SHA1 hash of all the files used to build the specs.
52  * The hash value is held in rec->digest if SELABEL_OPT_DIGEST set. To
53  * calculate the hash the hashbuf will hold a concatenation of all the files
54  * used. This is released once the value has been calculated.
55  */
56 #define DIGEST_SPECFILE_SIZE SHA1_HASH_SIZE
57 #define DIGEST_FILES_MAX 8
58 struct selabel_digest {
59 	unsigned char *digest;	/* SHA1 digest of specfiles */
60 	unsigned char *hashbuf;	/* buffer to hold specfiles */
61 	size_t hashbuf_size;	/* buffer size */
62 	size_t specfile_cnt;	/* how many specfiles processed */
63 	char **specfile_list;	/* and their names */
64 };
65 
66 extern int digest_add_specfile(struct selabel_digest *digest, FILE *fp,
67 						    char *from_addr,
68 						    size_t buf_len,
69 						    const char *path);
70 extern void digest_gen_hash(struct selabel_digest *digest);
71 
72 struct selabel_lookup_rec {
73 	char * ctx_raw;
74 	char * ctx_trans;
75 	int validated;
76 };
77 
78 struct selabel_handle {
79 	/* arguments that were passed to selabel_open */
80 	unsigned int backend;
81 	int validating;
82 
83 	/* labeling operations */
84 	struct selabel_lookup_rec *(*func_lookup) (struct selabel_handle *h,
85 						   const char *key, int type);
86 	void (*func_close) (struct selabel_handle *h);
87 	void (*func_stats) (struct selabel_handle *h);
88 	bool (*func_partial_match) (struct selabel_handle *h, const char *key);
89 	struct selabel_lookup_rec *(*func_lookup_best_match)
90 						    (struct selabel_handle *h,
91 						    const char *key,
92 						    const char **aliases,
93 						    int type);
94 	enum selabel_cmp_result (*func_cmp)(struct selabel_handle *h1,
95 					    struct selabel_handle *h2);
96 
97 	/* supports backend-specific state information */
98 	void *data;
99 
100 	/*
101 	 * The main spec file(s) used. Note for file contexts the local and/or
102 	 * homedirs could also have been used to resolve a context.
103 	 */
104 	size_t spec_files_len;
105 	char **spec_files;
106 
107 
108 	/* ptr to SHA1 hash information if SELABEL_OPT_DIGEST set */
109 	struct selabel_digest *digest;
110 };
111 
112 /*
113  * Validation function
114  */
115 extern int
116 selabel_validate(struct selabel_handle *rec,
117 		 struct selabel_lookup_rec *contexts) hidden;
118 
119 /*
120  * Compatibility support
121  */
122 extern int myprintf_compat;
123 extern void __attribute__ ((format(printf, 1, 2)))
124 (*myprintf) (const char *fmt, ...) hidden;
125 
126 #define COMPAT_LOG(type, fmt...) if (myprintf_compat)	  \
127 		myprintf(fmt);				  \
128 	else						  \
129 		selinux_log(type, fmt);
130 
131 extern int
132 compat_validate(struct selabel_handle *rec,
133 		struct selabel_lookup_rec *contexts,
134 		const char *path, unsigned lineno) hidden;
135 
136 /*
137  * The read_spec_entries function may be used to
138  * replace sscanf to read entries from spec files.
139  */
140 extern int read_spec_entries(char *line_buf, const char **errbuf, int num_args, ...);
141 
142 #endif				/* _SELABEL_INTERNAL_H_ */
143