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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 (at) 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 	unsigned lineno;
     77 };
     78 
     79 struct selabel_handle {
     80 	/* arguments that were passed to selabel_open */
     81 	unsigned int backend;
     82 	int validating;
     83 
     84 	/* labeling operations */
     85 	struct selabel_lookup_rec *(*func_lookup) (struct selabel_handle *h,
     86 						   const char *key, int type);
     87 	void (*func_close) (struct selabel_handle *h);
     88 	void (*func_stats) (struct selabel_handle *h);
     89 	bool (*func_partial_match) (struct selabel_handle *h, const char *key);
     90 	bool (*func_hash_all_partial_matches) (struct selabel_handle *h,
     91 	                                       const char *key, uint8_t *digest);
     92 	struct selabel_lookup_rec *(*func_lookup_best_match)
     93 						    (struct selabel_handle *h,
     94 						    const char *key,
     95 						    const char **aliases,
     96 						    int type);
     97 	enum selabel_cmp_result (*func_cmp)(struct selabel_handle *h1,
     98 					    struct selabel_handle *h2);
     99 
    100 	/* supports backend-specific state information */
    101 	void *data;
    102 
    103 	/*
    104 	 * The main spec file(s) used. Note for file contexts the local and/or
    105 	 * homedirs could also have been used to resolve a context.
    106 	 */
    107 	size_t spec_files_len;
    108 	char **spec_files;
    109 
    110 
    111 	/* ptr to SHA1 hash information if SELABEL_OPT_DIGEST set */
    112 	struct selabel_digest *digest;
    113 };
    114 
    115 /*
    116  * Validation function
    117  */
    118 extern int
    119 selabel_validate(struct selabel_handle *rec,
    120 		 struct selabel_lookup_rec *contexts) hidden;
    121 
    122 /*
    123  * Compatibility support
    124  */
    125 extern int myprintf_compat;
    126 extern void __attribute__ ((format(printf, 1, 2)))
    127 (*myprintf) (const char *fmt, ...) hidden;
    128 
    129 #define COMPAT_LOG(type, fmt...) if (myprintf_compat)	  \
    130 		myprintf(fmt);				  \
    131 	else						  \
    132 		selinux_log(type, fmt);
    133 
    134 extern int
    135 compat_validate(struct selabel_handle *rec,
    136 		struct selabel_lookup_rec *contexts,
    137 		const char *path, unsigned lineno) hidden;
    138 
    139 /*
    140  * The read_spec_entries function may be used to
    141  * replace sscanf to read entries from spec files.
    142  */
    143 extern int read_spec_entries(char *line_buf, const char **errbuf, int num_args, ...);
    144 
    145 #endif				/* _SELABEL_INTERNAL_H_ */
    146