libselinux/src/label_internal.h

/*
 * This file describes the internal interface used by the labeler
 * for calling the user-supplied memory allocation, validation,
 * and locking routine.
 *
 * Author : Eamon Walsh <ewalsh@epoch.ncsc.mil>
 */
#ifndef _SELABEL_INTERNAL_H_
#define _SELABEL_INTERNAL_H_

#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include <selinux/selinux.h>
#include <selinux/label.h>
#include "sha1.h"

#if defined(ANDROID) || defined(__APPLE__)
// Android and Mac do not have fgets_unlocked()
#define fgets_unlocked(buf, size, fp) fgets(buf, size, fp)
#endif

/*
 * Installed backends
 */
int selabel_file_init(struct selabel_handle *rec,
			    const struct selinux_opt *opts,
			    unsigned nopts) ;
int selabel_media_init(struct selabel_handle *rec,
			    const struct selinux_opt *opts,
			    unsigned nopts) ;
int selabel_x_init(struct selabel_handle *rec,
			    const struct selinux_opt *opts,
			    unsigned nopts) ;
int selabel_db_init(struct selabel_handle *rec,
			    const struct selinux_opt *opts,
			    unsigned nopts) ;
int selabel_property_init(struct selabel_handle *rec,
			    const struct selinux_opt *opts,
			    unsigned nopts) ;
int selabel_exact_match_init(struct selabel_handle *rec,
			    const struct selinux_opt *opts,
			    unsigned nopts) ;

/*
 * Labeling internal structures
 */

/*
 * Calculate an SHA1 hash of all the files used to build the specs.
 * The hash value is held in rec->digest if SELABEL_OPT_DIGEST set. To
 * calculate the hash the hashbuf will hold a concatenation of all the files
 * used. This is released once the value has been calculated.
 */
#define DIGEST_SPECFILE_SIZE SHA1_HASH_SIZE
#define DIGEST_FILES_MAX 8
struct selabel_digest {
	unsigned char *digest;	/* SHA1 digest of specfiles */
	unsigned char *hashbuf;	/* buffer to hold specfiles */
	size_t hashbuf_size;	/* buffer size */
	size_t specfile_cnt;	/* how many specfiles processed */
	char **specfile_list;	/* and their names */
};

extern int digest_add_specfile(struct selabel_digest *digest, FILE *fp,
						    char *from_addr,
						    size_t buf_len,
						    const char *path);
extern void digest_gen_hash(struct selabel_digest *digest);

struct selabel_lookup_rec {
	char * ctx_raw;
	char * ctx_trans;
	int validated;
	unsigned lineno;
};

struct selabel_handle {
	/* arguments that were passed to selabel_open */
	unsigned int backend;
	int validating;

	/* labeling operations */
	struct selabel_lookup_rec *(*func_lookup) (struct selabel_handle *h,
						   const char *key, int type);
	void (*func_close) (struct selabel_handle *h);
	void (*func_stats) (struct selabel_handle *h);
	bool (*func_partial_match) (struct selabel_handle *h, const char *key);
	bool (*func_get_digests_all_partial_matches) (struct selabel_handle *h,
						      const char *key,
						      uint8_t **calculated_digest,
						      uint8_t **xattr_digest,
						      size_t *digest_len);
	bool (*func_hash_all_partial_matches) (struct selabel_handle *h,
	                                       const char *key, uint8_t *digest);
	struct selabel_lookup_rec *(*func_lookup_best_match)
						    (struct selabel_handle *h,
						    const char *key,
						    const char **aliases,
						    int type);
	enum selabel_cmp_result (*func_cmp)(struct selabel_handle *h1,
					    struct selabel_handle *h2);

	/* supports backend-specific state information */
	void *data;

	/*
	 * The main spec file(s) used. Note for file contexts the local and/or
	 * homedirs could also have been used to resolve a context.
	 */
	size_t spec_files_len;
	char **spec_files;


	/* ptr to SHA1 hash information if SELABEL_OPT_DIGEST set */
	struct selabel_digest *digest;
};

/*
 * Validation function
 */
extern int
selabel_validate(struct selabel_handle *rec,
		 struct selabel_lookup_rec *contexts) ;

/*
 * Compatibility support
 */
extern int myprintf_compat;
extern void __attribute__ ((format(printf, 1, 2)))
(*myprintf) (const char *fmt, ...) ;

#define COMPAT_LOG(type, fmt...) do {			\
	if (myprintf_compat)				\
		myprintf(fmt);				\
	else						\
		selinux_log(type, fmt);			\
	} while (0)

extern int
compat_validate(struct selabel_handle *rec,
		struct selabel_lookup_rec *contexts,
		const char *path, unsigned lineno) ;

/*
 * The read_spec_entries function may be used to
 * replace sscanf to read entries from spec files.
 */
extern int read_spec_entries(char *line_buf, const char **errbuf, int num_args, ...);

#endif				/* _SELABEL_INTERNAL_H_ */