libselinux/src/label_backends_android.c - platform/external/selinux - Git at Google

 /*
  * Property Service contexts backend for labeling Android
  * property keys
  */

 #include <stdarg.h>
 #include <string.h>
 #include <ctype.h>
 #include <errno.h>
 #include <limits.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include "callbacks.h"
 #include "label_internal.h"

 /* A property security context specification. */
 typedef struct spec {
 	struct selabel_lookup_rec lr;	/* holds contexts for lookup result */
 	char *property_key;		/* property key string */
 } spec_t;

 /* Our stored configuration */
 struct saved_data {
 	/*
 	 * The array of specifications is sorted for longest
 	 * prefix match
 	 */
 	spec_t *spec_arr;
 	unsigned int nspec;	/* total number of specifications */
 };

 static int cmp(const void *A, const void *B)
 {
 	const struct spec *sp1 = A, *sp2 = B;

 	if (strncmp(sp1->property_key, "*", 1) == 0)
 		return 1;
 	if (strncmp(sp2->property_key, "*", 1) == 0)
 		return -1;

 	size_t L1 = strlen(sp1->property_key);
 	size_t L2 = strlen(sp2->property_key);

 	return (L1 < L2) - (L1 > L2);
 }

 /*
  * Warn about duplicate specifications. Return error on different specifications.
  * TODO: Remove duplicate specifications. Move duplicate check to after sort
  * to improve performance.
  */
 static int nodups_specs(struct saved_data *data)
 {
 	int rc = 0;
 	unsigned int ii, jj;
 	struct spec *curr_spec, *spec_arr = data->spec_arr;

 	for (ii = 0; ii < data->nspec; ii++) {
 		curr_spec = &spec_arr[ii];
 		for (jj = ii + 1; jj < data->nspec; jj++) {
 			if (!strcmp(spec_arr[jj].property_key,
 					    curr_spec->property_key)) {
 				if (strcmp(spec_arr[jj].lr.ctx_raw,
 						    curr_spec->lr.ctx_raw)) {
 					rc = -1;
 					errno = EINVAL;
 					selinux_log
 						(SELINUX_ERROR,
 						 "Multiple different specifications for %s  (%s and %s).\n",
 						 curr_spec->property_key,
 						 spec_arr[jj].lr.ctx_raw,
 						 curr_spec->lr.ctx_raw);
 				} else {
 					selinux_log
 						(SELINUX_WARNING,
 						 "Multiple same specifications for %s.\n",
 						 curr_spec->property_key);
 				}
 			}
 		}
 	}
 	return rc;
 }

 static int process_line(struct selabel_handle *rec,
 			const char *path, char *line_buf,
 			int pass, unsigned lineno)
 {
 	int items;
 	char *prop = NULL, *context = NULL;
 	struct saved_data *data = (struct saved_data *)rec->data;
 	spec_t *spec_arr = data->spec_arr;
 	unsigned int nspec = data->nspec;
 	const char *errbuf = NULL;

 	items = read_spec_entries(line_buf, &errbuf, 2, &prop, &context);
 	if (items < 0) {
 		items = errno;
 		selinux_log(SELINUX_ERROR,
 			"%s:  line %u error due to: %s\n", path,
 			lineno, errbuf ?: strerror(errno));
 		errno = items;
 		return -1;
 	}

 	if (items == 0)
 		return items;

 	if (items != 2) {
 		selinux_log(SELINUX_ERROR,
 			    "%s:  line %u is missing fields\n", path,
 			    lineno);
 		free(prop);
 		errno = EINVAL;
 		return -1;
 	}

 	if (pass == 0) {
 		free(prop);
 		free(context);
 	} else if (pass == 1) {
 		/* On the second pass, process and store the specification in spec. */
 		spec_arr[nspec].property_key = prop;
 		spec_arr[nspec].lr.ctx_raw = context;

 		if (rec->validating) {
 			if (selabel_validate(rec, &spec_arr[nspec].lr) < 0) {
 				selinux_log(SELINUX_ERROR,
 					    "%s:  line %u has invalid context %s\n",
 					    path, lineno, spec_arr[nspec].lr.ctx_raw);
 				errno = EINVAL;
 				return -1;
 			}
 		}

 		data->nspec = ++nspec;
 	}

 	return 0;
 }

 static int process_file(struct selabel_handle *rec, const char *path)
 {
 	struct saved_data *data = (struct saved_data *)rec->data;
 	char line_buf[BUFSIZ];
 	unsigned int lineno, maxnspec, pass;
 	struct stat sb;
 	FILE *fp;
 	int status = -1;
 	unsigned int nspec;
 	spec_t *spec_arr;

 	/* Open the specification file. */
 	if ((fp = fopen(path, "re")) == NULL)
 		return -1;

 	if (fstat(fileno(fp), &sb) < 0)
 		goto finish;

 	errno = EINVAL;

 	if (!S_ISREG(sb.st_mode))
 		goto finish;

 	/*
 	 * Two passes per specification file. First is to get the size.
 	 * After the first pass, the spec array is malloced / realloced to
 	 * the appropriate size. Second pass is to populate the spec array.
 	 */
 	maxnspec = UINT_MAX / sizeof(spec_t);
 	for (pass = 0; pass < 2; pass++) {
 		nspec = 0;
 		lineno = 0;

 		while (fgets(line_buf, sizeof(line_buf) - 1, fp) &&
 			nspec < maxnspec) {
 			if (process_line(rec, path, line_buf, pass, ++lineno))
 				goto finish;
 			nspec++;
 		}

 		if (pass == 0) {
 			if (nspec == 0) {
 				status = 0;
 				goto finish;
 			}

 			/* grow spec array if required */
 			spec_arr = realloc(data->spec_arr,
 					(data->nspec + nspec) * sizeof(spec_t));
 			if (spec_arr == NULL)
 				goto finish;

 			memset(&spec_arr[data->nspec], 0, nspec * sizeof(spec_t));
 			data->spec_arr = spec_arr;
 			maxnspec = nspec;
 			rewind(fp);
 		}
 	}

 	status = digest_add_specfile(rec->digest, fp, NULL, sb.st_size, path);

 finish:
 	fclose(fp);
 	return status;
 }

 static void closef(struct selabel_handle *rec);

 static int init(struct selabel_handle *rec, const struct selinux_opt *opts,
 		unsigned n)
 {
 	struct saved_data *data = (struct saved_data *)rec->data;
 	char **paths = NULL;
 	size_t num_paths = 0;
 	int status = -1;
 	size_t i;

 	/* Process arguments */
 	i = n;
 	while (i--) {
 		switch (opts[i].type) {
 		case SELABEL_OPT_PATH:
 			num_paths++;
 			break;
 		}
 	}

 	if (!num_paths)
 		return -1;

 	paths = calloc(num_paths, sizeof(*paths));
 	if (!paths)
 		return -1;

 	rec->spec_files = paths;
 	rec->spec_files_len = num_paths;

 	i = n;
 	while (i--) {
 		switch(opts[i].type) {
 		case SELABEL_OPT_PATH:
 			*paths = strdup(opts[i].value);
 			if (*paths == NULL)
 				goto finish;
 			paths++;
 		}
 	}

 	for (i = 0; i < num_paths; i++) {
 		status = process_file(rec, rec->spec_files[i]);
 		if (status)
 			goto finish;
 	}

 	/* warn about duplicates after all files have been processed. */
 	status = nodups_specs(data);
 	if (status)
 		goto finish;

 	qsort(data->spec_arr, data->nspec, sizeof(struct spec), cmp);

 	digest_gen_hash(rec->digest);

 finish:
 	if (status)
 		closef(rec);

 	return status;
 }

 /*
  * Backend interface routines
  */
 static void closef(struct selabel_handle *rec)
 {
 	struct saved_data *data = (struct saved_data *)rec->data;
 	struct spec *spec;
 	unsigned int i;

 	if (data->spec_arr) {
 		for (i = 0; i < data->nspec; i++) {
 			spec = &data->spec_arr[i];
 			free(spec->property_key);
 			free(spec->lr.ctx_raw);
 			free(spec->lr.ctx_trans);
 		}

 		free(data->spec_arr);
 	}

 	free(data);
 }

 static struct selabel_lookup_rec *property_lookup(struct selabel_handle *rec,
 					 const char *key,
 					 int __attribute__((unused)) type)
 {
 	struct saved_data *data = (struct saved_data *)rec->data;
 	spec_t *spec_arr = data->spec_arr;
 	unsigned int i;
 	struct selabel_lookup_rec *ret = NULL;

 	if (!data->nspec) {
 		errno = ENOENT;
 		goto finish;
 	}

 	for (i = 0; i < data->nspec; i++) {
 		if (strncmp(spec_arr[i].property_key, key,
 			    strlen(spec_arr[i].property_key)) == 0) {
 			break;
 		}
 		if (strncmp(spec_arr[i].property_key, "*", 1) == 0)
 			break;
 	}

 	if (i >= data->nspec) {
 		/* No matching specification. */
 		errno = ENOENT;
 		goto finish;
 	}

 	ret = &spec_arr[i].lr;

 finish:
 	return ret;
 }

 static struct selabel_lookup_rec *service_lookup(struct selabel_handle *rec,
 		const char *key, int __attribute__((unused)) type)
 {
 	struct saved_data *data = (struct saved_data *)rec->data;
 	spec_t *spec_arr = data->spec_arr;
 	unsigned int i;
 	struct selabel_lookup_rec *ret = NULL;

 	if (!data->nspec) {
 		errno = ENOENT;
 		goto finish;
 	}

 	for (i = 0; i < data->nspec; i++) {
 		if (strcmp(spec_arr[i].property_key, key) == 0)
 			break;
 		if (strcmp(spec_arr[i].property_key, "*") == 0)
 			break;
 	}

 	if (i >= data->nspec) {
 		/* No matching specification. */
 		errno = ENOENT;
 		goto finish;
 	}

 	ret = &spec_arr[i].lr;

 finish:
 	return ret;
 }

 static void stats(struct selabel_handle __attribute__((unused)) *rec)
 {
 	selinux_log(SELINUX_WARNING, "'stats' functionality not implemented.\n");
 }

 int selabel_property_init(struct selabel_handle *rec,
 			  const struct selinux_opt *opts,
 			  unsigned nopts)
 {
 	struct saved_data *data;

 	data = (struct saved_data *)calloc(1, sizeof(*data));
 	if (!data)
 		return -1;

 	rec->data = data;
 	rec->func_close = &closef;
 	rec->func_stats = &stats;
 	rec->func_lookup = &property_lookup;

 	return init(rec, opts, nopts);
 }

 int selabel_service_init(struct selabel_handle *rec,
 		const struct selinux_opt *opts, unsigned nopts)
 {
 	struct saved_data *data;

 	data = (struct saved_data *)calloc(1, sizeof(*data));
 	if (!data)
 		return -1;

 	rec->data = data;
 	rec->func_close = &closef;
 	rec->func_stats = &stats;
 	rec->func_lookup = &service_lookup;

 	return init(rec, opts, nopts);
 }
	/*
	* Property Service contexts backend for labeling Android
	* property keys
	*/

	#include <stdarg.h>
	#include <string.h>
	#include <ctype.h>
	#include <errno.h>
	#include <limits.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include "callbacks.h"
	#include "label_internal.h"

	/* A property security context specification. */
	typedef struct spec {
	struct selabel_lookup_rec lr; /* holds contexts for lookup result */
	char property_key; / property key string */
	} spec_t;

	/* Our stored configuration */
	struct saved_data {
	/*
	* The array of specifications is sorted for longest
	* prefix match
	*/
	spec_t *spec_arr;
	unsigned int nspec; /* total number of specifications */
	};

	static int cmp(const void A, const void B)
	{
	const struct spec sp1 = A, sp2 = B;

	if (strncmp(sp1->property_key, "*", 1) == 0)
	return 1;
	if (strncmp(sp2->property_key, "*", 1) == 0)
	return -1;

	size_t L1 = strlen(sp1->property_key);
	size_t L2 = strlen(sp2->property_key);

	return (L1 < L2) - (L1 > L2);
	}

	/*
	* Warn about duplicate specifications. Return error on different specifications.
	* TODO: Remove duplicate specifications. Move duplicate check to after sort
	* to improve performance.
	*/
	static int nodups_specs(struct saved_data *data)
	{
	int rc = 0;
	unsigned int ii, jj;
	struct spec curr_spec, spec_arr = data->spec_arr;

	for (ii = 0; ii < data->nspec; ii++) {
	curr_spec = &spec_arr[ii];
	for (jj = ii + 1; jj < data->nspec; jj++) {
	if (!strcmp(spec_arr[jj].property_key,
	curr_spec->property_key)) {
	if (strcmp(spec_arr[jj].lr.ctx_raw,
	curr_spec->lr.ctx_raw)) {
	rc = -1;
	errno = EINVAL;
	selinux_log
	(SELINUX_ERROR,
	"Multiple different specifications for %s (%s and %s).\n",
	curr_spec->property_key,
	spec_arr[jj].lr.ctx_raw,
	curr_spec->lr.ctx_raw);
	} else {
	selinux_log
	(SELINUX_WARNING,
	"Multiple same specifications for %s.\n",
	curr_spec->property_key);
	}
	}
	}
	}
	return rc;
	}

	static int process_line(struct selabel_handle *rec,
	const char path, char line_buf,
	int pass, unsigned lineno)
	{
	int items;
	char prop = NULL, context = NULL;
	struct saved_data data = (struct saved_data )rec->data;
	spec_t *spec_arr = data->spec_arr;
	unsigned int nspec = data->nspec;
	const char *errbuf = NULL;

	items = read_spec_entries(line_buf, &errbuf, 2, &prop, &context);
	if (items < 0) {
	items = errno;
	selinux_log(SELINUX_ERROR,
	"%s: line %u error due to: %s\n", path,
	lineno, errbuf ?: strerror(errno));
	errno = items;
	return -1;
	}

	if (items == 0)
	return items;

	if (items != 2) {
	selinux_log(SELINUX_ERROR,
	"%s: line %u is missing fields\n", path,
	lineno);
	free(prop);
	errno = EINVAL;
	return -1;
	}

	if (pass == 0) {
	free(prop);
	free(context);
	} else if (pass == 1) {
	/* On the second pass, process and store the specification in spec. */
	spec_arr[nspec].property_key = prop;
	spec_arr[nspec].lr.ctx_raw = context;

	if (rec->validating) {
	if (selabel_validate(rec, &spec_arr[nspec].lr) < 0) {
	selinux_log(SELINUX_ERROR,
	"%s: line %u has invalid context %s\n",
	path, lineno, spec_arr[nspec].lr.ctx_raw);
	errno = EINVAL;
	return -1;
	}
	}

	data->nspec = ++nspec;
	}

	return 0;
	}

	static int process_file(struct selabel_handle rec, const char path)
	{
	struct saved_data data = (struct saved_data )rec->data;
	char line_buf[BUFSIZ];
	unsigned int lineno, maxnspec, pass;
	struct stat sb;
	FILE *fp;
	int status = -1;
	unsigned int nspec;
	spec_t *spec_arr;

	/* Open the specification file. */
	if ((fp = fopen(path, "re")) == NULL)
	return -1;

	if (fstat(fileno(fp), &sb) < 0)
	goto finish;

	errno = EINVAL;

	if (!S_ISREG(sb.st_mode))
	goto finish;

	/*
	* Two passes per specification file. First is to get the size.
	* After the first pass, the spec array is malloced / realloced to
	* the appropriate size. Second pass is to populate the spec array.
	*/
	maxnspec = UINT_MAX / sizeof(spec_t);
	for (pass = 0; pass < 2; pass++) {
	nspec = 0;
	lineno = 0;

	while (fgets(line_buf, sizeof(line_buf) - 1, fp) &&
	nspec < maxnspec) {
	if (process_line(rec, path, line_buf, pass, ++lineno))
	goto finish;
	nspec++;
	}

	if (pass == 0) {
	if (nspec == 0) {
	status = 0;
	goto finish;
	}

	/* grow spec array if required */
	spec_arr = realloc(data->spec_arr,
	(data->nspec + nspec) * sizeof(spec_t));
	if (spec_arr == NULL)
	goto finish;

	memset(&spec_arr[data->nspec], 0, nspec * sizeof(spec_t));
	data->spec_arr = spec_arr;
	maxnspec = nspec;
	rewind(fp);
	}
	}

	status = digest_add_specfile(rec->digest, fp, NULL, sb.st_size, path);

	finish:
	fclose(fp);
	return status;
	}

	static void closef(struct selabel_handle *rec);

	static int init(struct selabel_handle rec, const struct selinux_opt opts,
	unsigned n)
	{
	struct saved_data data = (struct saved_data )rec->data;
	char **paths = NULL;
	size_t num_paths = 0;
	int status = -1;
	size_t i;

	/* Process arguments */
	i = n;
	while (i--) {
	switch (opts[i].type) {
	case SELABEL_OPT_PATH:
	num_paths++;
	break;
	}
	}

	if (!num_paths)
	return -1;

	paths = calloc(num_paths, sizeof(*paths));
	if (!paths)
	return -1;

	rec->spec_files = paths;
	rec->spec_files_len = num_paths;

	i = n;
	while (i--) {
	switch(opts[i].type) {
	case SELABEL_OPT_PATH:
	*paths = strdup(opts[i].value);
	if (*paths == NULL)
	goto finish;
	paths++;
	}
	}

	for (i = 0; i < num_paths; i++) {
	status = process_file(rec, rec->spec_files[i]);
	if (status)
	goto finish;
	}

	/* warn about duplicates after all files have been processed. */
	status = nodups_specs(data);
	if (status)
	goto finish;

	qsort(data->spec_arr, data->nspec, sizeof(struct spec), cmp);

	digest_gen_hash(rec->digest);

	finish:
	if (status)
	closef(rec);

	return status;
	}

	/*
	* Backend interface routines
	*/
	static void closef(struct selabel_handle *rec)
	{
	struct saved_data data = (struct saved_data )rec->data;
	struct spec *spec;
	unsigned int i;

	if (data->spec_arr) {
	for (i = 0; i < data->nspec; i++) {
	spec = &data->spec_arr[i];
	free(spec->property_key);
	free(spec->lr.ctx_raw);
	free(spec->lr.ctx_trans);
	}

	free(data->spec_arr);
	}

	free(data);
	}

	static struct selabel_lookup_rec property_lookup(struct selabel_handle rec,
	const char *key,
	int __attribute__((unused)) type)
	{
	struct saved_data data = (struct saved_data )rec->data;
	spec_t *spec_arr = data->spec_arr;
	unsigned int i;
	struct selabel_lookup_rec *ret = NULL;

	if (!data->nspec) {
	errno = ENOENT;
	goto finish;
	}

	for (i = 0; i < data->nspec; i++) {
	if (strncmp(spec_arr[i].property_key, key,
	strlen(spec_arr[i].property_key)) == 0) {
	break;
	}
	if (strncmp(spec_arr[i].property_key, "*", 1) == 0)
	break;
	}

	if (i >= data->nspec) {
	/* No matching specification. */
	errno = ENOENT;
	goto finish;
	}

	ret = &spec_arr[i].lr;

	finish:
	return ret;
	}

	static struct selabel_lookup_rec service_lookup(struct selabel_handle rec,
	const char *key, int __attribute__((unused)) type)
	{
	struct saved_data data = (struct saved_data )rec->data;
	spec_t *spec_arr = data->spec_arr;
	unsigned int i;
	struct selabel_lookup_rec *ret = NULL;

	if (!data->nspec) {
	errno = ENOENT;
	goto finish;
	}

	for (i = 0; i < data->nspec; i++) {
	if (strcmp(spec_arr[i].property_key, key) == 0)
	break;
	if (strcmp(spec_arr[i].property_key, "*") == 0)
	break;
	}

	if (i >= data->nspec) {
	/* No matching specification. */
	errno = ENOENT;
	goto finish;
	}

	ret = &spec_arr[i].lr;

	finish:
	return ret;
	}

	static void stats(struct selabel_handle __attribute__((unused)) *rec)
	{
	selinux_log(SELINUX_WARNING, "'stats' functionality not implemented.\n");
	}

	int selabel_property_init(struct selabel_handle *rec,
	const struct selinux_opt *opts,
	unsigned nopts)
	{
	struct saved_data *data;

	data = (struct saved_data )calloc(1, sizeof(data));
	if (!data)
	return -1;

	rec->data = data;
	rec->func_close = &closef;
	rec->func_stats = &stats;
	rec->func_lookup = &property_lookup;

	return init(rec, opts, nopts);
	}

	int selabel_service_init(struct selabel_handle *rec,
	const struct selinux_opt *opts, unsigned nopts)
	{
	struct saved_data *data;

	data = (struct saved_data )calloc(1, sizeof(data));
	if (!data)
	return -1;

	rec->data = data;
	rec->func_close = &closef;
	rec->func_stats = &stats;
	rec->func_lookup = &service_lookup;

	return init(rec, opts, nopts);
	}