1 /*
2 * Property Service contexts backend for labeling Android
3 * property keys
4 */
5
6 #include <stdarg.h>
7 #include <string.h>
8 #include <ctype.h>
9 #include <errno.h>
10 #include <limits.h>
11 #include <sys/types.h>
12 #include <sys/stat.h>
13 #include "callbacks.h"
14 #include "label_internal.h"
15
16 /* A property security context specification. */
17 typedef struct spec {
18 struct selabel_lookup_rec lr; /* holds contexts for lookup result */
19 char *property_key; /* property key string */
20 } spec_t;
21
22 /* Our stored configuration */
23 struct saved_data {
24 /*
25 * The array of specifications is sorted for longest
26 * prefix match
27 */
28 spec_t *spec_arr;
29 unsigned int nspec; /* total number of specifications */
30 };
31
cmp(const void * A,const void * B)32 static int cmp(const void *A, const void *B)
33 {
34 const struct spec *sp1 = A, *sp2 = B;
35
36 if (strncmp(sp1->property_key, "*", 1) == 0)
37 return 1;
38 if (strncmp(sp2->property_key, "*", 1) == 0)
39 return -1;
40
41 size_t L1 = strlen(sp1->property_key);
42 size_t L2 = strlen(sp2->property_key);
43
44 return (L1 < L2) - (L1 > L2);
45 }
46
47 /*
48 * Warn about duplicate specifications.
49 */
nodups_specs(struct saved_data * data,const char * path)50 static int nodups_specs(struct saved_data *data, const char *path)
51 {
52 int rc = 0;
53 unsigned int ii, jj;
54 struct spec *curr_spec, *spec_arr = data->spec_arr;
55
56 for (ii = 0; ii < data->nspec; ii++) {
57 curr_spec = &spec_arr[ii];
58 for (jj = ii + 1; jj < data->nspec; jj++) {
59 if (!strcmp(spec_arr[jj].property_key,
60 curr_spec->property_key)) {
61 rc = -1;
62 errno = EINVAL;
63 if (strcmp(spec_arr[jj].lr.ctx_raw,
64 curr_spec->lr.ctx_raw)) {
65 selinux_log
66 (SELINUX_ERROR,
67 "%s: Multiple different specifications for %s (%s and %s).\n",
68 path, curr_spec->property_key,
69 spec_arr[jj].lr.ctx_raw,
70 curr_spec->lr.ctx_raw);
71 } else {
72 selinux_log
73 (SELINUX_ERROR,
74 "%s: Multiple same specifications for %s.\n",
75 path, curr_spec->property_key);
76 }
77 }
78 }
79 }
80 return rc;
81 }
82
process_line(struct selabel_handle * rec,const char * path,char * line_buf,int pass,unsigned lineno)83 static int process_line(struct selabel_handle *rec,
84 const char *path, char *line_buf,
85 int pass, unsigned lineno)
86 {
87 int items;
88 char *prop = NULL, *context = NULL;
89 struct saved_data *data = (struct saved_data *)rec->data;
90 spec_t *spec_arr = data->spec_arr;
91 unsigned int nspec = data->nspec;
92 const char *errbuf = NULL;
93
94 items = read_spec_entries(line_buf, &errbuf, 2, &prop, &context);
95 if (items < 0) {
96 items = errno;
97 if (errbuf) {
98 selinux_log(SELINUX_ERROR,
99 "%s: line %u error due to: %s\n", path,
100 lineno, errbuf);
101 } else {
102 selinux_log(SELINUX_ERROR,
103 "%s: line %u error due to: %m\n", path,
104 lineno);
105 }
106 errno = items;
107 return -1;
108 }
109
110 if (items == 0)
111 return items;
112
113 if (items != 2) {
114 selinux_log(SELINUX_ERROR,
115 "%s: line %u is missing fields\n", path,
116 lineno);
117 free(prop);
118 errno = EINVAL;
119 return -1;
120 }
121
122 if (pass == 0) {
123 free(prop);
124 free(context);
125 } else if (pass == 1) {
126 /* On the second pass, process and store the specification in spec. */
127 spec_arr[nspec].property_key = prop;
128 spec_arr[nspec].lr.ctx_raw = context;
129
130 if (rec->validating) {
131 if (selabel_validate(rec, &spec_arr[nspec].lr) < 0) {
132 selinux_log(SELINUX_ERROR,
133 "%s: line %u has invalid context %s\n",
134 path, lineno, spec_arr[nspec].lr.ctx_raw);
135 errno = EINVAL;
136 return -1;
137 }
138 }
139 }
140
141 data->nspec = ++nspec;
142 return 0;
143 }
144
init(struct selabel_handle * rec,const struct selinux_opt * opts,unsigned n)145 static int init(struct selabel_handle *rec, const struct selinux_opt *opts,
146 unsigned n)
147 {
148 struct saved_data *data = (struct saved_data *)rec->data;
149 const char *path = NULL;
150 FILE *fp;
151 char line_buf[BUFSIZ];
152 unsigned int lineno, maxnspec, pass;
153 int status = -1;
154 struct stat sb;
155
156 /* Process arguments */
157 while (n--)
158 switch (opts[n].type) {
159 case SELABEL_OPT_PATH:
160 path = opts[n].value;
161 break;
162 }
163
164 if (!path)
165 return -1;
166
167 /* Open the specification file. */
168 if ((fp = fopen(path, "re")) == NULL)
169 return -1;
170
171 if (fstat(fileno(fp), &sb) < 0)
172 goto finish;
173 errno = EINVAL;
174 if (!S_ISREG(sb.st_mode))
175 goto finish;
176
177 /*
178 * Two passes of the specification file. First is to get the size.
179 * After the first pass, the spec array is malloced to the appropriate
180 * size. Second pass is to populate the spec array and check for
181 * dups.
182 */
183 maxnspec = UINT_MAX / sizeof(spec_t);
184 for (pass = 0; pass < 2; pass++) {
185 data->nspec = 0;
186 lineno = 0;
187
188 while (fgets(line_buf, sizeof(line_buf) - 1, fp)
189 && data->nspec < maxnspec) {
190 if (process_line(rec, path, line_buf, pass, ++lineno)
191 != 0)
192 goto finish;
193 }
194
195 if (pass == 1) {
196 status = nodups_specs(data, path);
197
198 if (status)
199 goto finish;
200 }
201
202 if (pass == 0) {
203 if (data->nspec == 0) {
204 status = 0;
205 goto finish;
206 }
207
208 if (NULL == (data->spec_arr =
209 calloc(data->nspec, sizeof(spec_t))))
210 goto finish;
211
212 maxnspec = data->nspec;
213 rewind(fp);
214 }
215 }
216
217 qsort(data->spec_arr, data->nspec, sizeof(struct spec), cmp);
218
219 status = digest_add_specfile(rec->digest, fp, NULL, sb.st_size, path);
220 if (status)
221 goto finish;
222
223 digest_gen_hash(rec->digest);
224
225 finish:
226 fclose(fp);
227 return status;
228 }
229
230 /*
231 * Backend interface routines
232 */
closef(struct selabel_handle * rec)233 static void closef(struct selabel_handle *rec)
234 {
235 struct saved_data *data = (struct saved_data *)rec->data;
236 struct spec *spec;
237 unsigned int i;
238
239 for (i = 0; i < data->nspec; i++) {
240 spec = &data->spec_arr[i];
241 free(spec->property_key);
242 free(spec->lr.ctx_raw);
243 free(spec->lr.ctx_trans);
244 }
245
246 if (data->spec_arr)
247 free(data->spec_arr);
248
249 free(data);
250 }
251
property_lookup(struct selabel_handle * rec,const char * key,int type)252 static struct selabel_lookup_rec *property_lookup(struct selabel_handle *rec,
253 const char *key,
254 int __attribute__((unused)) type)
255 {
256 struct saved_data *data = (struct saved_data *)rec->data;
257 spec_t *spec_arr = data->spec_arr;
258 unsigned int i;
259 struct selabel_lookup_rec *ret = NULL;
260
261 if (!data->nspec) {
262 errno = ENOENT;
263 goto finish;
264 }
265
266 for (i = 0; i < data->nspec; i++) {
267 if (strncmp(spec_arr[i].property_key, key,
268 strlen(spec_arr[i].property_key)) == 0) {
269 break;
270 }
271 if (strncmp(spec_arr[i].property_key, "*", 1) == 0)
272 break;
273 }
274
275 if (i >= data->nspec) {
276 /* No matching specification. */
277 errno = ENOENT;
278 goto finish;
279 }
280
281 ret = &spec_arr[i].lr;
282
283 finish:
284 return ret;
285 }
286
service_lookup(struct selabel_handle * rec,const char * key,int type)287 static struct selabel_lookup_rec *service_lookup(struct selabel_handle *rec,
288 const char *key, int __attribute__((unused)) type)
289 {
290 struct saved_data *data = (struct saved_data *)rec->data;
291 spec_t *spec_arr = data->spec_arr;
292 unsigned int i;
293 struct selabel_lookup_rec *ret = NULL;
294
295 if (!data->nspec) {
296 errno = ENOENT;
297 goto finish;
298 }
299
300 for (i = 0; i < data->nspec; i++) {
301 if (strcmp(spec_arr[i].property_key, key) == 0)
302 break;
303 if (strcmp(spec_arr[i].property_key, "*") == 0)
304 break;
305 }
306
307 if (i >= data->nspec) {
308 /* No matching specification. */
309 errno = ENOENT;
310 goto finish;
311 }
312
313 ret = &spec_arr[i].lr;
314
315 finish:
316 return ret;
317 }
318
stats(struct selabel_handle * rec)319 static void stats(struct selabel_handle __attribute__((unused)) *rec)
320 {
321 selinux_log(SELINUX_WARNING, "'stats' functionality not implemented.\n");
322 }
323
selabel_property_init(struct selabel_handle * rec,const struct selinux_opt * opts,unsigned nopts)324 int selabel_property_init(struct selabel_handle *rec,
325 const struct selinux_opt *opts,
326 unsigned nopts)
327 {
328 struct saved_data *data;
329
330 data = (struct saved_data *)calloc(1, sizeof(*data));
331 if (!data)
332 return -1;
333
334 rec->data = data;
335 rec->func_close = &closef;
336 rec->func_stats = &stats;
337 rec->func_lookup = &property_lookup;
338
339 return init(rec, opts, nopts);
340 }
341
selabel_service_init(struct selabel_handle * rec,const struct selinux_opt * opts,unsigned nopts)342 int selabel_service_init(struct selabel_handle *rec,
343 const struct selinux_opt *opts, unsigned nopts)
344 {
345 struct saved_data *data;
346
347 data = (struct saved_data *)calloc(1, sizeof(*data));
348 if (!data)
349 return -1;
350
351 rec->data = data;
352 rec->func_close = &closef;
353 rec->func_stats = &stats;
354 rec->func_lookup = &service_lookup;
355
356 return init(rec, opts, nopts);
357 }
358