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 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 */ 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, curr_spec->property_key))) { 60 rc = -1; 61 errno = EINVAL; 62 if (strcmp 63 (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 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, len; 88 char buf1[BUFSIZ], buf2[BUFSIZ]; 89 char *buf_p, *prop = buf1, *context = buf2; 90 struct saved_data *data = (struct saved_data *)rec->data; 91 spec_t *spec_arr = data->spec_arr; 92 unsigned int nspec = data->nspec; 93 94 len = strlen(line_buf); 95 if (line_buf[len - 1] == '\n') 96 line_buf[len - 1] = 0; 97 buf_p = line_buf; 98 while (isspace(*buf_p)) 99 buf_p++; 100 /* Skip comment lines and empty lines. */ 101 if (*buf_p == '#' || *buf_p == 0) 102 return 0; 103 items = sscanf(line_buf, "%255s %255s", prop, context); 104 if (items != 2) { 105 selinux_log(SELINUX_WARNING, 106 "%s: line %d is missing fields, skipping\n", path, 107 lineno); 108 return 0; 109 } 110 111 if (pass == 1) { 112 /* On the second pass, process and store the specification in spec. */ 113 spec_arr[nspec].property_key = strdup(prop); 114 if (!spec_arr[nspec].property_key) { 115 selinux_log(SELINUX_WARNING, 116 "%s: out of memory at line %d on prop %s\n", 117 path, lineno, prop); 118 return -1; 119 120 } 121 122 spec_arr[nspec].lr.ctx_raw = strdup(context); 123 if (!spec_arr[nspec].lr.ctx_raw) { 124 selinux_log(SELINUX_WARNING, 125 "%s: out of memory at line %d on context %s\n", 126 path, lineno, context); 127 return -1; 128 } 129 } 130 131 data->nspec = ++nspec; 132 return 0; 133 } 134 135 static int init(struct selabel_handle *rec, struct selinux_opt *opts, 136 unsigned n) 137 { 138 struct saved_data *data = (struct saved_data *)rec->data; 139 const char *path = NULL; 140 FILE *fp; 141 char line_buf[BUFSIZ]; 142 unsigned int lineno = 0, maxnspec, pass; 143 int status = -1; 144 struct stat sb; 145 146 /* Process arguments */ 147 while (n--) 148 switch (opts[n].type) { 149 case SELABEL_OPT_PATH: 150 path = opts[n].value; 151 break; 152 default: 153 selinux_log(SELINUX_WARNING, 154 "Argument type (%d) not recognized. Skipping\n", opts[n].type); 155 break; 156 } 157 158 /* Open the specification file. */ 159 if ((fp = fopen(path, "r")) == NULL) 160 return -1; 161 162 if (fstat(fileno(fp), &sb) < 0) 163 return -1; 164 if (!S_ISREG(sb.st_mode)) { 165 errno = EINVAL; 166 return -1; 167 } 168 169 /* 170 * Two passes of the specification file. First is to get the size. 171 * After the first pass, the spec array is malloced to the appropriate 172 * size. Second pass is to populate the spec array and check for 173 * dups. 174 */ 175 maxnspec = UINT_MAX / sizeof(spec_t); 176 for (pass = 0; pass < 2; pass++) { 177 data->nspec = 0; 178 179 while (fgets(line_buf, sizeof line_buf - 1, fp) 180 && data->nspec < maxnspec) { 181 if (process_line(rec, path, line_buf, pass, ++lineno) != 0) { 182 goto finish; 183 } 184 } 185 186 if (pass == 1) { 187 status = nodups_specs(data, path); 188 189 if (status) 190 goto finish; 191 } 192 193 if (pass == 0) { 194 195 if (data->nspec == 0) { 196 status = 0; 197 goto finish; 198 } 199 200 if (NULL == (data->spec_arr = 201 malloc(sizeof(spec_t) * data->nspec))) 202 goto finish; 203 204 memset(data->spec_arr, 0, sizeof(spec_t)*data->nspec); 205 maxnspec = data->nspec; 206 rewind(fp); 207 } 208 } 209 210 qsort(data->spec_arr, data->nspec, sizeof(struct spec), cmp); 211 212 status = 0; 213 finish: 214 fclose(fp); 215 return status; 216 } 217 218 /* 219 * Backend interface routines 220 */ 221 static void closef(struct selabel_handle *rec) 222 { 223 struct saved_data *data = (struct saved_data *)rec->data; 224 struct spec *spec; 225 unsigned int i; 226 227 for (i = 0; i < data->nspec; i++) { 228 spec = &data->spec_arr[i]; 229 free(spec->property_key); 230 free(spec->lr.ctx_raw); 231 free(spec->lr.ctx_trans); 232 } 233 234 if (data->spec_arr) 235 free(data->spec_arr); 236 237 free(data); 238 } 239 240 static struct selabel_lookup_rec *lookup(struct selabel_handle *rec, 241 const char *key, 242 int __attribute__((unused)) type) 243 { 244 struct saved_data *data = (struct saved_data *)rec->data; 245 spec_t *spec_arr = data->spec_arr; 246 unsigned int i; 247 struct selabel_lookup_rec *ret = NULL; 248 249 if (!data->nspec) { 250 errno = ENOENT; 251 goto finish; 252 } 253 254 for (i = 0; i < data->nspec; i++) { 255 if (strncmp(spec_arr[i].property_key, key, 256 strlen(spec_arr[i].property_key)) == 0) { 257 break; 258 } 259 if (strncmp(spec_arr[i].property_key, "*", 1) == 0) 260 break; 261 } 262 263 if (i >= data->nspec) { 264 /* No matching specification. */ 265 errno = ENOENT; 266 goto finish; 267 } 268 269 ret = &spec_arr[i].lr; 270 271 finish: 272 return ret; 273 } 274 275 static void stats(struct selabel_handle __attribute__((unused)) *rec) 276 { 277 selinux_log(SELINUX_WARNING, "'stats' functionality not implemented.\n"); 278 } 279 280 int selabel_property_init(struct selabel_handle *rec, struct selinux_opt *opts, 281 unsigned nopts) 282 { 283 struct saved_data *data; 284 285 data = (struct saved_data *)malloc(sizeof(*data)); 286 if (!data) 287 return -1; 288 memset(data, 0, sizeof(*data)); 289 290 rec->data = data; 291 rec->func_close = &closef; 292 rec->func_stats = &stats; 293 rec->func_lookup = &lookup; 294 295 return init(rec, opts, nopts); 296 } 297
