src/security-srv/server/security-server-cookie.c

   1 /*
   2  *  security-server
   3  *  Copyright (c) 2000 - 2011 Samsung Electronics Co., Ltd All Rights Reserved
   4  *
   5  *  Contact: Bumjin Im <bj.im@samsung.com>
   6  *
   7  *  Licensed under the Apache License, Version 2.0 (the "License");
   8  *  you may not use this file except in compliance with the License.
   9  *  You may obtain a copy of the License at
  10  *
  11  *      http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  *  Unless required by applicable law or agreed to in writing, software
  14  *  distributed under the License is distributed on an "AS IS" BASIS,
  15  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  *  See the License for the specific language governing permissions and
  17  *  limitations under the License
  18  *
  19  */
  20
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <sys/stat.h>
  24 #include <errno.h>
  25 #include <unistd.h>
  26 #include <string.h>
  27 #include <sys/types.h>
  28 #include <fcntl.h>
  29 #include <sys/smack.h>
  30
  31 #include "security-server-cookie.h"
  32
  33 /* Delete useless cookie item *
  34  * then connect prev and next */
  35 int free_cookie_item(cookie_list *cookie)
  36 {
  37         if(cookie->path != NULL)
  38                 free(cookie->path);
  39         if(cookie->permissions != NULL)
  40                 free(cookie->permissions);
  41         if(cookie->smack_label != NULL)
  42                 free(cookie->smack_label);
  43         if(cookie->prev != NULL)
  44                 cookie->prev->next = cookie->next;
  45         if(cookie->next != NULL)
  46                 cookie->next->prev = cookie->prev;
  47         free(cookie);
  48         cookie = NULL;
  49         return 0;
  50 }
  51
  52 /* Cut the link of the current cookie item and connect previous link and next line *
  53  * That is remove a cookie item *
  54  * Returns next cookie item  if exist, NULL for no more cookie item */
  55 cookie_list *delete_cookie_item(cookie_list *cookie)
  56 {
  57         cookie_list *retval = NULL;
  58         if(cookie == NULL)
  59         {
  60                 SEC_SVR_DBG("%s", "Cannot delete null cookie");
  61                 return retval;
  62         }
  63
  64         /* Reconnect cookie item */
  65         if(cookie->next != NULL)
  66         {
  67                 cookie->prev->next = cookie->next;
  68                 cookie->next->prev = cookie->prev;
  69                 retval = cookie->next;
  70         }
  71         else
  72         {
  73                 cookie->prev->next = NULL;
  74         }
  75
  76         free_cookie_item(cookie);
  77         return retval;
  78 }
  79
  80 cookie_list * garbage_collection(cookie_list *cookie)
  81 {
  82         char path[17];
  83         cookie_list *retval = NULL;
  84         struct stat statbuf;
  85         int ret;
  86
  87         while(cookie != NULL)
  88         {
  89                 /* Skip default cookie */
  90                 if(cookie->pid ==0)
  91                         return cookie;
  92
  93                 /* Try to find the PID directory from proc fs */
  94                 snprintf(path, sizeof(path), "/proc/%d", cookie->pid);
  95                 path[16] = 0;
  96                 ret = stat(path, &statbuf);
  97                 if(ret != 0)
  98                 {
  99                         /* If it's not exist, delete the cookie */
 100                         if(errno == ENOENT)
 101                         {
 102                                 SEC_SVR_DBG("Garbage found. PID:%d, deleting...", cookie->pid);
 103                                 cookie = delete_cookie_item(cookie);
 104                                 continue;
 105                         }
 106                         else
 107                         {
 108                                 /* Some error occurred */
 109                                 SEC_SVR_DBG("Error occurred on stat: errno = %d", errno);
 110                                 return cookie;
 111                         }
 112                 }
 113                 else
 114                 {
 115                         /* This is not a garbage. returning */
 116                         return cookie;
 117                 }
 118         }
 119         return retval;
 120 }
 121
 122 /* Search existing cookie from the cookie list for the client process *
 123  * At the same time, it collects garbage cookie which PID is no longer exist and delete them */
 124 cookie_list *search_existing_cookie(int pid, const cookie_list *c_list)
 125 {
 126         cookie_list *current =(cookie_list *)c_list, *cookie = NULL;
 127         char *cmdline = NULL, *debug_cmdline = NULL;
 128
 129         /* Search from the list */
 130         while(current != NULL)
 131         {
 132                 /* print_cookie(current);*/
 133                 current = garbage_collection(current);
 134                 if(current == NULL)
 135                         break;
 136
 137                 /* PID must be same */
 138                 if(current->pid == pid)
 139                 {
 140                         /* Found cookie for the pid. Check the cookie is reused by dirrent executable */
 141                         /* Check the path of the process */
 142                         cmdline = (char*)read_cmdline_from_proc(pid);
 143                         if(cmdline == NULL)
 144                         {
 145                                 SEC_SVR_DBG("%s", "cannot read cmdline");
 146                                 return NULL;
 147                         }
 148                         /* Check the path is different */
 149                         if(strncmp(cmdline, current->path, current->path_len) != 0 || strlen(cmdline) != current->path_len)
 150                         {
 151                                 SEC_SVR_DBG("pid [%d] has been reused by %s. deleting the old cookie.", pid, cmdline);
 152                                 debug_cmdline = malloc(current->path_len + 1);
 153                                 if(debug_cmdline == NULL)
 154                                 {
 155                                         SEC_SVR_DBG("%s", "out of memory error");
 156                                         free(cmdline);
 157                                         return NULL;
 158                                 }
 159                                 strncpy(debug_cmdline, current->path, current->path_len);
 160                                 debug_cmdline[current->path_len] = 0;
 161                                 SEC_SVR_DBG("[%s] --> [%s]", cmdline, debug_cmdline);
 162                                 if(debug_cmdline != NULL)
 163                                 {
 164                                         free(debug_cmdline);
 165                                         debug_cmdline = NULL;
 166                                 }
 167                                 /* Okay. delete current cookie */
 168                                 current = delete_cookie_item(current);
 169                                 if(cmdline != NULL)
 170                                 {
 171                                         free(cmdline);
 172                                         cmdline = NULL;
 173                                 }
 174                                 continue;
 175                         }
 176                         else
 177                         {
 178                                 SEC_SVR_DBG("%s", "cookie found");
 179                                 cookie = current;
 180                         }
 181
 182                         if(cmdline != NULL)
 183                         {
 184                                 free(cmdline);
 185                                 cmdline = NULL;
 186                         }
 187                 }
 188                 current = current->next;
 189         }
 190         return cookie;
 191 }
 192
 193 /* Search existing cookie from the cookie list for matching pid *
 194  * Default cookie (meaning PID 0) is not allowed in here */
 195 cookie_list *search_cookie_from_pid(cookie_list *c_list, int pid)
 196 {
 197         cookie_list *current = (cookie_list *)c_list, *retval = NULL;
 198
 199         /* Search from the list */
 200         while(current != NULL)
 201         {
 202                 /* print_cookie(current);*/
 203                 /* PID must be same */
 204                 current = garbage_collection(current);
 205                 if(current == NULL)
 206                         break;
 207
 208                 if(current->pid == pid)
 209                 {
 210                         SEC_SVR_DBG("%s", "cookie has been found");
 211                         retval = current;
 212                         goto finish;
 213                 }
 214                 current = current->next;
 215         }
 216 finish:
 217         return retval;
 218 }
 219
 220 /* Search existing cookie from the cookie list for matching cookie and privilege */
 221 /* If privilege is 0, just search cookie exists or not */
 222 cookie_list *search_cookie(const cookie_list *c_list, const unsigned char *cookie, int privilege)
 223 {
 224         cookie_list *current = (cookie_list *)c_list, *retval = NULL;
 225         int i;
 226
 227         /* Search from the list */
 228         while(current != NULL)
 229         {
 230                 /* print_cookie(current);*/
 231                 /* PID must be same */
 232                 current = garbage_collection(current);
 233                 if(current == NULL)
 234                         break;
 235
 236         //searching for cookie
 237                 if(memcmp(current->cookie, cookie, SECURITY_SERVER_COOKIE_LEN) == 0)
 238                 {
 239                         SEC_SVR_DBG("%s", "cookie has been found");
 240
 241             //check if this cookie belongs to root process
 242             if(current->is_roots_process == 1)
 243             {
 244                 SEC_SVR_DBG("%s", "Root process cookie, special privileges");
 245                 //we can skip privilege checking
 246                 retval = current;
 247                 goto finish;
 248             }
 249
 250                         for(i=0 ; i < current->permission_len ; i++)
 251                         {
 252                                 if(privilege == current->permissions[i])
 253                                 {
 254                                         SEC_SVR_DBG("Found privilege %d", privilege);
 255                                         retval = current;
 256                                         goto finish;
 257                                 }
 258                         }
 259                 }
 260                 current = current->next;
 261         }
 262 finish:
 263         return retval;
 264 }
 265
 266
 267 cookie_list *search_cookie_new(const cookie_list *c_list,
 268                                const unsigned char *cookie,
 269                                const char *object,
 270                                const char *access_rights)
 271 {
 272         cookie_list *current = (cookie_list *)c_list, *retval = NULL;
 273         int ret;
 274         int i;
 275
 276         /* Search from the list */
 277         while(current != NULL)
 278         {
 279                 /* print_cookie(current);*/
 280                 /* PID must be same */
 281                 current = garbage_collection(current);
 282                 if(current == NULL)
 283                         break;
 284
 285                 if(memcmp(current->cookie, cookie, SECURITY_SERVER_COOKIE_LEN) == 0)
 286                 {
 287                         SEC_SVR_DBG("%s", "cookie has been found");
 288
 289                                 ret = smack_have_access(current->smack_label, object, access_rights);
 290           SEC_SVR_DBG("smack_have_access, subject >%s< object >%s< access >%s< ===> %d",
 291                     current->smack_label, object, access_rights, ret);
 292                                 if (ret == 1)
 293                                 {
 294                                         retval = current;
 295                                         goto finish;
 296                                 }
 297                 }
 298                 current = current->next;
 299         }
 300 finish:
 301         return retval;
 302 }
 303
 304
 305 /* Generage a random stream value of size to cookie *
 306  * by reading /dev/uranddom file */
 307 int generate_random_cookie(unsigned char *cookie, int size)
 308 {
 309         int fd, ret;
 310
 311     if (cookie == NULL) {
 312         SEC_SVR_DBG("%s", "Null pointer passed to function");
 313         return SECURITY_SERVER_ERROR_UNKNOWN;
 314     }
 315         fd = open("/dev/urandom", O_RDONLY);
 316         if(fd < 0)
 317         {
 318                 SEC_SVR_DBG("%s", "Cannot open /dev/urandom");
 319                 return SECURITY_SERVER_ERROR_FILE_OPERATION;
 320         }
 321         ret = read(fd, cookie, size);
 322         if(ret < size)
 323         {
 324                 SEC_SVR_DBG("Cannot read /dev/urandom: %d", ret);
 325                 ret = SECURITY_SERVER_ERROR_FILE_OPERATION;
 326                 goto error;
 327         }
 328         close(fd);
 329         ret = SECURITY_SERVER_SUCCESS;
 330 error:
 331         if(fd >= 0)
 332                 close(fd);
 333         return ret;
 334 }
 335
 336 /* Create a cookie item from PID */
 337 cookie_list *create_cookie_item(int pid, int sockfd, cookie_list *c_list)
 338 {
 339         int ret, tempint;
 340         cookie_list *added = NULL, *current = NULL;
 341         char path[24], *cmdline = NULL;
 342         char *buf = NULL, inputed, *tempptr = NULL;
 343         char delim[] = ": ", *token = NULL;
 344         int *permissions = NULL, perm_num = 1, cnt, i, *tempperm = NULL;
 345         char *smack_label = NULL;
 346         FILE *fp = NULL;
 347
 348         current = search_existing_cookie(pid, c_list);
 349         if(current != NULL)
 350         {
 351                 /* There is a cookie for this process already */
 352                 added = current;
 353                 SEC_SVR_DBG("%s", "Existing cookie found");
 354                 goto error;
 355         }
 356
 357         /* Read command line of the PID from proc fs */
 358         cmdline = (char *)read_cmdline_from_proc(pid);
 359         if(cmdline == NULL)
 360         {
 361                 SEC_SVR_DBG("Error on reading /proc/%d/cmdline", pid);
 362                 goto error;
 363         }
 364
 365         /*
 366          * modified by security part
 367          *  - get gid from /etc/group
 368          */
 369         /* Read group info of the PID from proc fs - /proc/[PID]/status */
 370         snprintf(path, sizeof(path), "/proc/%d/status", pid);
 371         fp = fopen(path, "r");
 372
 373         /* Find the line which starts with 'Groups:' */
 374         i = 0;
 375
 376         while(1)
 377         {
 378                 buf = (char*)malloc(sizeof(char) * 128);
 379                 if(buf == NULL)
 380                 {
 381                         SEC_SVR_DBG("%s", "Error on malloc()");
 382                         goto error;
 383                 }
 384                 memset(buf, 0x00, 128);
 385                 cnt = 128;
 386
 387                 /* get one line from /proc/[PID]/status */
 388                 while(1)
 389                 {
 390                         tempint = fgetc(fp);
 391                         inputed = (char)tempint;
 392                         if(tempint == EOF)
 393                                 goto out_of_while;
 394                         else if(inputed == '\n')
 395                         {
 396                                 buf[i] = '\0';
 397                                 break;
 398                         }
 399                         else if((i == cnt) && (inputed != '\n'))
 400                         {
 401                                 tempptr = (char*)realloc(buf, sizeof(char) * (i + 128));
 402                                 if(tempptr == NULL)
 403                                 {
 404                                         SEC_SVR_DBG("%s", "Error on realloc()");
 405                                         goto error;
 406                                 }
 407                                 buf = tempptr;
 408                                 buf[i++] = inputed;
 409                                 cnt = i + 128;
 410                         }
 411                         else
 412                                 buf[i++] = inputed;
 413                 }
 414                 i = 0;
 415
 416                 /* find 'Groups:' */
 417                 if(strncmp(buf, "Groups:", 7) == 0)
 418                 {
 419                         /* get gid from the line and insert to 'permissions' array */
 420                         token = strtok(buf, delim); // first string is "Groups"
 421                         while((token = strtok(NULL, delim)))
 422                         {
 423                                 tempperm = realloc(permissions, sizeof(int) * perm_num);
 424                                 if(tempperm == NULL)
 425                                 {
 426                                         SEC_SVR_DBG("%s", "Error on realloc()");
 427                                         goto error;
 428                                 }
 429                                 permissions = tempperm;
 430                                 errno = 0;
 431                                 permissions[perm_num - 1] = strtoul(token, 0, 10);
 432                                 if (errno != 0)
 433                                 {
 434                                         SEC_SVR_DBG("cannot change string to integer [%s]", token);
 435                                         ret = SECURITY_SERVER_ERROR_SERVER_ERROR;
 436                                         goto error;
 437                                 }
 438                                 perm_num++;
 439                         }
 440                         perm_num--;
 441
 442                         /* goto out of while loop */
 443                         break;
 444                 }
 445                 if(buf != NULL)
 446                 {
 447                         free(buf);
 448                         buf = NULL;
 449                 }
 450         }
 451 out_of_while:
 452
 453         /* Each group ID is stored in each line of the file */
 454 //      while(fgets(permline, sizeof(permline), fp) != NULL)
 455 //      {
 456 //              permissions = realloc(permissions, sizeof(int) * perm_num);
 457 //              if(permissions == NULL)
 458 //              {
 459 //                      SEC_SVR_DBG("%s", "Error on realloc()");
 460 //                      goto error;
 461 //              }
 462 //              permissions[perm_num -1] = strtoul(permline, 0, 10);
 463 //              perm_num++;
 464 //      }
 465 //      perm_num--;
 466         /*
 467          * modifying end
 468          */
 469
 470         /* Go to last cookie from the list */
 471         current = c_list;
 472         while(current->next != NULL)
 473         {
 474                 current = current->next;
 475         }
 476
 477         /* Create a new one and assign values */
 478         added = malloc(sizeof(cookie_list));
 479         if(added == NULL)
 480                 goto error;
 481
 482         ret = generate_random_cookie(added->cookie, SECURITY_SERVER_COOKIE_LEN);
 483         if(ret != SECURITY_SERVER_SUCCESS)
 484         {
 485                 SEC_SVR_DBG("Error on making random cookie: %d", ret);
 486                 free(added);
 487                 added = NULL;
 488                 goto error;
 489         }
 490
 491         /* Check SMACK label */
 492         ret = smack_new_label_from_socket(sockfd, &smack_label);
 493         if (ret != 0)
 494         {
 495                 SEC_SVR_DBG("Error checking peer label: %d", ret);
 496                 free(added);
 497                 added = NULL;
 498                 goto error;
 499         }
 500
 501         added->path_len = strlen(cmdline);
 502         added->path = calloc(1, strlen(cmdline));
 503         memcpy(added->path, cmdline, strlen(cmdline));
 504
 505         added->permission_len = perm_num;
 506         added->pid = pid;
 507         added->permissions = permissions;
 508         added->smack_label = smack_label;
 509         added->prev = current;
 510         current->next = added;
 511         added->next = NULL;
 512
 513 error:
 514         if(cmdline != NULL)
 515                 free(cmdline);
 516         if(fp != NULL)
 517                 fclose(fp);
 518         if(buf != NULL)
 519                 free(buf);
 520
 521         if(added == NULL && permissions != NULL)
 522                 free(permissions);
 523
 524         return added;
 525 }
 526
 527 /* Check stored default cookie, if it's not exist make a new one and store it */
 528 int check_stored_cookie(unsigned char *cookie, int size)
 529 {
 530         int fd, ret;
 531
 532         /* First, check the default cookie is stored */
 533         fd = open(SECURITY_SERVER_DEFAULT_COOKIE_PATH, O_RDONLY);
 534         if(fd < 0)
 535         {
 536                 if(errno != ENOENT)
 537                 {
 538                         SEC_SVR_DBG("Cannot open default cookie. errno=%d", errno);
 539                         ret = SECURITY_SERVER_ERROR_FILE_OPERATION;
 540                         unlink(SECURITY_SERVER_DEFAULT_COOKIE_PATH);
 541                 }
 542
 543                 ret = generate_random_cookie(cookie, size);
 544
 545                 /* Save cookie to disk */
 546                 fd = open(SECURITY_SERVER_DEFAULT_COOKIE_PATH, O_WRONLY | O_CREAT, 0600);
 547                 if (fd < 0)
 548                 {
 549                         SEC_SVR_DBG("Cannot open default cookie errno=%d", errno);
 550                         ret = SECURITY_SERVER_ERROR_FILE_OPERATION;
 551                         goto error;
 552                 }
 553                 ret = write(fd, cookie, size);
 554                 if(ret < size)
 555                 {
 556                         SEC_SVR_DBG("%s", "Cannot save default cookie");
 557                         ret = SECURITY_SERVER_ERROR_FILE_OPERATION;
 558                         goto error;
 559                 }
 560
 561                 close(fd);
 562                 return SECURITY_SERVER_SUCCESS;
 563         }
 564
 565         ret = read (fd, cookie, size);
 566         if(ret < size)
 567         {
 568                 SEC_SVR_DBG("Cannot read default cookie errno=%d", errno);
 569                 ret = SECURITY_SERVER_ERROR_FILE_OPERATION;
 570                 goto error;
 571         }
 572         ret = SECURITY_SERVER_SUCCESS;
 573
 574 error:
 575         if(fd >= 0)
 576                 close(fd);
 577         return ret;
 578 }
 579 /* Create a cookie item from PID */
 580
 581 /* Create a default cookie when security server is executed *
 582  * Default cookie is for root processes that needs cookie */
 583 cookie_list *create_default_cookie(void)
 584 {
 585         cookie_list *first = NULL;
 586         int ret;
 587
 588         first = malloc(sizeof(cookie_list));
 589
 590         ret = check_stored_cookie(first->cookie, SECURITY_SERVER_COOKIE_LEN);
 591         if(ret != SECURITY_SERVER_SUCCESS)
 592         {
 593                 SEC_SVR_DBG("Error on making random cookie: %d", ret);
 594                 free(first);
 595                 return NULL;
 596         }
 597
 598         first->path_len = 0;
 599         first->permission_len = 0;
 600         first->pid = 0;
 601         first->path = NULL;
 602         first->permissions = NULL;
 603         first->smack_label = NULL;
 604         first->prev = NULL;
 605         first->next = NULL;
 606         return first;
 607 }